title: Serum vitamin-D predicts insulin resistance in individuals with prediabetes.
abstract: OBJECTIVE
  Patients with diabetes and vitamin-D insufficiency have increased insulin resistance. Similar observations among individuals with prediabetes are not well documented. The aim of this study was to find the occurrence of vitamin-D insufficiency/deficiency among individuals with prediabetes and to evaluate the relationship between vitamin-D status and insulin resistance.
  
  
  METHODS
  One hundred fifty seven individuals with prediabetes who fulfilled all the inclusion and exclusion criteria underwent clinical examination, anthropometric measurements (waist circumference, waist-hip ratio, waist-height ratio) and blood sampling after overnight fast for estimation of fasting blood glucose, fasting insulin, 25(OH)vitamin-D, intact parathyroid hormone (iPTH) and lipid profile. One hour post 75 g glucose (1hPG) blood glucose during oral glucose tolerance test was measured.
  
  
  RESULTS
  Vitamin-D deficiency/insufficiency was found in 115 (73.25%) individuals with prediabetes. Severe vitamin-D deficiency (<10 ng/ml) was seen in 14.65 per cent individuals. Individuals with the lowest vitamin-D levels (<10 ng/ml) had the highest insulin resistance (HOMA2-IR: 2.04 ± 0.67). Serum 25(OH)D had a statistically significant inverse correlation with insulin resistance (HOMA2-IR; r=-0.33; P=0.008), and positive correlation with insulin sensitivity (QUICKI; r=0.39; P=0.002), after adjusting for BMI and HbA1c. There was no correlation between vitamin-D status and estimated beta cell mass (HOMA-β). The mean waist-height ratio among individuals with prediabetes was 0.57 (normal<0.5) indicating a high risk of cardiovascular morbidity. Individuals with elevated 1hPG>155 mg/dl had significantly higher BMI and worse insulin resistance, and 1hPG correlated well with 2 hour post glucose blood glucose (r=0.57; P<0.001). INTERPRETATIONS & CONCLUSIONS: Vitamin-D deficiency/insufficiency may have some role in the development/worsening of insulin resistance in individuals with prediabetes in our country who have a high cardiovascular risk. Prospective studies on a large group of individuals need to be done to confirm the findings.
authors: Department of Endocrinology & Metabolism, Institute of Postgraduate Medical Education & Research & SSKM Hospital, Kolkata, India.
authors: Deep
authors: D
authors: Dutta
authors: Indira
authors: I
authors: Maisnam
authors: Ankit
authors: A
authors: Shrivastava
authors: Anirban
authors: A
authors: Sinha
authors: Sujoy
authors: S
authors: Ghosh
authors: Pradip
authors: P
authors: Mukhopadhyay
authors: Satinath
authors: S
authors: Mukhopadhyay
authors: Subhankar
authors: S
authors: Chowdhury
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D000328:Adult; D001786:Blood Glucose; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000473:pathology; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000235:genetics*; D008055:Lipids / Q000097:blood; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D011236:Prediabetic State / Q000097:blood*; D012307:Risk Factors; D014807:Vitamin D / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000097:blood / Q000473:pathology
chemical_list: D001786:Blood Glucose; D007328:Insulin; D008055:Lipids; D010281:Parathyroid Hormone; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2