Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Wehr, E.
The Role of Vitamin D in Polycystic Ovary Syndrome-Metabolic, Endocrine and Genetic Aspects
[ Dissertation ] Medical University of Graz; 2011. pp. 106
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- Autor*innen der Med Uni Graz:
- Lerchbaum Elisabeth
- Betreuer*innen:
- Kopera Daisy
- Obermayer-Pietsch Barbara
- Pieber Thomas
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- Abstract:
- Introduction: 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 insulin resistance. The association of vitamin D with endocrine, metabolic, and genetic aspects in PCOS is largely unknown. Methods: We performed a cross-sectional study including 206 PCOS women to investigate the association of serum 25-hydroxyvitamin D (25[OH]D) levels with metabolic and endocrine parameters. Moreover, we carried out an intervention study including 57 PCOS women, who received 20.000 IU cholecalciferol weekly for 24 weeks. Further, genotyping of vitamin D receptor (VDR) (Cdx-2, Bsm-I, Fok-I, Apa-I, and Taq-I), GC, DHCR7, and CYP2R1 polymorphisms was performed in 545 PCOS and 145 control women Results: We found a significantly negative correlation between 25(OH)D levels and BMI, weight, waist circumference, hip circumference, WHR, blood pressure, fasting and stimulated glucose, AUCglucose, fasting insulin, homeostatic model assessment-insulin resistance (HOMA-IR), HOMA-ß, triglycerides, and QChol/HDL and a positive correlation with Quantitative Insulin-sensitivity Check Index (QUCKI) and HDL (p<0.05 for all). In multivariate regression analysis, 25(OH)D and BMI were independent predictors of HOMA-IR and QUICKI (p<0.05 for all). PCOS women with impaired glucose tolerance and metabolic syndrome had lower 25(OH)D levels than PCOS women without these features (p<0.05 for all). In logistic regression analysis, 25(OH)D (OR 0.86, p=0.021) and BMI (OR 1.3, p<0.001) were independent predictors of metabolic syndrome in PCOS women. There were no significant associations of 25(OH)D with endocrine parameters in PCOS women. 46 PCOS women finished the study. 25(OH))D levels significantly increased from 28.0±11.0 ng/ml at baseline to 51.3±17.3 and 52.4±21.5 after 12 and 24 weeks, respectively (p<0.001). We observed a significant decrease of fasting and stimulated glucose (24 weeks, p<0.05) and C-peptide levels (12 and 24 weeks, p<0.001) after vitamin D treatment. Moreover, triglyceride and estradiol levels significantly decreased after 24 weeks(p=0.001) and 12 weeks (p=0.022), respectively, whereas total cholesterol (12 weeks, p=0.008) and LDL cholesterol levels (12 weeks, p=0.005; 24 weeks, p=0.026) significantly increased after vitamin D treatment. There were no changes in androgens. After 12 weeks, 14 out of 46 PCOS women previously affected by menstrual disturbances (30.4%) reported improvement of menstrual frequency; after 24 weeks, 23 out of 46 women (50.0%), who were oligo- or amenorrhoeic at baseline reported improvement. In PCOS women, the VDR Cdx-2 -AA¿ genotype was associated with lower fasting insulin (p=0.039) and HOMA-IR (p=0.041) and higher QUICKI (p=0.012) and MATSUDA-index (p=0.003). The VDR Apa-I -AA¿ genotype was associated with lower testosterone (p=0.028) levels. In PCOS women, 170 women (31.2%) presented with 25(OH)D levels <20 ng/ml. PCOS women carrying the GC -GG¿ genotype and the DHCR7 -GG¿ genotype had a significantly higher risk for 25(OH)D levels <20 ng/ml (OR 2.53 [1.27-5.06], p=0.009, and OR 2.66 [1.08-6.55], p=0.033, respectively) when compared to PCOS women carrying the GC -TT¿ genotype and DHCR -TT¿ genotype in multivariate analyses. We observed no association of genetic variations and PCOS susceptibility. Conclusion: We demonstrate that low 25(OH)D levels are associated with obesity, insulin resistance, impaired ß cell function, impaired gluc ...