Prospective Study on Metabolic Factors and Risk of Prostate Cancer

BACKGROUND: There are inconsistent data regarding the association between metabolic factors, separately and combined, and the risk of prostate cancer and death from prostate cancer. METHODS: In the Metabolic Syndrome and Cancer Project (Me-Can), data on body mass index (BMI); blood pressure; and blood levels of glucose, cholesterol, and triglycerides were collected for 289,866 men. Cox proportional hazard models were used to calculate relative risks (RRs) by exposures in quintiles as well as for z scores (with a mean of 0 and a standard deviation of 1) together with a composite sum of scores to assess the combined effect of metabolic factors. RRs were corrected for random errors in measurement. RESULTS: During a mean follow-up of 12 years, 6673 men were diagnosed with prostate cancer and 961 died of the disease. Men with high levels of glucose and triglycerides were found to have a decreased risk of prostate cancer: top versus bottom quintile of glucose: RR, 0.82 (95% confidence interval [95% CI], 0.62-1.08; P value for trend = .03) and top versus bottom quintile of triglycerides: RR, 0.88 (95% CI, 0.74-1.04; P value for trend = .001). High BMI, elevated blood pressure, and a high composite z score were found to be associated with an increased risk of death from prostate cancer: top versus bottom quintile of BMI: RR, 1.36 (95% CI, 1.08-1.71); systolic blood pressure: RR, 1.62 (95% CI, 1.07-2.45); and per 1-unit increase of the composite z score: RR, 1.13 (95% CI, 1.03-1.25). CONCLUSIONS: The authors found no evidence of an association between high levels of metabolic factors and the risk of prostate cancer, but high BMI, elevated blood pressure, and a composite score of all metabolic factors were associated with an increased risk of death from prostate cancer. Cancer 2012;118:6199-206. (C) 2012 American Cancer Society.