Multivariable Assessment of Vitamin D Status in Type 2 Diabetes: A Cross-Sectional Study from Kurdistan Region-Iraq

To investigate the effect of serum level of vitamin D on the glycemic indices and cardiovascular risk factors that associated with type 2 diabetes (T2D), in Kurdistan region of Iraq.

Two hundred patients having T2D were classified according to their serum vitamin D level, normal (> 30 ng/ml, n = 33), insufficient (20–30 ng/ml, n = 29) and deficient (<20 ng/ml, n = 138). Serum vitamin D, insulin, C-peptide and amylin were assayed by ELISA. Lipid profile and serum glucose were measured by spectrophotometer and anthropometric, glycemic indices were determined. The data were analyzed using Analysis of Variance (ANOVA) with post hoc Tukey test for continuous data, and Chi-square test for category data.

Vitamin D plasma level did not influence the anthropometric measurements, lipid profile or glycemic indices except glycated hemoglobin (HbA_1c%) was increased significantly in patients with deficient vitamin D level. Serum vitamin D level significantly correlated with fasting serum insulin (r = +0.153, P = 0.040), C-peptide (r = +0.0183, P = 0.010), amylin (r = +0.231, p = 0.001), HbA_1c% (r =-0.145, P = 0.040), and the homeostasis assessment model of β-pancreatic cell (r = +0.163, P = 0.021).

Vitamin D activates the pancreatic β-cell in T2D patients leading to a significant release of insulin, C-peptide and amylin. This effect reflected on the improvement of HOMA-β. There is no relationship between the serum level of vitamin D with the anthropometric measurements or lipid profile.