Abdominal fat quantity and distribution in women with polycystic ovary syndrome and extent of its relation to insulin resistance

Context: Increased abdominal fat has been linked to insulin resistance and increased cardiovascular risk. Because many patients with polycystic ovary syndrome (PCOS) present abdominal obesity, it may be the cause of insulin resistance in this disorder. Setting: Fat quantity and distribution were evaluated by dual x-ray absorptiometry at the Departments of Clinical Medicine at the University of Palermo and the University of Naples, Italy. Patients: A total of 110 patients with PCOS and 112 weight-matched controls were studied. Anthropometric data, blood glucose, serum insulin, and testosterone were evaluated. Total, trunk, and central abdominal fat quantity were measured by total-body dual x-ray absorptiometry. Results: Compared with weight-matched controls, patients with PCOS had similar quantity of total and trunk fat but higher quantity of central abdominal fat. This difference was not observed when comparing obese PCOS and obese controls but depended on differences between overweight and normoweight patients and controls. All obese subjects, independently of having PCOS or not, had increased central abdominal fat. The same parameter was increased in 71% of overweight PCOS, 50% of overweight controls, and 30% of normoweight PCOS patients. PCOS patients with increased central abdominal fat had significantly higher (P < 0.01) insulin levels and significantly reduced (P < 0.01) insulin sensitivity than controls with similar quantities of central abdominal fat. Overweight PCOS patients with normal abdominal fat had significantly higher (P < 0.05) insulin levels and significantly reduced (P < 0.05) insulin sensitivity than overweight controls with normal abdominal fat. Conclusions: Most obese subjects, independent of being affected by PCOS, have an abdominal form of obesity. However, abdominal fat excess may not be the only determinant of insulin resistance in PCOS.