Body mass index and mortality in prostate cancer patients: a dose response meta-analysis

BACKGROUND: Previous studies concerning the association between body mass index (BMI) and mortality in prostate cancer yielded mixed results. We investigated the association by performing a meta-analysis of all available studies. METHODS: Relevant studies were identified by searching PubMed and EMBASE to August 2015. We calculated the summary hazard ratio (HR) and 95% confidence interval (CI) using random-effects models. We estimated combined HRs associated with defined increments of BMI, using random -effects meta-analysis and dose response meta-regression models. RESULTS: Thirty-seven cohort studies and one case-control study involving 27 38 000 patients of prostate cancer were selected for meta-analysis. The summary results indicated higher prediagnosis BMI but not postdiagnosis BMI was associated with increased risk of death from prostate cancer. An increment of every 5 kg/m(2) in prediagnosis BMI was associated with a 15% higher prostate cancer-specific mortality (HR = 1.15, 95% CI: 1.07-1.23, P < 0.01). Prediagnosis or postdiagnosis BMI showed no effect on all-cause mortality in prostate cancer patients. CONCLUSIONS: In conclusion, higher prediagnosis BMI is associated with a higher risk of death from prostate cancer. Considering the significant heterogeneity among included studies, these findings require confirmation in future studies.