The status of 25-hydroxyvitamin D across the spectrum of glucose tolerance among middle-aged and elderly Chinese individuals.

ABSTRACT

CONTEXT Although vitamin D status and its inverse association with diabetes among White people have been recognized, little research on vitamin D status has been well conducted in Chinese individuals based on glucose tolerance. OBJECTIVE: To compare the vitamin D status of Chinese individuals aged 40-75 years based on the glucose tolerance status. DESIGN AND METHODS: Serum 25OHD was measured in a cross-sectional sample of 10 038 individuals aged 40-75 years from Lanzhou city, which is located in western China. RESULTS: People with normal glucose tolerance (NGT, n = 4744), prediabetes (n = 2808) or diabetes (n = 2486) aged 40-75 years were included in the study. The difference in 25OHD concentration between people with NGT and prediabetes was not significant (16·5 vs 16·0 ng/ml, P = 0·773), but the 25OHD concentration of diabetes was higher than that of subjects with NGT (16·5 vs 16·5 ng/ml, P = 0·025) and prediabetes (16·5 vs 16·0 ng/ml, P = 0·032) after adjusting confounders. There was no difference in the prevalence of vitamin D deficiency between people with NGT and diabetes (74·7% vs 74·0%, P = 0·535), but the prevalence of vitamin D deficiency of prediabetes was higher than that of people with NGT (77·0% vs 74·7%, P = 0·024) and diabetes (77·0% vs 74·0%, P = 0·012). CONCLUSIONS: Although vitamin D status was significantly different across the spectrum of glucose tolerance in middle-aged and elderly Chinese individuals, the difference was not clinically significant. The results, however, highlight the very high prevalence of vitamin D deficiency in this population and should raise the awareness of this important public health issue among health-care providers.