Caffeine consumption and fibrocystic breast disease: a case-control epidemiologic study.

In a hospital-based case-control study that included 634 women with fibrocystic breast disease and 1,066 comparison women in Connecticut, the occurrence of fibrocystic breast disease was positively associated with average daily consumption of caffeine. Women who consumed 31-250 mg of caffeine/day had a 1.5-fold increase in the odds of disease, whereas women who drank over 500 mg/day had a 2.3-fold increase in the odds. The association with caffeine consumption was especially high among women with atypical lobular hyperplasia and with sclerosing adenosis with concomitant papillomatosis or papillary hyperplasia, both of which have been associated with an increased breast cancer risk. The association was specific to fibrocystic breast disease in that there was no association of caffeine consumption with fibroadenoma or other forms of benign breast disease.