Higher serum carotenoid concentrations associated with a lower prevalence of the metabolic syndrome in middle-aged and elderly Chinese adults

The association between serum carotenoids and the metabolic syndrome (MetS) remains uncertain, and little is known about this relationship in the Chinese population. The present study examined the association between serum carotenoid concentrations and the MetS in Chinese adults. We conducted a community-based cross-sectional study in which 2148 subjects (1547 women and 601 men) aged 50-75 years were recruited in urban Guangzhou, China. Dietary data and other covariates were collected during face-to-face interviews. Blood pressure, waist circumference, blood lipids, glucose and serum carotenoids (alpha-, beta-carotene, beta-cryptoxanthin, lycopene and lutein/zeaxanthin) were examined. We found dose-response inverse relationships between individual serum carotenoid concentrations and total carotenoids and the prevalence of the MetS after adjusting for potential confounders (P for trend <0.001). The OR of the MetS for the highest (v. lowest) quartile were 0.31 (95% CI 0.20, 0.47) for alpha-carotene, 0.23 (95% CI 0.15, 0.36) for beta-carotene, 0.44 (95% CI 0.29, 0.67) for beta-cryptoxanthin, 0.39 (95% CI 0.26, 0.58) for lycopene, 0.28 (95% CI 0.18, 0.44) for lutein + zeaxanthin and 0.19 (95% CI 0.12, 0.30) for total carotenoids. Higher concentrations of each individual carotenoid and total carotenoids were significantly associated with a decrease in the number of abnormal MetS components (P for trend <0.001-0.023). Higher serum carotenoid levels were associated with a lower prevalence of the MetS and fewer abnormal MetS components in middle-aged and elderly Chinese adults.