The association between alcohol consumption and breast cancer has been largely investigated, but few studies have investigated the effects of average intake when the pattern of drinking is taken into account. We sought to examine the association between drinking pattern of alcoholic beverages, particularly wine, and breast cancer using different statistical approaches.
Our study included 437 cases of breast cancer, newly diagnosed in the period 2002-2004, and 922 residence- and age-matched controls.
Women who had an average consumption of less than 1.5 drinks per day had a lower risk (odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.34-0.97) when compared with nondrinkers. This protective effect was due substantially to wine consumption since the proportion of regular wine drinkers is predominant in our study population. Furthermore, women who consumed between 10 and 12 g/d of wine had a lower risk (OR = 0.51; 95% CI = 0.30-0.91) when compared with non-wine drinkers. Above 12 g per day of wine consumption, the risk of breast cancer increased, but the association was nonsignificant.
Although no association between the pattern of total alcohol consumption and breast cancer was found, the type of alcoholic beverage seemed to play an important role in this association. Our results support the hypothesis that there is a threshold effect that risk decreased or was not modified for consumption under a certain threshold. Above that threshold, risk increased, however. The drinking pattern of each type of specific beverage, especially wine, seems important in terms of alcohol-breast cancer association. Low and regular wine consumption does not increase breast cancer risk.