Low levels of 25(OH)D and insulin-resistance: 2 unrelated features or a cause-effect in PCOS?

Clin Nutr. 2012 Aug;31(4):476-80. doi: 10.1016/j.clnu.2011.12.010. Epub 2012 Jan 20.

Abstract

Background & aims: Recent investigations have identified low vitamin D status as a hypothetical mechanism of insulin-resistance in Polycystic Ovary Syndrome (PCOS). Instead, some authors supported the hypothesis that low vitamin D levels and insulin-resistance are 2 unrelated features of body size in PCOS. Hence, we aimed to explore the association of 25-hydroxyvitamin D (25(OH)D) with anthropometric, metabolic and hormonal features in PCOS.

Methods: We assessed the association of low 25(OH)D levels with endocrine parameters, insulin-sensitivity evaluated by hyperinsulinemic euglycemic clamp (HEC) and body composition measured by DEXA in 38 women affected by PCOS.

Results: Low 25(OH)D (25(OH)D < 50 nmo/L) was detected in 37% of the entire cohort of patients. Body Mass Index (BMI), in particular total fat mass (p < 0.001), resulted to be the most predictor factor of 25(OH)D levels whereas Sex Hormone Binding Globulin (SHBG), Free Androgen Index (FAI), glucose uptake and fat free mass were not.

Conclusions: Our data demonstrated that in PCOS low 25(OH)D levels are significantly determined by the degree of adiposity.

MeSH terms

  • Adult
  • Anthropometry
  • Blood Glucose / analysis
  • Body Composition
  • Female
  • Glucose Clamp Technique / methods
  • Humans
  • Insulin Resistance*
  • Multivariate Analysis
  • Polycystic Ovary Syndrome / etiology
  • Polycystic Ovary Syndrome / physiopathology*
  • Regression Analysis
  • Sex Hormone-Binding Globulin / metabolism
  • Vitamin D / administration & dosage
  • Vitamin D / analogs & derivatives
  • Vitamin D Deficiency / complications
  • Vitamin D Deficiency / physiopathology*
  • Young Adult

Substances

  • Blood Glucose
  • Sex Hormone-Binding Globulin
  • Vitamin D
  • 25-hydroxyvitamin D