Alcohol consumption and breast cancer in Italy

The relationship between alcohol consumption and breast cancer (BC) risk was investigated using data from a cooperative case-control study, conducted in Italy between 1991-1994 on 2569 incident, histologically confirmed BC cases and 2588 controls in hospital for acute, non-neoplastic, non-hormonal related conditions. Overall 799 (31.1%) cases and 930 (35.9%) controls were not drinkers. Compare with them the relative risk (RR) of BC was 1.5 for drinkers <3.7 g/day, and 1.33, 1.15, 1.23, 1.37 for the drinkers respectively in the following categories: >=3.7-<13, >=13-<15, >=15-<27 and >=27 g/day and the trend in risk was 9.97. The association was apparently strongher in premenopausal women (RR=1.79 CI=1.29-2.49 for the category >= 27 g/day). Evaluating the various alcoholic beverages types one by one (wine, beer, digestiv, grappa and other alcoholic beverages) and the risk of BC, for beer drinkers compared with non-beer drinkers no additional risk was found whereas for grappa, digestivs and other alcoholic beverages a increasing risk was evident. For wine a significantly positive trend in BC risk was seen with increasing consumption with a risk of 1.27 (CI=1.08-1.50) for the category >=27 g/day. No appreciable interaction was observed with body mass index, smoking or any other covariate considered. No relationship was observed with duration, nor with cumulative life time consumption. Thus, the present data based on the validate alcohol consumption questionnaire and on a population caracterized by high consumption woman confirm that alcohol drinking is moderately related to breast cancer risk. If causal, this association can explain the 12% (95%CI=5%-19%) breast cancer cases in Italy.