Smoking, plasma vitamins C, E, retinol, and carotene, and fatal prostate cancer: Seventeen-year follow-up of the prospective Basel study

BACKGROUND Prostate cancer has one of the highest incidence rates of all cancers. Vitamin intake and tobacco use may have an impact on incidence and mortality, but epidemiologic evidence is scarce and inconsistent. METHODS Plasma vitamins C, E, retinol, and carotene were measured in 1971–1973 in 2,974 men working in Basel, Switzerland. In 1990, the vital status of all participants was assessed. RESULTS Two hundred and ninety men had died from cancer, including 30 with prostate cancer. On average, prostate cancer cases were 15 years older and smoked slightly more frequently than survivors. The mean values of plasma carotene, and of vitamin C, were nonsignificantly lower in prostate cancer cases than in survivors. After calculation of relative risk using the Cox model with exclusion of mortality during the first 2 years of follow‐up, low vitamin E levels in smokers were related to an increased risk for prostate cancer. Relative risks of low vitamin C and carotene levels were about 1. A slightly but nonsignificantly increased risk was observed for low levels of retinol. CONCLUSIONS Given the profound implication if the risk of prostatic cancer could be reduced, the relationship with vitamin E and smoking requires further study. Prostate 38:189–198, 1999. © 1999 Wiley‐Liss, Inc.