The aim of the current study is to investigate the prevalence of vitamin D deficiency among patients with type 2 diabetes (T2DM) in a Chinese cohort. We enrolled 3025 patients with T2DM (aged 30-91 yrs) who were hospitalized in Qingdao Endocrine and Diabetes Hospital from Jan 2018 to Jan 2019. The exclusion criteria were as follows: (1) with other types of diabetes; (2) pregnant or lactating females; (3) with acute complications of diabetes or other stress states, such as surgery and trauma; (4) with rheumatologic, serious hepatic, cardiac, renal failure, malignancy, and endocrine diseases that affect the metabolism of vitamin D. Serum level of 25-OH-vitamin D ≥ 30 ng/mL was defined as normal, 20 ng/mL ≤ 25-OH-vitamin D < 30 ng/mL as vitamin D insufficiency (VDI) , and serum 25-OH-vitamin D < 20 ng/mL as vitamin D deficiency (VDD) . The chi-square test was used for group comparison of VDD or VDI prevalence. In all subjects, the prevalence of VDI was 35%. Male patients had higher prevalence of VDI than female patients (40.0% vs. 28.9%, P<0.05) . The prevalence of VDD was 48.8% in total while female had higher prevalence than male patients (57.2% vs. 41.8%, P<0.001) . We found a clear trend toward decreasing serum vitamin D concentration with rising HbA1c levels (P<0.001 in male and P<0.003 in female) . Dividing the HbA1c into deciles showed a linear association.

In conclusion, VDI and VDD is prevalent in patients with type 2 diabetes. Poor glucose control is related to lower serum level of vitamin D. Future studies are required to verify if vitamin D supplementation could be beneficial in patients with diabetes.


L. Zhang: n/a. J. Wang: None. Y. Yang: None. Y. Dong: None.

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