Document Type : Original Article

Authors

Department of Internal Medicine and Endocrinology, Isfahan Endocrine and Metabolism Research Center, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Objective: Considering the physiologic roles of vitamin D on insulin regulation, the effects 
of vitamin D treatment on insulin sensitivity and resistance indexes and beta cell function 
in pre‑diabetic vitamin D deficient patients were investigated.
Methods: In a randomized open clinical trial, 61 pre‑diabetic vitamin D deficient patients 
who were the first degree relatives of type 2 diabetic patients, were enrolled and randomized 
into three groups (A, B and C). GroupA (n = 21) were treated with intramuscular injection 
of 300,000 units of vitamin D at the beginning of the study and one month later. In 
group B (n = 20), injection of vitamin D plus 500 mg/d calcium and in group C (n = 20), just 
calcium was administered for two months. At baseline and two months later, oral glucose 
tolerance test was done. Homeostasis Model of Assessment-Insulin Resistance (HOMAIR), insulin resistance index, Homeostasis Model of Assessment-B (HOMA-B) which is a 
beta cell function index, and Matsuda index, an insulin sensitivity index, were calculated and 
compared before and after intervention and between three groups.
Findings: In vitamin D treated groups (A + B), the mean (SD) of HOMA‑IR increased 
from 2.46 (1.36) to 3.1 (2.3) (P  =  0.02), and Matsuda index decreased from 11 (3) to 
9.0 (2.3) (P = 0.001).
Conclusion: Injection of vitamin D increased insulin resistance and decreased insulin 
sensitivity indexes.

Keywords

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