Breastfeeding may benefit women with a family history of breast cancer

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Women who have watched a mother, sibling or child battle breast cancer can become understandably preoccupied, if not obsessed, with trying to reduce their own risk of the disease. One possible way to do that? Breastfeed.

In a study published online today in the Archives of Internal Medicine, researchers at Brigham and Women’s Hospital and Harvard Medical School analyzed information on 60,075 women who had given birth and who had provided information about, among many other things, their breastfeeding practices.

Earlier studies had hinted that breastfeeding might lower a woman’s chance of developing the disease, but those results were far from conclusive.

This study seems somewhat clearer. It found that women who had a so-called first-degree relative with breast cancer were less likely to develop pre-menopausal breast cancer if they had ever breastfed. Duration of breastfeeding didn’t affect risk, the study said, nor did whether the women supplemented with formula, nor did whether the women experienced a cessation of menstruation. Just the act of breastfeeding.

No such connection was found in women who didn’t have a family history of breast cancer.

Here’s a synopsis of the study; more on the risk factors for breast cancer, from the American Cancer Society; and a roundup of information on breastfeeding, from the National Institutes of Health’s Medline Plus.

(As for the women in this study, if you hadn’t guessed already, they were participants in the Nurses’ Health Study. Some years ago, thousands upon thousands of nurses answered detailed questions about seemingly every health factor imaginable. Researchers have been mining their answers ever since, and the possible connections between health and lifestyle gleaned from those participants just keep coming.)

In this study, the researchers conclude: ‘The observed 59% reduction in risk compares favorably
with hormonal treatments such as tamoxifen for women at high risk for breast cancer. Moreover, breastfeeding is associated with multiple other health benefits for both mother and child. These data suggest that women with a family history of breast cancer should be strongly encouraged to breastfeed.’

-- Tami Dennis