Meta-analysis for combining relative risks of alcohol consumption and prostate cancer

BACKGROUND. Prostate cancer has become the most common cancer among men in the United States, but Little is known about factors associated with prosta te cancer incidence. METHODS. A meta-analysis of studies published prior to July 1998 was conduc ted to pool relative risk (RR) estimates from the existing literature on th e association between prostate cancer and alcohol consumption, in an attemp t to determine whether there is an association, and if so, what its magnitu de is. RESULTS. The overall pooled RR estimate was 1.05 for both fixed and random effects models, based on six cohort studies and 27 case-control studies. Th e RR estimate varied Little by study design. Among types of consumption, th e highest risk was found for beer (RR = 1.27), but this was based on only e ight studies that reported type of alcohol consumed. A linear dose-response was fit to the 15 studies reporting amount of alcohol consumed, finding a RR of 1.05 (95% confidence interval (CI), 0.91-1.20) for each additional dr ink of alcohol per day or a RR of 1.21 for 4 drinks per day. When the avera ge drinks per day consumed in the 15 studies were used to estimate the over all risk for all 33 studies, a RR of 1.02 was found for each additional dri nk of alcohol per day. CONCLUSIONS. Overall, no association between prostate cancer and alcohol co nsumption was seen. While some categories of consumption showed an increase d risk, the studies reporting such categories appeared to be biased towards reporting a positive association among the categories. Prostate 42:56-66, 2000. (C) 2000 Wiley-Liss, Inc.