Serum carotenoid and retinol levels in African-Caribbean Tobagonian men with high prostate cancer risk in comparison with African-American men

Abstract

Black men are known to have a higher risk for prostate cancer (PC). Carotenoids and retinol, linked to PC, have not been compared in different black populations at risk. We examined serum carotenoid and retinol levels between PC-free African-Caribbean (AC) Tobagonian men with a high PC risk (high-grade prostatic intraepithelial neoplasia, atypical foci or repeated abnormal PC screenings) and African-American (AA) men with elevated serum prostate-specific antigen (PSA) levels (≥4 ng/ml). AC men who participated in the 2003 lycopene clinical trial and AA men who participated in the 2001-2006 National Health and Nutrition Examination Survey were compared. Serum specimens were analysed for carotenoid (β-carotene, α-carotene, β-cryptoxanthin, lutein/zeaxanthin and lycopene) and retinol levels by isocratic HPLC. Quantile regression was used to examine the association between serum carotenoid and retinol levels and black ethnicity, overall and among men with elevated serum PSA. There were sixty-nine AC men and sixty-five AA men, aged 41-79 years, included. AC men were associated with lower serum lycopene and retinol levels, and higher serum α- and β-carotenes and lutein/zeaxanthin levels compared with AA men, after adjusting for age, BMI, ever smoked cigarettes, education and hypertension (P≤0·03). Among men with elevated PSA, serum retinol was no longer statistically significant with ethnicity (P=0·06). Possible differences may be attributed to dietary intake, genetics and/or factors that influence bioavailability of these micronutrients. Prospective studies are warranted that investigate whether these differences in micronutrients between AC Tobagonian and AA men influence PC risk.