Association of hypovitaminosis D with metabolic disturbances in polycystic ovary syndrome

Objectives Women with polycystic ovary syndrome (PCOS) frequently suffer from metabolic disturbances, in particular from insulin resistance. Accumulating evidence suggests that vitamin D deficiency may contribute to the development of the metabolic syndrome (MS). Hence, the aim of our study was to investigate the association of 25(OH)D levels and the components of the MS in PCOS women. Methods 25(OH)D levels were measured by means of ELISA in 206 women affected by PCOS. Metabolic, endocrine, and anthropometric measurements and oral glucose tolerance tests were performed. Results The prevalence of insufficient 25(OH)D levels (<30 ng/ml) was 72.8% in women with PCOS. PCOS women with the MS had lower 25(OH)D levels than PCOS women without these features (17.3 vs 25.8 ng/ml respectively; P <0.05). In multivariate regression analysis including 25(OH)D, season, body mass index (BMI), and age, 25(OH)D and BMI were independent predictors of homeostatic model assessment-insulin resistance (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI; P <0.05 for all). In binary logistic regression analyses, 25(OH)D (OR 0.86, P =0.019) and BMI (OR 1.28, P <0.001) were independent predictors of the MS in PCOS women. We found significantly negative correlations of 25(OH)D levels with BMI, waist circumference, waist-to-hip ratio, systolic and diastolic blood pressure, fasting and stimulated glucose, area under the glucose response curve, fasting insulin, HOMA-IR, HOMA-β, triglycerides, and quotient total cholesterol/high-density lipoprotein (HDL) and positive correlations of 25(OH)D levels with QUICKI and HDL ( P <0.05 for all). Conclusion We demonstrate that low 25(OH)D levels are associated with features of the MS in PCOS women. Large intervention trials are warranted to evaluate the effect of vitamin D supplementation on metabolic disturbances in PCOS women.