Epidemiological studies have reported an inconsistent association between obesity and ovarian cancer. To update the current knowledge of and further qualify the association between overweight, obesity and ovarian cancer risk, we conducted a meta-analysis of published observational studies.Methods
Using the PubMed, MEDLINE and EMBASE databases, we performed a literature search of all of the case–control and cohort studies published as original articles in English before March 2015. We included 26 observational studies, of which 13 were case–control studies (7782 cases and 21 854 controls) and 13 were cohort studies (5181 cases). Fixed- and random-effects models were used to compute summary estimates and the corresponding 95% confidence intervals. Subgroup analyses were also performed.Results
The pooled relative risk for overweight and obesity compared with normal weight (body mass index = 18.5–24.9 kg/m2) was 1.07 (95% confidence interval: 1.02–1.12) and 1.28 (95% confidence interval: 1.16–1.41), respectively. In subgroup analyses, we found that overweight/obesity increased the risk of ovarian cancer in most groups, except for the postmenopausal group (overweight: pooled relative risk = 0.97, 95% confidence interval: 0.76–1.24; obesity: pooled relative risk = 0.93, 95% confidence interval: 0.61–1.42). There was no evidence of publication bias.Conclusions
Increased body weight was associated with an increased risk of ovarian cancer; in particular, severe obesity demonstrated a stronger risk effect. No statistically significant association was observed in the postmenopausal period, but was in the premenopausal period.