213 VITAMIN D, PARATHYROID HORMONE AND THEIR ASSOCIATIONS WITH METABOLIC SYNDROME IN A MIDDLE-AGED CHINESE POPULATION

Objective: Inconsistent evidence suggests that low levels of vitamin D and high levels of parathyroid hormone (PTH) are associated with metabolic syndrome (MetS). The aim of this study was to explore the association of serum vitamin D and PTH with MetS in a middle-aged Chinese population. Methods: A population-based cross-sectional study was conducted among 1435 Chinese participants aged 20-83 years in 2010. Anthropometric phenotypes and blood pressure were obtained, and serum lipid, 25-hydroxy-vitamin D [25(OH)D] and PTH were measured. Results: One thousand four hundred thirty five participants included 572 women (37.9%), and 488 (34.0%) hypertensive patients, of whom 214 (43.9%) took antihypertensive drugs. The overall prevalence of MetS was 25.9%. The prevalence of vitamin D deficiency (<50 nmol/l), insufficiency (50-75 nmol/l) and sufficiency (>75 nmol/l) was 39.9%, 41.6% and 18.5%, respectively. After adjusting for covariates, 25(OH)D was positively associated with serum HDL cholesterol and negatively associated with waist circumference, serum triglyceride and glucose. In multivariable adjusted logistic model, the highest tertile of 25(OH)D compared with the lowest tertile had an odds ratio (OR) for having MetS of 0.60 (95% confidence interval 0.44-0.82, P = 0.004). There was no significant association between PTH and risk of MetS. Conclusions: Vitamin D deficiency was common, and serum 25(OH)D was independently associated with MetS in middle-aged Chinese.