Body size and ovarian cancer: case-control study and systematic review (Australia)

Objective: Although increased body mass is an established risk factor for a variety of cancers, its relation with cancer of the ovary is unclear. We t herefore investigated the association between measures of body mass index ( BMI) and ovarian cancer risk. Methods: Data from an Australian case-control study of 775 ovarian cancer c ases and 846 controls were used to examine the association with BMI. We hav e also summarized the results from a number of other studies that have exam ined this association. Results: There was a significant increased risk of ovarian cancer with incr easing BMI, with women in the top 15% of the BMI range having an odds ratio (OR) of 1.9 (95% confidence interval (CI), 1.3-2.6) compared with those in the middle 30%. Stratifying by physical activity showed a stronger effect among inactive women (OR = 3.0, 95% CI 1.3-6.9). The overall effect was con sistent with the findings of most prior population-based case-control studi es, while cohort studies reported positive effects closer to the null. Hosp ital-based studies gave variable results. Conclusions: Taken together, the evidence is in favor of a small to moderat e positive relation between high BMI and occurrence of ovarian cancer.