Black Women, Breast Cancer, and Lactation

Breast cancers lacking estrogen receptors (ER−) carry a worse prognosis and are more common among black women in the U.S. To examine the relation between parity, lactation, and breast cancer subtypes, investigators for the African American Breast Cancer Epidemiology and Risk (AMBER) consortium analyzed data pooled from 4 studies including 3698 black women with breast cancer and 14180 without breast cancer.

In both unadjusted and multivariable analyses, risk for ER+ breast cancer was not affected by parity, but risk for ER− breast cancer increased with each additional birth among mothers who had not breast-fed. Overall, lactation did not affect risk for ER+ cancer but was associated with a 19% reduction in risk for ER− breast cancer.