Women who drink the equivalent of roughly two bottles of wine over a weekend more than double their risk of developing breast cancer, BBC News Online reports research as suggesting.
A Danish study of 17,647 nurses found twice the risk of breast cancer in women who drank 22-27 drinks a week compared with those who drank one to three drinks.
The risk was greatest when drinks were consumed in a short period, reported the European Journal Of Public Health.
Women in the study were aged over 44, and most drank a moderate amount of alcohol.
A drink was defined as a bottle of beer or a glass of wine or spirit, which in Denmark is roughly 12g of alcohol.