Does body mass index correlate with the mortality of prostate cancer? A dose-response meta-analysis of cohort studies

The relationship between body mass index (BMI) and mortality of prostate cancer (PCa) is still controversial. We performed a meta-analysis of cohort studies to evaluate potential linear and non-linear dose-response relationships between BMI and mortality of PCa. Studies were identified by comprehensively searching PubMed, Scopus, and Web of Science databases through June 22, 2016 without language restriction. Linear and non-linear dose-response meta-analyses were conducted to identify the effects of BMI on mortality of PCa. Nine cohort studies were finally included in this meta-analysis. Dose-response analysis indicated that the pooled relative risks (RRs) per 5 kg/m(2) increment of BMI were 1.16 (1.10-1.23) for fatal PCa. There was no evidence of a nonlinear relationship between BMI and fatal PCa (P = 0.908 for nonlinearity). Moderate heterogeneity was observed among included studies (P = 0.027, I-2 = 52.2%). Overall, the findings of this meta-analysis indicate that, based on available information, obesity is associated with a higher risk of fatal PCa.