Study: Breastfeeding Appears to Protect Against Breast Cancer

In addition to the health benefits it provides infants, breastfeeding appears to help protect mothers against developing breast cancer, according to an analysis by researchers at Oxford University in England.

In fact, the number of children a woman has, and the length of time she breastfeeds, may be more significant than genetic factors in determining a woman's breast cancer risk, the researchers reported in The Lancet.

Two hundred researchers examined 47 studies that looked women in 30 countries. The information included information on breastfeeding patterns and other aspects of childbearing for 50,302 women with invasive breast cancer and 96,973 healthy controls.

Researchers found that women with breast cancer had, on average, fewer children than the controls. Also, fewer mothers with cancer had ever breastfed and their average lifetime duration of breastfeeding was shorter. The relative risk of breast cancer decreased by 4.3 percent for every 12 months of breastfeeding in addition to a decrease of 7 percent for each birth, reported the study.

Researchers estimated that the cumulative incidence of breast cancer in developed countries would be reduced by more than half if women had the average number of births and lifetime duration of breastfeeding prevalent in developing countries until recently. "Breastfeeding could account for almost two-thirds of this estimated reduction in breast cancer," said the report.

Researchers concluded that the longer women breast feed, the more they are protected against breast cancer. "The lack of or short lifetime duration of breastfeeding typical of women in developed countries makes a major contribution to the high incidence of breast cancer in these countries," they said.

Other sources: The Lancet