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Physical Activity in Men and Women with Arthritis
Physical Activity in Men and Women with Arthritis National Health Interview Survey, 2002 Margaret Shih, MD, PhD, Jennifer M. Hootman, PhD, ATC, Judy Kruger, PhD, Charles G. Helmick, MD Background: Regular physical activity in persons with arthritis has been shown to decrease pain, improve function, and delay disability. This study estimates the national prevalence of leisure-time physical activity and identifies factors associated with physical inactivity in adults with arthritis. Methods:
Data from the 2002 National Health Interview Survey were analyzed in 2004 –2005 to estimate the proportion of adults with arthritis meeting four physical activity recommendations put forward in Healthy People 2010 and one arthritis-specific recommendation established by a national expert panel in arthritis and physical activity. Multivariate logistic regression was used to evaluate the association between inactivity and sociodemographic factors, body mass index, functional limitations, social limitations, need for special equipment, frequent anxiety/depression, affected joint location, joint pain, physical activity counseling, and access to a fitness facility.
Results:
Adults with arthritis were significantly less likely than adults without arthritis to engage in recommended levels of moderate or vigorous physical activity, and 37% of adults with arthritis were inactive. In both men and women with arthritis, inactivity was associated with older age, lower education, and having functional limitations; having access to a fitness facility was inversely associated with inactivity. Among women, inactivity was also associated with being Hispanic, non-Hispanic black, having frequent anxiety/depression or social limitations, needing special equipment, and not receiving physical activity counseling. Among men, inactivity was also associated with severe joint pain.
Conclusions: Although physical activity is a recommended therapy for people with arthritis, levels among adults with arthritis are insufficient, and those with arthritis have worse activity profiles than their peers without arthritis. Efforts to promote physical activity should include expanding access to evidence-based interventions and recreational facilities/programs. The importance of physical activity counseling and associated pain management measures by healthcare providers should be emphasized. (Am J Prev Med 2006;30(5):385–393) © 2006 American Journal of Preventive Medicine
Introduction
A
rthritis, the leading cause of disability in the United States,1 affected 43 million U.S. adults in 2002.2 This imposes an enormous economic burden, with total costs attributable to arthritis in 1997 estimated at $86 billion.3 Among those with arthritis, physical inactivity can contribute to deconditioning, impaired function, poor mental health, and an increased risk of obesity. A recent 2-year longitudinal From the Office of Health Assessment and Epidemiology, Los Angeles County Department of Health Services (Shih), Los Angeles, California; and Centers for Disease Control and Prevention (Hootman, Kruger, Helmick), Atlanta, Georgia Address correspondence to: Margaret Shih, MD, PhD, Office of Health Assessment and Epidemiology, Los Angeles County Department of Health Services, 313 N. Figueroa Street, Room 127, Los Angeles, CA 90012 E-mail: [email protected]. Address reprint requests to: Jennifer M. Hootman, PhD, Division of Adult and Community Health, CDC, 4770 Buford Highway NE, MS-K51, Atlanta, GA 30341.
study found that older adults with arthritis who did not engage in regular vigorous activity were twice as likely to experience functional decline as those who did.4 In addition, inactive adults have higher medical costs than those who are regularly active.5 Both strength training6 –22 and aerobic exercise16,22–31 have been shown to benefit people with osteoarthritis and rheumatoid arthritis, significantly decreasing pain while delaying disability and improving gait and function; other physical and psychological benefits have been reported in patients with fibromyalgia32 and systemic lupus erythematosus.33 Although studies have generally found that low-to-moderate– intensity physical activity does not worsen arthritis symptoms or disease activity,6,23,24,26,34,35 increasing physical activity in this population has been challenging, in part because of continued misconceptions about the potential harm to joints and concerns about increased pain.36,37
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Physical activity is one of the major non-pharmacologic interventions for managing arthritis,38,39 and physical activity is a focus area in Healthy People 2010 (HP2010).40 The purpose of this study is to conduct a secondary data analysis of a national data set to: (1) determine the national prevalence of various levels of leisure-time physical activity in adults with and without arthritis that are consistent with recommendations in HP2010 and recommendations of a 2002 national panel of experts in arthritis and physical activity,41 and (2) identify sociodemographic and other factors associated with physical inactivity in adults with arthritis to better identify those who might be at greater need for intervention.
Methods Data Sources Data from the 2002 National Health Interview Survey (NHIS) were analyzed in 2004 –2005. The NHIS is an ongoing, national household interview survey designed to represent the U.S. civilian, non-institutionalized population and uses a multistage, complex sampling design.42 The response rate for the sample adult component (18 years and older) in 2002 was 74.3% (n⫽31,044).43
Definition of Arthritis Doctor-diagnosed arthritis (n⫽6829), hereafter called arthritis, was defined by a “yes” response to “Have you ever been told by a doctor or other health professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?” Respondents who answered “no” and who did not have chronic joint symptoms (i.e., joint symptoms lasting 3 months or more) composed the no-arthritis group (n⫽20,676). The 3397 respondents with possible arthritis (i.e., chronic joint symptoms but no doctor-diagnosed arthritis) were excluded from the analysis because their arthritis status was not clear. Information regarding arthritis status was missing for 142 respondents.
Recommendations for Physical Activity In HP2010, which lists national health objectives for the year 2010,40 people with arthritis are an identified target for four objectives in Chapter 22, “Physical Activity and Fitness”: 22-1: Reduce the proportion of adults who engage in no leisure-time physical activity. 22-2: Increase the proportion of adults who engage regularly, preferably daily, in moderate physical activity for at least 30 minutes per day. 22-3: Increase the proportion of adults who engage in vigorous physical activity that promotes the development and maintenance of cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion. 22-4: Increase the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance. In addition to these four HP2010 physical activity objectives, a fifth, arthritis-specific recommendation was included:
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that people with arthritis accumulate 30 minutes of moderate-intensity physical activity at least 3 days a week. Because exercise studies in this population have had little variation in prescribed dosage of exercise, safety has not been established at higher doses. This consensus recommendation was developed by an expert panel in arthritis, physical activity, and public health, which was sponsored in 2002 by the Missouri Arthritis Rehabilitation and Research Center, the American College of Rheumatology, and the Association of Rheumatology Health Professionals, to review the evidence for the benefits of exercise and physical activity among those with arthritis.41
Measurement of Physical Activity The percentages of adults engaging in physical activity consistent with these recommendations were estimated by asking respondents to report on the frequency and duration of both moderate and vigorous physical activities: “How often do you do vigorous activities for at least 10 minutes that cause heavy sweating or large increases in breathing or heart rate?” and “How often do you do light or moderate activities for at least 10 minutes that cause only light sweating or a slight to moderate increase in breathing or heart rate?” For each question, respondents who reported engaging in such physical activity were asked to report the frequency (i.e., number of times per day/week/month/year) and duration (i.e., number of minutes or hours per time period) that they engaged in the activity. Those reporting that they never participated in, or were unable to participate in, light, moderate, or vigorous physical activity for at least 10 minutes per occasion were defined as “inactive.” Persons participating in moderateintensity activity at least 30 minutes per day, 5 or more days per week, or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week, were considered to be meeting HP2010 recommendations for “moderate” or “vigorous” physical activity; persons participating in “physical activities specifically designed to strengthen your muscles such as lifting weights or doing calisthenics” at least twice per week were considered to be meeting the HP2010 recommendation for “strengthening” exercise; and persons participating in moderate-intensity activity at least 30 minutes per day, 3 or more days per week were considered to be meeting the recommendations of the “expert panel in arthritis.”41
Covariates Independent variables that have previously demonstrated an association with physical activity were included in the analysis. These variables included gender; age (18 – 44, 45– 64, 65⫹ years); race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, non-Hispanic other/multiple race; education (high school or less, beyond high school); body mass index ([BMI⫽weight (kg)/height (m2)]; ⬍25, underweight/ normal weight; 25 to ⬍30, overweight; 30⫹, obese); and frequent anxiety/depression (determined by the question “During the past 12 months, have you been frequently depressed or anxious?”). To assess and adjust for the effect of comorbidities and health status, 16 self-reported medical conditions, 9 functional and 3 social/leisure limitations, and the respondent’s need for special equipment were included in the analysis. The
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16 medical conditions were: hypertension; high cholesterol; back pain; neck pain; cardiovascular condition (angina, congestive heart failure, myocardial infarction, coronary heart disease, other heart condition); stroke; respiratory condition (asthma, emphysema, chronic bronchitis); thyroid problem; neurologic condition (multiple sclerosis, Parkinson disease, neuropathy, seizures); cancer; diabetes; kidney disease; liver condition; vision problem (difficulty seeing, blindness, retinopathy, cataracts, glaucoma, macular degeneration); hearing impairment; and gastrointestinal condition (ulcer, inflammatory bowel, irritable bowel, severe constipation). Respondents were categorized as having none, one to three, or four or more functional limitations by the number of times they responded “very difficult” or “unable to” for a list of nine activities: walk a quarter mile, walk up ten steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. Respondents had at least one social/leisure limitation if they reported it was “very difficult” or they were “unable to” do any of three social/leisure activities: go out to things like shopping, movies, or sporting events; participate in social activities such as visiting friends, attending clubs and meetings, going to parties; or do things to relax at home or for leisure. Their need for special equipment was determined by the question “Do you now have any health problem that requires you to use special equipment, such as a cane, a wheelchair, a special bed, or a special telephone?” The analysis was extended to include arthritis symptoms and the facilitation of physical activity. Respondents reporting joint symptoms in the past 30 days were asked to rate the severity of their joint pain on a scale from 0 to 10 (0 –3, little to none; 4 – 6, moderate; 7⫹, severe) and which joints (upper extremity, lower extremity, both) were affected. Those reporting no joint symptoms were categorized as having no joint pain. Receipt of physical activity counseling was determined by responding “yes” to “Has a doctor or other health professional ever suggested physical activity or exercise to help your arthritis or joint symptoms?” Having access to a fitness program or facility was assessed by asking “Do you now have access to a health club, wellness program, or fitness facility that meets your needs, if you wanted to use one?”
Statistical Analyses The proportions of adults with and without arthritis meeting physical activity recommendations were age adjusted to the 2000 U.S. population to allow comparisons to HP2010 recommendations. Overall and gender-specific proportions and odds ratios for physical inactivity in adults with arthritis were calculated. A series of multivariate logistic regression models were run to evaluate the association between inactivity and the covariates listed above. In the initial model, which included all covariates, the location of the affected joint(s) was not significant and was excluded from subsequent models. Sociodemographic variables were retained in all models. Information regarding physical inactivity was missing for 142 of the 6829 respondents with arthritis, and these respondents were not included in the prevalence calculations or logistic regression modeling. The second phase of modeling examined the relationship between physical inactivity and the 16 medical conditions described previously. Conditions were modeled in several
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ways: (1) individually, (2) as a subset of conditions identified as associated with inactivity through logistic regression, and (3) by number of conditions. Regardless of how modeled, comorbidity was not significant in multivariable modeling and thus was not included in further modeling. In the third phase of modeling, testing was done for the interactions of all remaining covariates with gender and BMI. Interactions were found between gender and two variables (physical activity counseling, access to fitness facilities), but no interactions were found with BMI. Because of these interactions and known differences between men and women in patterns of physical activity, gender-stratified models were chosen for presentation. All prevalence estimates, confidence intervals, and odds ratios were calculated using SUDAAN (version 9.0.0; Research Triangle Institute, Research Triangle Park NC, 2004) to account for the complex sampling design and used sample adult weights. A significance level of ␣⫽0.05 was used.
Results Compared to adults without arthritis, adults with arthritis were more likely to be older, female, non-Hispanic white, less educated, obese, have frequent anxiety/ depression, have one or more functional or social limitations, need special equipment, have one or more comorbid conditions, and not be meeting HP2010 physical activity recommendations or the recommendation of an expert panel on arthritis41 (Table 1). After age adjustment, the percentages of adults with and without arthritis who were meeting physical activity recommendations were more similar (Table 2), with no difference found in prevalence of inactivity (37% arthritis, 38% no arthritis); in participation in strengthening exercise (20% both); or in meeting the recommendation of the expert panel on arthritis41 (37% arthritis, 39% no arthritis). However, adults with arthritis were significantly less likely to engage in HP2010recommended levels40 of moderate/vigorous (30% vs 33%, p⫽0.05) or vigorous activity (21% vs 24%, p⫽0.006). The highest prevalence of inactivity was among adults with arthritis who had four or more functional limitations, one or more social/leisure limitations, a need for special equipment, and who lacked access to a fitness facility (Table 3). Among those who reported a lack of access to a fitness facility, the most common reason given was “cost” (26%), followed by “lack of transportation” (5%); well over half (62%) indicated “no reason” preventing access. In adjusted models stratified by gender, variables associated with inactivity in both men and women with arthritis were older age (ⱖ45 years in men, ⱖ65 years in women); having less education; having functional limitations; and a lack of access to a fitness program/ facility. Among women but not men, inactivity was also associated with being Hispanic or non-Hispanic black, and having frequent anxiety/depression, one or more Am J Prev Med 2006;30(5)
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Table 1. Distribution of selected characteristics of study population, overall and by arthritis status (2002 NHIS) Overalla (N ⴝ 205,825b) Characteristic Age (years) 18–44 45–64 65 or older Gender Male Female Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other/multiple race Educatione Some college or more High school or less Body mass indexe Under/normal weight (⬍25) Overweight (25–29.9) Obese (ⱖ30) Frequent anxiety/depressione No Yes Functional limitationse,f 0 1–3 4 or more Social/leisure limitationse,g 0 1 or more Need special equipmente No Yes Comorbiditiese,h 0 1–2 3 or more Physical activity recommendationsi Inactive Moderate/vigorous Vigorous Strengthening Arthritis expert panel
Doctor-diagnosed arthritisc (N ⴝ 42,704)
No arthritisd (N ⴝ 138,927)
Weighted %
95% CI
Weighted %
95% CI
Weighted %
95% CI
52.5 31.4 16.1
51.7–53.4 30.8–32.1 15.5–16.6
19.8 43.4 36.8
18.7–21.0 41.9–44.8 35.4–38.3
63.1 27.1 9.9
62.1–64.0 26.3–27.9 9.4–10.4
48.0 52.0
47.3–48.7 51.3–52.8
39.4 60.6
38.0–40.9 59.1–62.0
49.9 50.1
49.0–50.8 49.2–51.0
72.7 11.2 11.0 5.1
71.8–73.5 10.6–11.9 10.5–11.6 4.7–5.5
80.4 10.5 6.2 3.0
79.1–81.6 9.6–11.4 5.6–6.8 2.5–3.6
69.6 11.6 12.9 5.8
68.7–70.6 10.9–12.4 12.3–13.6 5.4–6.3
52.8 45.9
52.0–53.7 45.1–46.8
46.7 52.4
45.3–48.1 50.9–53.8
54.8 43.9
53.8–55.8 42.9–44.9
39.5 33.4 22.4
38.7–40.2 32.7–34.0 21.8–23.0
28.9 33.3 33.2
27.7–30.2 32.0–34.6 31.9–34.5
43.5 33.1 18.4
42.6–44.4 32.4–33.9 17.7–19.0
83.9 15.7
83.4–84.5 15.2–16.3
73.5 26.2
72.2–74.8 24.9–27.5
89.0 10.7
88.5–89.5 10.2–11.2
86.0 8.8 5.0
85.4–86.5 8.4–9.2 4.7–5.3
59.6 23.8 16.2
58.0–61.1 22.6–25.0 15.2–17.4
95.0 3.4 1.4
94.6–95.4 3.1–3.7 1.2–1.6
96.2 3.4
96.0–96.5 3.1–3.6
89.4 9.9
88.5–90.2 9.1–10.8
98.5 1.2
98.3–98.7 1.1–1.4
94.4 5.5
94.1–94.7 5.2–5.8
83.3 16.6
82.2–84.3 15.7–17.7
98.1 1.8
97.9–98.3 1.6–2.1
34.4 39.2 26.4
33.7–35.1 38.5–39.8 25.8–27.0
8.3 31.1 60.4
7.6–9.1 30.2–32.5 59.1–61.7
45.1 40.7 14.2
44.2–46.0 39.8–41.5 13.7–14.8
37.5 31.9 23.5 20.5 38.2
36.5–38.5 31.1–32.7 22.8–24.2 19.8–21.1 37.4–39.0
43.6 25.8 16.3 16.3 32.3
42.0–45.2 24.5–27.1 15.2–17.4 15.2–17.4 30.9–33.8
36.4 33.4 25.4 21.5 39.5
35.3–37.6 32.4–34.4 24.5–26.3 20.8–22.4 38.5–40.5
a
Includes respondents with possible arthritis (i.e., joint symptoms lasting 3 months or more). Weighted number in thousands. Respondents answering “yes” to the question “Have you ever been told by a doctor or other heath professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?” d Respondents who reported not having doctor-diagnosed arthritis or possible arthritis. e Percentages do not sum to 100% due to nonresponse, which was approximately 5% for body mass index, 1% for education, and ⬍1% for other variables. f (Max 9): very difficult or unable to walk a quarter mile, walk up 10 steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. g (Max 3): very difficult or unable to “Go out to things like shopping, movies, or sporting events?”, “Participate in social activities such as visiting friends, attending clubs and meetings, going to parties?”, or “Do things to relax at home or for leisure.” h (Max 16): hypertension, high cholesterol, back pain, neck pain, cardiovascular condition, stroke, respiratory condition, thyroid problem, neurologic condition, cancer, diabetes, weak or failing kidneys, liver condition, vision condition, hearing impairment, gastrointestinal condition. i Inactive: never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes; Moderate/vigorous: participating in either moderate-intensity activity at least 30 minutes per day, 5 or more days per week; or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week; Vigorous: participating in vigorous-intensity activity at least 20 minutes per day, 3 or more days per week; Strengthening: participating in strengthening exercise at least twice per week; Arthritis expert panel: participating moderate-intensity activity for at least 30 minutes, a minimum of 3 days per week. CI, confidence interval; NHIS, National Health Interview Survey. b c
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Table 2. Age-adjusted percentages of adults meeting national physical activity objectives, by arthritis status (2002 NHIS)a NHIS 2002 Physical activity recommendation Healthy People 2010 40 22-1: Reduce the proportion of adults who engage in no leisure-time physical activityb 22-2: Increase proportion of adults who engage regularly, preferably daily, in moderate physical activity for at least 30 minutes per dayc 22-3: Increase the proportion of adults who engage in vigorous physical activity that promotes the development and maintenance of cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion 22-4: Increase the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance Arthritis expert panel recommendation41 Perform moderate physical activity for at least 30 minutes per day, 3 days per week
1997 Baseline (%)
Healthy People 2010 target40 (%)
Doctor-diagnosed arthritis (%)
No arthritis (%)
Overall (%)
37
38
38
40
20
30*
33
32
32
50
21**
24
23
23
30
20
20
21
18
30
37
39
38
NA
NA
a
All estimates are age-adjusted to the standard 2000 U.S. resident population. Measure used is the proportion of adults who are inactive, which is defined as never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes. c Includes those participating in either moderate-intensity activity at least 30 minutes per day, 5 or more days per week, or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week. *p ⫽ 0.05, no arthritis vs doctor-diagnosed arthritis. **p ⫽ 0.006, no arthritis vs doctor-diagnosed arthritis. NA, not applicable; NHIS, National Health Interview Survey. b
social/leisure limitations, a need for special equipment, and never receiving arthritis-related physical activity counseling. Among men but not women, inactivity was also associated with severe joint pain (Table 3).
Discussion These findings are the first report of physical activity levels among adults with and without arthritis using a national data source and a validated arthritis case definition. Despite substantial evidence showing that physical activity benefits people with arthritis, adults with arthritis are significantly less likely than adults without arthritis to be meeting HP2010 recommendations for moderate or vigorous physical activity, and overall physical activity levels in adults with arthritis remain low. These findings are consistent with four earlier studies showing low levels of physical activity among adults with arthritis. One study, which found physical activity profiles to be worse in persons with arthritis,44 reported an inactivity prevalence of 31%, but is not directly comparable because it measured lifestyle physical activity (which includes leisure time, occupational, transportaMay 2006
tion, and household activity) and used state-based data, as well as a different definition of arthritis. Another study using state-based data, which included adults with doctor-diagnosed arthritis but assessed physical activity differently, reported an inactivity prevalence of 24%, with a demographic profile similar to the findings in the present study.45 An update of that study found prevalence estimates relatively unchanged between 2001 and 2003.46 A study using data from the Canadian National Population Health Survey reported a prevalence of inactivity of 39% in community-dwelling adults aged 65 and older with arthritis.47 Participation in strengthening exercises among adults with arthritis was below the HP2010 target of 30% and was similar to the participation rate of adults without arthritis. In persons with arthritis, strengthening exercises have been shown to be similar in effectiveness to aerobic exercise in reducing pain and preserving function.22,48,49 Additional benefits of strength training in older adults include increasing muscle strength and bone density and decreasing risk for falls,50 yet older adults are especially unlikely to participate in this mode of exercise.51 Am J Prev Med 2006;30(5)
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Table 3. Unadjusted prevalence and adjusted odds of physical inactivity in adults with doctor-diagnosed arthritis, by selected characteristics Overall
Characteristic DEMOGRAPHICS Gender Male Female Age (years) 18–44 45–64 65 or older Race/Ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other/multiple race Education Some college or more High school or less Body mass index Under/normal weight (⬍25) Overweight (25–29.9) Obese (ⱖ30) MENTAL HEALTH Frequent anxiety/depression No Yes FUNCTIONING Functional limitationsc 0 1–3 4 or more Social/leisure limitationsd 0 1 or more Need special equipment No Yes ARTHRITIS SYMPTOMS Joint pain past 30 days Little to none (0–3) Moderate (4–6) Severe (7–10) PHYSICAL ACTIVITY FACILITATION Physical activity counseling Yes No Fitness program/facility access Lack access Have access
Men
Women
Prevalence Prevalence Prevalence n of inactivity Adjusted OR of inactivity Adjusted OR of inactivity Adjusted OR a b b (in thousands) % (ⴞSE) (95% CI) % (ⴞSE) (95% CI) % (ⴞSE) (95% CI)b
16,512 25,491
40.0 (1.2) 45.9 (1.0)
* *
— —
8,330 18,206 15,468
30.4 (1.5) 40.0 (1.2) 54.9 (1.2)
1.0 26.9 (2.3) 1.3 (1.1–1.6) 38.6 (1.7) 2.1 (1.7–2.6) 49.8 (1.8)
1.0 33.0 (2.0) 1.6 (1.2–2.2) 40.9 (1.5) 2.3 (1.6–3.2) 57.9 (1.4)
1.0 1.2 (0.9–1.5) 1.9 (1.5–2.5)
33,721 4,394 2,634 1,254
40.9 (0.9) 55.4 (2.0) 57.5 (2.3) 43.8 (4.3)
1.0 1.5 (1.2–1.8) 1.3 (1.1–1.7) 1.1 (0.7–1.7)
1.0 1.4 (1.0–2.0) 1.1 (0.8–1.4) 1.1 (0.6–1.9)
42.8 (1.2) 57.5 (2.3) 59.8 (2.7) 49.5 (6.5)
1.0 1.6 (1.2–2.0) 1.5 (1.1–2.0) 1.2 (0.6–2.2)
19,613 21,989
31.3 (1.0) 54.1 (1.1)
1.0 28.4 (1.3) 1.7 (1.5–2.0) 52.2 (1.7)
1.0 33.5 (1.3) 1.9 (1.5–2.4) 55.2 (1.3)
1.0 1.6 (1.4–1.9)
12,195 14,064 14,015
42.3 (1.3) 41.2 (1.3) 45.9 (1.3)
1.0 43.0 (2.3) 1.1 (0.9–1.2) 37.8 (1.9) 1.1 (0.9–1.3) 40.1 (2.0)
1.0 42.0 (1.6) 1.1 (0.8–1.4) 44.6 (1.7) 1.0 (0.7–1.4) 49.8 (1.6)
1.0 1.0 (0.9–1.3) 1.1 (0.9–1.4)
30,894 11,017
39.7 (1.4) 54.1 (0.9)
1.0 37.2 (1.3) 1.4 (1.2–1.6) 50.0 (2.4)
1.0 41.6 (1.2) 1.2 (0.9–1.5) 56.1 (1.7)
1.0 1.5 (1.2–1.8)
25,006 10,000 6,867
32.5 (1.0) 47.4 (1.5) 77.6 (1.4)
1.0 29.8 (1.4) 1.4 (1.2–1.6) 48.6 (2.6) 3.3 (2.6–4.2) 80.7 (2.5)
1.0 34.6 (1.2) 1.6 (1.2–2.1) 46.8 (1.8) 4.8 (3.1–7.5) 76.3 (1.8)
1.0 1.3 (1.0–1.6) 2.8 (2.1–3.8)
37,584 4,192
39.6 (0.9) 77.5 (1.9)
1.0 36.9 (1.2) 1.5 (1.1–1.9) 75.2 (3.7)
1.0 41.3 (1.0) 1.2 (0.7–2.0) 78.4 (2.1)
1.0 1.5 (1.1–2.1)
34,941 7,046
38.4 (0.9) 69.3 (1.5)
1.0 35.4 (1.3) 1.5 (1.2–1.8) 63.1 (2.8)
1.0 40.4 (1.1) 1.2 (0.9–1.7) 73.2 (1.7)
1.0 1.7 (1.3–2.2)
17,859 13,011 10,368
36.7 (1.2) 40.5 (1.3) 57.5 (1.4)
1.0 32.8 (1.6) 1.1 (0.9–1.3) 38.5 (2.1) 1.3 (1.1–1.6) 57.7 (2.5)
1.0 39.6 (1.5) 1.2 (0.9–1.5) 41.8 (1.7) 1.5 (1.1–2.0) 57.4 (1.6)
1.0 1.0 (0.9–1.3) 1.2 (1.0–1.5)
21,955 19,762
39.9 (1.0) 47.4 (1.1)
* *
38.9 (1.6) 41.0 (1.6)
1.0 40.5 (1.2) 1.2 (1.0–1.4) 52.4 (1.4)
1.0 1.8 (1.5–2.2)
17,189 23,639
58.6 (1.1) 32.1 (1.0)
* *
57.7 (1.8) 27.9 (1.4)
1.0 59.1 (1.3) 0.4 (0.3–0.5) 35.0 (1.3)
1.0 0.6 (0.5–0.7)
38.1 (1.3) 50.9 (3.8) 53.2 (4.0) 37.2 (5.5)
— —
— —
— —
a
Weighted percentage (⫾ standard error) of men and women who are inactive, which is defined as never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes. Adjusted for all other covariates listed in table. c (Max 9): very difficult or unable to: walk a quarter mile, walk up 10 steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. d (Max 3): very difficult or unable to: “Go out to things like shopping, movies, or sporting events?”, “Participate in social activities such as visiting friends, attending clubs and meetings, going to parties?”, or “Do things to relax at home or for leisure.” *Significant interactions between gender and physical activity counseling (p⬍0.001) and gender and access to fitness facility (p⫽0.002); see gender-specific models. Bold indicates p ⬍ 0.05. CI, confidence interval; OR, odds ratio; SE, standard error. b
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Differences by gender were found in the association of inactivity with several risk factors. For example, while the prevalence of inactivity was highest among nonHispanic blacks and Hispanics in both men and women, after adjustment for other covariates, a significant association was found only in women. While the reasons for these differences are not yet understood, this may reflect cultural gender differences in attitudes toward physical activity or in reporting such activity. Additionally, arthritis appears to affect racial/ethnic minorities disproportionately,2 and additional studies are needed to examine the underlying reasons for these disparities. An association was also found in women but not men between lack of healthcare provider counseling and being inactive. The Activity Counseling Trial, a randomized controlled trial of physical activity counseling interventions in the primary care setting, found that some interventions were effective only in women, also suggesting the value of counseling among women.52 Women are more likely than men to visit their healthcare provider for advice, and this finding suggests that gender-specific counseling and interventions may be helpful, and underscores the importance of healthcare providers not missing opportunities to provide counseling. Symptoms of frequent anxiety/depression and limitations in social/leisure activities were also associated with inactivity only in women, in whom a higher prevalence of anxiety and depression53,54 and a stronger role for psychosocial factors have been found.47,55 Improving depression care in older adults with arthritis has been shown to improve pain, function, and quality of life.56 Studies have found a higher prevalence of depression and anxiety in persons with arthritis,57–59 and mental health needs should be assessed in patients with arthritis, recognizing that women may be at higher risk. Finally, inactivity was found to be associated with severe pain only in men with arthritis, although a non-significant trend was observed in women. Persons experiencing pain are less likely to engage in physical activity, and participation may be increased by improving pain management, especially during the initiation of a physical activity regimen. Current evidence suggests that once some initial increase in pain subsides, pain is significantly improved in the long term for those persons with arthritis who engage in and adhere to prescribed physical activity.60 There are several limitations of the present study. First, the use of cross-sectional survey data cannot be used to infer causation. Second, due to the selfreported nature of the data, which is subject to recall bias, there is the possibility of misclassification bias in determining whether a person has arthritis and their level of physical activity. However, studies have shown this arthritis case definition to be valid for public health May 2006
surveillance,61,62 and although respondents may have been misclassified as “active” due to socially desirable reporting, this would tend to bias these results toward underestimating inactivity prevalence. Finally, the NHIS questions on physical activity do not account for occupational, household, or transportation activity, which may amount to a significant portion of a person’s daily activity. Important strengths of this study include the use of a large data source, which enabled us to estimate prevalence in relation to HP2010 physical activity objectives40 and those advocated by an expert panel on arthritis.41 In addition, adjustment for potential confounders was performed in evaluating factors associated with inactivity. In addition, the reliability and validity of similar questions on physical activity have been examined and found appropriate for classifying persons according to recommended physical activity levels.63 Future prevalence estimates can be compared to the results of this study to monitor progress toward public health goals. Efforts to promote physical activity should include expanding access to fitness facilities and existing evidence-based intervention programs such as the Arthritis Self-Help Course, the People with Arthritis Can Exercise program, and the Arthritis Foundation/YMCA Aquatics program,64 and increasing awareness of the benefits of both strength training and aerobic exercise in older adults. Changes to the local environment to promote access and reduce barriers have been shown to be effective in promoting physical activity and are strongly recommended by the Task Force on Community Preventive Services.65 Because people with arthritis often have multiple chronic comorbidities, such as obesity, diabetes, and heart disease, synergistically combining approaches to facilitating physical activity may help to maximize resources and program effectiveness.23 Several studies have also shown home-based exercise programs, which may be more acceptable to older adults and improve adherence, to be safe and effective in improving pain and function in persons with arthritis.8,12,13,49,66,67 Finally, the need for healthcare providers to counsel on physical activity, to manage pain adequately, and to recognize the risk from comorbid mental health disorders should be emphasized. Arthritis significantly affects health-related quality of life68 and is projected to increase markedly in prevalence69 as the population ages, even without taking into account the rising prevalence of obesity, another risk factor. Improving rates of physical activity for all persons is an important public health objective.70 Among those with arthritis, who represent a large and resistant target group, physical activity can have an even greater impact on health by decreasing pain, improving functioning, delaying disability, promoting mental wellbeing, and reducing the risk of comorbid diseases. Future research should focus on evaluating the effecAm J Prev Med 2006;30(5)
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tiveness of targeting groups at higher risk for inactivity, such as women; the elderly; and racial/ethnic minorities, as well as on improving adherence to exercise programs and performing longitudinal and dose–response studies of physical activity in persons with arthritis. This project was supported by a cooperative agreement from the Centers for Disease Control and Prevention through the Association of Teachers of Preventive Medicine. No financial conflict of interest was reported by the authors of this paper.
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18. Rall LC, Meydani SN, Kehayias JJ, Dawson-Hughes B, Roubenoff R. The effect of progressive resistance training in rheumatoid arthritis. Increased strength without changes in energy balance or body composition. Arthritis Rheum 1996;39:415–26. 19. Wyatt FB, Milam S, Manske RC, Deere R. The effects of aquatic and traditional exercise programs on persons with knee osteoarthritis. J Strength Cond Res 2001;15:337– 40. 20. Hopman-Rock M, Westhoff MH. The effects of a health educational and exercise program for older adults with osteoarthritis for the hip or knee. J Rheumatol 2000;27:1947–54. 21. van Baar ME, Assendelft WJ, Dekker J, Oostendorp RA, Bijlsma JW. Effectiveness of exercise therapy in patients with osteoarthritis of the hip or knee: a systematic review of randomized clinical trials. Arthritis Rheum 1999;42:1361–9. 22. Penninx BW, Messier SP, Rejeski WJ, et al. Physical exercise and the prevention of disability in activities of daily living in older persons with osteoarthritis. Arch Intern Med 2001;161:2309 –16. 23. Messier SP, Loeser RF, Miller GD, et al. Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial. Arthritis Rheum 2004;50:1501–10. 24. Neuberger GB, Press AN, Lindsley HB, et al. Effects of exercise on fatigue, aerobic fitness, and disease activity measures in persons with rheumatoid arthritis. Res Nurs Health 1997;20:195–204. 25. Ekdahl C, Andersson SI, Moritz U, Svensson B. Dynamic versus static training in patients with rheumatoid arthritis. Scand J Rheumatol 1990;19:17–26. 26. van den Ende CH, Hazes JM, le Cessie S, et al. Comparison of high and low intensity training in well controlled rheumatoid arthritis. Results of a randomised clinical trial. Ann Rheum Dis 1996;55:798 – 805. 27. van den Ende CH, Breedveld FC, le Cessie S, Dijkmans BA, de Mug AW, Hazes JM. Effect of intensive exercise on patients with active rheumatoid arthritis: a randomised clinical trial. Ann Rheum Dis 2000;59:615–21. 28. Minor MA, Hewett JE, Webel RR, Anderson SK, Kay DR. Efficacy of physical conditioning exercise in patients with rheumatoid arthritis and osteoarthritis. Arthritis Rheum 1989;32:1396 – 405. 29. Kovar PA, Allegrante JP, MacKenzie CR, Peterson MG, Gutin B, Charlson ME. Supervised fitness walking in patients with osteoarthritis of the knee. Ann Intern Med 1992;116:529 –34. 30. Mangione KK, McCully K, Gloviak A, Lefebvre I, Hofmann M, Craik R. The effects of high-intensity and low-intensity cycle ergometry in older adults with knee osteoarthritis. J Gerontol A Biol Sci Med Sci 1999;54:M184 –90. 31. Westby MD. A health professional’s guide to exercise prescription for people with arthritis: a review of aerobic fitness activities. Arthritis Rheum 2001;45:501–11. 32. Busch A, Schachter CL, Peloso PM, Bombardier C. Exercise for treating fibromyalgia syndrome. Cochrane Database Syst Rev 2002;3:CD003786. 33. Tench CM, McCarthy J, McCurdie I, White PD, D’Cruz DP. Fatigue in systemic lupus erythematosus: a randomized controlled trial of exercise. Rheumatology (Oxford) 2003;42:1050 – 4. 34. Hootman JM, Macera CA, Helmick CG, Blair SN. Influence of physical activity-related joint stress on the risk of self-reported hip/knee osteoarthritis: a new method to quantify physical activity. Prev Med 2003;36:636 – 44. 35. de Jong Z, Vlieland TP. Safety of exercise in patients with rheumatoid arthritis. Curr Opin Rheumatol 2005;17:177– 82. 36. Bruce DG, Devine A, Prince RL. Recreational physical activity levels in healthy older women: the importance of fear of falling. J Am Geriatr Soc 2002;50:84 –9. 37. Finch C, Owen, N, Price R. Current injury or disability as a barrier to being more physically active. Med Sci Sports Exerc 2001;33:778 – 82. 38. Recommendations for the Management of Osteoarthritis of the Hip and Knee: 2002 update. American College of Rheumatology Subcommittee on Osteoarthritis Guidelines. Arthritis Rheum 2000;43:1905–15. 39. Guidelines for the Management of Rheumatoid Arthritis: 2002 update. American College of Rheumatology Subcommittee on Rheumatoid Arthritis Guidelines. Arthritis Rheum 2002;46:328 – 46. 40. U.S. Department of Health and Human Services.Healthy People 2010. 2nd ed. Understanding and improving health and objectives for improving health.Washington DC: United States Government Printing Office; 2000. 41. Work group recommendations: 2002 Exercise and Physical Activity Conference, St. Louis, Missouri. Session V: evidence of benefit of exercise and physical activity in arthritis. Arthritis Rheum 2003;49:453– 4. 42. Design and estimation for the National Health Interview Survey, 1995– 2004. Vital Health Stat 2 2000;(130):1–31.
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43. National Center for Health Statistics. Data file documentation. ftp: ftp.cdc.gov/Health_Statistics/NCHS/Dataset_Documentation/NHIS/2002/ srvydesc.pdf. National Health Interview Survey, 2002 (machine-readable data file and documentation). Hyattsville MD: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2002. 44. Hootman JM, Macera CA, Ham SA, Helmick CG, Sniezek JE. Physical activity levels among the general U.S. adult population and in adults with and without arthritis. Arthritis Care Res 2003;49:129 –35. 45. Fontaine KR, Heo M, Bathon J. Are U.S. adults with arthritis meeting public health recommendations for physical activity? Arthritis Rheum 2004;50:624 – 8. 46. Fontaine KR, Heo M. Changes in the prevalence of U.S. adults with arthritis who meet physical activity recommendations, 2001–2003. J Clin Rheum 2005;11:13– 6. 47. Kaplan MS, Huguet N, Newsom JT, McFarland BH. Characteristics of physically inactive older adults with arthritis: results of a population-based study. Prev Med 2003;37:61–7. 48. Penninx BW, Rejeski WJ, Pandya J, et al. Exercise and depressive symptoms: a comparison of aerobic and resistance exercise effects on emotional and physical function in older persons with high and low depressive symptomatology. J Gerontol B Psychol Sci Soc Sci 2002;57:124 –32. 49. Roddy E, Zhang W, Doherty M, et al. Evidence-based recommendations for the role of exercise in the management of osteoarthritis of the hip or knee—the MOVE consensus. Rheumatology 2005;44:67–73. 50. Seguin R, Nelson ME. The benefits of strength training for older adults. Am J Prev Med 2003;25:141–9. 51. Kruger J, Brown D, Galuska D, Buchner D. Strength training among adults aged ⬎65 years—United States, 2001. MMWR Morb Mortal Wkly Rep 2004;53:25– 8. 52. Writing Group for the Activity Counseling Trial Research Group. Effects of physical activity counseling in primary care: the Activity Counseling Trial: a randomized controlled trial. JAMA 2001;286:677– 87. 53. Linzer M, Spitzer R, Kroenke K, et al. Gender, quality of life, and mental disorders in primary care: results from the PRIME-MD 1000 study. Am J Med 1996;101:526 –33. 54. Rapaport MH, Thompson PM, Kelsoe JR Jr, Golshan S, Judd LL, Gillin JC. Gender differences in outpatient research subjects with affective disorders: a comparison of descriptive variables. J Clin Psychiatry 1995;56:67–72. 55. Verbrugge LM. Gender and health: an update on hypotheses and evidence. J Health Soc Behav 1985;26:156 – 82. 56. Lin EH, Katon W, Von Korff M, et al. Effect of improving depression care on pain and functional outcomes among older adults with arthritis: a randomized controlled trial. JAMA 2003;290:2428 –9.
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57. Dickens C, McGowan L, Clark-Carter D, Creed F. Depression in rheumatoid arthritis: a systematic review of the literature with meta-analysis. Psychosom Med 2002;64:52– 60. 58. el-Miedany YM, el-Rasheed AH. Is anxiety a more common disorder than depression in rheumatoid arthritis? Joint Bone Spine 2002;69:300 – 6. 59. Wells KB, Stewart A, Hays RD, et al. The functioning and well-being of depressed patients. Results from the Medical Outcomes Study. JAMA 1989;262:914 –9. 60. van Gool CH, Penninx BW, Kempen GI, et al. Effects of exercise adherence on physical function among overweight older adults with knee osteoarthritis. Arthritis Rheum 2005;53:24 –32. 61. Sacks JJ, Harrold LR, Helmick CG, Gurwitz JH, Emani S, Yood RA. Validation of a surveillance case definition for arthritis. J Rheumatol 2005;32:340 –7. 62. Bombard JM, Powell KE, Martin ML, Helmick CG, Wilson WH. Validity and reliability of self-reported arthritis, Georgia senior citizens, 2000 –2001. Am J Prev Med 2005;28:251– 8. 63. Strath SJ, Bassett DR Jr, Ham SA, Swartz AM. Assessment of physical activity by telephone interview versus objective monitoring. Med Sci Sports Exerc 2003;35:2112– 8. 64. Brady TJ, Kruger J, Helmick CG, Callahan LF, Boutaugh ML. Intervention programs for arthritis and other rheumatic diseases. Health Educ Behav 2003;30:44 – 63. 65. Task Force on Community Preventive Services. Recommendations to increase physical activity in communities. Am J Prev Med 2002;22:67–72. 66. King AC, Haskell WL, Taylor CB, Kraemer HC, DeBusk RF. Group- vs home-based exercise training in healthy older men and women. A community-based clinical trial. JAMA 1991;266:1535– 42. 67. Fransen M, McConnell S, Bell M. Exercise for osteoarthritis of the hip or knee. Cochrane Database Syst Rev 2003;3:CD004286. 68. Mili F, Helmick CG, Moriarty DG. Health-related quality of life among adults reporting arthritis: analysis of data from the Behavioral Risk Factor Surveillance System, U.S., 1996 –1999. J Rheumatol 2003;30:160 – 6. 69. Hootman J, Helmick C, Langmaid G. Public health and aging: projected prevalence of self-reported arthritis or chronic joint symptoms among persons aged ⱖ65 years—United States, 2005–2030. MMWR Morb Mortal Wkly Rep 2003;52:489 –91. 70. U.S. Department of Health and Human Services.Physical activity and health: a report of the Surgeon General.Atlanta GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, 1996.
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Data from the 2002 National Health Interview Survey were analyzed in 2004 –2005 to estimate the proportion of adults with arthritis meeting four physical activity recommendations put forward in Healthy People 2010 and one arthritis-specific recommendation established by a national expert panel in arthritis and physical activity. Multivariate logistic regression was used to evaluate the association between inactivity and sociodemographic factors, body mass index, functional limitations, social limitations, need for special equipment, frequent anxiety/depression, affected joint location, joint pain, physical activity counseling, and access to a fitness facility.
Results:
Adults with arthritis were significantly less likely than adults without arthritis to engage in recommended levels of moderate or vigorous physical activity, and 37% of adults with arthritis were inactive. In both men and women with arthritis, inactivity was associated with older age, lower education, and having functional limitations; having access to a fitness facility was inversely associated with inactivity. Among women, inactivity was also associated with being Hispanic, non-Hispanic black, having frequent anxiety/depression or social limitations, needing special equipment, and not receiving physical activity counseling. Among men, inactivity was also associated with severe joint pain.
Conclusions: Although physical activity is a recommended therapy for people with arthritis, levels among adults with arthritis are insufficient, and those with arthritis have worse activity profiles than their peers without arthritis. Efforts to promote physical activity should include expanding access to evidence-based interventions and recreational facilities/programs. The importance of physical activity counseling and associated pain management measures by healthcare providers should be emphasized. (Am J Prev Med 2006;30(5):385–393) © 2006 American Journal of Preventive Medicine
Introduction
A
rthritis, the leading cause of disability in the United States,1 affected 43 million U.S. adults in 2002.2 This imposes an enormous economic burden, with total costs attributable to arthritis in 1997 estimated at $86 billion.3 Among those with arthritis, physical inactivity can contribute to deconditioning, impaired function, poor mental health, and an increased risk of obesity. A recent 2-year longitudinal From the Office of Health Assessment and Epidemiology, Los Angeles County Department of Health Services (Shih), Los Angeles, California; and Centers for Disease Control and Prevention (Hootman, Kruger, Helmick), Atlanta, Georgia Address correspondence to: Margaret Shih, MD, PhD, Office of Health Assessment and Epidemiology, Los Angeles County Department of Health Services, 313 N. Figueroa Street, Room 127, Los Angeles, CA 90012 E-mail: [email protected]. Address reprint requests to: Jennifer M. Hootman, PhD, Division of Adult and Community Health, CDC, 4770 Buford Highway NE, MS-K51, Atlanta, GA 30341.
study found that older adults with arthritis who did not engage in regular vigorous activity were twice as likely to experience functional decline as those who did.4 In addition, inactive adults have higher medical costs than those who are regularly active.5 Both strength training6 –22 and aerobic exercise16,22–31 have been shown to benefit people with osteoarthritis and rheumatoid arthritis, significantly decreasing pain while delaying disability and improving gait and function; other physical and psychological benefits have been reported in patients with fibromyalgia32 and systemic lupus erythematosus.33 Although studies have generally found that low-to-moderate– intensity physical activity does not worsen arthritis symptoms or disease activity,6,23,24,26,34,35 increasing physical activity in this population has been challenging, in part because of continued misconceptions about the potential harm to joints and concerns about increased pain.36,37
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Physical activity is one of the major non-pharmacologic interventions for managing arthritis,38,39 and physical activity is a focus area in Healthy People 2010 (HP2010).40 The purpose of this study is to conduct a secondary data analysis of a national data set to: (1) determine the national prevalence of various levels of leisure-time physical activity in adults with and without arthritis that are consistent with recommendations in HP2010 and recommendations of a 2002 national panel of experts in arthritis and physical activity,41 and (2) identify sociodemographic and other factors associated with physical inactivity in adults with arthritis to better identify those who might be at greater need for intervention.
Methods Data Sources Data from the 2002 National Health Interview Survey (NHIS) were analyzed in 2004 –2005. The NHIS is an ongoing, national household interview survey designed to represent the U.S. civilian, non-institutionalized population and uses a multistage, complex sampling design.42 The response rate for the sample adult component (18 years and older) in 2002 was 74.3% (n⫽31,044).43
Definition of Arthritis Doctor-diagnosed arthritis (n⫽6829), hereafter called arthritis, was defined by a “yes” response to “Have you ever been told by a doctor or other health professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?” Respondents who answered “no” and who did not have chronic joint symptoms (i.e., joint symptoms lasting 3 months or more) composed the no-arthritis group (n⫽20,676). The 3397 respondents with possible arthritis (i.e., chronic joint symptoms but no doctor-diagnosed arthritis) were excluded from the analysis because their arthritis status was not clear. Information regarding arthritis status was missing for 142 respondents.
Recommendations for Physical Activity In HP2010, which lists national health objectives for the year 2010,40 people with arthritis are an identified target for four objectives in Chapter 22, “Physical Activity and Fitness”: 22-1: Reduce the proportion of adults who engage in no leisure-time physical activity. 22-2: Increase the proportion of adults who engage regularly, preferably daily, in moderate physical activity for at least 30 minutes per day. 22-3: Increase the proportion of adults who engage in vigorous physical activity that promotes the development and maintenance of cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion. 22-4: Increase the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance. In addition to these four HP2010 physical activity objectives, a fifth, arthritis-specific recommendation was included:
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that people with arthritis accumulate 30 minutes of moderate-intensity physical activity at least 3 days a week. Because exercise studies in this population have had little variation in prescribed dosage of exercise, safety has not been established at higher doses. This consensus recommendation was developed by an expert panel in arthritis, physical activity, and public health, which was sponsored in 2002 by the Missouri Arthritis Rehabilitation and Research Center, the American College of Rheumatology, and the Association of Rheumatology Health Professionals, to review the evidence for the benefits of exercise and physical activity among those with arthritis.41
Measurement of Physical Activity The percentages of adults engaging in physical activity consistent with these recommendations were estimated by asking respondents to report on the frequency and duration of both moderate and vigorous physical activities: “How often do you do vigorous activities for at least 10 minutes that cause heavy sweating or large increases in breathing or heart rate?” and “How often do you do light or moderate activities for at least 10 minutes that cause only light sweating or a slight to moderate increase in breathing or heart rate?” For each question, respondents who reported engaging in such physical activity were asked to report the frequency (i.e., number of times per day/week/month/year) and duration (i.e., number of minutes or hours per time period) that they engaged in the activity. Those reporting that they never participated in, or were unable to participate in, light, moderate, or vigorous physical activity for at least 10 minutes per occasion were defined as “inactive.” Persons participating in moderateintensity activity at least 30 minutes per day, 5 or more days per week, or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week, were considered to be meeting HP2010 recommendations for “moderate” or “vigorous” physical activity; persons participating in “physical activities specifically designed to strengthen your muscles such as lifting weights or doing calisthenics” at least twice per week were considered to be meeting the HP2010 recommendation for “strengthening” exercise; and persons participating in moderate-intensity activity at least 30 minutes per day, 3 or more days per week were considered to be meeting the recommendations of the “expert panel in arthritis.”41
Covariates Independent variables that have previously demonstrated an association with physical activity were included in the analysis. These variables included gender; age (18 – 44, 45– 64, 65⫹ years); race/ethnicity (non-Hispanic white, non-Hispanic black, Hispanic, non-Hispanic other/multiple race; education (high school or less, beyond high school); body mass index ([BMI⫽weight (kg)/height (m2)]; ⬍25, underweight/ normal weight; 25 to ⬍30, overweight; 30⫹, obese); and frequent anxiety/depression (determined by the question “During the past 12 months, have you been frequently depressed or anxious?”). To assess and adjust for the effect of comorbidities and health status, 16 self-reported medical conditions, 9 functional and 3 social/leisure limitations, and the respondent’s need for special equipment were included in the analysis. The
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16 medical conditions were: hypertension; high cholesterol; back pain; neck pain; cardiovascular condition (angina, congestive heart failure, myocardial infarction, coronary heart disease, other heart condition); stroke; respiratory condition (asthma, emphysema, chronic bronchitis); thyroid problem; neurologic condition (multiple sclerosis, Parkinson disease, neuropathy, seizures); cancer; diabetes; kidney disease; liver condition; vision problem (difficulty seeing, blindness, retinopathy, cataracts, glaucoma, macular degeneration); hearing impairment; and gastrointestinal condition (ulcer, inflammatory bowel, irritable bowel, severe constipation). Respondents were categorized as having none, one to three, or four or more functional limitations by the number of times they responded “very difficult” or “unable to” for a list of nine activities: walk a quarter mile, walk up ten steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. Respondents had at least one social/leisure limitation if they reported it was “very difficult” or they were “unable to” do any of three social/leisure activities: go out to things like shopping, movies, or sporting events; participate in social activities such as visiting friends, attending clubs and meetings, going to parties; or do things to relax at home or for leisure. Their need for special equipment was determined by the question “Do you now have any health problem that requires you to use special equipment, such as a cane, a wheelchair, a special bed, or a special telephone?” The analysis was extended to include arthritis symptoms and the facilitation of physical activity. Respondents reporting joint symptoms in the past 30 days were asked to rate the severity of their joint pain on a scale from 0 to 10 (0 –3, little to none; 4 – 6, moderate; 7⫹, severe) and which joints (upper extremity, lower extremity, both) were affected. Those reporting no joint symptoms were categorized as having no joint pain. Receipt of physical activity counseling was determined by responding “yes” to “Has a doctor or other health professional ever suggested physical activity or exercise to help your arthritis or joint symptoms?” Having access to a fitness program or facility was assessed by asking “Do you now have access to a health club, wellness program, or fitness facility that meets your needs, if you wanted to use one?”
Statistical Analyses The proportions of adults with and without arthritis meeting physical activity recommendations were age adjusted to the 2000 U.S. population to allow comparisons to HP2010 recommendations. Overall and gender-specific proportions and odds ratios for physical inactivity in adults with arthritis were calculated. A series of multivariate logistic regression models were run to evaluate the association between inactivity and the covariates listed above. In the initial model, which included all covariates, the location of the affected joint(s) was not significant and was excluded from subsequent models. Sociodemographic variables were retained in all models. Information regarding physical inactivity was missing for 142 of the 6829 respondents with arthritis, and these respondents were not included in the prevalence calculations or logistic regression modeling. The second phase of modeling examined the relationship between physical inactivity and the 16 medical conditions described previously. Conditions were modeled in several
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ways: (1) individually, (2) as a subset of conditions identified as associated with inactivity through logistic regression, and (3) by number of conditions. Regardless of how modeled, comorbidity was not significant in multivariable modeling and thus was not included in further modeling. In the third phase of modeling, testing was done for the interactions of all remaining covariates with gender and BMI. Interactions were found between gender and two variables (physical activity counseling, access to fitness facilities), but no interactions were found with BMI. Because of these interactions and known differences between men and women in patterns of physical activity, gender-stratified models were chosen for presentation. All prevalence estimates, confidence intervals, and odds ratios were calculated using SUDAAN (version 9.0.0; Research Triangle Institute, Research Triangle Park NC, 2004) to account for the complex sampling design and used sample adult weights. A significance level of ␣⫽0.05 was used.
Results Compared to adults without arthritis, adults with arthritis were more likely to be older, female, non-Hispanic white, less educated, obese, have frequent anxiety/ depression, have one or more functional or social limitations, need special equipment, have one or more comorbid conditions, and not be meeting HP2010 physical activity recommendations or the recommendation of an expert panel on arthritis41 (Table 1). After age adjustment, the percentages of adults with and without arthritis who were meeting physical activity recommendations were more similar (Table 2), with no difference found in prevalence of inactivity (37% arthritis, 38% no arthritis); in participation in strengthening exercise (20% both); or in meeting the recommendation of the expert panel on arthritis41 (37% arthritis, 39% no arthritis). However, adults with arthritis were significantly less likely to engage in HP2010recommended levels40 of moderate/vigorous (30% vs 33%, p⫽0.05) or vigorous activity (21% vs 24%, p⫽0.006). The highest prevalence of inactivity was among adults with arthritis who had four or more functional limitations, one or more social/leisure limitations, a need for special equipment, and who lacked access to a fitness facility (Table 3). Among those who reported a lack of access to a fitness facility, the most common reason given was “cost” (26%), followed by “lack of transportation” (5%); well over half (62%) indicated “no reason” preventing access. In adjusted models stratified by gender, variables associated with inactivity in both men and women with arthritis were older age (ⱖ45 years in men, ⱖ65 years in women); having less education; having functional limitations; and a lack of access to a fitness program/ facility. Among women but not men, inactivity was also associated with being Hispanic or non-Hispanic black, and having frequent anxiety/depression, one or more Am J Prev Med 2006;30(5)
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Table 1. Distribution of selected characteristics of study population, overall and by arthritis status (2002 NHIS) Overalla (N ⴝ 205,825b) Characteristic Age (years) 18–44 45–64 65 or older Gender Male Female Race/ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other/multiple race Educatione Some college or more High school or less Body mass indexe Under/normal weight (⬍25) Overweight (25–29.9) Obese (ⱖ30) Frequent anxiety/depressione No Yes Functional limitationse,f 0 1–3 4 or more Social/leisure limitationse,g 0 1 or more Need special equipmente No Yes Comorbiditiese,h 0 1–2 3 or more Physical activity recommendationsi Inactive Moderate/vigorous Vigorous Strengthening Arthritis expert panel
Doctor-diagnosed arthritisc (N ⴝ 42,704)
No arthritisd (N ⴝ 138,927)
Weighted %
95% CI
Weighted %
95% CI
Weighted %
95% CI
52.5 31.4 16.1
51.7–53.4 30.8–32.1 15.5–16.6
19.8 43.4 36.8
18.7–21.0 41.9–44.8 35.4–38.3
63.1 27.1 9.9
62.1–64.0 26.3–27.9 9.4–10.4
48.0 52.0
47.3–48.7 51.3–52.8
39.4 60.6
38.0–40.9 59.1–62.0
49.9 50.1
49.0–50.8 49.2–51.0
72.7 11.2 11.0 5.1
71.8–73.5 10.6–11.9 10.5–11.6 4.7–5.5
80.4 10.5 6.2 3.0
79.1–81.6 9.6–11.4 5.6–6.8 2.5–3.6
69.6 11.6 12.9 5.8
68.7–70.6 10.9–12.4 12.3–13.6 5.4–6.3
52.8 45.9
52.0–53.7 45.1–46.8
46.7 52.4
45.3–48.1 50.9–53.8
54.8 43.9
53.8–55.8 42.9–44.9
39.5 33.4 22.4
38.7–40.2 32.7–34.0 21.8–23.0
28.9 33.3 33.2
27.7–30.2 32.0–34.6 31.9–34.5
43.5 33.1 18.4
42.6–44.4 32.4–33.9 17.7–19.0
83.9 15.7
83.4–84.5 15.2–16.3
73.5 26.2
72.2–74.8 24.9–27.5
89.0 10.7
88.5–89.5 10.2–11.2
86.0 8.8 5.0
85.4–86.5 8.4–9.2 4.7–5.3
59.6 23.8 16.2
58.0–61.1 22.6–25.0 15.2–17.4
95.0 3.4 1.4
94.6–95.4 3.1–3.7 1.2–1.6
96.2 3.4
96.0–96.5 3.1–3.6
89.4 9.9
88.5–90.2 9.1–10.8
98.5 1.2
98.3–98.7 1.1–1.4
94.4 5.5
94.1–94.7 5.2–5.8
83.3 16.6
82.2–84.3 15.7–17.7
98.1 1.8
97.9–98.3 1.6–2.1
34.4 39.2 26.4
33.7–35.1 38.5–39.8 25.8–27.0
8.3 31.1 60.4
7.6–9.1 30.2–32.5 59.1–61.7
45.1 40.7 14.2
44.2–46.0 39.8–41.5 13.7–14.8
37.5 31.9 23.5 20.5 38.2
36.5–38.5 31.1–32.7 22.8–24.2 19.8–21.1 37.4–39.0
43.6 25.8 16.3 16.3 32.3
42.0–45.2 24.5–27.1 15.2–17.4 15.2–17.4 30.9–33.8
36.4 33.4 25.4 21.5 39.5
35.3–37.6 32.4–34.4 24.5–26.3 20.8–22.4 38.5–40.5
a
Includes respondents with possible arthritis (i.e., joint symptoms lasting 3 months or more). Weighted number in thousands. Respondents answering “yes” to the question “Have you ever been told by a doctor or other heath professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?” d Respondents who reported not having doctor-diagnosed arthritis or possible arthritis. e Percentages do not sum to 100% due to nonresponse, which was approximately 5% for body mass index, 1% for education, and ⬍1% for other variables. f (Max 9): very difficult or unable to walk a quarter mile, walk up 10 steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. g (Max 3): very difficult or unable to “Go out to things like shopping, movies, or sporting events?”, “Participate in social activities such as visiting friends, attending clubs and meetings, going to parties?”, or “Do things to relax at home or for leisure.” h (Max 16): hypertension, high cholesterol, back pain, neck pain, cardiovascular condition, stroke, respiratory condition, thyroid problem, neurologic condition, cancer, diabetes, weak or failing kidneys, liver condition, vision condition, hearing impairment, gastrointestinal condition. i Inactive: never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes; Moderate/vigorous: participating in either moderate-intensity activity at least 30 minutes per day, 5 or more days per week; or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week; Vigorous: participating in vigorous-intensity activity at least 20 minutes per day, 3 or more days per week; Strengthening: participating in strengthening exercise at least twice per week; Arthritis expert panel: participating moderate-intensity activity for at least 30 minutes, a minimum of 3 days per week. CI, confidence interval; NHIS, National Health Interview Survey. b c
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Table 2. Age-adjusted percentages of adults meeting national physical activity objectives, by arthritis status (2002 NHIS)a NHIS 2002 Physical activity recommendation Healthy People 2010 40 22-1: Reduce the proportion of adults who engage in no leisure-time physical activityb 22-2: Increase proportion of adults who engage regularly, preferably daily, in moderate physical activity for at least 30 minutes per dayc 22-3: Increase the proportion of adults who engage in vigorous physical activity that promotes the development and maintenance of cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion 22-4: Increase the proportion of adults who perform physical activities that enhance and maintain muscular strength and endurance Arthritis expert panel recommendation41 Perform moderate physical activity for at least 30 minutes per day, 3 days per week
1997 Baseline (%)
Healthy People 2010 target40 (%)
Doctor-diagnosed arthritis (%)
No arthritis (%)
Overall (%)
37
38
38
40
20
30*
33
32
32
50
21**
24
23
23
30
20
20
21
18
30
37
39
38
NA
NA
a
All estimates are age-adjusted to the standard 2000 U.S. resident population. Measure used is the proportion of adults who are inactive, which is defined as never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes. c Includes those participating in either moderate-intensity activity at least 30 minutes per day, 5 or more days per week, or vigorous-intensity activity at least 20 minutes per day, 3 or more days per week. *p ⫽ 0.05, no arthritis vs doctor-diagnosed arthritis. **p ⫽ 0.006, no arthritis vs doctor-diagnosed arthritis. NA, not applicable; NHIS, National Health Interview Survey. b
social/leisure limitations, a need for special equipment, and never receiving arthritis-related physical activity counseling. Among men but not women, inactivity was also associated with severe joint pain (Table 3).
Discussion These findings are the first report of physical activity levels among adults with and without arthritis using a national data source and a validated arthritis case definition. Despite substantial evidence showing that physical activity benefits people with arthritis, adults with arthritis are significantly less likely than adults without arthritis to be meeting HP2010 recommendations for moderate or vigorous physical activity, and overall physical activity levels in adults with arthritis remain low. These findings are consistent with four earlier studies showing low levels of physical activity among adults with arthritis. One study, which found physical activity profiles to be worse in persons with arthritis,44 reported an inactivity prevalence of 31%, but is not directly comparable because it measured lifestyle physical activity (which includes leisure time, occupational, transportaMay 2006
tion, and household activity) and used state-based data, as well as a different definition of arthritis. Another study using state-based data, which included adults with doctor-diagnosed arthritis but assessed physical activity differently, reported an inactivity prevalence of 24%, with a demographic profile similar to the findings in the present study.45 An update of that study found prevalence estimates relatively unchanged between 2001 and 2003.46 A study using data from the Canadian National Population Health Survey reported a prevalence of inactivity of 39% in community-dwelling adults aged 65 and older with arthritis.47 Participation in strengthening exercises among adults with arthritis was below the HP2010 target of 30% and was similar to the participation rate of adults without arthritis. In persons with arthritis, strengthening exercises have been shown to be similar in effectiveness to aerobic exercise in reducing pain and preserving function.22,48,49 Additional benefits of strength training in older adults include increasing muscle strength and bone density and decreasing risk for falls,50 yet older adults are especially unlikely to participate in this mode of exercise.51 Am J Prev Med 2006;30(5)
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Table 3. Unadjusted prevalence and adjusted odds of physical inactivity in adults with doctor-diagnosed arthritis, by selected characteristics Overall
Characteristic DEMOGRAPHICS Gender Male Female Age (years) 18–44 45–64 65 or older Race/Ethnicity White, non-Hispanic Black, non-Hispanic Hispanic Other/multiple race Education Some college or more High school or less Body mass index Under/normal weight (⬍25) Overweight (25–29.9) Obese (ⱖ30) MENTAL HEALTH Frequent anxiety/depression No Yes FUNCTIONING Functional limitationsc 0 1–3 4 or more Social/leisure limitationsd 0 1 or more Need special equipment No Yes ARTHRITIS SYMPTOMS Joint pain past 30 days Little to none (0–3) Moderate (4–6) Severe (7–10) PHYSICAL ACTIVITY FACILITATION Physical activity counseling Yes No Fitness program/facility access Lack access Have access
Men
Women
Prevalence Prevalence Prevalence n of inactivity Adjusted OR of inactivity Adjusted OR of inactivity Adjusted OR a b b (in thousands) % (ⴞSE) (95% CI) % (ⴞSE) (95% CI) % (ⴞSE) (95% CI)b
16,512 25,491
40.0 (1.2) 45.9 (1.0)
* *
— —
8,330 18,206 15,468
30.4 (1.5) 40.0 (1.2) 54.9 (1.2)
1.0 26.9 (2.3) 1.3 (1.1–1.6) 38.6 (1.7) 2.1 (1.7–2.6) 49.8 (1.8)
1.0 33.0 (2.0) 1.6 (1.2–2.2) 40.9 (1.5) 2.3 (1.6–3.2) 57.9 (1.4)
1.0 1.2 (0.9–1.5) 1.9 (1.5–2.5)
33,721 4,394 2,634 1,254
40.9 (0.9) 55.4 (2.0) 57.5 (2.3) 43.8 (4.3)
1.0 1.5 (1.2–1.8) 1.3 (1.1–1.7) 1.1 (0.7–1.7)
1.0 1.4 (1.0–2.0) 1.1 (0.8–1.4) 1.1 (0.6–1.9)
42.8 (1.2) 57.5 (2.3) 59.8 (2.7) 49.5 (6.5)
1.0 1.6 (1.2–2.0) 1.5 (1.1–2.0) 1.2 (0.6–2.2)
19,613 21,989
31.3 (1.0) 54.1 (1.1)
1.0 28.4 (1.3) 1.7 (1.5–2.0) 52.2 (1.7)
1.0 33.5 (1.3) 1.9 (1.5–2.4) 55.2 (1.3)
1.0 1.6 (1.4–1.9)
12,195 14,064 14,015
42.3 (1.3) 41.2 (1.3) 45.9 (1.3)
1.0 43.0 (2.3) 1.1 (0.9–1.2) 37.8 (1.9) 1.1 (0.9–1.3) 40.1 (2.0)
1.0 42.0 (1.6) 1.1 (0.8–1.4) 44.6 (1.7) 1.0 (0.7–1.4) 49.8 (1.6)
1.0 1.0 (0.9–1.3) 1.1 (0.9–1.4)
30,894 11,017
39.7 (1.4) 54.1 (0.9)
1.0 37.2 (1.3) 1.4 (1.2–1.6) 50.0 (2.4)
1.0 41.6 (1.2) 1.2 (0.9–1.5) 56.1 (1.7)
1.0 1.5 (1.2–1.8)
25,006 10,000 6,867
32.5 (1.0) 47.4 (1.5) 77.6 (1.4)
1.0 29.8 (1.4) 1.4 (1.2–1.6) 48.6 (2.6) 3.3 (2.6–4.2) 80.7 (2.5)
1.0 34.6 (1.2) 1.6 (1.2–2.1) 46.8 (1.8) 4.8 (3.1–7.5) 76.3 (1.8)
1.0 1.3 (1.0–1.6) 2.8 (2.1–3.8)
37,584 4,192
39.6 (0.9) 77.5 (1.9)
1.0 36.9 (1.2) 1.5 (1.1–1.9) 75.2 (3.7)
1.0 41.3 (1.0) 1.2 (0.7–2.0) 78.4 (2.1)
1.0 1.5 (1.1–2.1)
34,941 7,046
38.4 (0.9) 69.3 (1.5)
1.0 35.4 (1.3) 1.5 (1.2–1.8) 63.1 (2.8)
1.0 40.4 (1.1) 1.2 (0.9–1.7) 73.2 (1.7)
1.0 1.7 (1.3–2.2)
17,859 13,011 10,368
36.7 (1.2) 40.5 (1.3) 57.5 (1.4)
1.0 32.8 (1.6) 1.1 (0.9–1.3) 38.5 (2.1) 1.3 (1.1–1.6) 57.7 (2.5)
1.0 39.6 (1.5) 1.2 (0.9–1.5) 41.8 (1.7) 1.5 (1.1–2.0) 57.4 (1.6)
1.0 1.0 (0.9–1.3) 1.2 (1.0–1.5)
21,955 19,762
39.9 (1.0) 47.4 (1.1)
* *
38.9 (1.6) 41.0 (1.6)
1.0 40.5 (1.2) 1.2 (1.0–1.4) 52.4 (1.4)
1.0 1.8 (1.5–2.2)
17,189 23,639
58.6 (1.1) 32.1 (1.0)
* *
57.7 (1.8) 27.9 (1.4)
1.0 59.1 (1.3) 0.4 (0.3–0.5) 35.0 (1.3)
1.0 0.6 (0.5–0.7)
38.1 (1.3) 50.9 (3.8) 53.2 (4.0) 37.2 (5.5)
— —
— —
— —
a
Weighted percentage (⫾ standard error) of men and women who are inactive, which is defined as never participating in, or being unable to participate in any leisure time physical activity for a minimum of 10 minutes. Adjusted for all other covariates listed in table. c (Max 9): very difficult or unable to: walk a quarter mile, walk up 10 steps, stand for 2 hours, sit for 2 hours, stoop/bend/kneel, reach overhead, grasp small objects, lift/carry up to 10 pounds, and push/pull large objects. d (Max 3): very difficult or unable to: “Go out to things like shopping, movies, or sporting events?”, “Participate in social activities such as visiting friends, attending clubs and meetings, going to parties?”, or “Do things to relax at home or for leisure.” *Significant interactions between gender and physical activity counseling (p⬍0.001) and gender and access to fitness facility (p⫽0.002); see gender-specific models. Bold indicates p ⬍ 0.05. CI, confidence interval; OR, odds ratio; SE, standard error. b
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Differences by gender were found in the association of inactivity with several risk factors. For example, while the prevalence of inactivity was highest among nonHispanic blacks and Hispanics in both men and women, after adjustment for other covariates, a significant association was found only in women. While the reasons for these differences are not yet understood, this may reflect cultural gender differences in attitudes toward physical activity or in reporting such activity. Additionally, arthritis appears to affect racial/ethnic minorities disproportionately,2 and additional studies are needed to examine the underlying reasons for these disparities. An association was also found in women but not men between lack of healthcare provider counseling and being inactive. The Activity Counseling Trial, a randomized controlled trial of physical activity counseling interventions in the primary care setting, found that some interventions were effective only in women, also suggesting the value of counseling among women.52 Women are more likely than men to visit their healthcare provider for advice, and this finding suggests that gender-specific counseling and interventions may be helpful, and underscores the importance of healthcare providers not missing opportunities to provide counseling. Symptoms of frequent anxiety/depression and limitations in social/leisure activities were also associated with inactivity only in women, in whom a higher prevalence of anxiety and depression53,54 and a stronger role for psychosocial factors have been found.47,55 Improving depression care in older adults with arthritis has been shown to improve pain, function, and quality of life.56 Studies have found a higher prevalence of depression and anxiety in persons with arthritis,57–59 and mental health needs should be assessed in patients with arthritis, recognizing that women may be at higher risk. Finally, inactivity was found to be associated with severe pain only in men with arthritis, although a non-significant trend was observed in women. Persons experiencing pain are less likely to engage in physical activity, and participation may be increased by improving pain management, especially during the initiation of a physical activity regimen. Current evidence suggests that once some initial increase in pain subsides, pain is significantly improved in the long term for those persons with arthritis who engage in and adhere to prescribed physical activity.60 There are several limitations of the present study. First, the use of cross-sectional survey data cannot be used to infer causation. Second, due to the selfreported nature of the data, which is subject to recall bias, there is the possibility of misclassification bias in determining whether a person has arthritis and their level of physical activity. However, studies have shown this arthritis case definition to be valid for public health May 2006
surveillance,61,62 and although respondents may have been misclassified as “active” due to socially desirable reporting, this would tend to bias these results toward underestimating inactivity prevalence. Finally, the NHIS questions on physical activity do not account for occupational, household, or transportation activity, which may amount to a significant portion of a person’s daily activity. Important strengths of this study include the use of a large data source, which enabled us to estimate prevalence in relation to HP2010 physical activity objectives40 and those advocated by an expert panel on arthritis.41 In addition, adjustment for potential confounders was performed in evaluating factors associated with inactivity. In addition, the reliability and validity of similar questions on physical activity have been examined and found appropriate for classifying persons according to recommended physical activity levels.63 Future prevalence estimates can be compared to the results of this study to monitor progress toward public health goals. Efforts to promote physical activity should include expanding access to fitness facilities and existing evidence-based intervention programs such as the Arthritis Self-Help Course, the People with Arthritis Can Exercise program, and the Arthritis Foundation/YMCA Aquatics program,64 and increasing awareness of the benefits of both strength training and aerobic exercise in older adults. Changes to the local environment to promote access and reduce barriers have been shown to be effective in promoting physical activity and are strongly recommended by the Task Force on Community Preventive Services.65 Because people with arthritis often have multiple chronic comorbidities, such as obesity, diabetes, and heart disease, synergistically combining approaches to facilitating physical activity may help to maximize resources and program effectiveness.23 Several studies have also shown home-based exercise programs, which may be more acceptable to older adults and improve adherence, to be safe and effective in improving pain and function in persons with arthritis.8,12,13,49,66,67 Finally, the need for healthcare providers to counsel on physical activity, to manage pain adequately, and to recognize the risk from comorbid mental health disorders should be emphasized. Arthritis significantly affects health-related quality of life68 and is projected to increase markedly in prevalence69 as the population ages, even without taking into account the rising prevalence of obesity, another risk factor. Improving rates of physical activity for all persons is an important public health objective.70 Among those with arthritis, who represent a large and resistant target group, physical activity can have an even greater impact on health by decreasing pain, improving functioning, delaying disability, promoting mental wellbeing, and reducing the risk of comorbid diseases. Future research should focus on evaluating the effecAm J Prev Med 2006;30(5)
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tiveness of targeting groups at higher risk for inactivity, such as women; the elderly; and racial/ethnic minorities, as well as on improving adherence to exercise programs and performing longitudinal and dose–response studies of physical activity in persons with arthritis. This project was supported by a cooperative agreement from the Centers for Disease Control and Prevention through the Association of Teachers of Preventive Medicine. No financial conflict of interest was reported by the authors of this paper.
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