Recreational physical activity and endometrioma risk.

Endometriosis, defined by implantation of endometrial tissue outside the uterus, is commonly found on the ovaries and is characterized by a range of symptoms and severity, including chronic pelvic pain and infertility. The role of modifiable exogenous factors such as exercise in the development of this disease is not well understood. The authors conducted a 1990-1994 case-control study (77 cases, 735 controls) to evaluate the risk of cystic ovarian endometriosis (endometrioma) associated with recreational physical activity among females aged 18-39 years enrolled in the Group Health Cooperative of Puget Sound, Washington. Physical activity was evaluated according to its duration, frequency, and intensity during two periods of exposure: 2 years prior to the reference date and at ages 12-21 years. Women who reported frequent, high-intensity activity during the 2 years prior to the reference date had a 76% reduced endometrioma risk (odds ratio = 0.24, 95% confidence interval: 0.08, 0.71) compared with women who engaged in no high-intensity activity. A nonsignificant 53% reduction in risk was observed for women who reported such activity at ages 12-21 years (odds ratio = 0.47, 95% confidence interval: 0.18, 2.23). Activities of lower intensity, frequency, and duration were not associated with a woman's risk of endometrioma.