Physical activity and reduced risk of ovarian cancer

OBJECTIVE: To examine the relation between leisure-time physical activity and ovarian cancer. METHODS: We used data from a population based case-control study. Cases (n = 767) were women 20-69 years of age in whom epithelial ovarian cancer was diagnosed during 1994-1998 and who resided in a defined region of Pennsylvania, New Jersey, or Delaware. Controls (n = 1367) were ascertained by using random-digit dialing and Health Care Financing Administration files and were frequency-matched to cases for age and county of residence. Information on lifetime leisure-time physical activity was obtained during in-person interviews. RESULTS: Leisure-time physical activity was significantly associated with reduced occurrence of ovarian cancer (P =.01). After adjustment for age, parity, oral contraceptive use, tubal ligation, family history of ovarian cancer, race, and body mass index, women with the highest level of activity had an odds ratio of 0.73 (95% CI 0.56, 0.94) for ovarian cancer compared with women with the lowest level of activity. When the relation was analyzed by various recalled time periods during life, the odds ratios for the highest versus the lowest category of activity at ages 14-17, 18-21, 22-29, 30-39, 40-49, and >50 years ranged from 0.64-0.78. CONCLUSION: Leisure-time physical activity is associated with reduced occurrence of epithelial ovarian cancer.