Effect of metabolic syndrome and its components on prostate cancer risk: Meta-analysis

Background: Literature data examining the role of metabolic syndrome and its components in prostate cancer risk are limited and contradictory. Aim: We did a meta-analysis of studies that evaluated the association between metabolic syndrome, its components, and risk of prostate cancer. Subjects and methods: We conducted an electronic search for articles published through September 2012 without restrictions. Every included study was to report risk estimates with 95% confidence intervals for the association between metabolic syndrome and prostate cancer. Results: The final number of papers included in the meta-analysis was 14, all published in English, with 4728 prostate cancer cases. Metabolic syndrome was associated with a 12% increase in prostate cancer risk (p=0.231), that was lower in cohort studies (7 studies, RR=1.04, p=0.791) than other studies (RR=1.23, p=0.125). The association was significant in the 8 European studies (RR=1.30, p=0.034), but not in the 4 U.S. or 2 Asiatic studies. The risk estimates of prostate cancer for higher values of body mass index, dysglycemia or dyslipidemia (high triglycerides, low HDL-cholesterol) were not significant; on the contrary, hypertension and waist circumference >102 cm were associated with a significant 15% (p=0.035) and 56% (p=0.007) greater risk of prostate cancer, respectively. Conclusions: Metabolic syndrome is weakly and non significantly associated with prostate cancer risk, but associations vary with geography. Among single components of the syndrome, hypertension and higher waist circumference are significantly associated with increased risk of prostate cancer.