Plasma Carotenoids and Prostate Cancer: A Population-Based Case-Control Study in Arkansas

Carotenoids possess antioxidant properties and thus may protect against prostate cancer. Epidemiological studies of dietary carotenoids and this malignancy were inconsistent, partially due to dietary assessment error. In this study, we aimed to investigate the relation between plasma concentrations of carotenoids and the risk of prostate cancer in a population-based case-control study in Arkansas. Cases (n = 193) were men with prostate cancer diagnosed in 3 major hospitals, and controls (n = 197) were matched to cases by age, race, and county of residence. After adjustment for confounders, plasma levels of lycopene, lutein/zeaxanthin, and β -cryptoxanthin were inversely associated with prostate cancer risk. Subjects in the highest quartile of plasma lycopene (513.7 μ g/l) had a 55% lower risk of prostate cancer than those in the lowest quartile (140.5 μ g/l; P trend = 0.042). No apparent association was observed for plasma α -carotene and β -carotene. Further adjustment for the other 4 carotenoids did not materially alter the risk estimates for plasma lycopene, lutein/zeaxanthin, and β -cryptoxanthin but appeared to result in an elevated risk with high levels of plasma α -carotene and β -carotene. The results of all analyses did not vary substantially by age, race, and smoking status. This study added to the emerging evidence that high circulating levels of lycopene, lutein/zeaxanthin, and β -cryptoxanthin are associated with a low risk of prostate cancer.