Parity and Breastfeeding among African-American Women: Differential Effects on Breast Cancer Risk by Estrogen Receptor Status in the Women’s Circle of Health Study
Published Date:Nov 19 2013
Source:Cancer Causes Control. 25(2):259-265.
Pubmed Central ID:PMC3903305
Funding:U58 DP003931/DP/NCCDPHP CDC HHS/United States
P30 CA016056/CA/NCI NIH HHS/United States
P30 CA072720/CA/NCI NIH HHS/United States
P01 CA151135/CA/NCI NIH HHS/United States
K22 CA138563/CA/NCI NIH HHS/United States
P30CA072720/CA/NCI NIH HHS/United States
R01 CA100598/CA/NCI NIH HHS/United States
It has long been held that parity reduces risk of breast cancer. However, accumulating evidence indicates that the effects of parity, as well as breast feeding, may vary according to estrogen receptor (ER) status. We evaluated these associations in a case-control study among African-American women New York City and New Jersey.
In the Women’s Circle of Health Study (WCHS), including 786 African-American women with breast cancer and 1015 controls, data on reproductive histories were collected from in-person interviews, with tumor characteristics abstracted from pathology reports. We calculated number of live births and months breastfeeding for each child, and examined each in relation to breast cancer by ER status, and for triple negative (TN) breast cancer.
Although associations were not statistically significant, having children was associated with reduced risk of ER+ breast cancer (odds ratio (OR) 0.82, 95% confidence interval (CI); 0.58–1.16), but increased risk of ER - tumors, with associations most pronounced for TN breast cancer (OR=1.81, 95% CI 0.93–3.51). Breastfeeding gave no additional benefit for ER+ cancer, but reduced the risk of ER− disease associated with parity.
Accumulating data from a number of studies, as well as our own in African-American women, indicate that the effects of parity and breastfeeding differ by ER status. African-American women are more likely to have children and not to breastfeed, and to have ER - and TN breast cancer; it is possible that breastfeeding in this population could reduce risk of more aggressive breast cancers.
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