Ethnicity-related variation in breast cancer risk factors.

BACKGROUND: A variety of factors are predictors of breast cancer risk. However, the studies conducted to establish these risk factors have rarely included African American women. The few studies with sufficient numbers of African-American women suggest that risk factors for breast cancer among African-American women are similar to those of white women. Although risk factors may be similar for African-American and white women, differences in the prevalence of risk factors may explain the differences in patterns of incidence.
METHODS: The authors reviewed the epidemiologic studies of breast cancer among African-American women and identified resources with information regarding the prevalence of risk factors among African American and white women.
RESULTS: Considerable variation exists in the studies of breast cancer risk factors among African American women. Because few studies have included sufficient numbers of African-American women, no firm conclusions can be drawn regarding whether risk estimates for African American women differ from those of white women. Estimates of the prevalence of breast cancer risk factors indicate that African American and white women differ in terms of their ages at menarche, menstrual cycle patterns, birth rates, lactation histories, patterns of oral contraceptive use, levels of obesity, frequency of menopausal hormone use, physical activity patterns, and alcohol intake.
CONCLUSIONS: The risk factor profile of African-American women appears to differ from that of white women. This may explain in part, the higher incidence rates for African Americans before age 45 years and the lower incidence rates at older ages. Discussions of these data at a workshop highlighted the need for future research on breast cancer risk among African Americans. This research should acknowledge the heterogeneous heritage, cultural beliefs, and cultural knowledge of African-American women. Studies conducted in collaboration with the African-American community of women and with the breast cancer advocacy community can benefit from assistance in the design of questionnaires and recruitment of participants.