(HealthDay News) — Consuming alcohol between menarche and first pregnancy is associated with an increased risk of breast cancer and proliferative benign breast disease (BBD), according to a study published online Aug. 28 in the Journal of the National Cancer Institute.
Ying Liu, M.D., Ph.D., from Washington University in St. Louis, and colleagues assessed breast cancer risk in 91,005 parous women participating in the Nurses’ Health Study II who had no history of cancer. Participants completed questions on early alcohol consumption in 1989 and were followed through June 2009. An analysis of proliferative BBD was conducted in a subset of 60,093 women who had no history of BBD or cancer in 1991 and were followed through June 2001.
The researchers identified 1,609 breast cancer cases and 970 proliferative BBD cases that were confirmed by central histology review. After adjustment for drinking after first pregnancy, alcohol consumption between menarche and first pregnancy correlated with risks of breast cancer (relative risk [RR], 1.11 per 10 g/day intake; 95 percent confidence interval [CI], 1.00 to 1.23) and proliferative BBD (RR, 1.16 per 10g/day intake; 95 percent CI, 1.02 to 1.32). There was a similar risk for breast cancer (RR, 1.09 per 10 g/day intake; 95 percent CI, 0.86 to 1.23), but not for BBD, associated with drinking after first pregnancy. Longer menarche to first pregnancy intervals seemed to indicate a stronger correlation between drinking before first pregnancy and breast neoplasia.
“Alcohol consumption before first pregnancy was consistently associated with increased risks of proliferative BBD and breast cancer,” the authors write.