To assess the association between glucose metabolism and ectopic lipid content in different clinical classifications of PCOS

Objective: There are emerging data indicating an association between PCOS (polycystic ovary syndrome) and metabolic derangements with potential impact on its clinical presentation. Therefore, this study aims to assess carbohydrate metabolism, ectopic lipids and their possible interaction in women with PCOS. Moreover, differences between the two established classifications of the disease should be evaluated.

Methods: Cross-sectional study conducted at the Medical University of Vienna. A detailed metabolic characterization was performed in 53 untreated PCOS patients as well as 20 controls including an extended OGTT (to assess insulin action, secretion and ß-cell function) as well as a nuclear magnetic resonance spectroscopy of liver and muscle.

Results: Women with PCOS classified by the original NIH 1990 definition showed a more adverse metabolic risk profile compared to women characterized by the additional Rotterdam 2003 phenotypes. Subtle metabolic derangements were detectable in both subgroups, including altered shapes of OGTT curves, impaired insulin action and hyperinsulinemia due to increased secretion and attenuated hepatic extraction. No differences were observed for ectopic lipids between the groups. However, particularly hepatocellular lipid content was significantly related to clinical parameters of PCOS like whole body insulin sensitivity, dyslipidemia and free androgen index.

Conclusions: Subtle alterations in carbohydrate metabolism are present in both PCOS classifications, but more profound in subjects meeting the NIH 1990 criteria. Females with PCOS and controls did not differ in ectopic lipids, however, liver fat was tightly related to hyperandrogenism and an adverse metabolic risk profile.