title: Vitamin D and glycemic control in diabetes mellitus type 2.
abstract: OBJECTIVE
  The extraskeletal effects of vitamin D have attracted considerable interest. Vitamin D deficiency appears to be related to the development of diabetes mellitus type 2 and the metabolic syndrome. Vitamin D may affect glucose homeostasis, vitamin D levels having been found to be inversely related to glycosylated hemoglobin levels in gestational diabetes mellitus. In addition, vitamin D appears to protect from the development of gestational diabetes mellitus. The aim was to study levels of 25-hydroxy vitamin D3 [25(OH)D3] and the relationship between 25(OH)D3 levels and glycemic control in patients with diabetes mellitus type 2.
  
  
  METHODS
  Glycosylated hemoglobin (HbA1c) and 25(OH)D3 levels were measured in a group of 120 diabetes mellitus type 2 patients. The same measurements were performed in a group of 120 control subjects of the same age and sex. 25(OH)D3 was measured by radioimmunoassay and glycosylated hemoglobin (HbA1c) was measured by high-performance liquid chromatography.
  
  
  RESULTS
  25(OH)D3 levels were lower in the diabetes mellitus type 2 patients than in the control group, being 19.26 ± 0.95 ng/ml and 25.49 ± 1.02 ng/ml, in the patient and control groups, respectively (p < 0.001, Student's t-test). 25(OH)D3 levels were found to be inversely associated with HbA1c levels in the diabetic patients (p = 0.008, r (2) = 0.058, linear regression). 25(OH)D3 levels were found to be inversely associated with HbA1c when the patient and control groups were analysed together (p < 0.001, r (2) = 0.086).
  
  
  CONCLUSIONS
  Vitamin D levels appeared to be lower in diabetes mellitus type 2 patients than in the control group, vitamin D levels being related to glycemic control in diabetes mellitus type 2. These findings may have therapeutic implications as cautious vitamin D supplementation may improve glycemic control in diabetes mellitus type 2.
authors.affiliation: Department of Endocrinology, Red Cross Hospital, 7 Korinthias street, GR115 26 Athens, Greece.
authors.forename: Ifigenia
authors.initials: I
authors.lastname: Kostoglou-Athanassiou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Athanassiou
authors.forename: Anastasios
authors.initials: A
authors.lastname: Gkountouvas
authors.forename: Philippos
authors.initials: P
authors.lastname: Kaldrymides
keywords: diabetes mellitus type 2; glycemic control; vitamin D