title: [Effects of vitamin D supplementation on insulin resistance in patients with type 2 diabetes mellitus].
abstract: OBJECTIVE
  To explore the effects of oral vitamin D supplementation on anthropometric parameters and insulin resistance (IR) in type 2 diabetes mellitus (T2DM).
  
  
  METHODS
  A total of 164 subjects with T2DM, aged 30-75 years, were randomly divided into two groups of intervention and control. The intervention group received a daily dose of 0.50 µg calcitriol while the control group maintained the original treatment regimen. At the beginning and end of 12-week supplementation trial, the demographic and anthropometric data were recorded and the serum levels of glucose, insulin, HbA1C and 25(OH)D measured. IR was assessed by the homeostasis model approximation index.
  
  
  RESULTS
  There was no significant inter-group difference at baseline. Compared with the baseline level, body mass index (BMI) ((-0.7 ± 1.7) vs (-0.4 ± 1.4) kg/m(2)) (P < 0.05), waist circumference (WC) ((-1.3 ± 1.3) vs ( -0.2 ± 1.1) cm) (P < 0.05) , fasting plasma glucose (FPG) ((-1.2 ± 2.3) vs (-0.6 ± 2.8) mmol/L) , fasting plasma insulin (FPI) ((-1.6 ± 2.2) vs (-0.32 ± 1.49) µU/ml) (P < 0.05), HbA1C ((-0.1 ± 0.6) vs (-0.03 ± 0.94))(P < 0.05), HOMA-IR ((-0.91 ± 2.63) % vs (-0.15 ± 1.78) %)(P < 0.05) and 25(OH)D ((20 ± 17) vs (1.0 ± 3.3) ng/ml) (P < 0.05) decreased obviously in the intervention group at the end of study. After stratifying by different baseline serum levels of 25(OH)D, HOMA-IR significantly decreased after supplementation in < 20 ng/ml group ((6 ± 3) vs (5 ± 3) ) (P < 0.05) , 20-30 ng/ml group ((6 ± 3) vs (5 ± 3)) (P < 0.05) and >30 ng/ml group ((5 ± 3) vs (4 ± 3)) (P < 0.05) . And BMI ((26 ± 6) vs (26 ± 4) kg/m(2)) (P < 0.05) , WC ((84 ± 11) vs (82 ± 12) cm) (P < 0.05) , FPG ((8 ± 4) vs (6 ± 4) mmol/L) (P < 0.05), FPI ((17 ± 4) vs (16 ± 4) µU/ml) (P < 0.05) and HbA1C((7.4 ± 0.9) % vs (7.0 ± 1.2) %) (P < 0.05) decreased statistically significant only in 15-20 ng/ml group. Multivariate regression analysis showed that HOMA-IR was a significant independent risk factor for 25 (OH) D (OR = 13, 95%CI = 4-39, P < 0.05).
  
  
  CONCLUSIONS
  There are significant improvements in BMI, WC, FPG, FPI, HbA1C and HOMA-IR after supplementation. Thus vitamin D supplementation may reduce insulin resistance in T2DM.
authors.affiliation: Department of Healthcare Endocrinology, Affiliated Shandong Provincial Hospital, Shandong University, Jinan 250021, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.forename: Haiyan
authors.initials: H
authors.lastname: Chen
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
authors.forename: Yinyin
authors.initials: Y
authors.lastname: Li
authors.affiliation: Email: liminglong@medmail.com.cn.
authors.forename: Minlong
authors.initials: M
authors.lastname: Li
authors.forename: Hongding
authors.initials: H
authors.lastname: Xiang
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2; D019587:Dietary Supplements; D005947:Glucose; D006706:Homeostasis; D006801:Humans; D007328:Insulin; D007333:Insulin Resistance; D008875:Middle Aged; D012307:Risk Factors; D014807:Vitamin D; D055105:Waist Circumference
chemical_list: D007328:Insulin; D014807:Vitamin D; D005947:Glucose