Risk factors of ovarian cancer of epithelial origin: a case control study.

Possible risk factors for ovarian cancer of epithelial origin were tested in a case control study consisting of personal interviews with 200 patients and 211 age-matched controls. Some lifestyle factors such as urban versus rural residence show differences between patients and controls, but this may be due to a low response rate in the randomly selected control group. Confirmation of the potentially protective effect of oral contraceptives will require several more years of use, as most of the women who are now reaching the age of highest incidence of ovarian cancer of epithelial origin had several children prior to the availability of oral contraceptives. The only consistent risk factor when a discriminant analysis is carried out is a low number of pregnancies.