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Vol. 1, 75-82. November/December 1991 Cancer Epidemiology, Biomarkers & Prevention 75<br />

<strong>Factors</strong> Affecting <strong>the</strong> Use <strong>of</strong> Screening Mammography <strong>among</strong><br />

<strong>African</strong> American Women1<br />

Joan R. Bloom,2 Kyle Grazier, Felicia Hodge, and<br />

William A. Hayes<br />

University <strong>of</strong> California School <strong>of</strong> Public Health, Berkeley, California<br />

94720 [J. R. B.. K. G., F. H.], and Nor<strong>the</strong>rn California Cancer Center,<br />

Belmont, California 94002 [1. R. B., F. H., W. A. H.]<br />

Abstract<br />

Our objective was to determine <strong>the</strong> influence <strong>of</strong> health<br />

consciousness in <strong>the</strong> utilization <strong>of</strong> <strong>mammography</strong> in<br />

asymptomatic <strong>African</strong> American women. The sample<br />

consisted <strong>of</strong> 670 women who participated in a<br />

ho<strong>use</strong>hold interview in two cities. Logistic regression<br />

was <strong>use</strong>d to determine <strong>the</strong> independent effects <strong>of</strong><br />

health consciousness, holding constant o<strong>the</strong>r factors<br />

believed to be related to <strong>mammography</strong> utilization.<br />

Health insurance, income below <strong>the</strong> poverty line, and<br />

an annual physical were not significant predictors. The<br />

single most important predidor <strong>of</strong> having a<br />

mammogram was <strong>the</strong> regular practice <strong>of</strong> breast selfexamination;<br />

<strong>the</strong> group <strong>of</strong> women who practiced selfexamination<br />

was almost twice as likely to have a<br />

mammogram.<br />

Introduction<br />

Mammography as an effective means <strong>of</strong> reducing cancer<br />

mortality through early detection is well accepted in <strong>the</strong><br />

medical community, particularly for women oven <strong>the</strong> age<br />

<strong>of</strong> 50 (1-5). National studies indicate that in <strong>African</strong><br />

American women oven 40, 83% had heard <strong>of</strong> <strong>the</strong> procedune,<br />

and 59% had had a mammognam, which is a<br />

doubling <strong>of</strong> estimates made as recently as 1987 (6, 7).<br />

These national figures differ from those <strong>of</strong> regional studies<br />

<strong>of</strong> special populations <strong>of</strong> Hispanic and <strong>African</strong> Amenican<br />

women (8, 9) where <strong>the</strong> rates were half as high.<br />

Recent regional estimates <strong>of</strong> <strong>the</strong>se particular populations<br />

indicate less dramatic improvements, perhaps reflecting<br />

greaten numbers <strong>of</strong> poorer women than may have been<br />

reached in telephone surveys. These recent surveys also<br />

indicate that far fewer women have had more than one<br />

mammogram (35%) (7).<br />

Several explanations may account for <strong>the</strong> discrepancy<br />

between what seems desirable for cancer control<br />

and current practice. One is cost, which can range from<br />

$40.00 to $200.00. Insurance usually does not pay for<br />

Received 2/13/91.<br />

, Supported by Grant CA40651 from <strong>the</strong> National Cancer Institute.<br />

2 To whom requests for reprints should be addressed, at University <strong>of</strong><br />

California School <strong>of</strong> Public Health, Department <strong>of</strong> Social and Administralive<br />

Health Sciences, Berkeley, CA 94720.<br />

3 The abbreviation <strong>use</strong>d is: HMO, health maintenance organization.<br />

preventive services beca<strong>use</strong> <strong>the</strong>ir demand is predictable,<br />

although several states now mandate that <strong>screening</strong><br />

<strong>mammography</strong> be covered, and Medicare coverage <strong>of</strong><br />

<strong>mammography</strong> is now in effect(10, 11).<br />

A second explanation <strong>of</strong> <strong>the</strong> low utilization <strong>of</strong> mammognaphy<br />

is <strong>the</strong> reluctance <strong>of</strong> <strong>the</strong> physician to recommend<br />

it. A decade ago <strong>the</strong> radiological risk posed by<br />

<strong>mammography</strong> was well publicized; this frightened<br />

women away from accepting physicians’ advice that <strong>the</strong>y<br />

be screened and discouraged physicians from recommending<br />

<strong>mammography</strong> to asymptomatic women (12).<br />

While current technology relies on lower doses <strong>of</strong> nadiation,<br />

many women still shy away from radiation exposure<br />

and, in <strong>the</strong> absence <strong>of</strong> symptoms, <strong>the</strong>ir physicians may<br />

be reluctant to recommend it. A recent survey <strong>of</strong> primarycane<br />

physicians by <strong>the</strong> American Cancer Society indicates<br />

that <strong>the</strong> percentage <strong>of</strong> physicians reporting that <strong>the</strong>y<br />

completely agree with American Cancer Society guidelines<br />

regarding <strong>mammography</strong> has increased in <strong>the</strong> past<br />

5 years from 41% to 72%. Only 37% indicate that <strong>the</strong>y<br />

actually follow <strong>the</strong>se guidelines. Cost (39%) and radiation<br />

exposure (25%) were <strong>the</strong> previous major sources <strong>of</strong><br />

disagreement, but physicians now cite disagreement with<br />

aspects <strong>of</strong> <strong>the</strong> guidelines. Some physicians still feel that<br />

35-39 is too young for a baseline mammogram (35%)<br />

and that annual <strong>screening</strong> after age 50 is too frequent<br />

(29%). Little disagreement was expressed with <strong>the</strong> biennial<br />

<strong>screening</strong> recommendation for ages 40-50 (13).<br />

Since patients rarely reject <strong>the</strong>ir physicians’ recommendation<br />

to have a mammognam, physician factors may play<br />

a major role (14).<br />

A third explanation is based on women’s health<br />

consciousness. Health consciousness is exhibited in behaviors<br />

and in expressions <strong>of</strong> beliefs. Performance <strong>of</strong><br />

o<strong>the</strong>r health behaviors, including breast self-examination,<br />

is positively associated with <strong>mammography</strong> <strong>use</strong> (15). In<br />

this study, <strong>the</strong> <strong>use</strong> <strong>of</strong> <strong>mammography</strong> was also associated<br />

with increased knowledge <strong>of</strong> cancer detection and treatment<br />

procedures. Within this model, health-conscious<br />

women are assumed to be more aware <strong>of</strong> <strong>the</strong> risk <strong>of</strong><br />

breast cancer and more likely to request <strong>mammography</strong><br />

and o<strong>the</strong>r cancer <strong>screening</strong> tests. Closely related to consciousness<br />

about health is <strong>the</strong> perception <strong>of</strong> an individual’s<br />

own risk <strong>of</strong> cancer, specifically personal vulnenability<br />

to breast cancer. One review found that increasing<br />

self-estimates <strong>of</strong> <strong>the</strong> likelihood <strong>of</strong> breast cancer are positively<br />

associated with <strong>mammography</strong> <strong>use</strong> (16). Perceptions<br />

<strong>of</strong> vulnerability have also been found to influence<br />

help-seeking, <strong>the</strong> purchase <strong>of</strong> health insurance, and o<strong>the</strong>r<br />

health-related behavior in multiple plan choice situations<br />

(17-19).<br />

The purpose <strong>of</strong> <strong>the</strong> current study is to evaluate <strong>the</strong><br />

role <strong>of</strong> health consciousness in <strong>the</strong> light <strong>of</strong> two alternative<br />

explanations for <strong>the</strong> utilization <strong>of</strong> <strong>mammography</strong> by<br />

Downloaded from cebp.aacrjournals.org on December 2, 2011<br />

Copyright © 1991 American Association for Cancer Research


76 Use <strong>of</strong> Screening Mammography <strong>among</strong> <strong>African</strong> American Women<br />

asymptomatic women. Of particular interest is <strong>the</strong> application<br />

<strong>of</strong> this model <strong>of</strong> <strong>screening</strong> behavior to <strong>African</strong><br />

American women.<br />

Methods<br />

Background<br />

This study is part <strong>of</strong> an intervention program to decrease<br />

<strong>the</strong> avoidable mortality from cancer <strong>among</strong> <strong>African</strong> Amenican<br />

residents <strong>of</strong> an urban community in nor<strong>the</strong>rn California.<br />

Prior to <strong>the</strong> initiation <strong>of</strong> <strong>the</strong> intervention program,<br />

a ho<strong>use</strong>hold survey was conducted in 1986 in two communities<br />

with large <strong>African</strong> American populations (9).<br />

Survey<br />

Design<br />

A two-stage probability sample was drawn (census blocks<br />

and ho<strong>use</strong>holds within blocks). One hundred randomly<br />

selected blocks were selected from each <strong>of</strong> <strong>the</strong> two<br />

communities (San Francisco and Oakland, California).<br />

Using <strong>the</strong> Kish (20) procedure, randomly selected mdividuals<br />

from <strong>the</strong> sampled ho<strong>use</strong>holds participated in a<br />

face-to-face interview. If <strong>the</strong> individuals were not at<br />

home during <strong>the</strong> first visit, intensive follow-up efforts<br />

were made to interview <strong>the</strong> selected respondents. Individuals<br />

20 years old or older were eligible to participate.<br />

The response rate was 67.6% in one community, resulting<br />

in 568 completed interviews, and 69.1% in <strong>the</strong> second<br />

community, resulting in 569 completed interviews.<br />

To determine whe<strong>the</strong>r a response bias existed, analyses<br />

were completed to determine <strong>the</strong> nepresentativeness <strong>of</strong><br />

respondents from different geographical areas in <strong>the</strong><br />

target community. Data from <strong>the</strong> 1980 census were<br />

compared by age, income adjusted to 1986 dollars, and<br />

gender. No statistically significant differences were<br />

found. Survey findings from <strong>the</strong> entire sample have already<br />

been reported (9, 21).<br />

Analysis<br />

First, descriptive analyses were performed to examine<br />

<strong>the</strong> bivaniate relationships between ever having had a<br />

mammogram and <strong>the</strong> socioeconomic, attitudinal, and<br />

provider factors <strong>of</strong> <strong>the</strong> model. Health consciousness was<br />

<strong>the</strong>n examined using logistic regression. The conceptual<br />

groups <strong>of</strong> variables were forced into <strong>the</strong> model in steps.<br />

Only women in <strong>the</strong> “at risk” sample, over age 35, who<br />

had even had a mammognam (n = 418) were included in<br />

this analysis. This is consistent with <strong>the</strong> American Cancer<br />

Society guidelines, and it recognizes local medical community<br />

practice, which dictates that <strong>screening</strong> should<br />

begin at this earlier age beca<strong>use</strong> younger <strong>African</strong> Amencan<br />

women are at higher risk for breast cancer and have<br />

a higher mortality rate (22). Finally, in order to evaluate<br />

<strong>the</strong> importance <strong>of</strong> health consciousness for o<strong>the</strong>r <strong>screening</strong><br />

tests for women, additional analyses were performed<br />

comparing <strong>mammography</strong> to breast physical exams and<br />

Pap test for cervical cancer. To be consistent with <strong>the</strong><br />

<strong>screening</strong> guidelines for a physical breast exam, all <strong>the</strong><br />

women over age 20 were included in this analysis.<br />

Measurement<br />

The dependent variable is even having had a mammogram<br />

for <strong>screening</strong> purposes. The cumulative nature <strong>of</strong><br />

this variable recognizes <strong>the</strong> role <strong>of</strong> increased age in <strong>the</strong><br />

likelihood <strong>of</strong> its occurrence; as such, age is considered a<br />

control ra<strong>the</strong>r than a predictive variable. O<strong>the</strong>r research<br />

on <strong>screening</strong> <strong>mammography</strong> has <strong>use</strong>d such a measure,<br />

as well as <strong>screening</strong> within <strong>the</strong> past year (23). Preliminary<br />

data from o<strong>the</strong>r portions <strong>of</strong> this study revealed that <strong>of</strong><br />

those who reported having had a mammognam, <strong>the</strong> test<br />

had occurred within <strong>the</strong> previous 5 years. However, no<br />

specific questions were asked about <strong>the</strong> pattern <strong>of</strong> <strong>use</strong><br />

<strong>of</strong> <strong>mammography</strong> prior to <strong>the</strong> study.<br />

The independent variables for <strong>the</strong>se analyses included<br />

patient behaviors and attitudes and physician<br />

behaviors. Respondents’ general health attitudes, beliefs,<br />

and health practices; attitudes and beliefs about cancer;<br />

insurance coverage; and sociodemognaphic descriptors<br />

were collected. Whe<strong>the</strong>r <strong>the</strong> provider recommended<br />

<strong>mammography</strong> and o<strong>the</strong>r <strong>screening</strong> tests during a physical<br />

exam on at any o<strong>the</strong>r time was also ascertained.<br />

Measures <strong>use</strong>d in this analysis are described below.<br />

Health Consciousness. Seven questions explored <strong>the</strong><br />

individual’s health consciousness. The first action-based<br />

variable measured <strong>the</strong> respondent’s frequency <strong>of</strong> breast<br />

self-examination: infrequently (


Cancer Epidemiology, Biomarkers & Prevention 77<br />

Vulnerability. The respondents’ perceived vulnenability<br />

to cancer was assessed on a 4-point Likert-type<br />

scale. Respondents were asked how likely it was that<br />

<strong>the</strong>y would get cancer. Individuals were “very” or “somewhat<br />

likely” to get cancer (coded as 1) or “not too likely”<br />

on “not likely at all” (coded as 0).<br />

Insurance. The survey probed for <strong>the</strong> existence,<br />

type, and level <strong>of</strong> health insurance within <strong>the</strong> family. Of<br />

importance to <strong>the</strong> study was <strong>the</strong> coverage for <strong>screening</strong><br />

tests, particularly those <strong>use</strong>d for preventive purposes in<br />

asymptomatic individuals. The coverage measure was<br />

tnichotomized: belonging to a health maintenance organization<br />

which covered all <strong>of</strong> <strong>the</strong> cost anchored one end<br />

<strong>of</strong> <strong>the</strong> scale; having an indemnity or service benefit plan<br />

on federal entitlements (Medicare on Medicaid) which<br />

covered some <strong>of</strong> <strong>the</strong> cost was <strong>the</strong> intermediate value;<br />

and having no health insurance which covered <strong>the</strong> cost<br />

anchored <strong>the</strong> o<strong>the</strong>r end <strong>of</strong> <strong>the</strong> scale.<br />

Poverty. To enhance understanding <strong>of</strong> <strong>the</strong> cost implications<br />

<strong>of</strong> having <strong>screening</strong> tests performed, a measure<br />

<strong>of</strong> poverty was also developed. It combines questions on<br />

ho<strong>use</strong>hold size and income. The measure was tnichotomized:<br />

whe<strong>the</strong>r <strong>the</strong> family income is more than 200% <strong>of</strong><br />

<strong>the</strong> poverty line (coded as 3), from 100 to 200% <strong>of</strong> <strong>the</strong><br />

poverty line (coded as 2), or less than 100% <strong>of</strong> <strong>the</strong><br />

poverty line (coded as 1) (24).<br />

Early Detection Tests. The respondents were also<br />

asked whe<strong>the</strong>r <strong>the</strong>y had received any early cancer detection<br />

tests as part <strong>of</strong> a routine physical examination on<br />

due to symptoms. The tests assessed in this analysis<br />

included <strong>the</strong> cervical Pap smear, <strong>the</strong> clinical breast exam,<br />

and <strong>the</strong> mammognam.<br />

Willingness to Be Tested. Women were also asked<br />

whe<strong>the</strong>r <strong>the</strong>y would have a mammognam if it were necommended,<br />

<strong>the</strong> reasons why <strong>the</strong>y would not have one,<br />

and how safe <strong>the</strong>y believed a mammogram to be. These<br />

data are <strong>use</strong>d in <strong>the</strong> descriptive analysis.<br />

Sociodemographic Characteristics <strong>of</strong> <strong>the</strong> Respondent.<br />

Chronological age, years <strong>of</strong> education, and several<br />

dimensions <strong>of</strong> access to cane were also ascertained.<br />

Physician Behavior. To determine whe<strong>the</strong>r physician<br />

behavior influenced <strong>the</strong> decision, respondents were<br />

asked whe<strong>the</strong>r <strong>the</strong> provider recommended a mammogram<br />

(or “breast X-ray”) during <strong>the</strong> physical exam on at<br />

ano<strong>the</strong>r time, ei<strong>the</strong>r due to symptoms or as a <strong>screening</strong><br />

test. Respondents were also asked whe<strong>the</strong>r <strong>the</strong>y had had<br />

<strong>the</strong> mammognam. The latter question was <strong>use</strong>d by itself<br />

for descriptive purposes. In calculating rates <strong>of</strong> women<br />

who had even had a mammognam, only women who<br />

were asymptomatic when <strong>the</strong>y had a mammognam were<br />

included. This measure was also developed for <strong>the</strong> dependent<br />

measure in <strong>the</strong> logistic regression model.<br />

Results<br />

The data reported here are for <strong>the</strong> total sample <strong>of</strong> <strong>African</strong><br />

American female adults from <strong>the</strong> two communities (n =<br />

670). Almost 40% <strong>of</strong> <strong>the</strong> respondents were under 35,<br />

30% <strong>of</strong> <strong>the</strong> respondents were between 35 and 49, and<br />

<strong>the</strong> remainder <strong>of</strong> <strong>the</strong> respondents were 50 and older.<br />

The sample was generally well educated: 8% had had 8<br />

years <strong>of</strong> education or less, 1 6% had had some high school<br />

education, 36% were high school graduates, 30% had<br />

had some college, and 9% reported <strong>the</strong>y had had four<br />

Table 1 Number and percentage <strong>of</strong> women 35 and aver who have<br />

ever had a mammogram (saciodemagraphic variables in <strong>the</strong> model)<br />

In = 415)’<br />

Predictor<br />

Insurance<br />

Age<br />

None<br />

Some<br />

HMO<br />

35-44yr<br />

45-54yr<br />

55-64 yr<br />

>65 yr<br />

Response<br />

Poverty” 100%<br />

101%1a200%<br />

>200%<br />

Education $22,400 for a family <strong>of</strong> four) (24). These<br />

data are representative <strong>of</strong> <strong>the</strong> area based on <strong>the</strong> 1980<br />

census.<br />

As seen in Table 1, women belonging to an HMO,<br />

and thus having coverage, are only slightly more likely to<br />

report even having had a mammogram than women who<br />

have some health insurance on none at all.<br />

It was also reasoned that perhaps, due to costs,<br />

physicians would not recommend <strong>mammography</strong> to<br />

women <strong>the</strong>y did not believe could afford it. This would<br />

be evidenced in <strong>the</strong> study in lower rates <strong>of</strong> necommendations<br />

for <strong>mammography</strong> to women at or below <strong>the</strong><br />

poverty line. The data do not support this, as women<br />

whose incomes are at or below <strong>the</strong> poverty line are just<br />

as likely to report ever having had a mammogram as<br />

those whose income is more than twice <strong>the</strong> poverty line.<br />

Finally, cost is cited by only two women as <strong>the</strong> reason<br />

<strong>the</strong>y did not follow <strong>the</strong>ir physicians’ <strong>mammography</strong><br />

recommendations.<br />

With regard to physician behavior, only 31.6% <strong>of</strong><br />

women over 35 stated that <strong>the</strong>ir physician had ever<br />

recommended <strong>the</strong>y have a mammognam. Of this group,<br />

87% indicated that <strong>the</strong>y had actually had <strong>the</strong> mammogram.<br />

When asked if <strong>the</strong>y would have a mammognam (on<br />

ano<strong>the</strong>r one) if <strong>the</strong> doctor recommended it, only 30<br />

women said <strong>the</strong>y possibly or definitely would not. Rcasons<br />

given for not having a (ano<strong>the</strong>r) mammogram were<br />

cost (


78 Use <strong>of</strong> Screening Mammography <strong>among</strong> <strong>African</strong> American Women<br />

Table 2 Number and percentage <strong>of</strong> women 35 and o yen who have ever ha d a mammogram (at titude and behavioral variables in <strong>the</strong> model) In = 415)<br />

Ever had a mammogram<br />

Predictor<br />

Response<br />

Number <strong>of</strong><br />

responses<br />

In = 1 1 5)<br />

Percentage<br />

responses<br />

<strong>of</strong><br />

x2<br />

Preventive behavior<br />

Hasn’t eaten something beca<strong>use</strong> unhealthy<br />

Eat food good for you<br />

Exercised beca<strong>use</strong> healthy<br />

If I take care <strong>of</strong> myself I can avoid getting sick<br />

Agree<br />

Disagree<br />

Agree<br />

Disagree<br />

Agree<br />

Disagree<br />

Agree<br />

Disagree<br />

Former smoker Yes<br />

No<br />

Breast self-exam Frequent<br />

Regular<br />

Rarely<br />

Annual physical exam Yes<br />

No<br />

56<br />

59<br />

90<br />

25<br />

56<br />

59<br />

102<br />

12<br />

25<br />

90<br />

46<br />

43<br />

26<br />

78<br />

36<br />

30. 1 1 . 1 3<br />

25.4<br />

27.8 0.05<br />

26.6<br />

29.3 0.58<br />

26.0<br />

28.4 1.50<br />

20.7<br />

34.3 2.01<br />

26.1<br />

37.1 9.25<br />

25.9<br />

20.3<br />

41.5 5.21<br />

21.3<br />

0.29<br />

0.82<br />

0.45<br />

0.22<br />

0.45<br />

0.01<br />

0.02<br />

Treatment efficacy’<br />

Surgery does mare good than harm More Good<br />

More Harm<br />

Chemo<strong>the</strong>rapy does mare good than harm More Good<br />

More Harm<br />

Radiation <strong>the</strong>rapy does more good than harm More Good<br />

More Harm<br />

60<br />

48<br />

48<br />

54<br />

42<br />

60<br />

29.6 2.67<br />

28.0<br />

23.4 3.41<br />

31.2<br />

25.2 0.84<br />

29.4<br />

0.26<br />

0.18<br />

0.66<br />

Negative attitudes’<br />

Getting cancer is a death sentence Agree<br />

73<br />

28.2 0.16<br />

0.69<br />

Disagree<br />

42<br />

26.4<br />

If you had cancer, you would ra<strong>the</strong>r not know Agree 25 24.5 0.72 0.40<br />

about it Disagree 90 28.9<br />

Surgery can expose cancer to <strong>the</strong> air and ca<strong>use</strong> Agree 94 28.2 0.49 0.49<br />

it to spread Disagree 20 24.4<br />

Getting treated for cancer is <strong>of</strong>ten worse than Agree 77 27.1 0.01 0.93<br />

<strong>the</strong> disease Disagree 35 27.6<br />

Perceived vulnerability Yes<br />

No<br />

a Middle category excluded from table for clarity.<br />

35<br />

79<br />

19.7 10.04<br />

33.8<br />

0.002<br />

b x2 based an 3 categories and 2 degrees <strong>of</strong> freedom.<br />

‘ Six-paint Likert scale dichotomized for this analysis.<br />

directly questioned about <strong>the</strong> safety <strong>of</strong> <strong>mammography</strong>,<br />

28.6% considered it a little risky and less than 5% considered<br />

it very risky. Even though almost one-third <strong>of</strong> <strong>the</strong><br />

sample thought a mammognam was risky, only 1% said<br />

<strong>the</strong>y would not have a (ano<strong>the</strong>r) mammognam due to<br />

radiation risk. In o<strong>the</strong>r words, women are likely to have<br />

a mammogram if <strong>the</strong> physician recommends it.<br />

As shown in Table 2, women who have an annual<br />

physical exam (41.5%, compared to 21.3% who don’t)<br />

and those who frequently or regularly examine <strong>the</strong>ir<br />

breasts for lumps (breast self-exam) are more likely<br />

(31.0% compared to 20.3%) to have a mammognam. In<br />

addition, being olden is strongly related to ever having<br />

had a mammognam (mean, 55.78 versus 49.64; t = 4.37;<br />

P< 0.0001).<br />

Multivariate Analysis. To fully evaluate <strong>the</strong> factors <strong>affecting</strong><br />

whe<strong>the</strong>r a woman had even had a <strong>screening</strong> test<br />

for breast cancer, logistic regression was also <strong>use</strong>d. The<br />

first model addresses only <strong>mammography</strong> and thus includes<br />

only women aged 35 and olden (Table 3). The<br />

second model expands <strong>the</strong> sample to include women 20<br />

years old and older. Even though women between 20<br />

and 35 are unlikely to have a <strong>screening</strong> mammognam,<br />

this model provides <strong>the</strong> necessary comparison group to<br />

women described below who report having a clinical<br />

breast exam and/on a cervical Pap smear (Table 5).<br />

To isolate <strong>the</strong> importance <strong>of</strong> health consciousness,<br />

each group <strong>of</strong> variables was forced into <strong>the</strong> model using<br />

a forward stepwise program with <strong>the</strong> demographic vanables<br />

first, followed by <strong>the</strong> fiscal factors, attitudes toward<br />

treatment, and attitudes toward cancer. The indicators <strong>of</strong><br />

a preventive orientation were put in last. Several interactions<br />

were tested, an age-squared term was added to<br />

examine <strong>the</strong> age relationship, and <strong>the</strong> effect <strong>of</strong> potential<br />

correlations <strong>among</strong> variables was carefully examined.<br />

Age/attitude interactions (7 items) were added to<br />

each model and <strong>the</strong>n eliminated. The contribution <strong>of</strong> <strong>the</strong><br />

interaction terms was not statistically significant for any<br />

<strong>of</strong> <strong>the</strong> independent variables; <strong>the</strong>refore, <strong>the</strong> remainder<br />

<strong>of</strong><strong>the</strong> analysis is based on <strong>the</strong> assumption that interaction<br />

effects are absent and a simple additive (on <strong>the</strong> logistic<br />

scale) model was <strong>use</strong>d.<br />

Age squared was added to each model to explore<br />

<strong>the</strong> improvement in fit <strong>of</strong> <strong>the</strong> models. As expected due<br />

to <strong>the</strong> nature <strong>of</strong> <strong>the</strong> dependent variable, <strong>the</strong> model x2<br />

was improved by its addition (65.96, df= 19 versus 46.65,<br />

dl = 18); <strong>the</strong> coefficient on <strong>the</strong> insurance variable also<br />

improved in significance (from P = 0.07 to P = 0.03). The<br />

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Copyright © 1991 American Association for Cancer Research


Cancer Epidemiology, Biomarkers & Prevention 79<br />

Table 3 Effect <strong>of</strong> health consciousness on rouli ne <strong>screening</strong> by mam mography fo r women 35 and older’ In = 380)”<br />

-<br />

Predictor<br />

. -<br />

Coefficient SE P<br />

Logoddṣ<br />

ratio<br />

95% .<br />

confidence<br />

.<br />

interval<br />

Preventive behavior<br />

Hasn’t eaten something beca<strong>use</strong> unhealthy<br />

Eat food good for you<br />

Exercised beca<strong>use</strong> healthy<br />

If I take care <strong>of</strong> myself I can avoid getting sick<br />

Former smoker<br />

Breast self-exam’<br />

Annual physical exam<br />

-0.151<br />

0.058<br />

0.027<br />

-0.534<br />

0.401<br />

0.396<br />

0.435<br />

0.102<br />

0.1 13<br />

0.093<br />

0.41 5<br />

0.313<br />

0.165<br />

0.265<br />

0.14<br />

0.61<br />

0.77<br />

0.20<br />

0.20<br />

0.02<br />

0.10<br />

0.85<br />

1.06<br />

0.97<br />

0.57<br />

1.49<br />

1.49<br />

1.54<br />

(0.82-1.03)<br />

(0.80-1.25)<br />

(0.83-1.20)<br />

(0.44-2.26)<br />

(0.54-1.85)<br />

(0.72-1.38)<br />

(0.59-1.68)<br />

Treatment efficacy<br />

Surgery does mare good than harm<br />

Chemo<strong>the</strong>rapy does more goad than harm<br />

Radiation <strong>the</strong>rapy does more good than harm<br />

-0.058<br />

0.095<br />

0.040<br />

0.144<br />

0.156<br />

0.158<br />

0.68<br />

0.54<br />

0.80<br />

0.94<br />

1.09<br />

0.96<br />

(0.75-1.33)<br />

(0.74-1.36)<br />

(0.74-1.36)<br />

Negative<br />

altitude<br />

Getting cancer is a death sentence<br />

Ifyou had cancer, you would ra<strong>the</strong>r not know about it<br />

Surgery can expose cancer to <strong>the</strong> air and ca<strong>use</strong> it to spread<br />

Getting treated for cancer is <strong>of</strong>ten worse than <strong>the</strong> disease<br />

-0.010<br />

0.019<br />

-0.001<br />

-0.004<br />

0.069<br />

0.066<br />

0.080<br />

0.073<br />

0.89<br />

0.78<br />

0.99<br />

0.96<br />

0.99<br />

1.02<br />

0.99<br />

1.00<br />

(0.87-1.14)<br />

(0.88-1.14)<br />

(0.85-1.17)<br />

(0.87-1.15)<br />

Perceived vulnerability -0.441 0.265 0.10 0.64 (0.59-1.68)<br />

Insurance” 0.394 0.220 0.07 1.48 (0.65-1.54)<br />

Age#{176} 0.047 0.012 0.00 1.05 10.98-1.02)<br />

Education 0.063 0.054 0.25 1.07 (0.90-1.11)<br />

a -2 log (likelihood ratio) = 395.43; P = 0.002.<br />

b Listwise deletion accounts for 35 missing observations.<br />

‘ Odds ratio from never performing self-exam to frequently performing self-exam is 2.20.<br />

dOdds ratio from no insurance to HMO is 2.199.<br />

#{176} Odds ratio age 35 compared to 65 is 4.096.<br />

o<strong>the</strong>r significant variables in <strong>the</strong> model were not affected.<br />

Since <strong>the</strong> exact fit <strong>of</strong> age in <strong>the</strong> model is unrelated to <strong>the</strong><br />

key variables (i.e., preventive behaviors) and since <strong>the</strong><br />

interpretability <strong>of</strong> <strong>the</strong> model is decreased, <strong>the</strong> age ra<strong>the</strong>r<br />

than <strong>the</strong> age-squared term was <strong>use</strong>d in <strong>the</strong> final model.<br />

With regard to financial barriers to cane, having<br />

health insurance to pay for <strong>screening</strong> tests was expected<br />

to predict increased <strong>use</strong> <strong>of</strong> <strong>screening</strong> tests, especially<br />

<strong>mammography</strong>. Closeness to <strong>the</strong> poverty line (a combination<br />

<strong>of</strong> income and family size) was predicted to have<br />

an independent, albeit negative, effect on having a mammognam.<br />

Even though <strong>the</strong> correlation between <strong>the</strong> fiscal<br />

factors (health insurance and <strong>the</strong> poverty index) was<br />

sufficiently low to make <strong>the</strong>m nonmulticolinean, beca<strong>use</strong><br />

<strong>of</strong> <strong>the</strong>ir potential importance <strong>the</strong>y were investigated fun<strong>the</strong>n.<br />

The model was nun with both variables in <strong>the</strong> model,<br />

with each removed separately, and with both removed.<br />

Beca<strong>use</strong> <strong>the</strong>re were incomplete data on income, <strong>the</strong><br />

poverty index could not be constructed for 48 subjects,<br />

although 38 remained in <strong>the</strong> multivaniate model. Thus,<br />

<strong>the</strong> models excluding <strong>the</strong> poverty index include more<br />

subjects. When insurance was removed from <strong>the</strong> model,<br />

<strong>the</strong> significance level <strong>of</strong> <strong>the</strong> o<strong>the</strong>r variables remained<br />

unchanged; <strong>the</strong> likelihood ratio between <strong>the</strong> model including<br />

insurance and excluding it is not significant (x2 =<br />

1 .81 ; df = 1; P > 0.05). The exclusion <strong>of</strong> poverty level is<br />

also not significant (x2 = 0.03; dl = 1; P > 0.05). Since<br />

<strong>the</strong> poverty index is unimportant in <strong>the</strong> model and beca<strong>use</strong><br />

<strong>of</strong> <strong>the</strong> missing data, <strong>the</strong> final model was nun without<br />

<strong>the</strong> poverty index, resulting in a sample size <strong>of</strong> 380.<br />

To determine whe<strong>the</strong>r each variable group made a<br />

significant contribution to <strong>the</strong> full model, <strong>the</strong> variable<br />

groups were removed from <strong>the</strong> model separately and<br />

contrasted with <strong>the</strong> full model using <strong>the</strong> likelihood ratio<br />

test. Women’s health consciousness was predicted to be<br />

independently related to having a mammognam (10, 11).<br />

Having a mammognam not only requires a physician- or<br />

patient-initiated request, but also <strong>the</strong> individual’s adherence<br />

to <strong>the</strong> recommendation, which takes place at a<br />

different time and location. The x2 resulting from <strong>the</strong><br />

likelihood ratio test between <strong>the</strong> full model and <strong>the</strong><br />

model without <strong>the</strong> preventive behaviors was 14.17 (df=<br />

7; P < 0.05). When both <strong>the</strong> insurance variable and<br />

poverty variables were removed, none <strong>of</strong> <strong>the</strong> individual<br />

variables in <strong>the</strong> model was affected, and <strong>the</strong> likelihood<br />

ratio for <strong>the</strong> model was not statistically significant (x2 =<br />

1 .79; dl = 2; P > 0.05). When <strong>the</strong> contrast was made<br />

between <strong>the</strong> full model and <strong>the</strong> model resulting from <strong>the</strong><br />

removal <strong>of</strong> <strong>the</strong> negative attitudes toward cancer, <strong>the</strong><br />

likelihood ratio test was not significant (x2 = 3.51; dl =<br />

4; P > 0.05). Finally, <strong>the</strong> test was not significant when <strong>the</strong><br />

model eliminating attitudes toward treatment efficacy<br />

was compared to <strong>the</strong> full model (x2 = 0.68; dl = 3; P><br />

0.05).<br />

Logistic Model for Mammography. The multiple logistic<br />

model indicates that five factors predict having a mammogram:<br />

(a) Olden women are more likely to have ever<br />

had a mammogram (P < 0.00001). Since <strong>the</strong> outcome<br />

measure is “ever had” a mammogram, it was expected<br />

that age, which was highly significant, would be positively<br />

related to <strong>mammography</strong> <strong>use</strong>. (b) Women who examine<br />

<strong>the</strong>ir breasts are significantly more likely to have a <strong>screening</strong><br />

mammogram (P < 0.02). This was <strong>the</strong> only indicator<br />

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80 Use <strong>of</strong><strong>screening</strong>Marnmography <strong>among</strong> <strong>African</strong> American Women<br />

Table 4 Probability’ <strong>of</strong> ever having had a mammognam as a function <strong>of</strong><br />

having a routine physical exam, having health insurance, or practicing<br />

breast self-exam for each age group (n = 380)”<br />

Age<br />

40 50 60 70<br />

Insurance<br />

None 0.05 0.08 0.13 0.19<br />

Some 0.08 0.12 0.18 0.26<br />

HMO 0.11 0.17 0.25 0.34<br />

Had a physical exam in <strong>the</strong> last year<br />

Yes 0.08 0.13 0.19 0.27<br />

No 0.05 0.08 0.13 0.19<br />

Perceived vulnerability to cancer<br />

Yes 0.04 0.06 0.09 0.13<br />

No 0.05 0.08 0.13 0.19<br />

Performs breast self-exam<br />

Never 0.05 0.08 0.13 0.19<br />

Regularly 0.08 0.12 0.18 0.26<br />

More frequently 0.1 1 0.17 0.25 0.35<br />

Practices regular breast self-exam’<br />

No health insurance 0.08 0.12 0.18 0.26<br />

Some health insurance 0.11 0.17 0.25 0.34<br />

HMO member 0.16 0.23 0.33 0.44<br />

a Based on estimated values from Table 3.<br />

b Thirty-five missing observations due to listwise deletion in logistic regressian<br />

(Table 3).<br />

‘ For this analysis breast self-exam frequency = 1.<br />

<strong>of</strong> preventive behavior that was significant. Three vanables<br />

were marginally significant. (c) Those with more<br />

insurance coverage are more likely to get a mammognam<br />

(P < 0.07). (d) Women who believe that <strong>the</strong>y are more<br />

likely to get cancer are less likely to have a <strong>screening</strong><br />

mammognam (P < 0.10). (e) Having an annual physical<br />

exam also improves <strong>the</strong> chance <strong>of</strong> having a mammognam<br />

(P < 0.10). The same relationships were reflected for <strong>the</strong><br />

odds ratios presented in <strong>the</strong> table.<br />

The probabilities <strong>of</strong> having a mammognam as a function<br />

<strong>of</strong> several key attributes estimated from <strong>the</strong> model<br />

were also calculated. The probability <strong>of</strong> having a mammognam,<br />

given increasing age, presence <strong>of</strong> health insunance,<br />

perceived vulnerability to cancer, having a routine<br />

physical exam, and self-examination <strong>of</strong> one’s breasts, is<br />

presented in Table 4.<br />

Having insurance which covers <strong>the</strong> cost <strong>of</strong> a mammognam<br />

increases <strong>the</strong> probability <strong>of</strong> having a mammogram<br />

by 2-fold oven no insurance. A 70-year-old woman<br />

with HMO coverage has a 33% chance <strong>of</strong> having a<br />

mammogram, whereas a 40-year-old woman with no<br />

health insurance has only a 5% chance.<br />

Surprisingly, perceiving oneself to be vulnerable to<br />

cancer actually decreases <strong>the</strong> probability <strong>of</strong> having a<br />

mammogram. The differences here, however, are less<br />

marked at <strong>the</strong> earlier ages.<br />

Finally, <strong>the</strong>re is slightly more than a 2-fold increase<br />

in <strong>the</strong> probability that an individual who tries to examine<br />

her breasts will have a mammognam. Practicing breast<br />

self-exam regularly is as important as having health insurance<br />

on seeing a physician for a yearly physical exam.<br />

A combination <strong>of</strong> practicing breast self-exam regularly<br />

and having health insurance doubles <strong>the</strong> probability <strong>of</strong><br />

having a mammognam (<strong>the</strong> intermediate level, examining<br />

one’s breasts regularly, ra<strong>the</strong>r than <strong>the</strong> highest level <strong>of</strong><br />

<strong>the</strong> variable is <strong>use</strong>d in this calculation). The strong effect<br />

<strong>of</strong> age is seen in each row <strong>of</strong> <strong>the</strong> table, increasing <strong>the</strong><br />

probability up to 3-fold <strong>of</strong> ever having had a<br />

mammognam.<br />

Logistic Model <strong>of</strong> Screening Tests. Expanding <strong>the</strong> logistic<br />

analysis to include Pap tests and clinical breast exams<br />

indicated that having a routine Pap test in <strong>the</strong> past year<br />

(Table 5) is predicted by having a routine annual physical<br />

exam, being younger, and having no health insurance.<br />

Having a routine clinical breast examination is also predicted<br />

by having a routine physical exam and examining<br />

one’s breasts for lumps. Years <strong>of</strong> education and age (less<br />

so) are also predictors. In addition, disagreeing with <strong>the</strong><br />

attitude that “if you had cancer, you would ra<strong>the</strong>r not<br />

know about it” is positively related to getting an exam.<br />

This final analysis compares <strong>the</strong> predictors <strong>of</strong> ever<br />

having had a routine mammogram with clinical breast<br />

exams and Pap tests. Both age and education are positively<br />

and significantly related to having had a mammogram.<br />

In addition, one measure <strong>of</strong> a preventive onientation<br />

(practicing breast self-examination) also predicts who<br />

will have an exam. In contrast to <strong>the</strong> o<strong>the</strong>r <strong>screening</strong><br />

tests, seeing <strong>the</strong> physician for a routine physical exam is<br />

not related to having had a mammogram.<br />

Discussion<br />

These analyses allowed commonly held explanations <strong>of</strong><br />

<strong>the</strong> utilization <strong>of</strong> <strong>mammography</strong> to be explored singularly<br />

and with regard to <strong>the</strong> role <strong>of</strong> being health conscious.<br />

One <strong>of</strong> <strong>the</strong> most widely accepted beliefs is that <strong>the</strong> cost<br />

<strong>of</strong> a mammognam prohibits women from getting one. If<br />

this explanation is valid, <strong>the</strong>n women who have health<br />

insurance should be more likely to receive a mammogram.<br />

This study shows that having health insurance that<br />

covers <strong>screening</strong> services is strongly associated with,<br />

although it does not by itself predict, <strong>mammography</strong>.<br />

The physician may also play a significant role in<br />

determining who gets a mammogram. It is plausible that<br />

<strong>the</strong> physician screens female patients for <strong>the</strong>ir ability to<br />

pay for <strong>mammography</strong>. Thus, if a woman is not believed<br />

to be able to afford a mammognam and/on is uninsured,<br />

<strong>the</strong> test is not recommended unless she is symptomatic.<br />

If this is true, one might expect that women at on below<br />

<strong>the</strong> poverty line would be less likely to have undergone<br />

<strong>mammography</strong>. However, as indicated, <strong>the</strong> poverty indcx<br />

variable does not have a strong effect on <strong>the</strong> probability<br />

<strong>of</strong> having a mammogram.<br />

Finally, <strong>the</strong> model posits that women who are<br />

“health conscious” are more likely to have a mammogram<br />

than are women in general. As indicated in Table 3, only<br />

one <strong>of</strong> <strong>the</strong> seven indicators <strong>of</strong> health-conscious behavions,<br />

examining one’s breasts, is significantly related to<br />

having a mammognam. Women who routinely practice<br />

breast self-exam are twice as likely to get a mammogram.<br />

Examining one’s breasts increases <strong>the</strong> probability <strong>of</strong> haying<br />

a mammognam to an extent equivalent to that <strong>of</strong> full<br />

insurance coverage and more than that <strong>of</strong> undergoing a<br />

physical exam (Table 4).<br />

Ano<strong>the</strong>r explanation, not examined in <strong>the</strong> logistic<br />

regression, is <strong>the</strong> physician’s reluctance to recommend<br />

<strong>mammography</strong>. The descriptive data from this study support<br />

this explanation. The data suggest that <strong>mammography</strong><br />

is not widely recommended to asymptomatic<br />

women. Only 31.6% <strong>of</strong> women over 35 and 38.8% <strong>of</strong><br />

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Copyright © 1991 American Association for Cancer Research


cancer Epidemiology, Biomarkers & Prevention 81<br />

Table 5 Effect <strong>of</strong> preventive behavior, attitudes regarding canc er, and sociademographic fa ctars an routine <strong>screening</strong> fa r women 20 years old and<br />

older In = 604)’<br />

Predictor<br />

Coefficient<br />

Mammography<br />

SE<br />

Caefficient<br />

Breast<br />

exam<br />

SE<br />

Coefficient<br />

Pap<br />

smear<br />

SE<br />

Preventive<br />

behavior<br />

Hasn’t eaten something beca<strong>use</strong> unhealthy<br />

Eat food good for you<br />

Exercised beca<strong>use</strong> healthy<br />

If I take care <strong>of</strong> myself I can avoid getting sick<br />

Former smoker<br />

Breast self-exam<br />

Annual physical exam<br />

-0.1 12 0.095<br />

0.040 0.106<br />

0.014 0.088<br />

-0.455 0.395<br />

0.461 0.291<br />

0.447 0. 1 56b<br />

0.307 0.247<br />

-0.087 0.073<br />

0.030 0.078<br />

0.044 0.067<br />

0.371 0.270<br />

-0.207 0.233<br />

0.253 0. 1 1 7’<br />

0.872 0,180d<br />

-0.061 0.076<br />

-0.006 0.081<br />

-0.046 0.070<br />

-0.475 0.274<br />

0.078 0.243<br />

0. 1 1 8 0.122<br />

0.860 0190d<br />

Treatment efficacy<br />

Surgery does mare good than harm<br />

Chemo<strong>the</strong>rapy does more goad than harm<br />

Radiation <strong>the</strong>rapy does more goad than harm<br />

-0.126 0.135<br />

-0.018 0.143<br />

-0.031 0.144<br />

0.032 -0.101<br />

0.086 0.105<br />

-0.149 0.106<br />

-0.091 0.106<br />

0.069 0.110<br />

0.034 0.111<br />

Negative attitudes<br />

Getting cancer is a death sentence<br />

If you had cancer, you would ra<strong>the</strong>r not know about it<br />

Surgery can expose cancer to <strong>the</strong> air and ca<strong>use</strong> it to spread<br />

Getting treated for cancer is <strong>of</strong>ten worse than <strong>the</strong> disease<br />

-0.022 0.065<br />

-0.008 0.063<br />

-0.055 0.074<br />

-0.036 0.069<br />

0.045 0.048<br />

-0. 1 55 0,049b<br />

-0.014 0.052<br />

-0.067 0.051<br />

0.063 0.050<br />

-0.069 0.050<br />

0.064 0.054<br />

-0.027 0.053<br />

Perceived vulnerability -0.385 0.246 -0.021 0.178 -0.059 0.187<br />

Insurance 0.317 0.206 0.134 0.143 -0.303 0.149’<br />

Age 0.063 0,009” 0.01 1 0.006 -0.055 0,007”<br />

Education 0.087 0.051’ 0.112 0,042” 0.015 0.44<br />

-2 log (likelihood ratio)<br />

47403d 76363d 71457d<br />

a Sixty-six observations missing due to Iistwise deletion.<br />

bp


82 Use <strong>of</strong> Screening Mammography<strong>among</strong><strong>African</strong> American Women<br />

self-exam precedes and is instrumental to having a mammogram.<br />

Before such a conclusion is warranted, longitudinal<br />

data would be necessary to test for a causal<br />

relationship.<br />

Conclusion. For <strong>the</strong> majority <strong>of</strong> women, cancer control<br />

efforts for this decade are directed toward encouraging<br />

re<strong>screening</strong>. However, since so few minority women<br />

have heeded <strong>the</strong> message to get a mammognam for <strong>the</strong><br />

first time, efforts will have to be made to increase <strong>the</strong><br />

number <strong>of</strong> women who get a first mammogram as well<br />

as to encourage repeat <strong>screening</strong>.<br />

Acknowledgments<br />

Appreciation is extended to Dr. Steve Selvin for his assistance on <strong>the</strong><br />

analytic techniques and to Drs. S. Leonard Syme and Patrick Romano for<br />

<strong>the</strong>ir critical review <strong>of</strong> an earlier draft. The technical assistance <strong>of</strong> Joan<br />

Chamberlain is gratefully acknowledged.<br />

References<br />

1. Seidman, A., GeIb, S. K., Silverbeng, F., et al. Survival experience in<br />

<strong>the</strong> breast cancer detection demonstration project. Cancer (Phila.), 37:<br />

258-290, 1987.<br />

2. Shapiro, S. Evidence on <strong>screening</strong> far breast cancer from randomized<br />

trial. Cancer (Phila.), 39: 2772-2782, 1977.<br />

3. Shapiro, S., Venet, W.. Strax, P., Venel, L., and Roesner, R. Ten to<br />

fourteen year effect <strong>of</strong> <strong>screening</strong> on breast cancer mortality. I. NaIl.<br />

Cancer Inst., 69: 349-355, 1982.<br />

4. Tabar, L., Fagerberg, C. J. G., Gad, A., et al. Reduction in mortality<br />

from breast cancer after mass <strong>screening</strong> with mammograph: randomized<br />

trial from <strong>the</strong> Breast Cancer Screening Working Group <strong>of</strong> <strong>the</strong> Swedish<br />

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5. Greenwald, P., and Sondik, E. J. (eds,(. Cancer control objectives for<br />

<strong>the</strong> nation: 1985-2000. NaIl. Cancer Inst. Manogn., 2: 3-74, 1986.<br />

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January-March, 1987. Morbidity Mortality Weekly Rep., 37: 417-419,<br />

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7, Marchant, D. J., and Sultan, S. M. Use <strong>of</strong> <strong>mammography</strong>-United<br />

States, Morbidity Mortality Weekly Rep., 39: 629-630, 1990.<br />

8. Richardson, J., Marks, G., Solis, J. M., Collins, L. M., Birba, L., and<br />

Hissenich, J. C. Frequency and adequacy <strong>of</strong> breast cancer <strong>screening</strong><br />

amang elderly Hispanic women. Prey. Med., 16: 761-774, 1987.<br />

9. Bloom, I. R., Hayes, W. A., Saunders, F., and FlaIl, S. Cancer awarene’ss<br />

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