Objective: The relation between type 2 diabetes mellitus (T2DM) and serum-25-hydroxyvitamin D (25[OH]D) is unclear. We aimed to explore the association of 25(OH)D with islet β cell function and insulin resistance in patients with T2DM.

Methods: A total of 466 patients with T2DM and 364 healthy people in our hospital from 2016 to 2017 were enrolled. The difference of 25(OH)D between T2DM group and non-DM group was compared. Patients with T2DM were divided into low 25(OH)D group (LVD group, <47.7nmol/L, n=326) and normal 25(OH)D group(NVD group, >47.7nmol/L, n=140). The correlation between fasting plasma glucose(FPG), fasting insulin(FINS), fasting c-peptid(FCP), glycosylated hemoglobin(HbAlc), HOMA-IR, HOMA-β and 25(OH)D were compared.

Results: Serum level of 25(OH)D in T2DM group was significantly lower than non-DM group (42.33±13.79 vs.69.16±10.78, P<0.001). Levels of FPG, FINS, FCP, HbAlc, HOMA-IR, and HOMA-β in LVD group were higher than NVD group, but there was no significant difference. Correlative analysis showed that there was negative correlation between 25(OH)D and FCP (r=-0.101, P=0.03), but there was no significant correlation with FPG, FINS, HbAlc, HOMA-IR and HOMA-β (r=-0.87, 0.043, -0.290, 0.032, 0.017, all P>0.05). The 25(OH)D of Duration ≥ 5 years was lower than the Duration < 5 years (42.39±13.96 vs. 42.46±13.45, P=0.964). The 25(OH)D of HbAlc ≥ 7% was lower than HbAlc < 7% (42.02±13.85 vs. 44.19±13.50, P=0.192). The 25(OH)D in microvascular group was lower than non-microvascular group (40.86±13.82 vs. 43.35±13.72, P=0.059). The 25(OH)D in macrovascular group was higher than non-macrovascula group (42.49±13.95 vs. 42.09±13.23, P=0.807).

Conclusion: The 25(OH)D in patients with T2DM is lower than healthy people and is downtrend with the increase of diabetic duration and HbAlc. There is no definite correlation between 25(OH)D and the pancreatic islet function. The critical significance should be further studied.


N. Li: None. M. Chen: None. J. Dong: None. S. Yang: None. L. Xu: None. Y. Wang: None. H. Sun: None. H. Li: None. S. Qu: None.

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