Body mass index at age 18 years and during adult life and ovarian cancer risk.

During the years 1994-1999, a nationwide ovarian cancer case-control study was conducted in Israel. The present analysis addresses the question: Is epithelial ovarian cancer associated with body mass index at age 18 years and/or with weight changes in body mass index between adolescence and adult life? The study is based on 1,269 women with epithelial ovarian cancer and 2,111 matched controls. A significant decrease in risk of ovarian cancer was observed with parity, oral contraceptive use, and postmenopausal status. A significant increase in risk with family history of ovarian/breast cancer was also found. No significant association with age at menarche or infertility was found. For body mass index at age 18 years, the odds ratio of the highest versus lowest body mass index quartile was 1.42 (95% confidence interval: 1.08, 1.85) and after adjusting for confounders was 1.54 (95% confidence interval: 1.17, 2.02). However, no statistically significant risk associated with change in weight from age 18 years to adult life was found. The authors conclude that, in their population, body mass index at age 18 years is an independent risk factor for ovarian cancer.