Physical activity, body size and composition, and risk of ovarian cancer

Objectives: We examined the association between risk of ovarian cancer and physical activity and anthropometry (body mass index, height, waist, fat, and fat-free mass) in the Melbourne Collaborative Cohort Study. Methods: This prospective cohort study included 18,700 women aged 26-76 years old at recruitment between 1990 and 1994. Participants were interviewed about their physical activity, including frequency and intensity. Body measurements were taken directly; fat mass and fat-free mass were calculated from bioelectrical impedance analysis. During an average of 10.2 years of follow-up, 113 ovarian cancers were ascertained. Cox regression was used to estimate hazard ratios. Results: After adjusting for potential confounders, compared with no physical activity, the hazard ratios for levels of total physical activity were 1.56 (95% CI: 0.81, 3.00) for low level, 1.92 (1.07, 3.45) for medium level, and 2.21 (1.16, 4.24) for high level (test for trend, p = 0.01). The hazard ratio for ovarian cancer in relation to BMI was 1.22 (95% CI: 1.00, 1.48; p-trend, 0.06) per 5 kg/m2 increment, and for fat mass, 1.23 (95% CI: 1.01, 1.49; p-trend, 0.04) per 10 kg increment. Conclusions: This study found some evidence for a possible relationship between higher levels of physical activity and body size and increased ovarian cancer risk. © 2010 Springer Science+Business Media B.V.