Prostate cancer is the most frequently diagnosed malignancy among American men, and mortality rates are particularly high among African American men in the Southeastern U.S. A recent study suggests that alpha-tocopherol supplementation decreases prostate cancer risk. The objective of the proposed study is to build on our prostate cancer risk. The proposed study will integrate traditional epidemiologic methods with contemporary nutritional biochemistry technique to examine small but potentially important differences in the consumption of alpha- tocopherol. Previous epidemiologic investigations may be flawed by the use of serum and plasma alpha-tocopherol measurements that may not reflect past alpha-tocopherol consumption. We propose a case-control biomarker study to test the hypothesis that consumption of alpha-tocopherol increases prostate cancer risk using stored erythrocyte membrane and adipose tissue samples from a case- control study of fatty acids and prostate cancer risk. The subjects, 134 cases and 87 controls, were recruited from the University of North Carolina Hospitals and the Durham Veterans Administration Medical Center. About 40% of the subjects are African-American. Analysis of the specimens will use gas chromatography and high performance liquid chromatography. We will use erythrocyte membrane and adipose tissue alpha-tocopherol composition as a biomarker of typical past consumption of alpha-tocopherol. The effect of alpha-tocopherol consumption of prostate cancer risk will be assessed using both the maximal chi-square statistic and by dividing the fatty acid exposure data into quartiles and calculating odd ratios, 95% confidence intervals and testing for trend. The proposed study may advance our understanding of the epidemiology of prostate cancer among black and white men in the Southeastern U.S. and will potentially provide important data for future dietary intervention studies and nutritional recommendations.
