Serum vitamin-D predicts insulin resistance in individuals with prediabetes

Indian J Med Res. 2013 Dec;138(6):853-60.

Abstract

Background & objectives: 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.

MeSH terms

  • 25-Hydroxyvitamin D 2 / blood*
  • Adult
  • Blood Glucose
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / pathology
  • Female
  • Humans
  • Insulin / blood
  • Insulin Resistance / genetics*
  • Lipids / blood
  • Male
  • Middle Aged
  • Parathyroid Hormone / blood
  • Prediabetic State / blood*
  • Risk Factors
  • Vitamin D / metabolism*
  • Vitamin D Deficiency / blood
  • Vitamin D Deficiency / pathology

Substances

  • Blood Glucose
  • Insulin
  • Lipids
  • Parathyroid Hormone
  • Vitamin D
  • 25-Hydroxyvitamin D 2