Association of serum vitamin D with insulin resistance and inflammatory factors in initially diagnosed type 2 diabetes mellitus / 医学研究生学报

ABSTRACT

Objective Previous studies have shown that vitamin D may be involved in the pathogenesis of type 2 diabetes mellitus ( DM) , but the exact mechanism is not clear .The aim of this study was to investigate the association of serum vitamin D with insulin resistance in initially diagnosed type 2 DM and explore the mediating role of inflammatory factors IL-6 and TNF-αin this associ-ation. Methods This retrospectively study included 155 patients initially diagnosed with type 2 DM and 120 normal healthy controls . The concentration of serum 25( OH) D3 was detected by electrochemiluminescence in all the participants .The insulin resistance ( IR) index of the DM patients was calculated by homeostasis model assessment ( HOMA) and the correlation between serum vitamin D and HOMA-IR assessed by linear regression analysis .The DM patients were further divided into a vitamin D deficiency (<20 ng/mL, n=101) and a non-vitamin D deficiency group (>20 ng/mL, n=54), and the concentrations of serum IL-6 and TNF-αwere measured by enzyme linked immunosorbent assay and compared between the two groups. Results The level of serum vitamin D was significantly lower in the DM patients than in the normal controls ( [ 17.78±6.73] vs [42.70±11.46] ng/mL, P<0.01) and was negatively correlated with HOMA-IR (r2=-0.289, P<0.01).Both the concentrations of serum IL-6 and TNF-αwere markedly higher in the vitamin D defi-ciency than in the non-vitamin D deficiency group . Conclusion 2 DM by promoting insulin resistance , which is probably mediated by inflammatory factors IL-6 and TNF-α.