Endocrine Abstracts

Background: Women affected by polycystic ovary syndrome (PCOS) frequently suffer from obesity, insulin resistance and impaired glucose tolerance. There is evidence showing an association of hypovitaminosis D with metabolic disturbances in PCOS women. We aimed to investigate the influence of vitamin D supplementation on metabolic and endocrine parameters in PCOS women.

Design: Forty-eight women with PCOS were included in the study. Cholecalciferol was administered orally 20 000 IU weekly for 12 weeks. 25-Hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D₃, PTH, endocrine and metabolic parameters were determined and oral glucose tolerance tests were performed at baseline and after 12 weeks of vitamin D treatment. Insulin resistance was determined using homeostasis model assessment (HOMA)-index.

Results: PCOS women were aged 26±6 years. Mean BMI was 25.5±6.5 at baseline. Mean 25(OH)D levels increased from 25.6±11.8 to 51.6±18.1 ng/ml and mean PTH levels decreased from 39.0±21.0 to 30.1±12.4 pg/ml after vitamin D treatment (P<0.001 for all). Vitamin D treatment significantly lowered levels of total testosterone, free testosterone, and triglycerides and increased LDL levels (all P<0.05). BMI, HOMA-index, fasting and stimulated glucose and insulin levels remained unchanged.

Conclusion: Vitamin D treatment in PCOS women results in decreased androgen levels after 12 weeks, whereas obesity and parameters of glucose homeostasis remained unchanged. Large placebo controlled intervention trials are warranted to confirm our findings and to evaluate whether vitamin D supplementation is beneficial for PCOS women.