About Half of Marin County Breast Cancer Cases Stem From Lifestyle or Demographics, Study Indicates
Approximately 50% of breast cancer cases in Marin County appear to be caused by lifestyle or demographic factors, according to an unpublished study presented Thursday at a meeting of the Marin County Department of Health and Human Services, the San Francisco Chronicle reports (Torassa, San Francisco Chronicle, 5/30). Researchers are studying women in Marin County because the county's breast cancer rate is 199 cases per year per 100,000 white, non-Latino women; the national average is 144 cases (California Healthline, 5/9). Christine Erdmann, a scientist at Lawrence Berkeley National Laboratory, interviewed 305 Marin County women, none of whom had breast cancer, and found that 84% of them had at least one of five key risk factors and that 44% had two or more, the Chronicle reports. Erdmann said that breast cancer rates would fall by half if the five risk factors -- having the first menstrual cycle before age 12, having a first child after age 30 or not having children at all, having a family history of breast cancer, starting menopause after age 55 and being overweight after menopause -- were eliminated from the Marin County population. Erdmann also said that some of the risk factors were more common in Marin County women than in other populations. For example, 31% of the county's breast cancer cases are linked to having children later in life, compared to 21% statewide, and 24% of cases in Marin County are linked to having a family history of breast cancer, compared to 16% statewide.
Erdmann said that alcohol consumption's overall contribution to the number of breast cancer cases is smaller than an earlier study suggested (San Francisco Chronicle, 5/30). Earlier this month, researchers at the University of California-San Francisco said that alcohol consumption is the primary risk factor for breast cancer among women living in Marin County (California Healthline, 5/9). Erdmann also said that hormone replacement therapy use did not seem to contribute to the high breast cancer rates among women who live in Marin County. She said a full report on the study would be available soon (San Francisco Chronicle, 5/30).This is part of the California Healthline Daily Edition, a summary of health policy coverage from major news organizations. Sign up for an email subscription.