Associations of serum vitamin A and carotenoid levels with markers of prostate cancer detection among US men

Associations of serum vitamin A and carotenoid levels with markers of prostate cancer detection were evaluated among 3,927 US men, 40-85 years of age, who participated in the 2001-2006 National Health and Nutrition Examination Surveys. Five recommended definitions of prostate cancer detection were adopted using total and free prostate-specific antigen (tPSA and fPSA) laboratory measurements. Men were identified as high risk based on alternative cutoffs, namely tPSA > 10 ng/ml, tPSA > 4 ng/ml, tPSA > 2.5 ng/ml, %fPSA < 25%, and %fPSA < 15%. %fPSA was defined as (fPSAA center dot tPSA)x 100%. Serum levels of vitamin A (retinol and retinyl esters) and carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein + zeaxanthin, lycopene) were defined as quartiles and examined as risk/protective factors for PSA biomarkers. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using binary logistic models. After adjustment for known demographic, socioeconomic, and lifestyle confounders, high serum levels of retinyl esters (tPSA > 10 ng/ml: Q4 vs. Q1 -> OR = 0.38, 95% CI: 0.14-1.00) and alpha-carotene (%fPSA < 15%: Q4 vs. Q1 -> OR = 0.49, 95% CI: 0.32-0.76) were associated with a lower odds, whereas high serum level of lycopene (tPSA > 2.5 ng/ml: Q4 vs. Q1 -> OR = 1.49, 95% CI: 1.01-2.14) was associated with a greater odds of prostate cancer detection. Apart from the three significant associations observed, no other exposure-outcome association was significant. Monitoring specific antioxidant levels may be helpful in the early detection of prostate cancer.