Plasma 25-hydroxyvitamin D concentration and metabolic syndrome among middle-aged and elderly Chinese individuals.
OBJECTIVE
To evaluate the association between 25-hydroxyvitamin D [25(OH)D] and metabolic syndrome in the Chinese population.


METHODS
Plasma 25(OH)D was measured in a cross-sectional sample of 1,443 men and 1,819 women aged 50-70 years from Beijing and Shanghai. Metabolic syndrome was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. Fasting plasma glucose, insulin, lipid profile, A1C, and inflammatory markers were measured.


RESULTS
The geometric mean of plasma 25(OH)D was 40.4 nmol/l, and percentages of vitamin D deficiency [25(OH)D <50 nmol/l] and insufficiency [50 <or= 25(OH)D <75 nmol/l] were 69.2 and 24.4%, respectively. Compared with the highest 25(OH)D quintile (>or=57.7 nmol/l), the odds ratio for metabolic syndrome in the lowest quintile (<or=28.7 nmol/l) was 1.52 (95% CI 1.17-1.98, P(trend) = 0.0002) after multiple adjustment. Significant inverse associations also existed between 25(OH)D and individual metabolic syndrome components plus A1C. Moreover, we observed significant inverse associations of 25(OH)D with fasting insulin and the insulin resistance index (homeostasis model assessment of insulin resistance [HOMA-IR]) in overweight and obese individuals (BMI >or=24 kg/m(2)) but not in their normal-weight counterparts (test for interaction: P = 0.0363 and 0.0187 for insulin and HOMA-IR, respectively).


CONCLUSIONS
Vitamin D deficiency is common in the middle-aged and elderly Chinese population, and a low 25(OH)D level is significantly associated with an increased risk of having metabolic syndrome and insulin resistance. Prospective studies and randomized clinical trials are warranted to determine the role of 25(OH)D in the development of metabolic syndrome and related metabolic diseases.
Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences, Shanghai, China.
Ling
L
Lu
Zhijie
Z
Yu
An
A
Pan
Frank B
FB
Hu
Oscar H
OH
Franco
Huaixing
H
Li
Xiaoying
X
Li
Xilin
X
Yang
Yan
Y
Chen
Xu
X
Lin
D000368:Aged; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology
D014807:Vitamin D; C104450:25-hydroxyvitamin D