SERUM 25(OH)D CONCENTRATION AND METABOLIC SYNDROME AMONG ADULTS IN SOUTHWEST CHINA

Background and objectives: Vitamin D deficiency has been suggested as a risk factor for various chronic metabolic diseases. However, evidence regarding this issue among Chinese population is limited. The present study aimed to examine the association between serum 25-hydroxy vitamin D (25(OH)D) and metabolic syndrome (MS) in Chinese adults. Methods: Serum 25(OH)D was measured in a cross-sectional sample of 920 non-diabetic adults (62.61% women) aged 25-65 years recruited from Southwest China. Data on dietary intake and physical activity were collected by validated questionnaires. MS was defined according to the criteria of Chinese Diabetes Society. Fasting plasma glucose (FPG), insulin, glycated hemoglobin (HbA1c), the homeostatic model assessment-insulin resistance (HOMA2-IR), lipid profile and blood pressure were evaluated. Anthropometry measurement included waist circumstance (WC), height and weight, and the last two were used to calculate body mass index (BMI). Data were analyzed by multivariable-adjusted regression models. Results: We observed that 7.17% participants had MS, and the percentage of overweight or obese individuals (BMI = 25kg/m2) in our study was 29.24%. Compared with the lowest tertile of serum 25(OH)D, a statistically significant 53% lower odds of metabolic syndrome was observed for adults in the highest tertile (OR: 0.47, 95%CI: 0.24-0.89), after adjusting for age, gender, personal monthly income, smoking status, energy intake, and physical activity. Moreover, we observed significant inverse associations of 25(OH)D with fasting insulin (p=0.0007), HbA1c (p=0.0001), HOMA2-IR (p=0.0007) after adjusting for potential confounders, but not with other MS components. Conclusions: A poor vitamin D status is significantly associated with an increased risk of having metabolic syndrome and insulin resistance among Chinese adults, warranting further investigation in large prospective studies.