Alcohol consumption between menarche and a womans first full-term pregnancy is linked to a higher risk of future breast cancer, according to data from the Nurses Health Study II.
The study, published Aug. 28 on the website of the Journal of the National Cancer Institute, is described as the first to find such an association. Previous studies have looked at breast cancer risk and alcohol consumption later in life or at the effect of adolescent drinking on noncancerous breast disease.
Females who average a drink per day between their first period and first full-term pregnancy increase their risk of breast cancer by 13%, said Graham Colditz, MD, a study co-author and associate director for cancer prevention and control at Siteman Cancer Center at Barnes-Jewish Hospital and the Washington University School of Medicine in St. Louis.
“More and more heavy drinking is occurring on college campuses and during adolescence, and not enough people are considering future risk,” Colditz said in a news release.
The researchers also found that for every bottle of beer, glass of wine or shot of liquor consumed daily, a young woman increases her risk of proliferative benign breast disease by 15%. The presence of such lesions increases breast cancer risk by as much as 500%, said Ying Liu, MD, PhD, the studys first author and an instructor in the Division of Public Health Sciences at the Washington University School of Medicine.
“Parents should educate their daughters about the link between drinking and risk of breast cancer and breast disease,” Liu said in the news release. “Thats very important because this time period is very critical.”
Researchers with Brigham and Womens Hospital, Harvard Medical School, Beth Israel Deaconess Medical Center and Harvard School of Public Health also contributed to the study.
The findings are based on a review of the health histories of 91,005 mothers enrolled in the Nurses Health Study II from 1989 to 2009. The researchers did not consider the effects of adolescent and early adulthood drinking on women who did not have a full-term pregnancy because not enough were represented among those studied, Liu said.
Breast tissue cells particularly are susceptible to cancer-causing substances as they undergo rapid proliferation during adolescence and later, the researchers noted. Adding to the risk is the lengthening time frame between the average age of a girls first menstrual cycle and the average age of a womans first full-term pregnancy.
Colditz does not foresee any shortening of that gap, which is why young women should lower their average daily alcohol consumption and, therefore, their risk of breast disease. “Reducing drinking to less than one drink per day, especially during this time period, is a key strategy to reducing lifetime risk of breast cancer,” he said.
Colditz said the findings call for more research into what young women can do to counteract alcohols adverse effects if they choose to drink. Past studies, which did not consider alcohol use, suggest eating more fiber and exercising more lower cancer risk for everyone.