Epidemiology
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To evaluate the relation between oral contraceptives and colon and rectal cancer, we analyzed combined data from two case-control studies conducted in six Italian regions between 1985 and 1996. The studies included 803 women with incident colon cancer, 429 with rectal cancer, and 2,793 controls with acute, nonneoplastic, nondigestive, non-hormone-related disorders. ⋯ Duration of use of oral contraceptives was inversely related to risk of colon but not rectal cancer. This study suggests that women who have ever used oral contraceptives are at lower risk of colon and rectal cancer.