(NaturalNews) Women who breastfeed their infants have a significantly lower risk of breast cancer, according to a study conducted by researchers from the University of North Carolina-Chapel Hill and published in the Archives of Internal Medicine.
Researchers examined the health records of 60,075 nurses who had provided detailed information about their medical history and breastfeeding habits for the second Harvard Nurses' Health Study in 1997. Breastfeeding history was compared with cancer risk after eight years, in June 2005.
In contrast to prior studies, which have repeatedly shown a connection between breastfeeding and lower cancer risk, the current study found little effect for pre-menopausal women. This could be due to the fact that 87 percent of the women in the study had breastfed, or due to some other confounding factor.
When the researchers looked only at women with a history of breast cancer in their immediate family, however, they found a remarkably strong trend: Women who had breastfed had a 59 percent lower risk of breast cancer than women who had not, making their risk comparable to that of women without a family history of the cancer.
"I was sort of stunned," lead author Alison M. Stuebe said. "It's an impressive reduction in risk. Other studies either hadn't looked at this or didn't include enough women with a family history to find a statistically significant difference."
Because women who breastfeed also tend to be better educated and have higher incomes than women who do not, the researchers said that more studies are needed to determine how directly the practice contributes to decreased cancer risk, and how much it is a mere effect of correlation.
Stuebe noted, however, that if the study's findings hold up, breastfeeding may reduce cancer risk as effectively as the drug Tamoxifen, which reduces estrogen activity in the body and is often prescribed to women with a family history of cancer.