Iranian diabetics may not be vitamin D deficient more than healthy subjects

ABSTRACT

There are some reports of decreased serum levels of 25[OH]D in the subjects with impaired glucose tolerance and type 2 diabetes mellitus [T2DM]. To assess vitamin D status of the Iranian diabetics, a pilot study was conducted on 90 subjects with either type 1 diabetes mellitus [T1DM] [n= 30], T2DM [n= 30], or apparently healthy subjects [n= 30] during fall and winter of 2005. Serum samples were analyzed for 25-hydroxycholecalciferol using three different methods: high-performance liquid chromatography [HPLC], competitive protein-binding assay [CPBA] and radioimmunoassay [RIA]. In this study serum levels of 25[OH]D were categorized as follows sufficient. 37 nmol/L; 25 nmol/L. mild deficiency < 37 nmol/L; 12.5 nmol/L. moderate deficiency < 25 nmol/L; severe deficiency < 12.5 nmol/L. Results showed that the occurrence of vitamin D insufficiency was almost the same in patients with T1DM and healthy controls. Mean serum level of 25[OH]D in patients with T2DM was significantly higher than in T1DM, as judged by HPLC [58.2'] 8.5 vs. 35'] 5 nmol/L, Mann Whitney U-Wilcoxon, P= 0.024]. Moreover, both CPBA and RIA showed some over-estimation of serum 25[OH]D compared to HPLC. Our findings suggest that, at least in the cold seasons, vitamin D status of the healthy subjects may not be higher than that of T1DM patients