Obesity and Risk of Bladder Cancer: A Meta-analysis of Cohort Studies

Abstract

<br/><b>Objective</b>: Previous epidemiologic studies demonstrated that obesity might associated with the risk ofbladder cancer. However, many of the actual association findings remained conflicting. To better clarify andprovide a comprehensive summary of the correlation between obesity and bladder cancer risk, we conducted ameta-analysis to summarize results of studies on the issue. Stratified analyses were also performed on potentialvariables and characteristics. <br/><b>Methods</b>: Studies were identified by searching in PubMed and Wanfang databases,covering all the papers published from their inception to March 10, 2013. Summary relative risks (SRRs) withtheir corresponding 95% confidence intervals (CIs) were calculated by either random-effect or fixed-effectmodels. <br/><b>Results</b>: A total of 11 cohort studies were included in our meta-analysis, which showed that obesity wasassociated with an increased risk for bladder cancer in all subjects (RR=1.10, 95% CI=1.06–1.16; p=0.215 forheterogeneity; I2=24.0%). Among the 9 studies that controlled for cigarette smoking, the pooled RR was 1.09(95% CI 1.01-1.17; p=0.131 for heterogeneity; I2=35.9%). No significant publication bias was detected (p = 0.244for Egger’s regression asymmetry test). <br/><b>Conclusions</b>: Our results support the conclusion that obesity is associatedwith the increased risk of bladder cancer. Further research is needed to generate a better understanding of thecorrelation and to provide more convincing evidence for clinical intervention in the prevention of bladder cancer.