Alcohol consumption and risk of breast cancer: the Framingham Study revisited.

Although many studies report that moderate-to-heavy alcohol intake increases breast cancer risk, the effect of light alcohol consumption remains controversial, and a consistent pattern of association with different types of alcoholic beverages is not evident. The authors examined the relation of average alcohol consumption and of different beverages to the risk of breast cancer in the Framingham Study (Framingham, Massachusetts). Of 2,764 women followed more than 40 years in the Original Cohort from 1948 to 1993 and 2,284 followed up to 24 years in the Offspring Cohort from 1971 to 1993, 221 and 66 incident breast cancer cases occurred, respectively. Breast cancer incidence decreased from 3.60 per 1,000 person-years to 2.47, 2.30, and 2.33 in increasing categories of average alcohol consumption (none, < 5.0, 5.0-< 15.0, and > or = 15.0 g/day) among the Original Cohort and from 3.07 to 1.26, 1.24, and 2.22, respectively, among the Offspring Cohort. With the two cohorts combined, multivariate-adjusted rate ratios of breast cancer in each increased category of alcohol consumption were 1.0 (nondrinkers), 0.8 (95% confidence interval (CI) 0.6-1.1), 0.7 (95% CI 0.5-1.1), and 0.7 (95% CI 0.5-1.1), respectively. Breast cancer was not associated with wine, beer, or spirits consumption when assessed separately. The findings suggest that the light consumption of alcohol or any type of alcoholic beverage is not associated with increased breast cancer risk.