Impact of obesity upon prostate cancer-associated mortality: A meta-analysis of 17 cohort studies

A number of epidemiological studies have suggested that obesity is associated, albeit inconsistently, with the incidence of prostate cancer (PCa). In order to provide a quantitative assessment of this association, the present study examined the correlation between obesity and the incidence and associated mortalities of PCa in an updated meta‑analysis of cohort studies. The cohort studies were identified by searching the EMBASE and MEDLINE databases on January 1, 2014. The summary relative risks (RRs) with 95% confidence intervals (CIs) were calculated using random‑effects models. In total, 17 studies, which included 3,569,926 individuals overall, were selected according to predefined inclusion criteria. Based upon the results of the random‑effects models, obesity was not significantly correlated with the incidence of PCa (RR, 1.00; 95% CI, 0.95‑1.06). However, further analysis revealed that obesity was significantly correlated with an increased risk of aggressive PCa (RR, 1.14; 95% CI, 1.04‑1.25). Furthermore, an increased risk of PCa‑associated mortality was significantly associated with obesity (RR, 1.24; 95% CI, 1.15‑2.33), without any heterogeneity between the studies (I2=0.0%; P=0.847). The present study provides preliminary evidence to demonstrate that obesity is a significant risk factor for aggressive PCa and PCa‑specific mortality. The low survival rates observed among obese males with PCa may be a likely explanation for this association.