Consumption of methylxanthine-containing beverages and the risk of breast cancer.

The idea that caffeine might be involved in the etiology of breast disease was first proposed by Minton et al. in 1979. Since that time, numerous experimental and epidemiologic studies evaluating the relationship between methylxanthines and breast disease have been conducted. Results from studies on benign breast disease have been inconsistent, with some investigators observing a positive association and others no association. However, all but one of the studies which have examined methylxanthine intake and malignant breast disease have concluded that methylxanthines do not play a role in the development of this cancer. Although various methodologies were employed and different populations were evaluated, results were consistently negative. Thus, there appears to be no evidence of an association between coffee and other methylxanthine-containing beverages and breast cancer.