Risk factors for ovarian cancer in central Italy

We conducted a case-control study to analyze risk factors for ovarian cancer.

Cases included 440 women (age range 13-80 years, median 54) with a histologically confirmed diagnosis of epithelial ovarian cancer who were admitted to the Gynecological Oncological Department of Gynecologic Oncology at the Catholic University Hospital in Rome, Italy. Controls were women admitted to the same hospital where cases were identified for acute nongynecological, nonhormonal, and nonneoplastic conditions. A total of 868 control women (age range 19-80 years, median 55) were interviewed.

In comparison with ever married women, the multivariate odds ratios (OR) of ovarian cancers was 2.0 (95% confidence interval, CI 1.3-3.2) for never married women. Cases and controls were similar as regards educational status and body mass index. No clear relation emerged between ovarian cancer and age at menarche, menopausal status, and age at menopause. In comparison with nulliparae, the estimated ORs were 0.8, 0.9, and 0.7, respectively, in women reporting one, two, or three births. Women reporting two or more induced abortions were at decreased risk of ovarian cancer (OR 0.5, 95% CI 0.3-1.0). In comparison with women reporting their first birth before 20 years of age, the multivariate ORs were 1.8, 2.0, and 2.8, respectively, for women reporting their first birth at age 20-24, 25-30, and >/=31 (chi(2) trend = 10.1). Breast-feeding for more than 1 year was associated with an OR of 0.5 (95% CI, 0.4-0.8). Forty-two (9.5%) cases and 164 (18.9%) controls reported ever oral contraceptive use: in comparison with never users, the multivariate OR was 0.4 (95% CI 0.3-0.6) for ever users, and the risk decreased with duration of use. The OR for ovarian cancer was 2.9 (95% CI, 1.5-5.8) for women with a family history of the disease.

This study, conducted on a relatively low-risk population, confirms the role of oral contraceptive on ovarian cancer risk and the direct association with family history of ovarian cancer. It also indicates that a later age at first birth is directly, and induced abortion and breast-feeding are inversely, related to the risk of the disease.