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Trend Analysis of Social and Economic Indicators of Mammography Use in Hawaii
Trend Analysis of Social and Economic Indicators of Mammography Use in Hawaii Seth Serxner, PhD, MPH Chin S. Chung, PhD
We examine the relationship between ethnicity and income as determinants of mammography use over a span of four years as a means of assessing community intervention impacts. The sample consisted of 1,44 7 women older than 34 years, living in Hawaii, who participated in the Behavioral Risk Factor Surveillance System (BRFSS). The percentage of women in the sample reporting a screening mammogram within the past two years was 31.4% in 1987, 54.1 % in 1989, and 51.6% in 1990. Women of Hawaiian ancestry had the lowest percentage of mammogram use in the past two years (38.7%), while Japanese women had the highest percentage (49.8%). Results of logistic
Breast cancer has been identified as a major public health problem in the nation. Of the approximately 150,000 women diagnosed with breast cancer each year, about 41,000 will die of the disease. 1 Current estimates are that one of nine women will get breast cancer in her lifetime. 2 The risk for breast cancer is associated with several factors, including age and race. In Hawaii, where breast cancer is the most commonly diagnosed cancer, a fact unique in the nation, a wide variation in incidence and mortality rates has been observed among ethnic groups.3-5 Hawaiian and part-Hawaiian women are at considerably greater risk of developing breast cancer than women of Japanese or Filipino ancestry.5 In addition, women of Hawaiian ancestry with breast cancer have a poorer prognosis than Caucasian or Japanese women, particularly in the perimenopausal subgroup (40-50 years of age.)3,5
From the Cancer Research Center of Hawaii (Serxner) and the School
of Public Health (Chung), University of Hawaii, Honolulu, Hawaii. Address reprint requests to Dr. Serxner, Cancer Research Center of Hawaii, University of Hawaii, 1236 Lauhala Street, Suite 406B, Honolulu, HI 96813 .
regression analysis indicate a significant increase in mammography use from 1987 to 1989 and no difference from 1989 to 1990. Findings also showed an association between age, income, and ethnicity with use in the past two years. Greater age, higher income, and Japanese origin, compared to Hawaiian, were all independently associated with increased odds of having had a mammogram in the past two years. We discuss results in terms of program evaluation and future research implications for community health surveys. [Am J Prev Med 1992;8:303-8)
In the late 1980s, political and social forces drew considerable attention to the breast cancer problem. Politically, the women's health movement began to exert pressure on the National Institutes of Health to address the needs of women in clinical research. In response, the National Cancer Institute issued several requests for applications in cancer prevention and control with emphasis on screening of breast and cervical cancers. Currently, breast cancer screening legislation is mandated in over half the states in the nation. This legislation generally addresses the cost of mammography and the source of payment. Such legislation attempts to increase access to services for populations who cannot afford to pay. Breast cancer prevention should prove to be more cost-effective than later stage disease treatment. 6 Social forces have also had a bearing on the increased public awareness of breast cancer. In October 1987, the media released information that Nancy Reagan was diagnosed with breast cancer. An analysis of the 1987 Behavioral Risk Factor Surveillance System (BRFSS) data for 33 states indicated a coincident increase in mammography use.7 Although less dramatic, media campaigns such as the one conducted by the American
Am J Prev Med 1992;8(5) 303
Cancer Society (ACS) in Spring 1987 have also contributed to an increase in mammography use. 7 The combination of forces that has increased the priority of breast cancer on the national health agenda has led to a flurry of intervention activities. Intervention for breast cancer involves education and awareness campaigns in which the use of mammography as an early detection mechanism is promoted. The severity of breast cancer outcome is positively related to stage at detection. Research indicates that 95% of those diagnosed with early stage breast cancer are likely to survive. Therefore, early detection is associated with increased probability of survival and minimized negative health outcomes. Mammography is often the focus of breast cancer interventions since it has been shown to be an effective technique in identifying breast cancer.8- 10 Based on data for 33 states participating in the BRFSS, the rate of screening mammography in the past year for women 50 years of age or older was 30% in 1987. This rate, however, varied considerably among the states. New Hampshire had the highest rate (46%), whereas Indiana had the lowest rate (15%). Hawaii had a rate of 30%, equal to the median of the sample.11 Overall, these rates indicate that a significant portion of at-risk women neglect to have mammography. Recently, there has been considerable research on factors associated with mammography use. Individual characteristics associated with mammography use include ethnicity,12- 14 age, education, income, 13- 16 marital status, 17 physician advice, 18 and various types of knowledge and attitudes.13,l 8 Specific examples of barriers to mammography include anxiety, embarrassment, concerns about cost and radiation, the belief that a mammogram is unnecessary in the absence of symptoms, perceptions of personal susceptibility to breast cancer, and the inconvenience of receiving the examination. 13,l8 On the other hand, physician recommendation and a friend's encouragement to seek a mammogram increase the probability that a woman will have the examination. 13·19 Race (i.e., white, black, other) 13 and level of education were significant predictors of mammography use.19 Many factors associated with mammography use have been investigated. However, ethnicity has received limited attention. Despite the significance of many research findings, the samples often consisted largely of Caucasian subjects and therefore were not necessarily representative of multiethnic populations. Some research has focused on black and Hispanic women, compared to white women; 20- 23 however, information on the growing Asian and Pacific Island populations is scarce. The impact of the recent educational and legislative intervention activities has yet to be thoroughly assessed. Whether the interventions are affecting the intended populations is of particular importance. More specifically, are the ethnic minorities and low-income groups with the highest rates of breast cancer benefiting from intervention activities? Few studies have examined the impact of mammography promotions over time for low-income groups and ethnic minorities. Our research examines the relationship between ethnicity and income as determinants of mammography use over a four-year period. We wished to detect any significant increase in mammography use in Hawaii from 1987 through 1990. This article will examine which ethnic groups were especially likely to have received a mammogram in the past two years, while accounting for known factors which predict use.
METHODS
Sample. The data for this investigation are from the BRFSS, operated by the Hawaii State Health Department, in cooperation with the Centers for Disease Control. Since 1986, Hawaii has been part of the nationwide system, with the University of Hawaii School of Public Health serving as the state's center for data processing and analysis. The main purposes of the BRFSS are to determine the prevalence of behavioral health risk factor: in adult populations and to detect trends in these factors. This investigation uses data from surveys collected in 1987, 1989, and 1990. The survey did not include items on mammography in 1988. Following a cluster sampling design of the entire population of the state, survey subjects were randomly chosen through tele· phone numbers from the adult members of a household in accordance with the general design of the Centers for Disease Control. 24 There were 5,408 completed interviews; an additional 1,796 persons refused to participate, for an overall refusal rate of 18.8%. From an original sample of 5,408 completed interviews, we collected a total of 2,953 women (1,013 in 1987, 976 in 1989, and 964 in 1990) 18 years of age or older. The sample for this investigation included women 35 years of age or older who did not receive a mammogram because of breast problems or follow-up cancer treatment. Therefore 1,601 women were eligi· ble for a screening mammogram: 482 women in 1987, 561 in 1989, and 558 in 1990. Analysis. We conducted logistic regression analyses using whether she "had a mammogram within the past two years" (coded as 0 = no, and 1 = yes) as the dependent variable. Mammography use in the past two years measures recent behavior pos· sibly influenced by current events and local activities. The three independent variables of primary interest were ethnicity, income, and year of the survey. The ethnicity variable was based on the four major groups in Hawaii: Caucasian, Jap· anese, Hawaiian or part-Hawaiian, and Filipino. We refer to people of Hawaiian ancestry as Hawaiians and use them as the reference group in the modeling procedures. We coded income as a binary variable (0 for less than the median income of $25,000 or 1 for $25,000 and above). The year of interview was included as a categorical variable. The control variables used in the analyses were age (four categories: 35-44, 45-54, 55- 64, and 65 or older); education (four categories: less than high school, high school graduate, some college, college graduate or more); employment status (1 for employed or 0 for not); and marital status (1 for married or 0 for not). We examined logistic regression models to determine the factors associated with mammography use in the past two years. The first stage model included all the variables described above (i.e., age, income, education, ethnicity, employment status, and marital status) with the exception of the year of the survey. The second model tested the effect of year after fitting the significant sociodemographic variables from the full model. At the final stage, we analyzed within each year the sociodemographic variables found to be significant in the first stage.
304 American Journal of Preventive Medicine, volume 8, number 5
RESULTS We further reduced the sample of 1,601 women to 1,447 with exclusions of ethnic groups other than major groups of Japa-
Table 1. Descriptive information from the BRFSS for 1987, 1989, and 1990
n
Age 35-44 45-54 55 -64 ~65
Ethnicity Hawaiian/part Hawaiian Caucasian Filipino Japanese Income Under 25,000 ~$25,000
Education Less than high school High school graduate Some college College graduate or more Employment status Not employed Employed Marital status Not married Married Year of survey 1987 1989 1990 Total BRFSS
=
Percentage had mammogram in past two years
Percentage
541 290 283 333
37.4 20.0 19.6 23.0
34.2 52.8 52.7 55.0
199 596 192 460
13.8 41.2 13.3 31.8
38.7 47.5 42.2 49.8
602 651
41.6 45.0
41.5 50.1
265 402 379 399
18.3 27.8 26.2 27.6
46.4 45.8 43.5 49.1
579 868
40 .0 60.0
52.5 42.2
594 853
41.1 58.9
42.4 49.0
443 512 492 1,447
30.6 35.4 34.0 100
31.4 54.1 51.6 46.3
Behavioral Risk factor Surveillance System.
nese, Caucasians, Filipinos, and Hawaiians. Table 1 describes the data. About a fifth of the sample had less than high school education, more than a quarter completed high school only, and the remainder had either technical school, college, or advanced degree experience. A little less than half of the sample reported household incomes of less than $25,000. Hawaiian, Japanese, and Caucasian women 35 years and older constitute 13.3%, 25.8%, and 33.5% of Hawaii's general population, whereas they represent 13.8%, 31.8%, and 41.2% of the sample, respectively. Table 1 also summarizes the data on the prevalences of mammogram examinations. It shows that nearly half of the sample had a screening mammogram in the past two years (i.e., 670/1,447). There was a significant increase in lifetime mammography use from 1987 to 1990, with the greatest use reported in 1989. Table 2 shows the percentage of women in the sample who reported having had a screening mammogram within the past two years. . Use patterns by race over the four-year study period appear m Table 2. Over the four-year period, Hawaiian women were the group with the lowest percentage of mammogram use in the past two years, whereas Japanese women had the highest percentage. In 1987 there was relatively little difference in use
among the ethnic groups; however, in 1989, the Japanese and the Caucasian groups showed more pronounced increases in screening in the past two years (X~ = 8.31, P = .04). But the increase occurred in all ethnic groups. The pattern for 1990 remains similar to that for 1989, except for the Japanese. In particular, the percentage of Japanese reporting having a screening mammogram in the past two years almost doubled from 1987 to 1989 and showed a slight decrease in 1990 (Figure 1). Table 3 shows the results of the logistic regression analysis of
Table 2. Mammography use rates of past two years by ethnicity and survey year
Caucasian Japanese Filipino Hawaiian Total
Percentage in 1987
Percentage in 1989
Percentage in 1990
Mean
30.4 31.8 34.0 31.2 31.4
55.3 60.1 45.0 42.6 54.1
54.9 52.9 45.6 44.4 51.6
47.5 49.8 42.2 38.7 46.3
Had a mammogram in past two years,
x~ =
Am
8.31, P
=
.04.
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305
Table 4. Results of logistic regression paired models for mammography in past two years
1987
1990
1989
•
Caucasian
D
Japanese
•
Filipino
<>
Hawaiian
Figure 1. Mammography in past two years, ethnicity by survey year. two-year screening mammography rates in a model with all variables except year of the survey. Younger women had onethird the odds of those of women in the oldest age group. Income of $25,000 or more per year increased a woman's odds of having a mammogram in the past two years by almost twothirds over the lower income group. Ethnicity was significantly associated with use only for Japanese women, compared to Hawaiians (OR= 1.47; 95% CI 1.01, 2.16). Education, employment status, and marital status were not associated with use in the model. Table ·f shows the result of the model testing the year effect after fitting the sociodemographic variables found significant in the preceding analysis. The result shows significantly more mammography use in 1989 than in 1987, but no difference between 1989 and 1990. Women surveyed in 1987 had about one-third of the odds of having had a mammogram in the past two years compared to women in 1989. Age and income
Constant Age 2:65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino Year 1989 1987 1990
OR
95% CI
.17 .19 .19 .13
1.00 .32 .79 .83 1.72
.23, .54, .57, 1.33,
.28 .34 .19
.19 .19 .23
1.00 1.33 1.41 1.21
.92, 1.91 .96, 2.07 .77, 1.90
-1.03 - .19
.15 .14
1.00 .36 .82
.27, .48 .62, 1.09
Beta
SE
.21
.22
-1.14 .23 .19 .54
remained associated to use in the model, but ethnicity was no longer significantly related. We explored additional logistic regression models of mammography use by year of survey to determine possible interactions of year and age, income, and ethnic groups (Table 5). The age effect remained consistent for the four-year period. However, the income effect was reduced in 1990, showing a nonsignificant association. Increase in mammography use in 1989 over 1987 was much more conspicuous in Japanese women, who had twice the odds of having had a mammogram in the past two years compared to Hawaiians. By 1990, the ethnic differences equalized.
Table 3. Logistic regression results for mammogram in past two years
Constant Age 2:65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino Education College graduate or more Less than high school High school graduate Some college Employment status Marital status
OR
95% CI
.21 .22 .20 .14
1.00 .33 .81 .84 1.62
.22, .52, .57, 1.22,
.32 .39 .26
.19 .19 .23
1.00 1.37 1.47 1.29
.95, 1.98 1.01, 2.16 .82, 2.03
.23 .04 .09 .10 .22
.22 .17 .16 .16 .13
1.00 .80 .96 .91 .91 1.24
Beta
SE
- .18
.26
-1.10 .22 .18 .48
.45 1.16 1.21 2.22
306 American Journal of Preventive Medicine, volume 8, number 5
.52, .69, .67, .67, .96,
.50 1.24 1.24 2.15
1.22 1.35 1.24 1.23 1.60
r-•
Table 5. Results of logistic regression by year of survey on mammography use in the past two years 1989 (n = 512)
1987 (n = 443) Beta Constant Age 2::65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino
SE
OR
-.50
.34
-.95 -.64 -.23 .66
.23 .35 .35 .25
1.00 .32 .79 .83 1.72
-.16 -.13 .07
.33 .35 .42
1.00 1.33 1.41 1.21
1990 (n = 492)
Beta
SE
- .17
.36
.72 1.06 1.57 3.15
-1.23 .06 .35 .75
.30 .34 .33 .22
1.00 .29 1.06 .70 2.13
.16, .54, .37, 1.38,
.45, 1.62 .44, 1.75 .47, 2.45
.55 .82 .33
.31 .33 .40
1.00 1.74 2.28 1.38
.94, 3.22 1.20, 4.35 .63, 3.04
95% Cl
.21, .26, .40, 1.18,
DISCUSSION The results of this research indicate that mammography use has increased over the period from 1987 through 1990. Peak activity was most apparent in 1989. Additionally, the results of the surveys provide evidence of use differences among certain age, income, and ethnic groups in Hawaii. These findings have both practical and theoretical implications. The practical implications of these findings are relevant to understanding the impact of various planned and unplanned breast cancer-related events. In addition to the national media exposure concerning the significance of breast cancer and mammography, several local interventions were conducted in the late 1980s in Hawaii. The ACS, the Department of Health, and others conducted local mammography promotion activities. In 1987 the ACS began to promote mammography by offering low-cost mammograms to their volunteers through a network of participating providers. The program expanded in scope from 1988 through 1990 by increasing access to low-cost mammograms to the public. In 1989, a two-year mammography promotion project began, and the campaigns targeting native Hawaiian women by offering low-cost mammograms were publicized through informal social networks. Access to health service use was increased in a number of ways. For example, several clinics opened that were nonthreatening breast screening centers targeted to walk-in patients. Additional mammography availability occurred in the rural leeward coast of Oahu (known as the Waianae) through the donation of screening technology. Also, a large HMO (Kaiser Permanente) began screening patients at no charge as part of the prevention-oriented health services. Other hospitals began advertising and promoting their mammography services. One hospital began a mobile mammography program, which increased access and reduced barriers to use, especially in rural settings and neighbor islands. These local activities seemed to affect high income households, Japanese women, and, to a lesser extent, Caucasian groups. Certain high-risk groups seemed to be unaffected by various intervention activities; thus, programs need to be modi-
OR
95% CI
.52 2.08 1.34 3.28
Beta
SE
OR
95% CI
.09
.35
-1.14 .11 .08 .27
.29 .33 .33 .22
1.00 .32 .90 1.08 1.32
.18, .47, .57, .86,
.3637 .33 .24 .35 .20 .39
1.00 1.44 1.27 1.22
.76, 2.74 .64, 2.49 .57, 2.62
.56 1.71 2.06 2.02
fied. For example, written information campaigns may be less effective among Hawaiians, who are more likely to respond to personal interaction among family and friends. 25 The relevance of Nancy Reagan's breast cancer may be limited in local Hawaiian and Pacific Island populations, since she is a wealthy Caucasian mainlander. However, media attention to national events seems to be appropriate and worth exploiting to bring attention to breast cancer and the need for early detection. In any event, responses to public media recommending early detection and breast cancer screening may simply be slower for certain groups, as suggested by the disappearance of differences in 1990. Interestingly, although the overall data suggest significant differences in use because of social and economic factors, those differences were reduced or absent in 1990. In 1990, the percentage of women reporting having had a mammogram in the past two years ranged from 44.4 % for Hawaiians to 54.9% for Caucasians (range = 10.5%), whereas in 1989 the corresponding figures were 42.6% for Hawaiians and 60.1 % for Japanese (range = 17.5% ). These findings imply that no one social or economic group was significantly more likely to have had a mammogram in 1990. Although Japanese women responded more quickly to the interventions, by 1990 the rates stabilized across all ethnic and income groups. This trend may mean that the interventions have erased many of the ethnic differences in use. Further, income was not associated with use in 1990, whereas it was in 1987 and 1989. Additional implications refer to policies and interventions that can be designed to address use issues. In Hawaii, legislation went into effect in 1991 that increases health insurance coverage in the state to include screening mammograms. Whether by policy mandate or institutional design, interventions that break the social and economic barriers to mammography use are likely to have the greatest impact on behavior. These interventions, however, must be promoted by culturally and socially diverse mechanisms in order to influence a multiethnic population. Structural interventions include improved access to care through more screening facilities within culturally acceptable
Am
J Prev
Med 1992;8(5) 307
environments. Health insurance coverage that includes preventive services, such as mammography and Pap smears, is an important element in removing the economic barriers to use. However, improved coverage can do little without medical professionals who consider the varied social and economic backgrounds of their patients. This research implies that attempts to model mammography use behavior should address the complex relationships between social and economic indicators. Although cost is not always articulated as a primary barrier to mammography use, it does influence behavior. The costs of time away from work, child care, transportation, and service all provide barriers to use. Social barriers related to cultural values and practices that may inhibit the use of services among certain ethnic groups should be measured in a more detailed manner and addressed in intervention designs. Use would increase if programs were low cost, employed ethnically diverse health service professionals, and overcame obstacles of transportation and child care. From a methodological perspective, research using the BRFSS survey data provides a model for intervention assessment. Behavioral trends among underrepresented groups can be identified within the community, and the information can then be used for program promotion and implementation. The impact of the new mandated health insurance coverage, for example, will be monitored, using BRFSS data prior to and after the policy implementation.
This study was supported in part by a grant from the Centers for Disease Control, R48 /CCR903111-2. We thank the Health Promotion and Education Branch of the Hawaii Department of Health for making the data available for this research.
REFERENCES 1. Silverberg E, Boring CC, Squires TS. Cancer statistics, 1990. Cancer 1990;40 :9-26. 2. American Cancer Society. Cancer facts and figures-1990. New York: American Cancer Society, 1990. 3. LeMarchand L, Kolonel LN, Nomura AMY. Relationship of ethnicity and other prognostic factors to breast cancer survival patterns in Hawaii. J Natl Can Inst 1984;73 :1259-65. 4. LeMarchand L, Kolonel LN, Nomura AMY. Breast cancer survival among Hawaiian Japanese and Caucasian women: ten-year rates and survival by place of birth. Am J Epidemiol 1985;122:571-8. 5. U.S. Department of Health and Human Services. Surveillance, epidemiology, and end results (SEER) report. Washington, DC : DHHS, 1984. 6. Thompson GB, Kessler LG, Boss LP. Breast cancer screening legislation in the United States: a commentary. Am J Public Health 1989;79:1541-3. 7. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control. Trends in screening mammograms for women 50 years of age and older-behavioral risk factor surveillance system, 1987. MMWR 1989;38(9):137-40.
8. Shapiro S. Evidence on screening for breast cancer from a randomized trial. Cancer 1977;39:2772. 9. Baker LH. Breast cancer detection demonstration project: five-year summary report. New York: American Cancer Society, 1982. 10. Tabar L, Gad A, Holmberg HL, et al. Reduction in mortality from breast cancer after mass screening with mammography. Lancet 1985;829. 11. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control. Chronic disease reports: deaths from breast cancer among women-United States, 1986, MMWR 1989;38(33 ): 565-71. 12. Maruc DM, Fried VM, Klienman JC. National trends in the use of preventive health care by women. Am J Pub Health 1989;79:21-6. 13. Lerman C, Rimer B, Trock B, Balshem A, Engstrom P. Factors associated with repeat adherence to breast cancer screening. Prev Med 1990;19:279-90. 14. Centers for Disease Control. Use of mammography-United States, 1990. MMWR 1990;39:621-30. 15. Hayward RA, Shapiro MF, Freeman HE, Corey CR. Who gets screened for cervical and breast cancer? Results from a new national survey. Arch Intern Med 1988;148:1177-81. 16. Neale AV, Tilley BC, Vernon SW. Marital status delay in seeking treatment and survival from breast cancer. Soc Sci Med 1986;23:30512. 17. Coll PP, O'Connor PJ, Crabtree BF, Besdine RW. Effects of age, education, and physician advice on utilization of screening mammography. J Am Geriatr Soc 1989;37:957-62. 18. Rimer BK, Keintz MK, Kessler HB, Engstrom PF, Rosan JR. Why women resist screening mammography: patient-related barriers. Radio! 1989;172:2436. 19. Zapka JG, Staddard AM, Costanza ME, Greene HL. Breast cancer screening by mammography: utilization and associated factors. Am J Pub Health 1989;79:1499-502. 20. Stein JA, Fox SA, Murata PJ. The influence of ethnicity, socioeconomic status and psychological barriers on use of mammography. J Health Soc Beh 1991;32:101-13. 21. Fox SA, Klos DS, Tsou CV. Underuse of screening mammography by family physicians. Radio! 1988 ;166:431-3. 22. Burack RC, Liang J. The acceptance and completion of mammography by older black women. Am J Public Health 1989;79:721-26. 23. Richardson JL, Marks G, Solis JM, Collins L, Birba L, Hisserich JC. Frequency and adequacy of breast cancer screening among elderly Hispanic women. Prev Med 1987; 16:761-74. 24. Marks JS, Hogelin GC, Jones JT, Gaines KL, Foreman MR, Trowbridge FL. The behavioral risk factor surveys: I. State-specific prevalence estimates of behavior risk factors. Am J Prev Med 1985;1:1-8. 25. Wegner EL. The health of native Hawaiians. A selective report on health status and health care in the 1980's. Social Process in Hawaii 1989;32: 113-33.
308 American journal of Preventive Medicine, volume 8, number 5
,....
•
We examine the relationship between ethnicity and income as determinants of mammography use over a span of four years as a means of assessing community intervention impacts. The sample consisted of 1,44 7 women older than 34 years, living in Hawaii, who participated in the Behavioral Risk Factor Surveillance System (BRFSS). The percentage of women in the sample reporting a screening mammogram within the past two years was 31.4% in 1987, 54.1 % in 1989, and 51.6% in 1990. Women of Hawaiian ancestry had the lowest percentage of mammogram use in the past two years (38.7%), while Japanese women had the highest percentage (49.8%). Results of logistic
Breast cancer has been identified as a major public health problem in the nation. Of the approximately 150,000 women diagnosed with breast cancer each year, about 41,000 will die of the disease. 1 Current estimates are that one of nine women will get breast cancer in her lifetime. 2 The risk for breast cancer is associated with several factors, including age and race. In Hawaii, where breast cancer is the most commonly diagnosed cancer, a fact unique in the nation, a wide variation in incidence and mortality rates has been observed among ethnic groups.3-5 Hawaiian and part-Hawaiian women are at considerably greater risk of developing breast cancer than women of Japanese or Filipino ancestry.5 In addition, women of Hawaiian ancestry with breast cancer have a poorer prognosis than Caucasian or Japanese women, particularly in the perimenopausal subgroup (40-50 years of age.)3,5
From the Cancer Research Center of Hawaii (Serxner) and the School
of Public Health (Chung), University of Hawaii, Honolulu, Hawaii. Address reprint requests to Dr. Serxner, Cancer Research Center of Hawaii, University of Hawaii, 1236 Lauhala Street, Suite 406B, Honolulu, HI 96813 .
regression analysis indicate a significant increase in mammography use from 1987 to 1989 and no difference from 1989 to 1990. Findings also showed an association between age, income, and ethnicity with use in the past two years. Greater age, higher income, and Japanese origin, compared to Hawaiian, were all independently associated with increased odds of having had a mammogram in the past two years. We discuss results in terms of program evaluation and future research implications for community health surveys. [Am J Prev Med 1992;8:303-8)
In the late 1980s, political and social forces drew considerable attention to the breast cancer problem. Politically, the women's health movement began to exert pressure on the National Institutes of Health to address the needs of women in clinical research. In response, the National Cancer Institute issued several requests for applications in cancer prevention and control with emphasis on screening of breast and cervical cancers. Currently, breast cancer screening legislation is mandated in over half the states in the nation. This legislation generally addresses the cost of mammography and the source of payment. Such legislation attempts to increase access to services for populations who cannot afford to pay. Breast cancer prevention should prove to be more cost-effective than later stage disease treatment. 6 Social forces have also had a bearing on the increased public awareness of breast cancer. In October 1987, the media released information that Nancy Reagan was diagnosed with breast cancer. An analysis of the 1987 Behavioral Risk Factor Surveillance System (BRFSS) data for 33 states indicated a coincident increase in mammography use.7 Although less dramatic, media campaigns such as the one conducted by the American
Am J Prev Med 1992;8(5) 303
Cancer Society (ACS) in Spring 1987 have also contributed to an increase in mammography use. 7 The combination of forces that has increased the priority of breast cancer on the national health agenda has led to a flurry of intervention activities. Intervention for breast cancer involves education and awareness campaigns in which the use of mammography as an early detection mechanism is promoted. The severity of breast cancer outcome is positively related to stage at detection. Research indicates that 95% of those diagnosed with early stage breast cancer are likely to survive. Therefore, early detection is associated with increased probability of survival and minimized negative health outcomes. Mammography is often the focus of breast cancer interventions since it has been shown to be an effective technique in identifying breast cancer.8- 10 Based on data for 33 states participating in the BRFSS, the rate of screening mammography in the past year for women 50 years of age or older was 30% in 1987. This rate, however, varied considerably among the states. New Hampshire had the highest rate (46%), whereas Indiana had the lowest rate (15%). Hawaii had a rate of 30%, equal to the median of the sample.11 Overall, these rates indicate that a significant portion of at-risk women neglect to have mammography. Recently, there has been considerable research on factors associated with mammography use. Individual characteristics associated with mammography use include ethnicity,12- 14 age, education, income, 13- 16 marital status, 17 physician advice, 18 and various types of knowledge and attitudes.13,l 8 Specific examples of barriers to mammography include anxiety, embarrassment, concerns about cost and radiation, the belief that a mammogram is unnecessary in the absence of symptoms, perceptions of personal susceptibility to breast cancer, and the inconvenience of receiving the examination. 13,l8 On the other hand, physician recommendation and a friend's encouragement to seek a mammogram increase the probability that a woman will have the examination. 13·19 Race (i.e., white, black, other) 13 and level of education were significant predictors of mammography use.19 Many factors associated with mammography use have been investigated. However, ethnicity has received limited attention. Despite the significance of many research findings, the samples often consisted largely of Caucasian subjects and therefore were not necessarily representative of multiethnic populations. Some research has focused on black and Hispanic women, compared to white women; 20- 23 however, information on the growing Asian and Pacific Island populations is scarce. The impact of the recent educational and legislative intervention activities has yet to be thoroughly assessed. Whether the interventions are affecting the intended populations is of particular importance. More specifically, are the ethnic minorities and low-income groups with the highest rates of breast cancer benefiting from intervention activities? Few studies have examined the impact of mammography promotions over time for low-income groups and ethnic minorities. Our research examines the relationship between ethnicity and income as determinants of mammography use over a four-year period. We wished to detect any significant increase in mammography use in Hawaii from 1987 through 1990. This article will examine which ethnic groups were especially likely to have received a mammogram in the past two years, while accounting for known factors which predict use.
METHODS
Sample. The data for this investigation are from the BRFSS, operated by the Hawaii State Health Department, in cooperation with the Centers for Disease Control. Since 1986, Hawaii has been part of the nationwide system, with the University of Hawaii School of Public Health serving as the state's center for data processing and analysis. The main purposes of the BRFSS are to determine the prevalence of behavioral health risk factor: in adult populations and to detect trends in these factors. This investigation uses data from surveys collected in 1987, 1989, and 1990. The survey did not include items on mammography in 1988. Following a cluster sampling design of the entire population of the state, survey subjects were randomly chosen through tele· phone numbers from the adult members of a household in accordance with the general design of the Centers for Disease Control. 24 There were 5,408 completed interviews; an additional 1,796 persons refused to participate, for an overall refusal rate of 18.8%. From an original sample of 5,408 completed interviews, we collected a total of 2,953 women (1,013 in 1987, 976 in 1989, and 964 in 1990) 18 years of age or older. The sample for this investigation included women 35 years of age or older who did not receive a mammogram because of breast problems or follow-up cancer treatment. Therefore 1,601 women were eligi· ble for a screening mammogram: 482 women in 1987, 561 in 1989, and 558 in 1990. Analysis. We conducted logistic regression analyses using whether she "had a mammogram within the past two years" (coded as 0 = no, and 1 = yes) as the dependent variable. Mammography use in the past two years measures recent behavior pos· sibly influenced by current events and local activities. The three independent variables of primary interest were ethnicity, income, and year of the survey. The ethnicity variable was based on the four major groups in Hawaii: Caucasian, Jap· anese, Hawaiian or part-Hawaiian, and Filipino. We refer to people of Hawaiian ancestry as Hawaiians and use them as the reference group in the modeling procedures. We coded income as a binary variable (0 for less than the median income of $25,000 or 1 for $25,000 and above). The year of interview was included as a categorical variable. The control variables used in the analyses were age (four categories: 35-44, 45-54, 55- 64, and 65 or older); education (four categories: less than high school, high school graduate, some college, college graduate or more); employment status (1 for employed or 0 for not); and marital status (1 for married or 0 for not). We examined logistic regression models to determine the factors associated with mammography use in the past two years. The first stage model included all the variables described above (i.e., age, income, education, ethnicity, employment status, and marital status) with the exception of the year of the survey. The second model tested the effect of year after fitting the significant sociodemographic variables from the full model. At the final stage, we analyzed within each year the sociodemographic variables found to be significant in the first stage.
304 American Journal of Preventive Medicine, volume 8, number 5
RESULTS We further reduced the sample of 1,601 women to 1,447 with exclusions of ethnic groups other than major groups of Japa-
Table 1. Descriptive information from the BRFSS for 1987, 1989, and 1990
n
Age 35-44 45-54 55 -64 ~65
Ethnicity Hawaiian/part Hawaiian Caucasian Filipino Japanese Income Under 25,000 ~$25,000
Education Less than high school High school graduate Some college College graduate or more Employment status Not employed Employed Marital status Not married Married Year of survey 1987 1989 1990 Total BRFSS
=
Percentage had mammogram in past two years
Percentage
541 290 283 333
37.4 20.0 19.6 23.0
34.2 52.8 52.7 55.0
199 596 192 460
13.8 41.2 13.3 31.8
38.7 47.5 42.2 49.8
602 651
41.6 45.0
41.5 50.1
265 402 379 399
18.3 27.8 26.2 27.6
46.4 45.8 43.5 49.1
579 868
40 .0 60.0
52.5 42.2
594 853
41.1 58.9
42.4 49.0
443 512 492 1,447
30.6 35.4 34.0 100
31.4 54.1 51.6 46.3
Behavioral Risk factor Surveillance System.
nese, Caucasians, Filipinos, and Hawaiians. Table 1 describes the data. About a fifth of the sample had less than high school education, more than a quarter completed high school only, and the remainder had either technical school, college, or advanced degree experience. A little less than half of the sample reported household incomes of less than $25,000. Hawaiian, Japanese, and Caucasian women 35 years and older constitute 13.3%, 25.8%, and 33.5% of Hawaii's general population, whereas they represent 13.8%, 31.8%, and 41.2% of the sample, respectively. Table 1 also summarizes the data on the prevalences of mammogram examinations. It shows that nearly half of the sample had a screening mammogram in the past two years (i.e., 670/1,447). There was a significant increase in lifetime mammography use from 1987 to 1990, with the greatest use reported in 1989. Table 2 shows the percentage of women in the sample who reported having had a screening mammogram within the past two years. . Use patterns by race over the four-year study period appear m Table 2. Over the four-year period, Hawaiian women were the group with the lowest percentage of mammogram use in the past two years, whereas Japanese women had the highest percentage. In 1987 there was relatively little difference in use
among the ethnic groups; however, in 1989, the Japanese and the Caucasian groups showed more pronounced increases in screening in the past two years (X~ = 8.31, P = .04). But the increase occurred in all ethnic groups. The pattern for 1990 remains similar to that for 1989, except for the Japanese. In particular, the percentage of Japanese reporting having a screening mammogram in the past two years almost doubled from 1987 to 1989 and showed a slight decrease in 1990 (Figure 1). Table 3 shows the results of the logistic regression analysis of
Table 2. Mammography use rates of past two years by ethnicity and survey year
Caucasian Japanese Filipino Hawaiian Total
Percentage in 1987
Percentage in 1989
Percentage in 1990
Mean
30.4 31.8 34.0 31.2 31.4
55.3 60.1 45.0 42.6 54.1
54.9 52.9 45.6 44.4 51.6
47.5 49.8 42.2 38.7 46.3
Had a mammogram in past two years,
x~ =
Am
8.31, P
=
.04.
J Prev Med 1992;8(5)
305
Table 4. Results of logistic regression paired models for mammography in past two years
1987
1990
1989
•
Caucasian
D
Japanese
•
Filipino
<>
Hawaiian
Figure 1. Mammography in past two years, ethnicity by survey year. two-year screening mammography rates in a model with all variables except year of the survey. Younger women had onethird the odds of those of women in the oldest age group. Income of $25,000 or more per year increased a woman's odds of having a mammogram in the past two years by almost twothirds over the lower income group. Ethnicity was significantly associated with use only for Japanese women, compared to Hawaiians (OR= 1.47; 95% CI 1.01, 2.16). Education, employment status, and marital status were not associated with use in the model. Table ·f shows the result of the model testing the year effect after fitting the sociodemographic variables found significant in the preceding analysis. The result shows significantly more mammography use in 1989 than in 1987, but no difference between 1989 and 1990. Women surveyed in 1987 had about one-third of the odds of having had a mammogram in the past two years compared to women in 1989. Age and income
Constant Age 2:65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino Year 1989 1987 1990
OR
95% CI
.17 .19 .19 .13
1.00 .32 .79 .83 1.72
.23, .54, .57, 1.33,
.28 .34 .19
.19 .19 .23
1.00 1.33 1.41 1.21
.92, 1.91 .96, 2.07 .77, 1.90
-1.03 - .19
.15 .14
1.00 .36 .82
.27, .48 .62, 1.09
Beta
SE
.21
.22
-1.14 .23 .19 .54
remained associated to use in the model, but ethnicity was no longer significantly related. We explored additional logistic regression models of mammography use by year of survey to determine possible interactions of year and age, income, and ethnic groups (Table 5). The age effect remained consistent for the four-year period. However, the income effect was reduced in 1990, showing a nonsignificant association. Increase in mammography use in 1989 over 1987 was much more conspicuous in Japanese women, who had twice the odds of having had a mammogram in the past two years compared to Hawaiians. By 1990, the ethnic differences equalized.
Table 3. Logistic regression results for mammogram in past two years
Constant Age 2:65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino Education College graduate or more Less than high school High school graduate Some college Employment status Marital status
OR
95% CI
.21 .22 .20 .14
1.00 .33 .81 .84 1.62
.22, .52, .57, 1.22,
.32 .39 .26
.19 .19 .23
1.00 1.37 1.47 1.29
.95, 1.98 1.01, 2.16 .82, 2.03
.23 .04 .09 .10 .22
.22 .17 .16 .16 .13
1.00 .80 .96 .91 .91 1.24
Beta
SE
- .18
.26
-1.10 .22 .18 .48
.45 1.16 1.21 2.22
306 American Journal of Preventive Medicine, volume 8, number 5
.52, .69, .67, .67, .96,
.50 1.24 1.24 2.15
1.22 1.35 1.24 1.23 1.60
r-•
Table 5. Results of logistic regression by year of survey on mammography use in the past two years 1989 (n = 512)
1987 (n = 443) Beta Constant Age 2::65 35-44 45-54 55-64 Income Ethnicity Hawaiian Caucasian Japanese Filipino
SE
OR
-.50
.34
-.95 -.64 -.23 .66
.23 .35 .35 .25
1.00 .32 .79 .83 1.72
-.16 -.13 .07
.33 .35 .42
1.00 1.33 1.41 1.21
1990 (n = 492)
Beta
SE
- .17
.36
.72 1.06 1.57 3.15
-1.23 .06 .35 .75
.30 .34 .33 .22
1.00 .29 1.06 .70 2.13
.16, .54, .37, 1.38,
.45, 1.62 .44, 1.75 .47, 2.45
.55 .82 .33
.31 .33 .40
1.00 1.74 2.28 1.38
.94, 3.22 1.20, 4.35 .63, 3.04
95% Cl
.21, .26, .40, 1.18,
DISCUSSION The results of this research indicate that mammography use has increased over the period from 1987 through 1990. Peak activity was most apparent in 1989. Additionally, the results of the surveys provide evidence of use differences among certain age, income, and ethnic groups in Hawaii. These findings have both practical and theoretical implications. The practical implications of these findings are relevant to understanding the impact of various planned and unplanned breast cancer-related events. In addition to the national media exposure concerning the significance of breast cancer and mammography, several local interventions were conducted in the late 1980s in Hawaii. The ACS, the Department of Health, and others conducted local mammography promotion activities. In 1987 the ACS began to promote mammography by offering low-cost mammograms to their volunteers through a network of participating providers. The program expanded in scope from 1988 through 1990 by increasing access to low-cost mammograms to the public. In 1989, a two-year mammography promotion project began, and the campaigns targeting native Hawaiian women by offering low-cost mammograms were publicized through informal social networks. Access to health service use was increased in a number of ways. For example, several clinics opened that were nonthreatening breast screening centers targeted to walk-in patients. Additional mammography availability occurred in the rural leeward coast of Oahu (known as the Waianae) through the donation of screening technology. Also, a large HMO (Kaiser Permanente) began screening patients at no charge as part of the prevention-oriented health services. Other hospitals began advertising and promoting their mammography services. One hospital began a mobile mammography program, which increased access and reduced barriers to use, especially in rural settings and neighbor islands. These local activities seemed to affect high income households, Japanese women, and, to a lesser extent, Caucasian groups. Certain high-risk groups seemed to be unaffected by various intervention activities; thus, programs need to be modi-
OR
95% CI
.52 2.08 1.34 3.28
Beta
SE
OR
95% CI
.09
.35
-1.14 .11 .08 .27
.29 .33 .33 .22
1.00 .32 .90 1.08 1.32
.18, .47, .57, .86,
.3637 .33 .24 .35 .20 .39
1.00 1.44 1.27 1.22
.76, 2.74 .64, 2.49 .57, 2.62
.56 1.71 2.06 2.02
fied. For example, written information campaigns may be less effective among Hawaiians, who are more likely to respond to personal interaction among family and friends. 25 The relevance of Nancy Reagan's breast cancer may be limited in local Hawaiian and Pacific Island populations, since she is a wealthy Caucasian mainlander. However, media attention to national events seems to be appropriate and worth exploiting to bring attention to breast cancer and the need for early detection. In any event, responses to public media recommending early detection and breast cancer screening may simply be slower for certain groups, as suggested by the disappearance of differences in 1990. Interestingly, although the overall data suggest significant differences in use because of social and economic factors, those differences were reduced or absent in 1990. In 1990, the percentage of women reporting having had a mammogram in the past two years ranged from 44.4 % for Hawaiians to 54.9% for Caucasians (range = 10.5%), whereas in 1989 the corresponding figures were 42.6% for Hawaiians and 60.1 % for Japanese (range = 17.5% ). These findings imply that no one social or economic group was significantly more likely to have had a mammogram in 1990. Although Japanese women responded more quickly to the interventions, by 1990 the rates stabilized across all ethnic and income groups. This trend may mean that the interventions have erased many of the ethnic differences in use. Further, income was not associated with use in 1990, whereas it was in 1987 and 1989. Additional implications refer to policies and interventions that can be designed to address use issues. In Hawaii, legislation went into effect in 1991 that increases health insurance coverage in the state to include screening mammograms. Whether by policy mandate or institutional design, interventions that break the social and economic barriers to mammography use are likely to have the greatest impact on behavior. These interventions, however, must be promoted by culturally and socially diverse mechanisms in order to influence a multiethnic population. Structural interventions include improved access to care through more screening facilities within culturally acceptable
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environments. Health insurance coverage that includes preventive services, such as mammography and Pap smears, is an important element in removing the economic barriers to use. However, improved coverage can do little without medical professionals who consider the varied social and economic backgrounds of their patients. This research implies that attempts to model mammography use behavior should address the complex relationships between social and economic indicators. Although cost is not always articulated as a primary barrier to mammography use, it does influence behavior. The costs of time away from work, child care, transportation, and service all provide barriers to use. Social barriers related to cultural values and practices that may inhibit the use of services among certain ethnic groups should be measured in a more detailed manner and addressed in intervention designs. Use would increase if programs were low cost, employed ethnically diverse health service professionals, and overcame obstacles of transportation and child care. From a methodological perspective, research using the BRFSS survey data provides a model for intervention assessment. Behavioral trends among underrepresented groups can be identified within the community, and the information can then be used for program promotion and implementation. The impact of the new mandated health insurance coverage, for example, will be monitored, using BRFSS data prior to and after the policy implementation.
This study was supported in part by a grant from the Centers for Disease Control, R48 /CCR903111-2. We thank the Health Promotion and Education Branch of the Hawaii Department of Health for making the data available for this research.
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