Prior studies have consistently demonstrated a linear dose-response relation between alcohol consumption and breast cancer risk, with an increased risk mainly observed among women who consumed the equivalent of at least one alcoholic beverage daily, but power was limited at the lower levels of alcohol consumption to determine whether there was a lower threshold. 2, 3, 5-11 Our data demonstrated that even consumption of alcohol as low as 5-9.9 gms/day (3 to 6 glasses of wine per week) may be associated with a modest increase in risk. We observed a 10% increase in risk with each 10 gm/day of alcohol intake, which is somewhat stronger than the risk reported in a previous large meta-analysis that used a single measure of alcohol intake at baseline (RR for each 10 gm per day = 1.07).1 Consistent with other studies, we did not find any difference by type of alcoholic beverage (i.e. beer, wine, or liquor).2, 3, 18, 19
