Endocrine Abstracts

Background: Fat distribution in women with polycystic ovary syndrome (PCOS) is thought to favour accumulation of abdominal visceral fat, but there has been no systematic comparison of fat distribution in PCOS and normal controls using MRI scanning.

Aim: Our aim was to compare distributions of visceral, abdominal subcutaneous and gluteo-femoral subcutaneous adipose tissue in PCOS cases versus control women using a cross-sectional design.

Methods: Fat depot measurements from axial MRI images taken at anatomically pre-defined sites, were compared between 22 BMI/fat mass-matched pairs of PCOS cases and controls. Whole-group comparisons of fat depot measurements were made between 50 PCOS cases versus 28 female controls. All subjects were of UK British/Irish origin. Measurements included cross-sectional areas of adipose tissue within visceral (mid-L4), abdominal (mid-L4) subcutaneous and gluteo-femoral (greater trochanteric and mid-femoral) subcutaneous fat depots. Other measurements included body mass index (BMI), testosterone, SHBG and homeostasis model assessment of insulin resistance (HOMA2 IR, a measure of insulin sensitivity). Whole-group analyses were adjusted for fat mass and age. The study was approved by the local research ethics committee.

Results: There were no significant differences in fat-depot measurements between BMI/fat mass-matched pairs of PCOS cases and controls: mid-L4 visceral (P=0.40), abdominal subcutaneous (P=0.22), gluteal subcutaneous (P=0.67) and mid-femoral subcutaneous (P=0.37) depots. Whole-group comparisons gave similar results following adjustments for fat mass and age. Fasting serum insulin concentrations (P=0.03) and HOMA2 IR (P=0.03) were significantly higher in the PCOS group than in BMI/fat mass-matched controls.

Conclusions: PCOS cases and BMI/fat mass-matched control women are indistinguishable with respect to distribution of fat within visceral, abdominal subcutaneous and gluteo-femoral subcutaneous depots, despite significant differences in insulin resistance between these two groups.