Alcohol drinking may increase risk of breast cancer in men: a European population-based case-control study

It has been estimated that alcohol drinking increases the risk of breast cancer in women by approximately 7% for each increment of 10 g alcohol per day. However, the few studies conducted on breast cancer among men have failed to detect an association with quantitative measures of alcohol drinking, even if the alcohol intake is generally higher in men than in women. On the other hand, increased risks of male breast cancer were inconsistently reported in alcoholics or patients with liver cirrhosis. We have investigated the role of alcohol drinking in male breast cancer using data collected in a population-based case-control study on seven rare cancers, conducted in Denmark, France, Germany, Italy, and Sweden.

The cases were 74 histologically verified male breast cancer patients aged 35-70 years. The controls (n = 1432) were selected from population registers, and frequency-matched to the cases by age group and geographic area. To check for consistency, a separate analysis was conducted using as controls the patients with a rare cancer other than male breast recruited simultaneously in the European study (n = 519 men).

Based on population controls, the risk of developing breast cancer in men increased by 16% (95% CI: 7-26%) per 10 g alcohol /day (p < 0.001). An odds ratio of 5.89 (95% CI: 2.21-15.69) was observed for alcohol intake greater than 90 g per day, as compared with light consumers (< 15 g per day). Similar associations were observed when other rare cancers patients were used as controls.

We found that the relative risk of breast cancer in men is comparable to that in women for alcohol intakes below 60 g per day. It continues to increase at high consumption levels not usually studied in women.