Vitamin D in polycystic ovary syndrome: Relationship to BMI and insulin sensitivity — ASN Events
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Vitamin D in polycystic ovary syndrome: Relationship to BMI and insulin sensitivity (#119)

Anju E Joham 1 2 , Samantha Cassar 3 , Nigel K Stepto 3 , Cheryce L Harrison 1 , Samantha Hutchison 1 2 , Sanjeeva Ranasinha 1 , Helena Teede 1 2
  1. Monash Applied Research Stream, School of Public Health and Preventative Medicine, Monash University, Clayton, VIC, Australia
  2. Southern Health, Clayton, VIC, Australia
  3. School of Sport and Exercise Science, Victoria University, Melbourne, Australia

Background: Vitamin D is a fat soluble vitamin that has been correlated with insulin resistance (IR) [1]. Weight loss has been shown to improve both IR and Vitamin D levels [2]; however relationships between adiposity, Vitamin D and IR are unclear.

Objective: To explore the relationships between Vitamin D, IR and body mass index (BMI) in women with PCOS and weight-matched controls.

Design: Cross-sectional study

Setting: Tertiary medical centre

Participants: 21 overweight and 22 lean women with PCOS and 16 overweight and 19 lean BMI-matched control women without PCOS were studied at baseline.

Method: Following recruitment from community advertisement and screening, women were withdrawn from interfering medications and studied following a 3 month washout period. Blood samples were taken for Vitamin D and metabolic markers. Detailed body composition measures and gold standard euglycaemic hyperinsulinaemic clamps were performed.

Main Outcome Measures: Plasma levels of Vitmain D and glucose infusion rate (GIR) on clamp study and adiposity measures.

Results: Vitamin D levels were lower in overweight PCOS women compared with overweight controls (31.6 and 46.1 nmol/L respectively, p=0.01). Overall correlations revealed strong correlation between GIR and BMI (r=-0.58) and moderate correlation with BMI (r=-0.34) and GIR (r=0.30). Independent regression analysis between Vitamin D and BMI revealed a beta coefficient of -0.86 (p=0.002), indicating for every 1 unit increase in BMI, Vitamin D is reduced by 0.86 nmol/L. For GIR and Vitamin D, the beta coefficient was 0.06, p=0.012.

Sub-group analysis of the overweight cohort (n=37) showed that the PCOS group had significantly lower Vitamin D levels compared to the overweight non-PCOS group (beta coefficient -14.46, p=0.01). This difference in Vitamin D levels remained significant after adjusting for BMI (beta coefficient =-13.96, p=0.01). However, when adjusted for GIR this difference in Vitamin D was no longer significant between the two groups.


Conclusions: Vitamin D levels are lower in overweight women with PCOS compared to overweight controls but were similar within the lean cohort. Overall, BMI is the key correlate of Vitamin D status and this relationship may be in part mediated by IR.

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  1. Chiu KC, Chu A, Go VL, Saad MF. Hypovitaminosis D is associated with insulin resistance and beta cell dysfunction. Am. J. Clin. Nutr. 2004;79(5):820-5.
  2. 2. Tzotzas T, Papadopoulou FG, Tziomalos K, Karras S, Gastaris K, Perros P, et al. Rising serum 25-hydroxy-vitamin D levels after weight loss in obese women correlate with improvement in insulin resistance. J Clin Endocrinol Metab 2010;95(9):4251-7.
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