This case-control study aimed to determine critical factors influencing the use of clinical breast examination and mammography among women workers in Monterrey, Mexico.
We determined case and control status from survey results. Cases were defined in accordance with the guidelines of the Official Mexican Standard as lack of at least one clinical breast examination during the past year by surveyed women. For women older than 40 years, cases were further defined as lack of at least one mammogram in the previous 2 years and, for women older than 50, lack of a mammogram in the previous year. Controls were defined as adherence by surveyed women to these guidelines. Participants (N = 306 clerks aged 18–60) provided information about their practices, knowledge, and perceptions regarding breast cancer screening. Factors identified by odds ratio analysis as significantly different between cases and controls were analyzed by multivariate logistic regression.
Survey participants' knowledge about the utility of breast self-examination (odds ratio, 6.0; 95% confidence interval, 1.0–33.9), perception that the health care system has enough equipment and personnel for clinical breast examination (odds ratio, 4.7; 95% confidence interval, 1.7–13.2), and perception that they have enough time to wait for and receive clinical breast examinations (odds ratio, 2.5; 95% confidence interval, 1.1–5.8) significantly predisposed women to use screening services independent of years of formal education, number of pregnancies, number of living children, hours worked per week, and monthly family income.
Perception of organizational and structural factors played a significant role in screening use. Our findings have implications for the general population, provider practices, community interventions, and future development of strategies to increase use of screening services in similar locales.
Two decades ago, breast cancer was not a major health concern in the developing world (
With the goal of formulating recommendations for early detection of breast cancer in developing countries, the 2002 Global Summit Consensus Conference on International Breast Health Care focused on several key issues, including educating and empowering women to adhere to guidelines for breast screening, developing infrastructure for diagnosing and treating breast cancer, and educating primary health care professionals. The 2002 Global Summit also identified social and cultural variables that may be barriers to use of breast cancer screening services, including beliefs that cancer is invariably fatal, spouse/partner lack of acceptance of screening, fear of lack of social support, and preference for traditional medicine (
Mexico exemplifies a country caught in this demographic and epidemiologic transition. With socioeconomic development, urbanization, and increased entrance of women into the labor market have come trends linked to increased breast cancer incidence, including obesity, sedentary lifestyle, late parity, nulliparity, and oral contraceptive use (
Monterrey, the capital of the state of Nuevo León, is one of many urban areas where chronic diseases such as diabetes, heart disease, and cancer are leading causes of morbidity and mortality (
The Health Belief Model describes and predicts preventive actions related to cancer by focusing on interactions among health behaviors, practices, and use of services (
Therefore, we identified and quantified critical factors related to use of breast cancer screening services among women workers in Monterrey, generating novel results for understanding patterns of advanced-stage diagnosis and for modeling strategies to increase early breast cancer detection.
This case-control study included formally employed female store clerks working and residing in Monterrey, Mexico. Clerks were selected on the basis of their ability to be surveyed in their place of work away from family and peer influences that could interfere with accurate questionnaire response. The majority of women surveyed (94%) were the only workers present at the place of business; when more than one female worker was present and eligible to be surveyed, we emphasized the importance of each woman responding individually.
Women aged 18 years or older were eligible to participate because BSE and CBE are recommended for women starting at this age, and screening at young ages offers an opportunity for women and their doctors or nurses to discuss changes in their breasts, methods of early detection, and factors in the woman's history that might predict future breast cancer. We excluded women with a history of cancer. A minimum sample size of 149 cases and 149 controls was established for 95% confidence in the results and 80% power to detect an odds ratio (OR) of 2.
We determined case-control status from survey results. Cases were defined in accordance with the Official Mexican Standard (
Before administration, surveys — written in basic Spanish to be easily understood by the general population — were validated with a small sample of working women (N = 15) and revised to increase participant comprehension and compliance. The first author (KMW) visited 312 randomly selected businesses throughout Monterrey, accounting for districts of various sizes, and distributed one-third of surveys during each of the three work shifts. Six businesses did not have at least one eligible female clerk on shift. In businesses with eligible participants, the first author explained the purpose of the study and survey, including its anonymous and voluntary nature. The first author left surveys with participants in their place of work and collected them later the same day at a time requested by the participant, usually within 1 hour, to allow for adequate response time during shift breaks or lulls. At collection, respondents were asked if they needed clarification on any of the questions.
Of the 379 women asked to participate, 330 (87.1%) agreed and gave informed consent, and 49 (12.9%) declined. Those who declined most frequently cited lack of time (92%), followed by the belief that cancer is invariably fatal, therefore negating the utility of the survey (8%). We excluded the six (1.8%) participants who did not complete at least 80% of the survey.
The survey asked about sociodemographic, sociocultural, educational, and organizational and structural factors related to the health care system. Sociodemographic variables included respondent's age, age at first childbirth, number of pregnancies and living children, hours worked per week, and monthly family income. Other variables determined the repeat breast cancer screening practices of the respondents, including the number of BSEs in the previous year and lifetime number of CBEs and mammograms. Response types were 1) open-ended, 2) categorical yes/no, or 3) ranked on a 5-point Likert scale.
Sociocultural variables were defined as beliefs and values ingrained in a culture. Respondents provided answers on a 5-point Likert scale (from "very little" to "very much") to the following questions: Are you afraid/feel embarrassed to have your breast examined/receive a mammography from health care personnel? Does your spouse/partner accept that health care personnel examine your breasts/perform a mammography? Do you believe cancer is always fatal?
Educational factors included years of formal education and knowledge about breast cancer screening utility and guidelines. Respondents answered the questions: Do you feel BSE/CBE/mammography is important for good health (5-point Likert scale ranging from "marginally" to "extremely" reduced to categorical accurate vs inaccurate)? Do you know how often you should examine your breasts (weekly, monthly, every 3 months, yearly; reduced to categorical accurate vs inaccurate)? Do you know the screening recommendations for CBE/mammography (weekly, monthly, every 3 months, yearly; reduced to categorical accurate vs inaccurate)?
Organizational and structural factors related to the health care system are built into medical encounters that may influence use of services, such as availability of heath resources and quality of care. The survey focused on the respondent's subjective point of view, given that perceptions can be barriers to screening regardless of the objective state of the health care system. Respondents answered the following questions: Did you feel health care personnel and equipment were sufficient for providing CBE/mammography tests (5-point Likert scale ranging from "marginally" to "extremely" reduced to categorical yes vs no)? Did you feel the quality of service provided for CBE/mammography testing was sufficient (5-point Likert scale ranging from "marginally" to "extremely" reduced to categorical yes vs no)? Other structural factors related to the health care system encompass an individual's resources and opportunities to obtain medical attention, such as costs and waiting times. All formally employed persons in Mexico are provided government-funded health insurance covering CBE and mammography screening services, thus removing financial problems as a barrier to screening. Respondents answered how they felt about the waiting time for obtaining CBE and mammography the last time they solicited such services and the waiting time for receiving examinations.
We created two education-related indices, each comprising three variables. The first assessed participant knowledge of BSE, CBE, and mammography utility ("screening utility index"). This index coded for accurate versus inaccurate knowledge of the utility of all three detection methods. However, because of an unacceptable level of internal consistency (Cronbach α = 0.48), items could not be combined and were retained in the analysis as separate variables. The second index evaluated participant knowledge of BSE, CBE, and mammography screening guidelines ("screening guidelines index"). This index coded for accurate versus inaccurate knowledge of screening guidelines for all three detection methods. This index reached an acceptable level of internal consistency (Cronbach α = 0.75) and was retained in the analysis along with the individual variables comprising the index.
Survey data were entered directly into SPSS 10.0 for Windows (1999) (SPSS, Inc, Chicago, Illinois). Sociodemographic data and quantitative information concerning cancer screening practices were analyzed by descriptive statistics and
Significantly more control women than case women had a formal education of high school or more, had at least one pregnancy and at least one living child, and worked 40 hours per week or more (
Variables most strongly associated with use of CBE and mammography were related to educational factors (
Four survey variables (data not shown) were not significantly associated with case-control status as determined by OR analysis. These were the belief that cancer is not invariably fatal (OR, 0.7; 95% confidence interval [CI], 0.5–1.1), spouse/partner acceptance of CBE (OR, 3.1; 95% CI, 0.5–17.2), spouse/partner acceptance of mammography (OR, 1.6; 95% CI, 0.5–4.6), and perceptions of reasonable waiting time to receive results of mammography (OR, 2.8; 95% CI, 0.7–12.2).
Variables identified as significantly associated with screening use were entered into multivariate logistic regression analysis (
Our study directly linked the use of breast cancer screening services with years of formal education and accurate knowledge of early detection guidelines. A principal factor for use of screening services was knowledge about BSE screening guidelines, a well-documented indicator in studies of Hispanic women (
Survey participants who perceived that enough equipment and personnel were available for CBE were more inclined to adhere to national screening guidelines for both CBE and mammography. Previous studies indicate the importance of these organizational factors to use of preventive services (
Social change and epidemiologic transition, especially regarding changes in fertility and breast cancer incidence and awareness in Mexico, also may influence perceptions of the accessibility and quality of medical care concerning sufficient equipment and personnel for CBE. As educational and workforce opportunities improve for women, health awareness and the consequent demand for quality health services increase (
In addition, participants who perceive they have enough time to wait for and obtain an annual CBE were more inclined to adhere to both CBE and mammography in accordance with national screening guidelines. Structural barriers, such as lack of time, have been described in relation to breast cancer screening, especially the inability of employed women to take work leave or pay child care expenses during an absence (
Finally, we investigated the influence of fear and embarrassment with regard to CBE and mammography, spouse/partner acceptance of CBE and mammography, and cancer fatality beliefs. Although the sociocultural profile of a population must be considered if a cancer-detection program is to be effective (
Our study is subject to information bias because of participants' potential inability to quantitatively recall screening practices and the inaccurate disclosure of personal information such as sexual and reproductive history. To minimize this bias, we surveyed participants away from family and peer influence, assured them of response anonymity, and gave them enough time to carefully consider and answer all questions. Because of these considerations and the high participant response rate, we believe our data are generalizable and have reliably determined critical factors related to use of the breast cancer screening service by this population.
We based our study on the assumption that misperceptions can be barriers to screening, regardless of the objective state of the health care system. Therefore, we aimed to determine how users and potential users perceived this system. For example, perceptions of inadequacies in equipment and personnel for CBE may represent actual deficiencies of the system or may result from misconceptions by the general population. The actual state of the breast cancer screening program must be evaluated in terms of these perceptions to determine whether community interventions to increase breast cancer education, screening awareness, and breast health priority are enough or whether macro-level policy interventions aimed at organizational reform of the current system also are necessary.
Accurate information and perceptions of the availability of sufficient resources (i.e., personnel, equipment, and time) most strongly determined use of breast cancer screening services. Hypothesized sociocultural factors did not play a significant role. Our findings describing the lack of use of screening services by women workers in Monterrey have implications for the general population, provider practices, community interventions, and future development of strategies to increase use of screening services in similar locales.
We thank the women of Monterrey who participated in this study and the people who provided editorial support, particularly Annita Steussy and Tiffany Carrell.
Sociodemographic Profile and Repeat Breast Cancer Screening Practices Among Women Workers in Monterrey, Mexico, 2006
| Variable | Case | Control | |
|---|---|---|---|
| 18–39 | 80.4% | 79.7% | .40 |
| ≥40 | 19.6% | 20.3% | |
| Low (less than high school) | 60.9% | 31.8% | <.0001 |
| High (high school or more) | 39.1% | 68.2% | |
| Yes | 56.9% | 79.7% | .005 |
| No | 43.1% | 20.3% | |
| Yes | 52.9% | 78.4% | .003 |
| No | 47.1% | 21.6% | |
| ≤39 | 31.4% | 20.3% | .009 |
| ≥40 | 68.6% | 79.7% | |
| Yes | 34.6% | 95.4% | <.0001 |
| No | 65.4% | 4.6% | |
| Yes | 26.8% | 93.5% | <.0001 |
| No | 73.2% | 6.5% | |
| Yes | 30.0% | 93.5% | <.0001 |
| No | 70.0% | 6.5% | |
A case was defined as lack of at least one clinical breast examination during the previous year by surveyed women. For women older than 40, a case was further defined as lack of at least one mammogram in the previous 2 years and, for women older than 50, in the previous year.
A control was defined as adherence by surveyed women to the above guidelines.
Among women aged 40 or older (31 controls, 30 cases).
Knowledge and Perceptions About Use of Breast Cancer Screening Services Among Women Workers in Monterrey, Mexico, 2006
| Factor | Case | Control | OR (95% CI) |
|---|---|---|---|
| Utility of BSE | 87 (56.9) | 151 (98.7) | 57.3 (13.7–239.7) |
| Utility of CBE | 133 (86.9) | 150 (98.0) | 7.5 (2.2–25.9) |
| Utility of mammography | 128 (83.7) | 145 (94.8) | 3.5 (1.5–8.1) |
| BSE screening guidelines | 45 (29.4) | 119 (77.8) | 8.4 (5.0–14.0) |
| CBE screening guidelines | 41 (26.8) | 143 (93.5) | 39.1 (18.8–81.4) |
| Mammography screening guidelines | 29 (19.0) | 97 (63.4) | 7.4 (4.4–12.5) |
| Screening guidelines index | 18 (11.8) | 109 (71.2) | 18.6 (10.1–34.0) |
| CBE: No fear or embarrassment | 112 (73.2) | 142 (92.8) | 4.7 (2.3–9.6) |
| Mammography: No fear or embarrassment | 116 (75.8) | 135 (88.2) | 2.4 (1.3–4.4) |
| CBE: Enough time to wait for and obtain | 35 (22.9) | 70 (45.8) | 6.2 (3.7–10.2) |
| Mammography: Enough time to wait for and obtain | 30 (19.6) | 68 (44.4) | 3.3 (2.0–5.5) |
| CBE: Enough equipment and personnel | 31 (62.0) | 141 (92.2) | 7.2 (3.2–16.4) |
| Mammography: Enough equipment and personnel | 14 (46.7) | 24 (77.4) | 3.9 (1.3–11.8) |
| CBE: Quality of attention | 34 (68.0) | 48 (31.4) | 13.9 (4.8–40.7) |
| Mammography: Quality of attention | 14 (46.7) | 24 (77.4) | 3.9 (1.3– 11.8) |
OR indicates odds ratio; CI, confidence interval; BSE, breast self-examination; CBE, clinical breast examination.
A case was defined as lack of at least one CBE during the previous year by surveyed women. For women older than 40, a case was further defined as lack of at least one mammogram in the previous 2 years and, for women older than 50, in the previous year.
A control was defined as adherence by surveyed women to the above guidelines.
Among women who received at least one CBE in their lifetime (153 controls, 50 cases).
Among women aged 40 or older (31 controls, 30 cases).
Results of Multivariate Logistic Regression Analysis of Factors Associated With Use of Breast Cancer Screening Services Among Women Workers in Monterrey, Mexico, 2006
| Factor | Adjusted OR (95% CI) | |
|---|---|---|
| Accurate knowledge of utility of BSE | 6.0 (1.0–33.9) | .04 |
| Perception that the health care system has enough equipment and personnel for CBE | 4.7 (1.7–13.2) | .003 |
| Perception that women have enough time to obtain CBE | 2.5 (1.1–5.8) | .03 |
OR indicates odds ratio; CI, confidence interval; BSE, breast self-examination; CBE, clinical breast examination.
OR for each variable adjusted for years of formal education, number of pregnancies, number of living children, hours worked per week, and monthly family income.
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