Return to Table of Contents
Screening mammography has been shown to lead to earlier diagnosis and to reduced mortality from breast cancer. National health objectives for the Year 2000 were established in Healthy People 2000 (1). Healthy People 2000 aims to significantly reduce preventable death and disability, enhance Americans' quality of life, and reduce health status disparities in various population groups. To reduce breast cancer mortality in the United States, the Year 2000 objectives call for 80 percent of women aged 40 and over to have had at least one mammogram, and for 60 percent of women aged 50 and over to have been screened within the prior two years. These objectives specifically target black and Hispanic women, women from low income households, those with less than a high school education, and women aged 70 and older. This chapter uses data from the California Behavioral Risk Factor Surveillance System (BRFSS) to examine the prevalence and frequency of mammography utilization in California (2).
The goal of the BRFSS is to collect, analyze and interpret state-specific behavioral risk factor data that can be used in planning, implementing and monitoring public health programs. Data are collected monthly by telephone interviews with a random sample of Californians who live in households with telephones. The BRFSS is administered by the computer-assisted telephone interviewing (CATI) unit of the California Department of Health Services (DHS). The BRFSS is a collaborative effort by the Cancer Surveillance Section of the DHS, the Centers for Disease Control and Prevention, and the California Public Health Foundation. California and 14 other states began conducting monthly interviews as part of the surveillance system in 1984. During 1994, all states, the District of Columbia, and most of the territories participated in the BRFSS.
BRFSS data are used to assess the prevalence of and trends in health-related behaviors in the California adult population. California BRFSS participants are asked questions about a variety of behaviors such as seat belt use, exercise, weight control, diet, tobacco and alcohol consumption, utilization of cancer screening procedures and other preventive health measures. They also are asked for basic demographic information such as age, race/ethnicity, marital and employment status, household income and education. All data are self-reported.
In 1984, 99 BRFSS interviews were completed per month in California. This gradually increased to 336 interviews per month in 1994. To obtain a representative sample, standardized procedures are followed for calling back numbers that ring with no answer or give a busy signal, or for encouraging selected respondents who may be reluctant to participate. Rigorous quality control procedures are followed so that the highest quality data possible are collected.
Questions regarding mammography became part of the BRFSS core questionnaire in 1987. Following an explanation A mammogram is an x-ray of the breast to check for cancer and involves pressing the breast between two plastic plates, respondents are asked: Have you ever had a mammogram? . Women who report having had a mammogram are then asked: How long has it been since you had your last mammogram? and Was your last mammogram done as part of a routine checkup, because of a breast problem, or because you've already had breast cancer? .
The following data examine utilization among asymptomatic women only. Women who reported that their last breast exam was done because of a breast problem or because they had already had breast cancer were excluded from this analysis.
In 1987, only 46.7 percent of California women aged 40 and over reported having ever had a mammogram (Table 6.1). By 1994, this figure had increased to 82.8 percent. Since 1987, the proportion of women aged 40 and over who reported having had at least one mammogram has increased dramatically for all age groups (Table 6.2). However, women aged 80 and over consistently reported lower screening rates (Figure 6.1).
The Year 2000 objective that 60 percent of women aged 50 and older receive a mammogram within the prior two years was achieved in 1989 (Table 6.1, Figure 6.2). The proportion of women aged 50 and over who reported having a mammogram at the target interval increased from 35.6 percent in 1987 to 73.9 percent in 1994. Again, a lower proportion of women aged 80 and over (55.1 percent) reported being screened within the prior two years (Table 6.2, Figure 6.3).
While an increasingly greater proportion of women aged 40 and over report having had at least one mammogram, women who are not high school graduates are screened at a lower rate than are high school graduates (Table 6.3). In 1994, 86.1 percent of high school graduates aged 40 and over reported having ever had a mammogram compared with 68.1 percent of less educated women (Figure 6.4). High school graduates achieved the Year 2000 goal of 80 percent in 1991, while women with less education have not yet achieved this goal. Similarly, a lower percentage of women aged 40 and over who reside in low income households (i.e., less than $15,000 per year) reported having had at least one mammogram (Table 6.4). During 1994, 87.2 percent of higher income women aged 40 and over reported ever having a mammogram compared with 70.7 percent of lower income women (Figure 6.5). Women who reported incomes greater than $15,000 achieved the Year 2000 goal in 1991, while women with lower incomes have yet to reach the goal.
Regardless of education or income, women aged 50 and over have achieved the Year 2000 goal that 60 percent have a mammogram within the prior two years. However, among this age group, a higher proportion of high school graduates and women from higher income households reported being screened at the target interval than did women with less education and those from lower income households (Figure 6.6 and Figure 6.7).
Among women aged 50 and over, 76.1 percent of high school graduates and 79.3 percent of those with higher incomes were screened within the target two year interval in 1994. During the same year, 65.0 percent of women with less education and 61.3 percent of women from lower income households reported receiving a mammogram within the prior two years. High school graduates aged 50 and over attained the 60 percent goal in 1989, whereas women with less than a high school education did not achieve the objective until 1993. Higher income women achieved the Year 2000 objective in 1988 and women from lower income households achieved it in 1991.
In the earlier years of the BRFSS, the number of interviews was too small to create stable estimates of mammography use among Asian/Other, black and Hispanic women. However, race/ethnic differences in mammography use are partially addressed by comparing rates for non-Hispanic white women to those for all other women combined (Table 6.5). When this is done, it can be seen that while mammography utilization increased significantly for both groups, it was consistently higher among non-Hispanic white women (Figure 6.8 and Figure 6.9).
Examination of combined 1993 and 1994 data show that among women aged 40 and over, greater than 80 percent of black and white women reported having had at least one mammogram. Asian/Other and Hispanic women reported lower screening rates, 68.9 and 73.6 percent, respectively (Table 6.6). When examining age-specific screening rates, the proportion of Asian/Other, black and Hispanic women aged 40 to 49 and 50 to 59 who reported having ever had a mammogram are nearly identical but diverge dramatically in the later age groups (Figure 6.10). Black, Hispanic and white women age 50 and over achieved the Year 2000 goal that 60 percent be screened within the prior two years. Asian/Other women age 50 to 59 achieved this goal, however, those aged 60 and over were not screened at the target interval (Figure 6.11).
More than 60 percent of women aged 50 and over who reported having a medical examination during the prior year reported having a mammogram within the prior two years (Table 6.7) compared with 41.9 percent of women who did not report having a routine medical examination. Asian/Other and Hispanic women continue to report lower rates of screening even if they reported seeing a physician within the prior year. Regardless of race/ethnicity, screening rates among women who did not report having a routine medical examination during the prior year were dramatically lower.
Mammography use in California has increased markedly in the past eight years. In 1994, 82.8 percent of women aged 40 and over reported having had at least one mammogram, and 73.9 percent of women aged 50 and over reported having been screened within the prior two years. Overall, California women have achieved the Year 2000 goals for mammography utilization. However, Asian/Other and Hispanic women, less educated women, and those reporting a lower household income are less likely to have been screened. These women, therefore, are at greater risk for being diagnosed with breast cancer at a later stage.
Return to Table of Contents
Return to Chapter 5
Go to Table 6.1
Go to Chapter 7