Updated on August 29 to change 13% to 11% after further clarification from study co-author Graham Colditz.

A new study out of Washington University suggests that young women who drink regularly are at increased risk for developing breast cancer.

The study focused on women between the age of first menstruation and first pregnancy. The researchers reviewed data on the breast cancer incidence and drinking habits of just over 91,000 mothers who were enrolled in the Nurses’ Health Study II from 1989 to 2009.

“More and more heavy drinking is occurring on college campuses and during adolescence, and not enough people are considering future risk,” said study co-author Graham Colditz. “But, according to our research, the lesson is clear: if a female averages a drink per day between her first period and her first full-term pregnancy, she increases her risk of breast cancer by 11 percent.” This value for increased breast cancer risk accounts for differences in alcohol intake after first pregnancy, as well as other breast cancer risk factors.

According to the researchers, this is the first study to link drinking and breast cancer in this age group.

Their findings are published online in the Journal of the National Cancer Institute.

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