P-0542-Association of hypovitaminosis D with pancreatic beta cell dysfunction in Bangladeshi impaired fasting glucose subjects
Author block: L. Ali, I.A. Hossain 
Bangladesh Biochemistry and Cell Biology, Bangladesh University of Health Sciences (BUHS), Dhaka, Bangladesh.
Background: Impaired fasting glucose (IFG) subjects in Bangladeshi population have previously been shown to have insulin secretory defect; however, the risk factors and underlying mechanism(s) of this defect vary substantially from population to population.
Aims: Vitamin D is known to play a role in insulin secretion. Accordingly, the association of serum vitamin D with pancreatic ß cell dysfunction in IFG subjects has been investigated in the present study. 
Methods: Under an observational analytic study a group of 48 IFG subjects (M/F, 16/32; age in years, 41±10; BMI in kg/m2, 24.43±3.47; M±SD) and 37 age/-, sex- and BMI-matched healthy Controls (M/F, 14/23; age in years, 40±12; BMI in kg/m2, 24.18±4.34) were investigated. IFG was diagnosed as per WHO Study Group criteria following a 2-sample OGTT. Serum glucose was measured by the glucose-oxidase method. Serum insulin and vitamin D reflecting 25-hydroxyvitamin D [25(OH)D] were measured by ELISA techniques. Insulin secretory capacity (HOMA%B) was calculated by homeostasis model assessment (HOMA). Data were analyzed by univariate, bivariate and multivariate analysis as appropriate.
Results: IFG subjects showed significantly lower levels of HOMA%B compared to the Control subject (102.06±32.65 vs. 143.08±34.40, M±SD; p<0.001). They also showed significantly lower levels of [25(OH)D] (20.63±9.67 vs. 34.80±5.59, ng/ml, p<0.001). On binary logistic regression analysis [after adjusting the effects of waist circumference (WC) and TG] lower levels of HOMA%B and [25(OH)D] were found to be independent determinants of the IFG state [HOMA%B odds ratio (OR) 0.947, p=0.003] and [25(OH)D (OR) 0.849, p=0.012] respectively. On pearson’s correlation analysis, [25(OH)D] showed significant positive correlation with HOMA%B (r=0.380, p=0.001) in IFG subjects. On multiple linear regression analysis, HOMA%B in the IFG subjects showed significant positive association with [25(OH)D] (β=0.441, p<0.001) after adjusting the effects of WC and TG. 
Conclusion: Reduced levels of 25-Hydroxyvitamin D seem to have an association with defects in insulin secretion which is the basic defect in IFG subjects.