• Two or more full-term births put African-American women at higher risk.
• Increased risk occurred only in women who did not breast-feed.
PHILADELPHIA — African-American women are at higher risk for hormoneA chemical substance produced in the body that controls and regulates the activity of certain cells or organs. receptor-negative breast cancer, one of the most difficult subtypes to treat, but this risk could be ameliorated somewhat by breast-feeding their children.
“African-American women are more likely to have had a greater number of full-term births and less likely to have breast-fed their babies,” said Julie Palmer, Sc.D., professor of epidemiologyThe study, assessment, and analysis of public health concerns in a given population; the tracking of patterns and effects of diseases. at the Slone EpidemiologyThe study, assessment, and analysis of public health concerns in a given population; the tracking of patterns and effects of diseases. Center at Boston University. “This study shows a clear link between that and hormone receptor-negative breast cancer.”
Palmer based her report, published in a recent issue of Cancer Epidemiology, BiomarkersA distinct biochemical, genetic, or molecular characteristic or substance that is an indicator of a particular biological condition or process. & Prevention, a journal of the American Association for Cancer Research, on the Black Women’s Health Study, which has followed 59,000 African-American women since 1995.
Between 1995 and 2009, researchers recorded 457 cases of hormone receptor-positive breast cancer and 318 cases of hormone receptor-negative breast cancer among study participants.
For women who had two or more children, there was a 50 percent increased risk of hormone receptor-negative breast cancer. However, among women who breast-fed, there was no longer a significant increased risk.
For estrogen receptor-positive breast cancer, a higher birth rate was associated with a decreased risk and breast-feeding had no effect.
“The adverse effect of high childbirth without subsequent breast-feeding seems to be confined to the hormone receptor-negative breast cancer, which carries a higher mortality rateThe measure of the number of deaths in a particular population. and is more common in African-Americans,” said Palmer.