Methylxanthine consumption and the risk of ovarian malignancy.

Between 1970 and 1988, reports were published about two ecological studies, six case-control studies and one cohort study that evaluated the relationship between methylxanthine consumption and the risk of ovarian cancer. Because of the limitations of ecological studies, no inferences are based on them. All of the case-control studies recruited hospital controls. Nevertheless, four of the six had risk ratios of 1.5 or less. The one cohort study, which showed no relationship between coffee drinking and ovarian cancer, has low power. From these studies, it appears that coffee and tea consumption do not increase the risk of ovarian cancer.