Paper Title
Investigation of Vitamin D Levels in Iraqi Patients with Type 2 Diabetes Mellitus

Abstract
Vitamin D deficiency is common in the majority of the world's regions. Its deficiency or insufficiency contributes to cardiac disease, infectious diseases, bone disorders, metabolic and autoimmune disorders, such as type 2 diabetes mellitus (T2DM).This study aims to investigate the association between vitamin D levels and development of T2DM in Iraqi population. Methods: A case-control study was carried out on 200 T2DM patients and 200 healthy control groups. Standard methods were used to determine vitamin D, insulin, and fasting blood glucose (FBG) levels. A homeostatic model assessment (HOMA-IR) was used to evaluate insulin resistance (IR). Results: The patients' body mass index (BMI), fasting blood glucose, vitamin D levels, insulin levels, and insulin resistance were all significantly raised in patients with T2DM than in the healthy control group (P<0.05). Vitamin D deficiency and insufficiency were observed to be (20.5%, 28%) in the healthy control group and (37%, 35.5%) in the T2DM group, respectively. Individuals with vitamin D deficiency (less than 20 ng/ml) had a three-fold increased risk of T2DM, whereas those with vitamin D insufficiency (20–30 ng/ml) had a two-fold increased the risk. Vitamin D levels were negatively correlated with BMI, FBG, insulin levels, and insulin resistance (IR). Conclusions: Deficiency and insufficiency of Serum vitamin D levels were revealed to be risk factors for the development of T2DM in the Iraqi population and direct the development of insulin resistance. Keywords - T2DM; Vitamin D; Insulin Resistance; Vitamin D insufficiency.