Gene mutation found in some women may decrease effectiveness of tamoxifen breast cancer drug

July 26, 2017

The authors found live births and breastfeeding lowered the risk of breast cancer for both races. The overall risk reduction from these reproductive practices was more pronounced among white women, although the differences between the groups were not statistically significant. Among women aged 35 to 49, the risk reduction of breast cancer per live birth was 13 percent for white women and 10 percent for African American women. Among women aged 50 to 64, the risk reduction was 10 percent for white women and 6 percent for African American women per live birth.

In addition, the data found the longer a woman breastfed, the lower her risk of breast cancer. This was applicable only to the younger women, with the protection most pronounced during the first five years after pregnancy.

The study also found that younger African American women were having fewer pregnancies than in the past and, more importantly, breastfed less often and for shorter duration than white women. If this trend continues, the authors write, "then this could result in a more rapid increase in breast cancer rates in this group than in whites."

Wiley InterScience