- Email: [email protected]
Physical Activity and Native Americans
Review and Special Articles
Physical Activity and Native Americans A Review James D. Coble, BEd, Ryan E. Rhodes, PhD Abstract:
The physical activity behaviors of Native-American populations in the United States and Canada have received little attention in the health literature. The purpose of this review was to unite the literature regarding the physical activity behaviors of Native Americans. A majority of the literature was obtained using online databases. Reference lists were also reviewed to gain further access to the literature. Key-word searches included various combinations of Aboriginal, Native Indian, American Indian, Native American, First Nation, Métis, or Alaska Native with physical activity, exercise, and health behavior. Articles included were those published in English-language, peer-reviewed journals from 1990 until November 2005 that focused on participants aged 18 years and older. This review is organized according to ecologic models of health behavior, which take into account several correlates to explain human behavior, including demographic, personal health, environmental, and psychosocial. Correlates were included if they appeared at least three times in the literature. As a result of these inclusion criteria, the number of reviewed articles includes 28 quantitative, 4 qualitative, and 3 intervention studies. Results indicate that age, gender, and social support are important factors associated with physical activity. The remaining correlates show inconsistent or indeterminate results due in part to the paucity of research. It is suggested that an increase in the number of studies, especially those using longitudinal designs, is needed. Further, the application of psychosocial models to understand physical activity motivations as well as culturally appropriate and validated measurement tools are largely absent in the Native-American physical activity literature. (Am J Prev Med 2006;31(1):36 – 46) © 2006 American Journal of Preventive Medicine
Introduction
R
egular physical activity (PA) and its association with increased health benefits have been well documented.1–3 It was evident that even moderate increases in PA are associated with various health benefits especially in previously sedentary individuals.1 Recent research suggests that quality of life is greatly enhanced in adults regardless of age and state of health.4 Unfortunately, 56% of Canadian adults and more than 60% of American adults do not engage in enough regular PA to achieve optimal health benefits.1,5 Among the least-active segments of the North-American population are ethnic minorities.6 – 8 Despite the PA disparities between minorities and their nonminority counterparts, there have been relatively few studies that document the health and PA behaviors of Native Americans.9 –12 The few studies that do exist have shown less-than-optimal PA levels.9,10,13,14 For example, From the School of Physical Education, Behavioral Medicine Laboratory, Faculty of Education, University of Victoria, Victoria, British Columbia, Canada Address correspondence and reprint requests to: James Coble, School of Physical Education, Behavioral Medicine Laboratory, Faculty of Education, University of Victoria, P.O. Box 3015 STN CSC, Victoria BC, V8W 3P1, Canada. E-mail: [email protected].
36
the U.S. Department of Health and Human Services15 indicates that 46% of Native Americans report no leisure-time PA compared to 38% of their nonminority counterparts. It was suggested that a change in the traditional lifestyle of Native Americans has had a large impact on their current health.16,17 Indeed, Native-American women from the United States recognize that current generations have very different eating habits and do not engage in daily activities characteristic of past generations.18 Currently, many Native-American communities have either high or increasing rates of obesity,19 –21 type 2 diabetes,22–24 and cardiovascular disease.25–27 Research has shown that increased levels of PA in Native Americans are positively associated with increased lipoprotein levels, specifically, high-density lipoprotein cholesterol and apolipoprotein AI, which have a protective effect against coronary heart disease,28 and are inversely associated with fasting insulin levels,29,30 lower mean body mass index (BMI) levels, and percentage of fat and fat mass.31,32 There is a need to improve the PA habits of the Native-American population to reduce the risk of disease and premature death. Previous PA research has often focused on those factors or correlates that determine PA habits. The most commonly studied correlates
Am J Prev Med 2006;31(1) © 2006 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/06/$–see front matter doi:10.1016/j.amepre.2006.03.004
of PA are generally divided into two categories: those considered modifiable, such as economic status, education, personal traits, social support, or environmental situation, and those considered immutable, such as age, gender, and ethnicity.33 Determining the strength of the interactions between various correlates and PA are the integral first steps to promoting a physically active lifestyle and improved health.4 To date, no research has attempted to review the correlates of PA in NativeAmerican men and women. Considering the current state of Native-American health and the beneficial effects of regular PA, a review of the correlates of PA in Native Americans was warranted. The purpose of the following narrative review was to unite the literature on PA and Native Americans from the United States and Canada.
Methods The majority of the literature was obtained using online databases including PubMed, ERIC, PsychInfo, MEDLINE, Web of Science, CINAHL, and Health Source: Nursing/ Academic Edition. Reference lists of identified articles were reviewed to increase access to the relevant literature. For the purpose of this review, “Native American” will be the term used to describe all populations indigenous to the United States and Canada. Key-word searches included various combinations of Native American, Native Indian, American Indian, Aboriginal, First Nation, Métis, or Alaska Native with PA, exercise, and health behavior. There are varying definitions of PA, and this review will use the definition posited by Bouchard and Shephard.33 Physical activity was “any body of movement provided by the skeletal muscles that results in a substantial increase over the resting energy expenditure.”33 Therefore, any study that measured leisure-time PA, occupational activities, household activities, exercise, and sport was included. A total of 3169 references were screened from the electronic database. If an article was not available in full-text format, the article was retrieved using interlibrary loan procedures, and all articles that were thought to have been relevant to this review were screened to determine if they indeed met the inclusion criteria. Articles included in this review were those published in English-language peer-reviewed journals from 1990 until November 2005. No articles involving Native Americans and PA that met the inclusion criteria published before 1990 were found. Studies involving only indigenous populations to the United States and Canada were preferred. However, study samples often involved more than one ethnic population. Only those studies that reported results separately for each ethnic group or those that contained tables with results outlined for each ethnic group were included. Further, only studies with participants aged ⱖ18 years or studies that included separate analyses for Native-American adults apart from children and adolescents were included. As research with PA and Native Americans was scant, the review also included any experimental or observational evaluation studies, cross-sectional designs, controlled or uncontrolled prospective/retrospective design studies, intervention studies, and phenomenologic and interpretive studies. Conversely,
July 2006
studies that employed historic designs and intervention designs where PA was not the dependent variable were excluded. In order to unify the results, this review employed methods used by Sallis et al.34 The number of studies that identify an association between a correlate and PA was divided by the total number of potential associations for that relationship.34 If an association occurred 0% to 33% of the time, no overall association was evident.34 If an association occurred 34% to 59% of the time, the overall association was inconsistent.34 Finally, if an association was evident 60% to 100% of the time, the overall association would be considered consistently positive or negative.34 The inclusion of a correlate or psychosocial model was based on the number of times that it was measured in the literature. As per Sallis et al.,34 a potential correlate or model was included if it appeared in the literature at least three times. Due to the wide variation of the results and the few samples measuring a given correlate, a meta-analysis was not chosen as the method of review. Although a meta-analysis involves clearly defined methods and results, such results could be misleading.35 Further, although there was no defined minimum number of studies needed for a meta-analysis, a narrative review was thought to be a more appropriate method for uniting the existing literature. For the purposes of this review, efforts were made to determine whether an association was evident, as well as the direction of that association. Whenever possible, the significance and magnitude of such associations are also highlighted (e.g., effect size d, h, r, and odds ratio).36,37 This review was organized according to ecologic models of health behavior. Such models attempt to reconcile the complicated nature of human behavior, suggesting that a number of factors can influence a given behavior at any given time, modifiable or otherwise.38 Therefore, the review findings are discussed under the categories of demographic, personal health, environmental, and psychosocial correlates. As a result of these inclusion criteria, the number of reviewed articles included 28 quantitative, four qualitative, and three intervention studies.
Results Table 1 highlights studies that have quantified the relationships between potential correlates and PA. As such, intervention studies, qualitative studies, and portions of those quantitative studies that used freeresponse questions, such as those related to describing barriers to PA, are not included. These studies, however, are included as a part of the results and conclusion.
Demographic Age. Of the 14 studies reviewed here, 62% of the comparisons revealed significant or meaningful negative associations,10,13,30,31,39,40,45– 48 while the remaining comparisons from four studies found no associations.44 – 47 Two studies did not report significance values or standard deviations, and thus the results appear to show negative associations.30,31 Although Am J Prev Med 2006;31(1)
37
38
Table 1. Quantitative studies of the correlates of Native-American physical activity behaviora
American Journal of Preventive Medicine, Volume 31, Number 1
Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Age
Goldberg (1991)13
Telephone interview recall survey (LTPA)
⫺ (M I, II), 0 (F I, II)
No sig. values reported; small to medium ES in men (h⫽0.39 and h⫽0.49).
Zurlo (1992)39
n⫽463; American Indians from two MT populations; aged ⱖ25 n⫽180; Pima Indians (103 men, 77 women); aged ⱖ18
Respiratory chamber (spontaneous PA)
⫺ (M), ⫺ (F)
Rising (1994)40
n⫽30; Pima Indians from AZ; aged ⱖ18
-
Fitzgerald (1997)31
n⫽2452; Pima Indians (976 men, 1476 women); aged ⱖ21
Objective energy expenditure measures (total 24-hour PA) Interview recall survey (LTPA and non-LTPA)
No sig. associations for men or women (p⬎0.05), although both measures reveal small ES (r⫽⫺0.17 and r⫽⫺0.19); sig. associations for men and women combined (p⬍0.05); small ES (r⫽⫺0.17). Sig. inverse association (r⫽⫺0.36, p⬍0.05); medium ES.
Mendlein (1997)41
n⫽788; Navajo Indians (303 men, 485 women); aged 20–91
0 (M), 0 (F)
Nelson (1997)42
n⫽665; n⫽244 American Indians from MT (136 women, 108 men); aged ⱖ18 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25
Interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA) Interview recall survey (LTPA and non-LTPA)
⫺ (M I, II), ⫺ (F I, II)
n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽530; Sandy Lake First Nation (299 women, 231 men); aged ⱖ18
Interview recall survey (LTPA)
0 (I–III)
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (LTPA and non-LTPA)
0
Not sig. (p⬎0.05).
Appears ⫺ (M I, II), Appears ⫺ (F), 0 (F)
n⫽350; Native American women from Southwest United States; aged 20–50 n⫽483; Native Americans from Southwest United States (240 women and 143 men); aged ⱖ18 n⫽310; n⫽127 First Nation women from NM; aged ⱖ40
Interview recall survey (no parameters given for type of PA) Recall survey (LTPA)
0 (I), ⫺ (II–IV)
No sig. values or standard deviations reported; values reported as average median hours per week over the past year. No sig. associations although three measures indicate small ES by amount of PA (OR⫽1.45–2.28, CI 0.81–5.86). Sig. association in women (p⬍0.05).
24-hour PA record books for walking patterns; pedometers
-
Fischer (1999)10 Harnack (1999)43 King (2000)44 Kriska (2001)30 Thompson (2003)45
www.ajpm-online.net
Cuaderes (2004)46 Whitt (2004)47
Appears ⫺ (M), Appears ⫺ (F)
0
0 (M), ⫺ (F)
No sig. values reported; results reported as median metabolic equivalent task hours per week. No sig. differences among men and women aged 20–39, 40–59, ⱖ60 (p⬎0.05). No sig. differences among 18–29, 30–39, 40–49 age groups (p⬎0.05). No sig. values reported; small to medium ES in men (OR⫽2.3 and OR⫽5.1, CI 1.4–10); small ES in women (OR⫽2.1 and OR⫽3.1, CI 1.5–4.9). No sig. differences by intensity of PA (p⬎0.05).
Sig. association (r⫽⫺0.23, p⬍0.01); small ES. (continued on next page)
July 2006
Table 1. (continued) Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Age
Brunet (2005)48
Interview recall survey (LTPA and non-LTPA)
0 (I–III), ⫺ (IV–VII)
Gender
Goldberg (1991)13
Telephone interview recall survey (LTPA)
⫹ (I, II), 0 (III, IV)
Sugarman (1992)14
n⫽34; Aboriginals from Alberta (15 male and 18 female); aged ⱖ18 n⫽463; American Indians from two MT populations; aged ⱖ25 n⫽1055; American Indians from United States; aged ⱖ18
⫹
Zurlo (1992)39 Fitzgerald (1997)31
n⫽180; Pima Indians (103 men, 77 women); aged ⱖ18 n⫽2452; Pima Indians (976 men, 1476 women); 20
Telephone interview recall survey (no parameters given for type of PA) Respiratory chamber (spontaneous PA) Interview recall survey (LTPA and non-LTPA)
No sig. associations (p⬎0.05) although four measures show small ES ranging from r⫽⫺0.11 to r⫽⫺0.20. No sig. values reported; small ES for two measures (h⫽0.4 and h ⫽0.27) (M⬎F). No sig. values reported; small ES (h⫽0.30) (M⬎F).
Mendlein (1997)41
n⫽788; Navajo Indians (303 men, 485 women); aged 20–91
Nelson (1997)42
n⫽665; n⫽244 American Indians from MT (136 women, 108 men); aged ⱖ18 n⫽151; Midwest American Indians from ND (87 women, 64 men); aged ⱖ48 n⫽4549; American Indians from AZ, OK, ND, SD (2703 women, 1846 men); aged 45– 74 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25
Plaud (1998)49 Yurgalevitch (1998)28 Fischer (1999)10
Am J Prev Med 2006;31(1)
Harnack (1999)43 Kriska (2001)30 Bursac (2003)50 Denny (2003)9 Brunet (2005)48
n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽530; Sandy Lake First Nation (299 women, 231 men); aged ⱖ18 n⫽3732; American Indians from OK
39
n⫽4167; American Indians (2389 women, 1778 men); aged ⱖ18 n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18
⫹
Sig. differences (p⬍0.05) (M⬎F).
Appears ⫹ (I, II)
Interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA)
0
No sig. or standard deviation values reported; values reported as median hours (M⬎F). No sig. differences (p⬎0.05).
0
No sig. differences (p⬎0.05).
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA combined)
⫹
Sig. difference (p⬍0.05); no SD’s reported. (M⬎F)
⫹ (I), 0 (II, III)
No sig. values reported; small ES for one measure (h⫽0.21). (M⬎F)
Interview recall survey (LTPA and non-LTPA)
⫹ (I, II), ⫺ (III), 0 (IV, V)
Interview recall survey (LTPA)
⫹ (I, II), 0 (III)
Interview recall survey (LTPA and non-LTPA)
Appears ⫹ (I, II, III), Appears 0 (IV)
Telephone interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA)
0
No sig. values reported; small to medium ES for two measures (h⫽0.27 and h⫽0.63) (M⬎F); medium ES in one measure (h⫽0.53) (F⬎M). Sig. differences (p⬍0.05); Medium to large ES for two measures (d⫽0.88 and d⫽0.68). (M⬎F) No sig. or SD values reported; values reported as average median hours per week over past year. (M⬎F) No sig. values reported; trivial ES (h⫽0.18).
0
No sig. values reported; trivial ES (h⫽0.05).
Interview recall survey (LTPA and non-LTPA)
0 (I), ⫹ (II–VII)
No sig. associations (p⬎0.05) although six measures show small ES ranging from r⫽0.14 to r⫽0.21. (M⬎F) (continued on next page)
40
Table 1. (continued)
American Journal of Preventive Medicine, Volume 31, Number 1
Correlate
Education
Study
Participants
Measures
Associationb
Sig. and ES values
Denny (2005)51
n⫽3123 Native Americans (1349 men, 1774 women; from larger sample of n⫽130,610); aged ⱖ18 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽653 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50
Telephone interview recall survey (LTPA)
0
No sig. values reported; trivial ES.
Interview recall survey (LTPA and non-LTPA)
0 (M), 0 (F)
Interview recall survey (LTPA)
0 (I–III)
No sig. values reported; trivial ES for men and women (OR⫽1.2 and OR⫽1.1, CI 0.8–2.0). No sig. associations (p⬎0.05).
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA)
⫹
Sig. association (p⬍0.05); trivial ES (OR⫽1.21, CI 1.02–1.44).
0 (I–III), ⫹ (IV–VI)
Sig. association for one measure (OR⫽2.95, CI 0.88–5.86, p⬍0.05); two measures not sig. (p⬎0.05) although reveal small ES (OR⫽2.72 and OR⫽1.77, CI 0.56–9.21). Sig. association (r⫽0.20, p⬍0.05); small ES.
Fischer (1999)10 Harnack (1999)43 King (2000)44 Thompson (2003)45
Whitt (2004)47 Employment
Fischer (1999)10 King (2000)44 Thompson (2003)45
Income
Fischer (1999)10 Thompson (2003)45
Health
Fischer (1999)10
www.ajpm-online.net
King (2000)44 Harwell (2003)26
n⫽127 Native American women from NM (in larger sample, n⫽310); aged ⱖ40 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽2006; MT American Indians; aged ⱖ18
24-hour PA record books and pedometers for walking patterns Interview recall survey (LTPA and non-LTPA)
⫹ 0 (M), 0 (F)
No sig. values reported; trivial ES (OR⫽1.3 and OR⫽1.3, CI 0.8–2.1).
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
0
No sig. associations (p⬎0.05).
0 (I, II)
No sig. associations (p⬎0.05).
0 (M), ⫹ (F)
No sig. values reported; small ES for women (OR⫽1.9, CI 1.4–2.6).
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
0 (I–IV)
No sig. associations (p⬎0.05).
⫹ (F I, M II), 0 (F III, M IV)
Telephone interview recall survey (LTPA and nonLTPA combined) Telephone interview recall survey (no parameters given for type of PA)
0 (I, II), ⫹ (III)
No sig. values reported, although two measures reveal small ES (OR⫽1.9 and OR⫽1.8, CI 1.1–3.0). Sig. association (OR⫽0.83, p⬍0.05).
⫹ (I), 0 (II)
Sig. association for unadjusted comparison (p⬍0.05); trivial ES for adjusted comparison (OR⫽1.17, CI 0.89–1.54). (continued on next page)
July 2006
Table 1. (continued) Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Health
Thompson (2003)45
Sig. association (OR⫽1.74, CI 1.07–2.85); small ES.
Fitzgerald (1997)31
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
⫹ (I), 0 (II)
Body weight
n⫽350; Native American women from Southwest United States; aged 20–50 n⫽2452; Pima Indians (976 men and 1476 women)
Sig. associations (r⫽⫺.15, r⫽⫺0.12, r⫽⫺0.20, r⫽⫺0.14, p⬍0.05); small ES.
n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽219; Lakota Indians from SD (126 women and 92 men); aged ⱖ18 n⫽80; U.S. and Mexican Pima Indians (40 United States, 40 Mexican); aged ⱖ18 n⫽483; Native Americans from Southwest United States (240 women, 143 men); aged ⱖ18 n⫽127 First Nation women from NM (from larger sample, ;n⫽310); aged ⱖ40 n⫽653 American Indian-Alaskan Native women (from larger sample, ;n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18 n⫽2912; n⫽639 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽653 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50
Interview recall survey (LTPA and non-LTPA)
⫺ (M I–II, F III–IV), 0 (M V–VIII, F IX– XII) 0 (F I, M II)
Interview recall survey (LTPA)
⫺(I,II), 0 (III)
Sig. associations (p⬍0.05); small ES (d⫽0.44 and d⫽0.28).
Doubly labeled water test
⫺ (I), 0 (II)
Sig. association (r⫽⫺0.38, p⬍0.02); medium ES.
Recall survey (LTPA)
⫺ (M), 0 (F)
Sig. association (p⬍0.05).
24-hour PA record books for walking patterns; pedometers Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
-
Sig. association (r⫽⫺0.33, p⬍0.01); medium ES.
0 (I–XII)
No sig. associations (p⬎0.05); trivial ES.
0 (I–XVI), ⫹ (XVII, XVIII)
No sig. associations (p⬎0.05), although two measures reveal small ES (OR⫽1.57 and 1.52, CI 0.97–2.44). No sig. associations (p⬎0.05) although 11 measures show small ES ranging from r⫽0.11 to r⫽0.26. No sig. values reported; small ES (OR⫽0.43, OR⫽2.64, OR⫽2.12, OR⫽1.8, OR⫽1.64, OR⫽2.29, CI 0.28– 6.87). No association (p⬎0.05).
Fischer (1999)10 Harnack (1999)43 Esparza (2000)32 Cuaderes (2004)46 Whitt (2004)47 Physical King environment (2000)44 Thompson (2003)45 Brunet (2005)48 Social Eyler environment (1999)52 Am J Prev Med 2006;31(1)
King (2000)44 Thompson (2003)45
0 (I–III), ⫺ (IV–XIV)
Telephone interview recall survey (lifestyle PA and regular exercise)
⫺ (I), 0 (II, III), ⫹ (IV–VIII)
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA)
0 (I–V) ⫺ (I, II), ⫹ (III–IX), 0(X)
No sig. values reported; trivial ES for both measures.
41
Two sig. associations (p⬍0.05) with small (OR⫽0.62, CI 0.4–0.94) and medium ES (OR⫽0.38, CI 0.19–0.74); four sig. measures (p⬍0.05) with small (OR⫽2.6, OR⫽2.14, CI 1.11–4.49) and medium ES (OR⫽5.23 and OR⫽3.81, CI 1.66–10.14); three associations not sig. but have small ES (OR⫽1.52, OR⫽1.75, OR⫽1.53, CI 0.72–3.19). (continued on next page)
Absence of F or M means combined samples unless otherwise indicated in Participants column. a All studies were cross-sectional in design. b Negative, positive, and absent associations are represented by minus symbol (---), plus symbol (⫹), and 0, respectively. Roman numerals indicate various subgroup measurements in no particular order (e.g., type of PA, different locations, amount of PA, etc.). AZ, Arizona; ES, effect size; CI, confidence interval; d, independent mean effect size; F, female; h, independent proportion effect size; LTPA, leisure-time physical activity; M⫽male; MT, Montana; ND, North Dakota; NM, New Mexico; OK, Oklahoma; OR, odds ratio; PA, physical activity; r, Pearson product moment correlation; SD, South Dakota; sig., significance/significant.
No sig. associations (p⬎0.05), although five measures show small ES ranging from r⫽0.10 to r⫽0.23 and r⫽⫺0.11 to r⫽⫺0.17. 0 (I, II), ⫹ (III–VII) Interview recall survey (LTPA and non-LTPA) n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18 Brunet (2005)48
Sig. and ES values Associationb Measures Participants Study Correlate
Table 1. (continued) 42
Brunet et al.,48 Zurlo et al.,39 and Thompson et al.45 did not find significant associations between age and PA, a majority of the comparisons in each study revealed small effect sizes. Effect sizes ranged from small to medium in magnitude among most studies. Qualitative research by Henderson and Ainsworth53 found that Native-American women perceived that PA steadily declined as they approached adulthood. Nonetheless, as Table 1 highlights, the current evidence shows a consistently negative association between age and PA in Native Americans. Gender. Of 15 cross-sectional studies, the results indicate that 61% of the comparisons showed a significant or meaningful difference in PA levels between NativeAmerican men and women.10,13,14,28,30,31,39,43,48,49 Five studies found no significant differences at all in activity levels.9,41,42,50,51 Of note, three studies with very large sample sizes (n ⬎3000) revealed no significant differences between male and female PA levels.9,50,51 Contrary to a majority of the comparisons, Fischer et al.10 found that women were more active than their male counterparts from one sample location. Harnack et al.43 found a large effect (d ⫽0.88) for the differences in strenuous PA levels between men and women. As Table 1 indicates, six studies reveal meaningful effect sizes ranging from small to large. The nature of the existing data suggests that Native-American men have consistently higher PA levels than women. Education. Five cross-sectional studies assessed the relationship between PA and education in Native Americans. Only 38% of the comparisons showed that more education was associated with PA with, at most, small effect sizes.44,45,47 Education was not associated with PA in two studies.10,43 Thompson et al.45 found that women with some college education were almost three times as likely to do some activity compared to women with less than a high school education. Despite this finding, women with some college education were just as likely to fail to meet the American College of Sports Medicine’s recommendations as those women with less education.45 Similarly, although King et al.44 found significant results, a majority of the women in this study were also considered under-active. The current research indicates that an association between education and PA was inconsistent in Native Americans. Employment and income. As Table 1 indicates, three cross-sectional studies found no association between PA and employment.10,44,45 However, Fischer et al.10 found that ⬎90% of Native-American men and women report daily walking as a characteristic of their occupations. Qualitative research has shown that Native-American women believe that they are physically active going to work and at work during the day.54 Similar to the findings of Eyler et al.,38 none of the studies attempted to determine if PA varied by type of occupation. Unlike
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net
employment, at least one study found mixed positive associations between PA and income.10 However, of all the comparisons for income, only 17% of them revealed an association between PA and income. The current literature dealing with both employment and income reveals that there was no overall association with PA.
Personal Health Health/perceived health. Of the four studies, 45% of the comparisons indicated negative associations between PA and health.10,26,44,45 Qualitative research shows that Native-American women perceive that as they develop health problems, chronic or otherwise, they become less active.53,55 Further support for this view was found in two studies using open-ended questions by Harnack et al.,43,56 both of which found that Native-American men and women report health problems as barriers to regular PA. The overall association between PA and health in the quantitative research was inconsistent, as was evidenced by the occurrence of mixed associations. However, the qualitative literature and those studies that use open-ended questions suggest a trend toward a positive association between health and PA. Body weight. Five of six studies found inverse associations between PA and weight.10,31,32,43,47 Of 22 comparisons, 41% revealed that as body weight increases, PA levels decrease. Only one study found no association between PA and body weight.10 Despite the mixed results, Whitt et al.47 and Esparza et al.32 reported medium inverse correlations between PA and BMI. Other significant associations reveal small effect sizes at most.31,43 The research was indicative of an inconsistent relationship between PA and body weight.
Environment Physical environment. Two of three studies reported that certain aspects of the physical environment are related to PA.45,48 Of a possible 44 comparisons, only 30% revealed positive associations, none of which revealed anything more than small effect sizes. Qualitative research has shown that Native Americans believe that the physical environment affects their PA participation.18,53,54 Further research suggests safety concerns, lack of facilities/programs, bad weather, and poor infrastructure (e.g., sidewalks) are considered barriers to PA.43,56,57 As most of the comparisons are considered nil, the results of studies to date suggest that no overall association exists between PA and the physical environment. Social environment. Of the four studies reviewed here, 67% of the comparisons indicate significant or meaningful negative associations,45,48,52 while two studies found no associations.44,47 Thompson et al.45 found the July 2006
most compelling evidence that social support may play an integral role in the PA behaviors of Native Americans. Specifically, those who know people who exercise were five times more likely to do some activity compared to those who do not know anyone who exercised, and those people who saw other people exercising in the neighborhood were almost four times more likely to do some activity compared to those who did not see anyone exercising.45 The notion of the potential effects that social support has on PA was also reported in the qualitative literature.18,53–55 Such findings are further bolstered by Harnack et al.43,56 and Heesch et al.,57 all of whom found that certain aspects of the social environment act as barriers or enablers for NativeAmerican women. The data suggest that the social environment was an important correlate of PA in Native Americans, especially considering the occurrence of small to medium effect sizes.
Psychosocial Correlates Stages of change. The stages-of-change model posits that people progress through five stages of behavioral change: precontemplation, contemplation, preparation, action, and maintenance.58 In the domain of PA, this progression moves from not thinking about engaging in PA to regular engagement in PA for ⬎6 months.58 To date, only three cross-sectional PA studies make use of this model in Native-American research.57,59,60 Bull et al.59 and Stolarczyk et al.60 found that a majority of Native Americans are in the precontemplation to preparation stages of exercise. A second assessment by Bull et al.,59 in which the definition of PA was more inclusive than that of exercise, showed that the majority of the participants were in the action or maintenance stages. It was also found that NativeAmerican women were less likely to be in the maintenance stage of exercise and PA compared to their non–Native-American female counterparts.59 Heesch et al.57 sought to determine the differences in the perceived barriers to exercise among ethnically diverse women at the same stage of exercise and those at an adjacent stage. Results suggested that Native-American women in the precontemplation stage ranked being too tired, bad health, lack of energy, and lack of time as the most frequently cited barriers to exercise.57 Women in the contemplation stage ranked lack of energy, lack of time, and being too tired as barriers to exercise. Women in the preparation and active stages ranked lack of energy, being too tired, and lack of time as barriers to exercise.57
Interventions Only three intervention studies met the inclusion criteria.61– 63 Kochevar et al.61 sought to determine the efficacy of a community-based exercise program to increase PA in a group (n ⫽20) of Native-American Am J Prev Med 2006;31(1)
43
elders over a 6-week period. It was found that exercise participants significantly (p ⬍0.05) improved selfreported exercise frequencies, whereas control-group measures failed to show improvements.61 The intervention also showed that exercise can improve several other subjective and objective health outcome measures.61 Witmer et al.62 undertook a randomized controlled trial pilot study (n ⫽76) to test an intervention designed specifically for Alaska Native-American women. The impetus for the pilot study was to develop a culturally sensitive intervention program to decrease the risk of cardiovascular disease.62 The 12-week pilot study found that participants significantly (p ⬍0.05) improved their self-reported PA levels as well as their confidence to engage in regular PA.62 Finally, Narayan et al.63 tested adherence to various lifestyle interventions in a randomized pilot study among Pima Indians from Arizona (n ⫽95). It was found that participants of two intervention groups (exercise and diet) reported an increase in PA after 6 months (although no alpha values were reported), with increases still reported after 12 months (p ⬍0.01).63 No significant differences were found between the groups after both measurement periods.63 In total, all three interventions appeared to show an increase in PA levels.
Conclusion The purpose of this review was to unite the literature concerning Native-American populations and PA. The focus was on the correlates of PA behavior and psychosocial theories, as well as interventions to increase PA. The most important finding of this review was how very little is known about the PA behaviors of Native Americans. It is prudent to highlight that although many of the associations were not unique to Native Americans, they should be considered indeterminate until more research can be conducted. However, age, gender, and social support are the most consistent correlates of PA as a result of the research conducted thus far. The results of this review show that as Native Americans age, PA levels tend to decrease. Despite this similarity, overall PA levels of Native Americans tend to be lower than in nonminorities.15 There are factors that need to be considered that may add to the understanding of the relationship between PA and age. Just as previous reviews indicated, the lack of a significant association among many age comparisons may be the result of restricted age ranges.38 It is also worthy to note that the occurrence of even small effect sizes, regardless of whether statistical significance was achieved, could have practical or clinical implications.48 Contrary to the findings here, there was evidence to suggest that some Native-American women experience a resurgence of PA as they approach older adulthood.53 Although age was found to be consistently associated with PA, as is the case in the general population, further research is 44
needed to determine PA patterns at different life stages.64 Physical activity at these stages may be affected as much by life situations as by choice.53 Like age, gender was also associated consistently with PA, suggesting that Native-American men are more active than their female counterparts. However, time spent in all forms of PA was not consistently measured among the reviewed studies. For example, Fischer et al.10 found that when non–leisure-time PA was measured, such as hours of housework per week, women engaged in more activity than men. The difficulty with including such activities in any study is the degree to which lower-intensity activities are over-estimated and whether such activities lead to improved health.10 It was not uncommon for self-reported assessment tools, in the absence of objective tools, to inaccurately measure activities such as occupational walking.65 Future research that includes myriad types of PA may find that PA levels do not differ significantly by gender in Native Americans. Future research should also determine dose–response relationships for occupational or household activity. The social environment was an integral part of the PA behavior of Native Americans. The occurrence of several small to moderate effect sizes reaffirms the role of the social environment. A potentially important finding by Eyler et al.52 was that support in any form may be more important than the source of the support in affecting PA behavior. Although social support was important, greater attention needs to be focused on the role that sociocultural expectations play in the lives of Native Americans. As Thompson et al.18 indicate, Native Americans are interested in finding ways to enhance their PA behaviors through means that are compatible with their communities’ norms. Therefore, it was not only social support that was important but culturally relevant support. Education, employment, income, health, body weight, and the physical environment have thus far not been consistently associated with PA in Native Americans. The findings that education, employment, income, and body weight are not associated with PA are contrary to reviews dealing with the general population.4,64 Despite these findings, it should be noted that very little research is available that examines these correlates in Native Americans. As such, to state that education or income does not influence PA behavior would be an oversight. Ultimately, it must be reemphasized that much more research is needed before any conclusions can be drawn and comparisons with other populations can be made. Specifically, there is a lack of longitudinal research as well as research that deals with psychosocial correlates of PA behavior in Native American populations. It is not surprising that there are only a few intervention studies that attempted to increase PA levels in Native Americans, considering that relatively little re-
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net
search exists that attempts to understand the factors that influence PA behavior. Nonetheless, the small sample sizes of both Kochevar et al.61 (n ⫽20) and Witmer et al.62 (n ⫽76) limit any conclusions that can be made regarding the true efficacy of such interventions. Narayan et al.63 did not include a control group suggesting that there was no conclusive evidence that an increase in PA was actually the result of the experimental condition. Kochevar et al.61 experienced a sizeable attrition rate (37.5%) in an already small sample, which also limits the number of conclusions that can be made about the efficacy of their intervention. Despite such limitations, more intervention research is needed, as it is imperative to test the relative effectiveness of various programs. There are several inherent limitations associated with the current research, one of which relates to the appropriateness of measurement tools. Notwithstanding certain exceptions, not all existing measurement tools have been validated in Native-American populations. For example, Fischer et al.10 admit that the tool they used to measure PA has never undergone validity or reliability studies. Ideally, to accurately assess the PA behaviors of Native Americans, measurement tools need to be tailored to cultural and traditional lifestyles.66 Perhaps an increased emphasis should be placed on qualitative research methods, for as McDonald and McAvoy67 reaffirm, Native Americans tend to rely on oral traditions to communicate histories, values, and beliefs. The results of qualitative research could then be used to inform the development of culturally appropriate measurement tools. Many of the reviewed studies make use of standard terminology and self-report tools to measure PA. Terms such as leisure can be problematic, especially for minority populations.55,66 Much research assumes that participants should attach analogous meanings to such terms.68 The validity of a self-report tool depends on the participants’ ability to accurately evaluate and attach meaning to the various dimensions and terminology used to describe PA.69 Meanings attached to words may vary by specific characteristics such as culture, gender, socioeconomic status, or age.66 These interpretations are further complicated in light of the fact that much of social science research relies on nonminorities as sources of validation for current knowledge.70 This reinforces the need to validate existing measurement tools or develop new tools specific to a given population. The primary limitations associated with this review are twofold. First, the review was limited to published research. Reports and unpublished work may be present, but such research may be too difficult to retrieve systematically. Second, this review did not use meta-analytic methods, which can be useful in synthesizing effects. However, as indicated previously, considJuly 2006
ering the nature of the existing research, a narrative review was thought to be more appropriate. Despite the limited amount of research with Native Americans, the current research was paramount to understanding the PA behaviors of Native Americans. Future research can help to close the gap in the health disparities between Native Americans and the general population. The beneficial effects of PA in mitigating risk factors for disease and chronic illness warrant a greater interest in studying the PA behaviors of Native Americans. RER was supported by a scholar award from the Michael Smith Foundation for Health Research and with funds from the Social Sciences and Humanities Research Council of Canada. No financial conflict of interest was reported by the authors of this paper.
References 1. U.S. Department of Health and Human Services. Physical activity and health: a report of the Surgeon General. Atlanta GA: Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion. 1996. 2. Pate RR, Pratt M, Blair N, et al. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402–7. 3. Bouchard C, Shephard RJ, Stephens T, et al., eds. Exercise, fitness, and health: international proceedings and consensus statement. Champaign IL: Human Kinetics, 1994. 4. Seefeldt V, Malina RM, Clark MA. Factors affecting levels of physical activity in adults. Sports Med 2002;32:143– 68. 5. Canadian Fitness and Lifestyle Research Institute. 2001 Physical Activity Monitor. Available at: www.cflri.ca. Accessed July 21, 2005. 6. Crespo C, Smit E, Anderson R, et al. Race/ethnicity, social class and their relation to physical inactivity during leisure time: results form the Third National Health and Nutrition Examination Survey 1988 –1994. Am J Prev Med 2000;18:46 –53. 7. Jones D, Ainsworth B, Croft J, et al. Moderate leisure-time physical activity: who was meeting the public health recommendations? Arch Fam Med 1998;7:285–9. 8. Kriska AM, Rexroad A. The role of physical activity in minority populations. Women Health Issues 1998;8:98 –103. 9. Denny C, Holtzman D, Cobb N. Surveillance for health behaviors of American Indians and Alaska Natives: findings from the Behavioral Risk Factor Surveillance System, 1997–2000. MMWR Surveill Summ 2003;52:1–13. 10. Fischer ID, Brown DR, Blanton CJ, et al. Physical activity patterns of Chippewa and Menominee Indians: the Inter-Tribal Heart Project. Am J Prev Med 1999;17:189 –97. 11. Myers HF, Kagawa-Singer M, Kumanyika SK, et al. Panel III: behavioral risk factors related to chronic diseases in ethnic minorities. Health Psychol 1995;14:613–21. 12. Wilcox S, Castro C, King AC, et al. Determinants of leisure time physical activity in rural compared with urban older and ethnically diverse women in the United States. J Epidemiol Community Health 2000;54:667–72. 13. Goldberg HI, Warren CW, Oge LL, et al. Prevalence of behavioral risk factors in two American Indian populations in Montana. Am J Prev Med 1991;7:155– 60. 14. Sugarman JR, Warren CW, Oge LL, et al. Using the Behavioral Risk Factor Surveillance System to monitor year 2000 objectives among American Indians. Public Health Rep 1992;107:449 –56. 15. U.S. Department of Health and Human Services. Healthy people 2010. 2nd ed. Atlanta GA: Centers for Disease Control and Prevention, 2000. 16. Joe JR. Out of harmony: health problems and young Native American men. J Am Coll Health 2001;49:237– 42.
Am J Prev Med 2006;31(1)
45
17. Pargee D, Lara-Albers E, Puckett K. Building on tradition: promoting physical activity with American Indian community coalitions. J Health Educ 1999;30:S37– 43. 18. Thompson JL, Allen P, Cunningham-Sabo L, et al. Environmental, policy and cultural factors related to physical activity in sedentary American Indian women. Women Health 2002;36:57–72. 19. Broussard BA, Sugarman JR, Bachman-Carter K, et al. Toward comprehensive obesity prevention programs in Native American communities. Obes Res 1995;3(suppl 2):289 –97. 20. Katzmarzyk PT, Malina RM. Obesity and relative subcutaneous fat distribution among Canadians of First Nation and European ancestry. Int J Obes Relat Metab Disord 1998;22:1127–31. 21. Zephier E, Himes JH, Story M. Prevalence of overweight and obesity in American Indian school children and adolescents in the Aberdeen area: a population study. Int J Obes Relat Metab Disord 1999;23(suppl 2):S28 –30. 22. Burrows NR, Geiss LS, Engelgau MM, et al. Prevalence of diabetes among Native Americans and Alaska Natives, 1990 –1997. Diabetes Care 2000;23:1786 –90. 23. Delisle HF, Ekoe JM. Prevalence of non-insulin dependent diabetes mellitus and impaired glucose tolerance in two Algonquin communities in Quebec. CMAJ 1993;148:41–7. 24. Harris SB, Gittelsohn J, Hanley AJ, et al. The prevalence of NIDDM and associated risk factors in Native Canadians. Diabetes Care 1997;20:185–7. 25. Anand S, Tookenay V. Cardiovascular diseases and Native American peoples. Can J Cardiol 1999;15(suppl G):44G– 6G. 26. Harwell TS, Moore K, McDowall JM, et al. Cardiovascular risk factors in Montana American Indians with and without diabetes. Am J Prev Med 2003;24:265–9. 27. Howard BV, Lee ET, Cowan LD, et al. Rising tide of cardiovascular disease in American Indians: the Strong Heart Study. Circulation 1999;99:2389 –95. 28. Yurgalevitch SM, Kriska AM, Welty TK, et al. Physical activity and lipids and lipoproteins in American Indians ages 45–74. Med Sci Sports Exerc 1998;30:543–9. 29. Irwin ML, Mayer-Davis EJ, Addy CL, et al. Moderate-intensity physical activity and fasting insulin levels in women: the cross-cultural activity participation study. Diabetes Care 2000;23:449 –54. 30. Kriska AM, Hanley AJ, Harris SB, et al. Physical activity, physical fitness, and insulin and glucose concentrations in an isolated Native Canadian population experiencing rapid lifestyle change. Diabetes Care 2001;24:1787–92. 31. Fitzgerald SJ, Kriska AM, Pereira MA, et al. Associations among physical activity, television watching, and obesity in adult Pima Indians. Med Sci Sports Exerc 1997;29:910 –5. 32. Esparza J, Fox C, Harper IT, et al. Daily energy expenditure in Mexican and USA Pima Indians: low physical activity as a possible cause of obesity. Int J Obes Relat Metab Disord 2000;24:55–9. 33. Bouchard C, Shephard RJ. Physical activity, fitness and health: the model and key concepts. In: Bouchard C, Shephard RJ, Stephens T, et al., eds. Physical activity, fitness and health: international proceedings and consensus statement. Champaign IL: Human Kinetics, 1994:77– 88. 34. Sallis JF, Prochaska JJ, Taylor WC. A review of correlates of physical activity of children and adolescents. Med Sci Sports Exerc 2000;32:963–75. 35. Egger M, Smith DS, Altman DG. Systematic reviews in health care: meta-analysis in context. London: BMJ Books, 2001. 36. Cohen J. A power primer. Psychol Bull 1992;112:155–9. 37. Hopkins WG. A new view of statistics: a scale of magnitudes for effect statistics. Available at: www.sportsci.org/resource/stats/effectmag.html. Accessed July 28, 2005. 38. Eyler AE, Wilcox S, Matson-Koffman D, et al. Correlates of physical activity among women from diverse racial/ethnic groups. J Womens Health Gend Based Med 2002;11:239 –53. 39. Zurlo F, Ferraro RT, Fontvieille AM, et al. Spontaneous physical activity and obesity: Cross-sectional and longitudinal studies in Pima Indians. Am J Physiol 1992;263:E296 –300. 40. Rising R, Harper IT, Fontvieille AM, et al. Determinants of total energy expenditure: variability in physical activity. Am J Clin Nutr 1994;59:800 – 4. 41. Mendlein JM, Freedman DS, Peter DG, et al. Risk factors for coronary heart disease among Navajo Indians: findings from the Navajo Health and Nutrition Survey. J Nutr 1997;127(suppl):2099S–105S. 42. Nelson DE, Moon RW, Holtzman D, et al. Patterns of health risk behaviors for chronic disease: a comparison between adolescent and adult American Indians living on or near reservations in Montana. J Adolesc Health 1997;21:25–32. 43. Harnack L, Story M, Rock BH. Diet and physical activity patterns of Lakota Indian adults. J Am Diet Assoc 1999;99:829 –35.
46
44. King AC, Castro C, Wilcox S, et al. Personal and environmental factors associated with physical inactivity among different racial-ethnic groups of U.S. middle-aged and older-aged women. Health Psychol 2000;19:354 – 64. 45. Thompson JL, Wolfe VK, Wilson N, et al. Personal, social, and environmental correlates of physical activity in Native American women. Am J Prev Med 2003;25(suppl):53– 60. 46. Cuaderes ET, Parker Burgin CE. Leisure time physical activity in adult Native Americans. South Online J Nurs Res 2004;5:1–18. 47. Whitt MC, DuBose KD, Ainsworth BE, et al. Walking patterns in a sample of African American, Native American, and Caucasian women: the CrossCultural Activity Participation Study. Health Educ Behav 2004; 31(suppl):45S–56S. 48. Brunet S, Plotnikoff RC, Raine K et al. Physical activity of Aboriginals with type 2 diabetes: an exploratory study. Ethn Dis 2005;15:256 – 66. 49. Plaud JJ, Schweigman K, Welty TK. Health-related and cultural gender differences in an aging American Indian population. J Clin Geropsychol 1998;4:111– 8. 50. Bursac Z, Campbell JE. From risky behaviors to chronic outcomes: current status and Healthy People 2010 goals for American Indians in Oklahoma. J Okla State Med Assoc 2003;96:569 –73. 51. Denny CH, Holtzman D, Goins T, et al. Disparities in chronic disease risk factors and health status between American Indian/Alaska Native and white elders: findings from a telephone survey, 2001 and 2002. Am J Public Health 2005;95:825–7. 52. Eyler AA, Brownson RC, Donatelle RJ, et al. Physical activity social support and middle- and older-aged minority women: results from a U.S. survey. Soc Sci Med 1999;49:781–9. 53. Henderson KA, Ainsworth BE. Physical activity and human development among older Native American women. J Aging Phys Act 2001;9:285–99. 54. Henderson KA, Ainsworth BE. Enablers and constraints to walking for older African American and American Indian women: the Cultural Activity Participation Study. Res Q Exerc Sport 2000;71:313–21. 55. Eyler AA, Baker E, Cromer L. Physical activity and minority women: a qualitative study. Health Educ Behav 1998;25:640 –52. 56. Harnack L, Sherwood N, Story M. Diet and physical activity patterns of urban American Indian women. Am J Health Promot 1999;13:233– 6. 57. Heesch KC, Brown DR, Blanton CJ. Perceived barriers to exercise and stage of exercise adoption in older women of different racial/ethnic groups. Women Health 2000;30:61–76. 58. Prochaska JO, Marcus BH. The transtheoretical model: applications to exercise. In: Dishman R, ed. Advances in exercise adherence. Champaign IL: Human Kinetics, 1994:161– 80. 59. Bull FC, Eyler AA, King AC, et al. Stage of readiness to exercise in ethnically diverse women: a U.S. survey. Med Sci Sports Exerc 2001;33:1147–56. 60. Stolarczyk LM, Gilliland SS, Lium DJ, et al. Knowledge, attitude and behaviors related to physical activity among Native Americans with diabetes. Ethn Dis 1999;9:59 – 69. 61. Kochevar AJ, Smith KL, Bernard MA. Effects of community-based intervention to increase physical activity in American Indian elders. J Okla State Med Assoc 2001;94:455– 60. 62. Witmer JM, Hensel MR, Holck PS, et al. Heart disease prevention for Alaska Native women: a review of pilot study findings. J Womens Health 2004;13:569 –78. 63. Narayan KM, Hoskin M, Kozak D, et al. Randomized clinical trial of lifestyle interventions in Pima Indians: a pilot study. Diabet Med 1998;15:66 –72. 64. Trost SG, Owen N, Bauman AE, et al. Correlates of adults’ participation in physical activity: review and update. Med Sci Sports Exerc 2002; 34:1996 –2001. 65. Bates JH, Serdula MK, Khan LK, et al. Total and leisure-time walking among U.S. adults: Should every step count? Am J Prev Med 2005;29:46 –50. 66. Masse LC, Ainsworth BE, Tortolero S, et al. Measuring physical activity in midlife, older, and minority women: issues from an expert panel. J Womens Health 1998;7:57– 67. 67. McDonald D, McAvoy L. Native Americans and leisure: state of the research and future directions. J Leisure Res 1997;29:145– 66. 68. Tudor-Lock C, Henderson KA, Wilcox S, et al. In their own voices: definitions and interpretations of physical activity. Women Health Issues 2003;13:194 –9. 69. Aadahl M, Jorgensen T. Validation of a new self-report instrument for measuring physical activity. Med Sci Sports Exerc 2003;35:1196 –202. 70. Im E. Nursing research on physical activity: a feminist critique. Int J Nurs Stud 2001;38:185–94.
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net
Physical Activity and Native Americans A Review James D. Coble, BEd, Ryan E. Rhodes, PhD Abstract:
The physical activity behaviors of Native-American populations in the United States and Canada have received little attention in the health literature. The purpose of this review was to unite the literature regarding the physical activity behaviors of Native Americans. A majority of the literature was obtained using online databases. Reference lists were also reviewed to gain further access to the literature. Key-word searches included various combinations of Aboriginal, Native Indian, American Indian, Native American, First Nation, Métis, or Alaska Native with physical activity, exercise, and health behavior. Articles included were those published in English-language, peer-reviewed journals from 1990 until November 2005 that focused on participants aged 18 years and older. This review is organized according to ecologic models of health behavior, which take into account several correlates to explain human behavior, including demographic, personal health, environmental, and psychosocial. Correlates were included if they appeared at least three times in the literature. As a result of these inclusion criteria, the number of reviewed articles includes 28 quantitative, 4 qualitative, and 3 intervention studies. Results indicate that age, gender, and social support are important factors associated with physical activity. The remaining correlates show inconsistent or indeterminate results due in part to the paucity of research. It is suggested that an increase in the number of studies, especially those using longitudinal designs, is needed. Further, the application of psychosocial models to understand physical activity motivations as well as culturally appropriate and validated measurement tools are largely absent in the Native-American physical activity literature. (Am J Prev Med 2006;31(1):36 – 46) © 2006 American Journal of Preventive Medicine
Introduction
R
egular physical activity (PA) and its association with increased health benefits have been well documented.1–3 It was evident that even moderate increases in PA are associated with various health benefits especially in previously sedentary individuals.1 Recent research suggests that quality of life is greatly enhanced in adults regardless of age and state of health.4 Unfortunately, 56% of Canadian adults and more than 60% of American adults do not engage in enough regular PA to achieve optimal health benefits.1,5 Among the least-active segments of the North-American population are ethnic minorities.6 – 8 Despite the PA disparities between minorities and their nonminority counterparts, there have been relatively few studies that document the health and PA behaviors of Native Americans.9 –12 The few studies that do exist have shown less-than-optimal PA levels.9,10,13,14 For example, From the School of Physical Education, Behavioral Medicine Laboratory, Faculty of Education, University of Victoria, Victoria, British Columbia, Canada Address correspondence and reprint requests to: James Coble, School of Physical Education, Behavioral Medicine Laboratory, Faculty of Education, University of Victoria, P.O. Box 3015 STN CSC, Victoria BC, V8W 3P1, Canada. E-mail: [email protected].
36
the U.S. Department of Health and Human Services15 indicates that 46% of Native Americans report no leisure-time PA compared to 38% of their nonminority counterparts. It was suggested that a change in the traditional lifestyle of Native Americans has had a large impact on their current health.16,17 Indeed, Native-American women from the United States recognize that current generations have very different eating habits and do not engage in daily activities characteristic of past generations.18 Currently, many Native-American communities have either high or increasing rates of obesity,19 –21 type 2 diabetes,22–24 and cardiovascular disease.25–27 Research has shown that increased levels of PA in Native Americans are positively associated with increased lipoprotein levels, specifically, high-density lipoprotein cholesterol and apolipoprotein AI, which have a protective effect against coronary heart disease,28 and are inversely associated with fasting insulin levels,29,30 lower mean body mass index (BMI) levels, and percentage of fat and fat mass.31,32 There is a need to improve the PA habits of the Native-American population to reduce the risk of disease and premature death. Previous PA research has often focused on those factors or correlates that determine PA habits. The most commonly studied correlates
Am J Prev Med 2006;31(1) © 2006 American Journal of Preventive Medicine • Published by Elsevier Inc.
0749-3797/06/$–see front matter doi:10.1016/j.amepre.2006.03.004
of PA are generally divided into two categories: those considered modifiable, such as economic status, education, personal traits, social support, or environmental situation, and those considered immutable, such as age, gender, and ethnicity.33 Determining the strength of the interactions between various correlates and PA are the integral first steps to promoting a physically active lifestyle and improved health.4 To date, no research has attempted to review the correlates of PA in NativeAmerican men and women. Considering the current state of Native-American health and the beneficial effects of regular PA, a review of the correlates of PA in Native Americans was warranted. The purpose of the following narrative review was to unite the literature on PA and Native Americans from the United States and Canada.
Methods The majority of the literature was obtained using online databases including PubMed, ERIC, PsychInfo, MEDLINE, Web of Science, CINAHL, and Health Source: Nursing/ Academic Edition. Reference lists of identified articles were reviewed to increase access to the relevant literature. For the purpose of this review, “Native American” will be the term used to describe all populations indigenous to the United States and Canada. Key-word searches included various combinations of Native American, Native Indian, American Indian, Aboriginal, First Nation, Métis, or Alaska Native with PA, exercise, and health behavior. There are varying definitions of PA, and this review will use the definition posited by Bouchard and Shephard.33 Physical activity was “any body of movement provided by the skeletal muscles that results in a substantial increase over the resting energy expenditure.”33 Therefore, any study that measured leisure-time PA, occupational activities, household activities, exercise, and sport was included. A total of 3169 references were screened from the electronic database. If an article was not available in full-text format, the article was retrieved using interlibrary loan procedures, and all articles that were thought to have been relevant to this review were screened to determine if they indeed met the inclusion criteria. Articles included in this review were those published in English-language peer-reviewed journals from 1990 until November 2005. No articles involving Native Americans and PA that met the inclusion criteria published before 1990 were found. Studies involving only indigenous populations to the United States and Canada were preferred. However, study samples often involved more than one ethnic population. Only those studies that reported results separately for each ethnic group or those that contained tables with results outlined for each ethnic group were included. Further, only studies with participants aged ⱖ18 years or studies that included separate analyses for Native-American adults apart from children and adolescents were included. As research with PA and Native Americans was scant, the review also included any experimental or observational evaluation studies, cross-sectional designs, controlled or uncontrolled prospective/retrospective design studies, intervention studies, and phenomenologic and interpretive studies. Conversely,
July 2006
studies that employed historic designs and intervention designs where PA was not the dependent variable were excluded. In order to unify the results, this review employed methods used by Sallis et al.34 The number of studies that identify an association between a correlate and PA was divided by the total number of potential associations for that relationship.34 If an association occurred 0% to 33% of the time, no overall association was evident.34 If an association occurred 34% to 59% of the time, the overall association was inconsistent.34 Finally, if an association was evident 60% to 100% of the time, the overall association would be considered consistently positive or negative.34 The inclusion of a correlate or psychosocial model was based on the number of times that it was measured in the literature. As per Sallis et al.,34 a potential correlate or model was included if it appeared in the literature at least three times. Due to the wide variation of the results and the few samples measuring a given correlate, a meta-analysis was not chosen as the method of review. Although a meta-analysis involves clearly defined methods and results, such results could be misleading.35 Further, although there was no defined minimum number of studies needed for a meta-analysis, a narrative review was thought to be a more appropriate method for uniting the existing literature. For the purposes of this review, efforts were made to determine whether an association was evident, as well as the direction of that association. Whenever possible, the significance and magnitude of such associations are also highlighted (e.g., effect size d, h, r, and odds ratio).36,37 This review was organized according to ecologic models of health behavior. Such models attempt to reconcile the complicated nature of human behavior, suggesting that a number of factors can influence a given behavior at any given time, modifiable or otherwise.38 Therefore, the review findings are discussed under the categories of demographic, personal health, environmental, and psychosocial correlates. As a result of these inclusion criteria, the number of reviewed articles included 28 quantitative, four qualitative, and three intervention studies.
Results Table 1 highlights studies that have quantified the relationships between potential correlates and PA. As such, intervention studies, qualitative studies, and portions of those quantitative studies that used freeresponse questions, such as those related to describing barriers to PA, are not included. These studies, however, are included as a part of the results and conclusion.
Demographic Age. Of the 14 studies reviewed here, 62% of the comparisons revealed significant or meaningful negative associations,10,13,30,31,39,40,45– 48 while the remaining comparisons from four studies found no associations.44 – 47 Two studies did not report significance values or standard deviations, and thus the results appear to show negative associations.30,31 Although Am J Prev Med 2006;31(1)
37
38
Table 1. Quantitative studies of the correlates of Native-American physical activity behaviora
American Journal of Preventive Medicine, Volume 31, Number 1
Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Age
Goldberg (1991)13
Telephone interview recall survey (LTPA)
⫺ (M I, II), 0 (F I, II)
No sig. values reported; small to medium ES in men (h⫽0.39 and h⫽0.49).
Zurlo (1992)39
n⫽463; American Indians from two MT populations; aged ⱖ25 n⫽180; Pima Indians (103 men, 77 women); aged ⱖ18
Respiratory chamber (spontaneous PA)
⫺ (M), ⫺ (F)
Rising (1994)40
n⫽30; Pima Indians from AZ; aged ⱖ18
-
Fitzgerald (1997)31
n⫽2452; Pima Indians (976 men, 1476 women); aged ⱖ21
Objective energy expenditure measures (total 24-hour PA) Interview recall survey (LTPA and non-LTPA)
No sig. associations for men or women (p⬎0.05), although both measures reveal small ES (r⫽⫺0.17 and r⫽⫺0.19); sig. associations for men and women combined (p⬍0.05); small ES (r⫽⫺0.17). Sig. inverse association (r⫽⫺0.36, p⬍0.05); medium ES.
Mendlein (1997)41
n⫽788; Navajo Indians (303 men, 485 women); aged 20–91
0 (M), 0 (F)
Nelson (1997)42
n⫽665; n⫽244 American Indians from MT (136 women, 108 men); aged ⱖ18 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25
Interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA) Interview recall survey (LTPA and non-LTPA)
⫺ (M I, II), ⫺ (F I, II)
n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽530; Sandy Lake First Nation (299 women, 231 men); aged ⱖ18
Interview recall survey (LTPA)
0 (I–III)
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (LTPA and non-LTPA)
0
Not sig. (p⬎0.05).
Appears ⫺ (M I, II), Appears ⫺ (F), 0 (F)
n⫽350; Native American women from Southwest United States; aged 20–50 n⫽483; Native Americans from Southwest United States (240 women and 143 men); aged ⱖ18 n⫽310; n⫽127 First Nation women from NM; aged ⱖ40
Interview recall survey (no parameters given for type of PA) Recall survey (LTPA)
0 (I), ⫺ (II–IV)
No sig. values or standard deviations reported; values reported as average median hours per week over the past year. No sig. associations although three measures indicate small ES by amount of PA (OR⫽1.45–2.28, CI 0.81–5.86). Sig. association in women (p⬍0.05).
24-hour PA record books for walking patterns; pedometers
-
Fischer (1999)10 Harnack (1999)43 King (2000)44 Kriska (2001)30 Thompson (2003)45
www.ajpm-online.net
Cuaderes (2004)46 Whitt (2004)47
Appears ⫺ (M), Appears ⫺ (F)
0
0 (M), ⫺ (F)
No sig. values reported; results reported as median metabolic equivalent task hours per week. No sig. differences among men and women aged 20–39, 40–59, ⱖ60 (p⬎0.05). No sig. differences among 18–29, 30–39, 40–49 age groups (p⬎0.05). No sig. values reported; small to medium ES in men (OR⫽2.3 and OR⫽5.1, CI 1.4–10); small ES in women (OR⫽2.1 and OR⫽3.1, CI 1.5–4.9). No sig. differences by intensity of PA (p⬎0.05).
Sig. association (r⫽⫺0.23, p⬍0.01); small ES. (continued on next page)
July 2006
Table 1. (continued) Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Age
Brunet (2005)48
Interview recall survey (LTPA and non-LTPA)
0 (I–III), ⫺ (IV–VII)
Gender
Goldberg (1991)13
Telephone interview recall survey (LTPA)
⫹ (I, II), 0 (III, IV)
Sugarman (1992)14
n⫽34; Aboriginals from Alberta (15 male and 18 female); aged ⱖ18 n⫽463; American Indians from two MT populations; aged ⱖ25 n⫽1055; American Indians from United States; aged ⱖ18
⫹
Zurlo (1992)39 Fitzgerald (1997)31
n⫽180; Pima Indians (103 men, 77 women); aged ⱖ18 n⫽2452; Pima Indians (976 men, 1476 women); 20
Telephone interview recall survey (no parameters given for type of PA) Respiratory chamber (spontaneous PA) Interview recall survey (LTPA and non-LTPA)
No sig. associations (p⬎0.05) although four measures show small ES ranging from r⫽⫺0.11 to r⫽⫺0.20. No sig. values reported; small ES for two measures (h⫽0.4 and h ⫽0.27) (M⬎F). No sig. values reported; small ES (h⫽0.30) (M⬎F).
Mendlein (1997)41
n⫽788; Navajo Indians (303 men, 485 women); aged 20–91
Nelson (1997)42
n⫽665; n⫽244 American Indians from MT (136 women, 108 men); aged ⱖ18 n⫽151; Midwest American Indians from ND (87 women, 64 men); aged ⱖ48 n⫽4549; American Indians from AZ, OK, ND, SD (2703 women, 1846 men); aged 45– 74 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25
Plaud (1998)49 Yurgalevitch (1998)28 Fischer (1999)10
Am J Prev Med 2006;31(1)
Harnack (1999)43 Kriska (2001)30 Bursac (2003)50 Denny (2003)9 Brunet (2005)48
n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽530; Sandy Lake First Nation (299 women, 231 men); aged ⱖ18 n⫽3732; American Indians from OK
39
n⫽4167; American Indians (2389 women, 1778 men); aged ⱖ18 n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18
⫹
Sig. differences (p⬍0.05) (M⬎F).
Appears ⫹ (I, II)
Interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA)
0
No sig. or standard deviation values reported; values reported as median hours (M⬎F). No sig. differences (p⬎0.05).
0
No sig. differences (p⬎0.05).
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA combined)
⫹
Sig. difference (p⬍0.05); no SD’s reported. (M⬎F)
⫹ (I), 0 (II, III)
No sig. values reported; small ES for one measure (h⫽0.21). (M⬎F)
Interview recall survey (LTPA and non-LTPA)
⫹ (I, II), ⫺ (III), 0 (IV, V)
Interview recall survey (LTPA)
⫹ (I, II), 0 (III)
Interview recall survey (LTPA and non-LTPA)
Appears ⫹ (I, II, III), Appears 0 (IV)
Telephone interview recall survey (no parameters given for type of PA) Telephone interview recall survey (LTPA)
0
No sig. values reported; small to medium ES for two measures (h⫽0.27 and h⫽0.63) (M⬎F); medium ES in one measure (h⫽0.53) (F⬎M). Sig. differences (p⬍0.05); Medium to large ES for two measures (d⫽0.88 and d⫽0.68). (M⬎F) No sig. or SD values reported; values reported as average median hours per week over past year. (M⬎F) No sig. values reported; trivial ES (h⫽0.18).
0
No sig. values reported; trivial ES (h⫽0.05).
Interview recall survey (LTPA and non-LTPA)
0 (I), ⫹ (II–VII)
No sig. associations (p⬎0.05) although six measures show small ES ranging from r⫽0.14 to r⫽0.21. (M⬎F) (continued on next page)
40
Table 1. (continued)
American Journal of Preventive Medicine, Volume 31, Number 1
Correlate
Education
Study
Participants
Measures
Associationb
Sig. and ES values
Denny (2005)51
n⫽3123 Native Americans (1349 men, 1774 women; from larger sample of n⫽130,610); aged ⱖ18 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽219; Lakota Indians from SD (126 women, 92 men); aged ⱖ18 n⫽653 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50
Telephone interview recall survey (LTPA)
0
No sig. values reported; trivial ES.
Interview recall survey (LTPA and non-LTPA)
0 (M), 0 (F)
Interview recall survey (LTPA)
0 (I–III)
No sig. values reported; trivial ES for men and women (OR⫽1.2 and OR⫽1.1, CI 0.8–2.0). No sig. associations (p⬎0.05).
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA)
⫹
Sig. association (p⬍0.05); trivial ES (OR⫽1.21, CI 1.02–1.44).
0 (I–III), ⫹ (IV–VI)
Sig. association for one measure (OR⫽2.95, CI 0.88–5.86, p⬍0.05); two measures not sig. (p⬎0.05) although reveal small ES (OR⫽2.72 and OR⫽1.77, CI 0.56–9.21). Sig. association (r⫽0.20, p⬍0.05); small ES.
Fischer (1999)10 Harnack (1999)43 King (2000)44 Thompson (2003)45
Whitt (2004)47 Employment
Fischer (1999)10 King (2000)44 Thompson (2003)45
Income
Fischer (1999)10 Thompson (2003)45
Health
Fischer (1999)10
www.ajpm-online.net
King (2000)44 Harwell (2003)26
n⫽127 Native American women from NM (in larger sample, n⫽310); aged ⱖ40 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽2912; n⫽653 American Indian-Alaskan Native women; aged ⱖ40 n⫽2006; MT American Indians; aged ⱖ18
24-hour PA record books and pedometers for walking patterns Interview recall survey (LTPA and non-LTPA)
⫹ 0 (M), 0 (F)
No sig. values reported; trivial ES (OR⫽1.3 and OR⫽1.3, CI 0.8–2.1).
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
0
No sig. associations (p⬎0.05).
0 (I, II)
No sig. associations (p⬎0.05).
0 (M), ⫹ (F)
No sig. values reported; small ES for women (OR⫽1.9, CI 1.4–2.6).
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
0 (I–IV)
No sig. associations (p⬎0.05).
⫹ (F I, M II), 0 (F III, M IV)
Telephone interview recall survey (LTPA and nonLTPA combined) Telephone interview recall survey (no parameters given for type of PA)
0 (I, II), ⫹ (III)
No sig. values reported, although two measures reveal small ES (OR⫽1.9 and OR⫽1.8, CI 1.1–3.0). Sig. association (OR⫽0.83, p⬍0.05).
⫹ (I), 0 (II)
Sig. association for unadjusted comparison (p⬍0.05); trivial ES for adjusted comparison (OR⫽1.17, CI 0.89–1.54). (continued on next page)
July 2006
Table 1. (continued) Correlate
Study
Participants
Measures
Associationb
Sig. and ES values
Health
Thompson (2003)45
Sig. association (OR⫽1.74, CI 1.07–2.85); small ES.
Fitzgerald (1997)31
Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
⫹ (I), 0 (II)
Body weight
n⫽350; Native American women from Southwest United States; aged 20–50 n⫽2452; Pima Indians (976 men and 1476 women)
Sig. associations (r⫽⫺.15, r⫽⫺0.12, r⫽⫺0.20, r⫽⫺0.14, p⬍0.05); small ES.
n⫽1344; Chippewa and Menominee Indians (843 women, 501 men); aged ⱖ25 n⫽219; Lakota Indians from SD (126 women and 92 men); aged ⱖ18 n⫽80; U.S. and Mexican Pima Indians (40 United States, 40 Mexican); aged ⱖ18 n⫽483; Native Americans from Southwest United States (240 women, 143 men); aged ⱖ18 n⫽127 First Nation women from NM (from larger sample, ;n⫽310); aged ⱖ40 n⫽653 American Indian-Alaskan Native women (from larger sample, ;n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50 n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18 n⫽2912; n⫽639 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽653 American Indian-Alaskan Native women (from larger sample, n⫽2912); aged ⱖ40 n⫽350; Native American women from Southwest United States; aged 20–50
Interview recall survey (LTPA and non-LTPA)
⫺ (M I–II, F III–IV), 0 (M V–VIII, F IX– XII) 0 (F I, M II)
Interview recall survey (LTPA)
⫺(I,II), 0 (III)
Sig. associations (p⬍0.05); small ES (d⫽0.44 and d⫽0.28).
Doubly labeled water test
⫺ (I), 0 (II)
Sig. association (r⫽⫺0.38, p⬍0.02); medium ES.
Recall survey (LTPA)
⫺ (M), 0 (F)
Sig. association (p⬍0.05).
24-hour PA record books for walking patterns; pedometers Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA) Interview recall survey (LTPA and non-LTPA)
-
Sig. association (r⫽⫺0.33, p⬍0.01); medium ES.
0 (I–XII)
No sig. associations (p⬎0.05); trivial ES.
0 (I–XVI), ⫹ (XVII, XVIII)
No sig. associations (p⬎0.05), although two measures reveal small ES (OR⫽1.57 and 1.52, CI 0.97–2.44). No sig. associations (p⬎0.05) although 11 measures show small ES ranging from r⫽0.11 to r⫽0.26. No sig. values reported; small ES (OR⫽0.43, OR⫽2.64, OR⫽2.12, OR⫽1.8, OR⫽1.64, OR⫽2.29, CI 0.28– 6.87). No association (p⬎0.05).
Fischer (1999)10 Harnack (1999)43 Esparza (2000)32 Cuaderes (2004)46 Whitt (2004)47 Physical King environment (2000)44 Thompson (2003)45 Brunet (2005)48 Social Eyler environment (1999)52 Am J Prev Med 2006;31(1)
King (2000)44 Thompson (2003)45
0 (I–III), ⫺ (IV–XIV)
Telephone interview recall survey (lifestyle PA and regular exercise)
⫺ (I), 0 (II, III), ⫹ (IV–VIII)
Telephone interview recall survey (LTPA and nonLTPA combined) Interview recall survey (no parameters given for type of PA)
0 (I–V) ⫺ (I, II), ⫹ (III–IX), 0(X)
No sig. values reported; trivial ES for both measures.
41
Two sig. associations (p⬍0.05) with small (OR⫽0.62, CI 0.4–0.94) and medium ES (OR⫽0.38, CI 0.19–0.74); four sig. measures (p⬍0.05) with small (OR⫽2.6, OR⫽2.14, CI 1.11–4.49) and medium ES (OR⫽5.23 and OR⫽3.81, CI 1.66–10.14); three associations not sig. but have small ES (OR⫽1.52, OR⫽1.75, OR⫽1.53, CI 0.72–3.19). (continued on next page)
Absence of F or M means combined samples unless otherwise indicated in Participants column. a All studies were cross-sectional in design. b Negative, positive, and absent associations are represented by minus symbol (---), plus symbol (⫹), and 0, respectively. Roman numerals indicate various subgroup measurements in no particular order (e.g., type of PA, different locations, amount of PA, etc.). AZ, Arizona; ES, effect size; CI, confidence interval; d, independent mean effect size; F, female; h, independent proportion effect size; LTPA, leisure-time physical activity; M⫽male; MT, Montana; ND, North Dakota; NM, New Mexico; OK, Oklahoma; OR, odds ratio; PA, physical activity; r, Pearson product moment correlation; SD, South Dakota; sig., significance/significant.
No sig. associations (p⬎0.05), although five measures show small ES ranging from r⫽0.10 to r⫽0.23 and r⫽⫺0.11 to r⫽⫺0.17. 0 (I, II), ⫹ (III–VII) Interview recall survey (LTPA and non-LTPA) n⫽34; Aboriginals from Alberta (15 men, 18 women); aged ⱖ18 Brunet (2005)48
Sig. and ES values Associationb Measures Participants Study Correlate
Table 1. (continued) 42
Brunet et al.,48 Zurlo et al.,39 and Thompson et al.45 did not find significant associations between age and PA, a majority of the comparisons in each study revealed small effect sizes. Effect sizes ranged from small to medium in magnitude among most studies. Qualitative research by Henderson and Ainsworth53 found that Native-American women perceived that PA steadily declined as they approached adulthood. Nonetheless, as Table 1 highlights, the current evidence shows a consistently negative association between age and PA in Native Americans. Gender. Of 15 cross-sectional studies, the results indicate that 61% of the comparisons showed a significant or meaningful difference in PA levels between NativeAmerican men and women.10,13,14,28,30,31,39,43,48,49 Five studies found no significant differences at all in activity levels.9,41,42,50,51 Of note, three studies with very large sample sizes (n ⬎3000) revealed no significant differences between male and female PA levels.9,50,51 Contrary to a majority of the comparisons, Fischer et al.10 found that women were more active than their male counterparts from one sample location. Harnack et al.43 found a large effect (d ⫽0.88) for the differences in strenuous PA levels between men and women. As Table 1 indicates, six studies reveal meaningful effect sizes ranging from small to large. The nature of the existing data suggests that Native-American men have consistently higher PA levels than women. Education. Five cross-sectional studies assessed the relationship between PA and education in Native Americans. Only 38% of the comparisons showed that more education was associated with PA with, at most, small effect sizes.44,45,47 Education was not associated with PA in two studies.10,43 Thompson et al.45 found that women with some college education were almost three times as likely to do some activity compared to women with less than a high school education. Despite this finding, women with some college education were just as likely to fail to meet the American College of Sports Medicine’s recommendations as those women with less education.45 Similarly, although King et al.44 found significant results, a majority of the women in this study were also considered under-active. The current research indicates that an association between education and PA was inconsistent in Native Americans. Employment and income. As Table 1 indicates, three cross-sectional studies found no association between PA and employment.10,44,45 However, Fischer et al.10 found that ⬎90% of Native-American men and women report daily walking as a characteristic of their occupations. Qualitative research has shown that Native-American women believe that they are physically active going to work and at work during the day.54 Similar to the findings of Eyler et al.,38 none of the studies attempted to determine if PA varied by type of occupation. Unlike
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net
employment, at least one study found mixed positive associations between PA and income.10 However, of all the comparisons for income, only 17% of them revealed an association between PA and income. The current literature dealing with both employment and income reveals that there was no overall association with PA.
Personal Health Health/perceived health. Of the four studies, 45% of the comparisons indicated negative associations between PA and health.10,26,44,45 Qualitative research shows that Native-American women perceive that as they develop health problems, chronic or otherwise, they become less active.53,55 Further support for this view was found in two studies using open-ended questions by Harnack et al.,43,56 both of which found that Native-American men and women report health problems as barriers to regular PA. The overall association between PA and health in the quantitative research was inconsistent, as was evidenced by the occurrence of mixed associations. However, the qualitative literature and those studies that use open-ended questions suggest a trend toward a positive association between health and PA. Body weight. Five of six studies found inverse associations between PA and weight.10,31,32,43,47 Of 22 comparisons, 41% revealed that as body weight increases, PA levels decrease. Only one study found no association between PA and body weight.10 Despite the mixed results, Whitt et al.47 and Esparza et al.32 reported medium inverse correlations between PA and BMI. Other significant associations reveal small effect sizes at most.31,43 The research was indicative of an inconsistent relationship between PA and body weight.
Environment Physical environment. Two of three studies reported that certain aspects of the physical environment are related to PA.45,48 Of a possible 44 comparisons, only 30% revealed positive associations, none of which revealed anything more than small effect sizes. Qualitative research has shown that Native Americans believe that the physical environment affects their PA participation.18,53,54 Further research suggests safety concerns, lack of facilities/programs, bad weather, and poor infrastructure (e.g., sidewalks) are considered barriers to PA.43,56,57 As most of the comparisons are considered nil, the results of studies to date suggest that no overall association exists between PA and the physical environment. Social environment. Of the four studies reviewed here, 67% of the comparisons indicate significant or meaningful negative associations,45,48,52 while two studies found no associations.44,47 Thompson et al.45 found the July 2006
most compelling evidence that social support may play an integral role in the PA behaviors of Native Americans. Specifically, those who know people who exercise were five times more likely to do some activity compared to those who do not know anyone who exercised, and those people who saw other people exercising in the neighborhood were almost four times more likely to do some activity compared to those who did not see anyone exercising.45 The notion of the potential effects that social support has on PA was also reported in the qualitative literature.18,53–55 Such findings are further bolstered by Harnack et al.43,56 and Heesch et al.,57 all of whom found that certain aspects of the social environment act as barriers or enablers for NativeAmerican women. The data suggest that the social environment was an important correlate of PA in Native Americans, especially considering the occurrence of small to medium effect sizes.
Psychosocial Correlates Stages of change. The stages-of-change model posits that people progress through five stages of behavioral change: precontemplation, contemplation, preparation, action, and maintenance.58 In the domain of PA, this progression moves from not thinking about engaging in PA to regular engagement in PA for ⬎6 months.58 To date, only three cross-sectional PA studies make use of this model in Native-American research.57,59,60 Bull et al.59 and Stolarczyk et al.60 found that a majority of Native Americans are in the precontemplation to preparation stages of exercise. A second assessment by Bull et al.,59 in which the definition of PA was more inclusive than that of exercise, showed that the majority of the participants were in the action or maintenance stages. It was also found that NativeAmerican women were less likely to be in the maintenance stage of exercise and PA compared to their non–Native-American female counterparts.59 Heesch et al.57 sought to determine the differences in the perceived barriers to exercise among ethnically diverse women at the same stage of exercise and those at an adjacent stage. Results suggested that Native-American women in the precontemplation stage ranked being too tired, bad health, lack of energy, and lack of time as the most frequently cited barriers to exercise.57 Women in the contemplation stage ranked lack of energy, lack of time, and being too tired as barriers to exercise. Women in the preparation and active stages ranked lack of energy, being too tired, and lack of time as barriers to exercise.57
Interventions Only three intervention studies met the inclusion criteria.61– 63 Kochevar et al.61 sought to determine the efficacy of a community-based exercise program to increase PA in a group (n ⫽20) of Native-American Am J Prev Med 2006;31(1)
43
elders over a 6-week period. It was found that exercise participants significantly (p ⬍0.05) improved selfreported exercise frequencies, whereas control-group measures failed to show improvements.61 The intervention also showed that exercise can improve several other subjective and objective health outcome measures.61 Witmer et al.62 undertook a randomized controlled trial pilot study (n ⫽76) to test an intervention designed specifically for Alaska Native-American women. The impetus for the pilot study was to develop a culturally sensitive intervention program to decrease the risk of cardiovascular disease.62 The 12-week pilot study found that participants significantly (p ⬍0.05) improved their self-reported PA levels as well as their confidence to engage in regular PA.62 Finally, Narayan et al.63 tested adherence to various lifestyle interventions in a randomized pilot study among Pima Indians from Arizona (n ⫽95). It was found that participants of two intervention groups (exercise and diet) reported an increase in PA after 6 months (although no alpha values were reported), with increases still reported after 12 months (p ⬍0.01).63 No significant differences were found between the groups after both measurement periods.63 In total, all three interventions appeared to show an increase in PA levels.
Conclusion The purpose of this review was to unite the literature concerning Native-American populations and PA. The focus was on the correlates of PA behavior and psychosocial theories, as well as interventions to increase PA. The most important finding of this review was how very little is known about the PA behaviors of Native Americans. It is prudent to highlight that although many of the associations were not unique to Native Americans, they should be considered indeterminate until more research can be conducted. However, age, gender, and social support are the most consistent correlates of PA as a result of the research conducted thus far. The results of this review show that as Native Americans age, PA levels tend to decrease. Despite this similarity, overall PA levels of Native Americans tend to be lower than in nonminorities.15 There are factors that need to be considered that may add to the understanding of the relationship between PA and age. Just as previous reviews indicated, the lack of a significant association among many age comparisons may be the result of restricted age ranges.38 It is also worthy to note that the occurrence of even small effect sizes, regardless of whether statistical significance was achieved, could have practical or clinical implications.48 Contrary to the findings here, there was evidence to suggest that some Native-American women experience a resurgence of PA as they approach older adulthood.53 Although age was found to be consistently associated with PA, as is the case in the general population, further research is 44
needed to determine PA patterns at different life stages.64 Physical activity at these stages may be affected as much by life situations as by choice.53 Like age, gender was also associated consistently with PA, suggesting that Native-American men are more active than their female counterparts. However, time spent in all forms of PA was not consistently measured among the reviewed studies. For example, Fischer et al.10 found that when non–leisure-time PA was measured, such as hours of housework per week, women engaged in more activity than men. The difficulty with including such activities in any study is the degree to which lower-intensity activities are over-estimated and whether such activities lead to improved health.10 It was not uncommon for self-reported assessment tools, in the absence of objective tools, to inaccurately measure activities such as occupational walking.65 Future research that includes myriad types of PA may find that PA levels do not differ significantly by gender in Native Americans. Future research should also determine dose–response relationships for occupational or household activity. The social environment was an integral part of the PA behavior of Native Americans. The occurrence of several small to moderate effect sizes reaffirms the role of the social environment. A potentially important finding by Eyler et al.52 was that support in any form may be more important than the source of the support in affecting PA behavior. Although social support was important, greater attention needs to be focused on the role that sociocultural expectations play in the lives of Native Americans. As Thompson et al.18 indicate, Native Americans are interested in finding ways to enhance their PA behaviors through means that are compatible with their communities’ norms. Therefore, it was not only social support that was important but culturally relevant support. Education, employment, income, health, body weight, and the physical environment have thus far not been consistently associated with PA in Native Americans. The findings that education, employment, income, and body weight are not associated with PA are contrary to reviews dealing with the general population.4,64 Despite these findings, it should be noted that very little research is available that examines these correlates in Native Americans. As such, to state that education or income does not influence PA behavior would be an oversight. Ultimately, it must be reemphasized that much more research is needed before any conclusions can be drawn and comparisons with other populations can be made. Specifically, there is a lack of longitudinal research as well as research that deals with psychosocial correlates of PA behavior in Native American populations. It is not surprising that there are only a few intervention studies that attempted to increase PA levels in Native Americans, considering that relatively little re-
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net
search exists that attempts to understand the factors that influence PA behavior. Nonetheless, the small sample sizes of both Kochevar et al.61 (n ⫽20) and Witmer et al.62 (n ⫽76) limit any conclusions that can be made regarding the true efficacy of such interventions. Narayan et al.63 did not include a control group suggesting that there was no conclusive evidence that an increase in PA was actually the result of the experimental condition. Kochevar et al.61 experienced a sizeable attrition rate (37.5%) in an already small sample, which also limits the number of conclusions that can be made about the efficacy of their intervention. Despite such limitations, more intervention research is needed, as it is imperative to test the relative effectiveness of various programs. There are several inherent limitations associated with the current research, one of which relates to the appropriateness of measurement tools. Notwithstanding certain exceptions, not all existing measurement tools have been validated in Native-American populations. For example, Fischer et al.10 admit that the tool they used to measure PA has never undergone validity or reliability studies. Ideally, to accurately assess the PA behaviors of Native Americans, measurement tools need to be tailored to cultural and traditional lifestyles.66 Perhaps an increased emphasis should be placed on qualitative research methods, for as McDonald and McAvoy67 reaffirm, Native Americans tend to rely on oral traditions to communicate histories, values, and beliefs. The results of qualitative research could then be used to inform the development of culturally appropriate measurement tools. Many of the reviewed studies make use of standard terminology and self-report tools to measure PA. Terms such as leisure can be problematic, especially for minority populations.55,66 Much research assumes that participants should attach analogous meanings to such terms.68 The validity of a self-report tool depends on the participants’ ability to accurately evaluate and attach meaning to the various dimensions and terminology used to describe PA.69 Meanings attached to words may vary by specific characteristics such as culture, gender, socioeconomic status, or age.66 These interpretations are further complicated in light of the fact that much of social science research relies on nonminorities as sources of validation for current knowledge.70 This reinforces the need to validate existing measurement tools or develop new tools specific to a given population. The primary limitations associated with this review are twofold. First, the review was limited to published research. Reports and unpublished work may be present, but such research may be too difficult to retrieve systematically. Second, this review did not use meta-analytic methods, which can be useful in synthesizing effects. However, as indicated previously, considJuly 2006
ering the nature of the existing research, a narrative review was thought to be more appropriate. Despite the limited amount of research with Native Americans, the current research was paramount to understanding the PA behaviors of Native Americans. Future research can help to close the gap in the health disparities between Native Americans and the general population. The beneficial effects of PA in mitigating risk factors for disease and chronic illness warrant a greater interest in studying the PA behaviors of Native Americans. RER was supported by a scholar award from the Michael Smith Foundation for Health Research and with funds from the Social Sciences and Humanities Research Council of Canada. No financial conflict of interest was reported by the authors of this paper.
References 1. U.S. Department of Health and Human Services. Physical activity and health: a report of the Surgeon General. Atlanta GA: Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion. 1996. 2. Pate RR, Pratt M, Blair N, et al. Physical activity and public health: a recommendation from the Centers for Disease Control and Prevention and the American College of Sports Medicine. JAMA 1995;273:402–7. 3. Bouchard C, Shephard RJ, Stephens T, et al., eds. Exercise, fitness, and health: international proceedings and consensus statement. Champaign IL: Human Kinetics, 1994. 4. Seefeldt V, Malina RM, Clark MA. Factors affecting levels of physical activity in adults. Sports Med 2002;32:143– 68. 5. Canadian Fitness and Lifestyle Research Institute. 2001 Physical Activity Monitor. Available at: www.cflri.ca. Accessed July 21, 2005. 6. Crespo C, Smit E, Anderson R, et al. Race/ethnicity, social class and their relation to physical inactivity during leisure time: results form the Third National Health and Nutrition Examination Survey 1988 –1994. Am J Prev Med 2000;18:46 –53. 7. Jones D, Ainsworth B, Croft J, et al. Moderate leisure-time physical activity: who was meeting the public health recommendations? Arch Fam Med 1998;7:285–9. 8. Kriska AM, Rexroad A. The role of physical activity in minority populations. Women Health Issues 1998;8:98 –103. 9. Denny C, Holtzman D, Cobb N. Surveillance for health behaviors of American Indians and Alaska Natives: findings from the Behavioral Risk Factor Surveillance System, 1997–2000. MMWR Surveill Summ 2003;52:1–13. 10. Fischer ID, Brown DR, Blanton CJ, et al. Physical activity patterns of Chippewa and Menominee Indians: the Inter-Tribal Heart Project. Am J Prev Med 1999;17:189 –97. 11. Myers HF, Kagawa-Singer M, Kumanyika SK, et al. Panel III: behavioral risk factors related to chronic diseases in ethnic minorities. Health Psychol 1995;14:613–21. 12. Wilcox S, Castro C, King AC, et al. Determinants of leisure time physical activity in rural compared with urban older and ethnically diverse women in the United States. J Epidemiol Community Health 2000;54:667–72. 13. Goldberg HI, Warren CW, Oge LL, et al. Prevalence of behavioral risk factors in two American Indian populations in Montana. Am J Prev Med 1991;7:155– 60. 14. Sugarman JR, Warren CW, Oge LL, et al. Using the Behavioral Risk Factor Surveillance System to monitor year 2000 objectives among American Indians. Public Health Rep 1992;107:449 –56. 15. U.S. Department of Health and Human Services. Healthy people 2010. 2nd ed. Atlanta GA: Centers for Disease Control and Prevention, 2000. 16. Joe JR. Out of harmony: health problems and young Native American men. J Am Coll Health 2001;49:237– 42.
Am J Prev Med 2006;31(1)
45
17. Pargee D, Lara-Albers E, Puckett K. Building on tradition: promoting physical activity with American Indian community coalitions. J Health Educ 1999;30:S37– 43. 18. Thompson JL, Allen P, Cunningham-Sabo L, et al. Environmental, policy and cultural factors related to physical activity in sedentary American Indian women. Women Health 2002;36:57–72. 19. Broussard BA, Sugarman JR, Bachman-Carter K, et al. Toward comprehensive obesity prevention programs in Native American communities. Obes Res 1995;3(suppl 2):289 –97. 20. Katzmarzyk PT, Malina RM. Obesity and relative subcutaneous fat distribution among Canadians of First Nation and European ancestry. Int J Obes Relat Metab Disord 1998;22:1127–31. 21. Zephier E, Himes JH, Story M. Prevalence of overweight and obesity in American Indian school children and adolescents in the Aberdeen area: a population study. Int J Obes Relat Metab Disord 1999;23(suppl 2):S28 –30. 22. Burrows NR, Geiss LS, Engelgau MM, et al. Prevalence of diabetes among Native Americans and Alaska Natives, 1990 –1997. Diabetes Care 2000;23:1786 –90. 23. Delisle HF, Ekoe JM. Prevalence of non-insulin dependent diabetes mellitus and impaired glucose tolerance in two Algonquin communities in Quebec. CMAJ 1993;148:41–7. 24. Harris SB, Gittelsohn J, Hanley AJ, et al. The prevalence of NIDDM and associated risk factors in Native Canadians. Diabetes Care 1997;20:185–7. 25. Anand S, Tookenay V. Cardiovascular diseases and Native American peoples. Can J Cardiol 1999;15(suppl G):44G– 6G. 26. Harwell TS, Moore K, McDowall JM, et al. Cardiovascular risk factors in Montana American Indians with and without diabetes. Am J Prev Med 2003;24:265–9. 27. Howard BV, Lee ET, Cowan LD, et al. Rising tide of cardiovascular disease in American Indians: the Strong Heart Study. Circulation 1999;99:2389 –95. 28. Yurgalevitch SM, Kriska AM, Welty TK, et al. Physical activity and lipids and lipoproteins in American Indians ages 45–74. Med Sci Sports Exerc 1998;30:543–9. 29. Irwin ML, Mayer-Davis EJ, Addy CL, et al. Moderate-intensity physical activity and fasting insulin levels in women: the cross-cultural activity participation study. Diabetes Care 2000;23:449 –54. 30. Kriska AM, Hanley AJ, Harris SB, et al. Physical activity, physical fitness, and insulin and glucose concentrations in an isolated Native Canadian population experiencing rapid lifestyle change. Diabetes Care 2001;24:1787–92. 31. Fitzgerald SJ, Kriska AM, Pereira MA, et al. Associations among physical activity, television watching, and obesity in adult Pima Indians. Med Sci Sports Exerc 1997;29:910 –5. 32. Esparza J, Fox C, Harper IT, et al. Daily energy expenditure in Mexican and USA Pima Indians: low physical activity as a possible cause of obesity. Int J Obes Relat Metab Disord 2000;24:55–9. 33. Bouchard C, Shephard RJ. Physical activity, fitness and health: the model and key concepts. In: Bouchard C, Shephard RJ, Stephens T, et al., eds. Physical activity, fitness and health: international proceedings and consensus statement. Champaign IL: Human Kinetics, 1994:77– 88. 34. Sallis JF, Prochaska JJ, Taylor WC. A review of correlates of physical activity of children and adolescents. Med Sci Sports Exerc 2000;32:963–75. 35. Egger M, Smith DS, Altman DG. Systematic reviews in health care: meta-analysis in context. London: BMJ Books, 2001. 36. Cohen J. A power primer. Psychol Bull 1992;112:155–9. 37. Hopkins WG. A new view of statistics: a scale of magnitudes for effect statistics. Available at: www.sportsci.org/resource/stats/effectmag.html. Accessed July 28, 2005. 38. Eyler AE, Wilcox S, Matson-Koffman D, et al. Correlates of physical activity among women from diverse racial/ethnic groups. J Womens Health Gend Based Med 2002;11:239 –53. 39. Zurlo F, Ferraro RT, Fontvieille AM, et al. Spontaneous physical activity and obesity: Cross-sectional and longitudinal studies in Pima Indians. Am J Physiol 1992;263:E296 –300. 40. Rising R, Harper IT, Fontvieille AM, et al. Determinants of total energy expenditure: variability in physical activity. Am J Clin Nutr 1994;59:800 – 4. 41. Mendlein JM, Freedman DS, Peter DG, et al. Risk factors for coronary heart disease among Navajo Indians: findings from the Navajo Health and Nutrition Survey. J Nutr 1997;127(suppl):2099S–105S. 42. Nelson DE, Moon RW, Holtzman D, et al. Patterns of health risk behaviors for chronic disease: a comparison between adolescent and adult American Indians living on or near reservations in Montana. J Adolesc Health 1997;21:25–32. 43. Harnack L, Story M, Rock BH. Diet and physical activity patterns of Lakota Indian adults. J Am Diet Assoc 1999;99:829 –35.
46
44. King AC, Castro C, Wilcox S, et al. Personal and environmental factors associated with physical inactivity among different racial-ethnic groups of U.S. middle-aged and older-aged women. Health Psychol 2000;19:354 – 64. 45. Thompson JL, Wolfe VK, Wilson N, et al. Personal, social, and environmental correlates of physical activity in Native American women. Am J Prev Med 2003;25(suppl):53– 60. 46. Cuaderes ET, Parker Burgin CE. Leisure time physical activity in adult Native Americans. South Online J Nurs Res 2004;5:1–18. 47. Whitt MC, DuBose KD, Ainsworth BE, et al. Walking patterns in a sample of African American, Native American, and Caucasian women: the CrossCultural Activity Participation Study. Health Educ Behav 2004; 31(suppl):45S–56S. 48. Brunet S, Plotnikoff RC, Raine K et al. Physical activity of Aboriginals with type 2 diabetes: an exploratory study. Ethn Dis 2005;15:256 – 66. 49. Plaud JJ, Schweigman K, Welty TK. Health-related and cultural gender differences in an aging American Indian population. J Clin Geropsychol 1998;4:111– 8. 50. Bursac Z, Campbell JE. From risky behaviors to chronic outcomes: current status and Healthy People 2010 goals for American Indians in Oklahoma. J Okla State Med Assoc 2003;96:569 –73. 51. Denny CH, Holtzman D, Goins T, et al. Disparities in chronic disease risk factors and health status between American Indian/Alaska Native and white elders: findings from a telephone survey, 2001 and 2002. Am J Public Health 2005;95:825–7. 52. Eyler AA, Brownson RC, Donatelle RJ, et al. Physical activity social support and middle- and older-aged minority women: results from a U.S. survey. Soc Sci Med 1999;49:781–9. 53. Henderson KA, Ainsworth BE. Physical activity and human development among older Native American women. J Aging Phys Act 2001;9:285–99. 54. Henderson KA, Ainsworth BE. Enablers and constraints to walking for older African American and American Indian women: the Cultural Activity Participation Study. Res Q Exerc Sport 2000;71:313–21. 55. Eyler AA, Baker E, Cromer L. Physical activity and minority women: a qualitative study. Health Educ Behav 1998;25:640 –52. 56. Harnack L, Sherwood N, Story M. Diet and physical activity patterns of urban American Indian women. Am J Health Promot 1999;13:233– 6. 57. Heesch KC, Brown DR, Blanton CJ. Perceived barriers to exercise and stage of exercise adoption in older women of different racial/ethnic groups. Women Health 2000;30:61–76. 58. Prochaska JO, Marcus BH. The transtheoretical model: applications to exercise. In: Dishman R, ed. Advances in exercise adherence. Champaign IL: Human Kinetics, 1994:161– 80. 59. Bull FC, Eyler AA, King AC, et al. Stage of readiness to exercise in ethnically diverse women: a U.S. survey. Med Sci Sports Exerc 2001;33:1147–56. 60. Stolarczyk LM, Gilliland SS, Lium DJ, et al. Knowledge, attitude and behaviors related to physical activity among Native Americans with diabetes. Ethn Dis 1999;9:59 – 69. 61. Kochevar AJ, Smith KL, Bernard MA. Effects of community-based intervention to increase physical activity in American Indian elders. J Okla State Med Assoc 2001;94:455– 60. 62. Witmer JM, Hensel MR, Holck PS, et al. Heart disease prevention for Alaska Native women: a review of pilot study findings. J Womens Health 2004;13:569 –78. 63. Narayan KM, Hoskin M, Kozak D, et al. Randomized clinical trial of lifestyle interventions in Pima Indians: a pilot study. Diabet Med 1998;15:66 –72. 64. Trost SG, Owen N, Bauman AE, et al. Correlates of adults’ participation in physical activity: review and update. Med Sci Sports Exerc 2002; 34:1996 –2001. 65. Bates JH, Serdula MK, Khan LK, et al. Total and leisure-time walking among U.S. adults: Should every step count? Am J Prev Med 2005;29:46 –50. 66. Masse LC, Ainsworth BE, Tortolero S, et al. Measuring physical activity in midlife, older, and minority women: issues from an expert panel. J Womens Health 1998;7:57– 67. 67. McDonald D, McAvoy L. Native Americans and leisure: state of the research and future directions. J Leisure Res 1997;29:145– 66. 68. Tudor-Lock C, Henderson KA, Wilcox S, et al. In their own voices: definitions and interpretations of physical activity. Women Health Issues 2003;13:194 –9. 69. Aadahl M, Jorgensen T. Validation of a new self-report instrument for measuring physical activity. Med Sci Sports Exerc 2003;35:1196 –202. 70. Im E. Nursing research on physical activity: a feminist critique. Int J Nurs Stud 2001;38:185–94.
American Journal of Preventive Medicine, Volume 31, Number 1
www.ajpm-online.net