A case-control study of caffeine and methylxanthines in benign breast disease.

A dietary case-control study of 854 histologically diagnosed cases of benign breast disease (BBD), 755 matched surgical controls, and 723 matched neighborhood controls was conducted in Israel between 1977 and 1980. No association between coffee consumption and BBD was found. Analyses by histological type, degree of ductal atypia, age, sex, and ethnic origin, controlling for several confounding factors, confirmed the lack of association. The estimated mean intake of methylxanthines was also similar for cases and controls (302, 312, and 313 mg for cases, surgical controls, and neighborhood controls, respectively). No evidence of a dose-response was noted. Our results suggest that there is no association between coffee or methylxanthine consumption and BBD, although we had a 70% chance of finding a risk ratio of 1.5 with an error of 5%.