The resting metabolic rate in women with polycystic ovary syndrome and its relation to the hormonal milieu, insulin metabolism, and body fat distribution: a cohort study

PURPOSE: To evaluate possible alterations of a major determinant of energy expenditure, the resting metabolic rate (RMR), in women with polycystic ovary syndrome (PCOS) compared with age-BMI similar controls. To assess whether the hormonal milieu, the body fat distribution and the insulin metabolism may affect energy consumption in these patients. METHODS: This is a monocentric observational prospective cohort study, including 109 Caucasian PCOS subjects and 31 healthy control women. (Median age PCOS 26.0 ± 9.2 years, controls 25.5 ± 8.5 years; median BMI-body mass index PCOS 26.4 ± 9.4 kg/m2, controls 27.2 ± 12.8 kg/m2). RMR was evaluated by the SenseWear Armband (SWA), a reliable and validated metabolic holter, never previously used in the PCOS population to this purpose. Hormonal assessment, insulin metabolism evaluated by HOMA-IR and OGTT, anthropometric features (BMI and WHR) were also assessed. RESULTS: Median RMR resulted similar in PCOS and control women: 1520.0 ± 248.00 kcal/day vs 1464.0 ± 332.70 kcal/day (p = 0.472), even after adjusting for BMI, fat distribution, insulin metabolism parameters. RMR resulted significantly correlated with BMI, WHR, estradiol levels, SHBG, total cholesterol, triglycerides, basal glycaemia, basal insulinemia, AUC insulin 240', and HOMA. In the subgroup of patients with WHR > 0.85, PCOS women showed a significantly lower RMR compared with controls. CONCLUSIONS: The higher prevalence of obesity, which negatively influences the reproductive and general health of PCOS women, could be related to factors other than an intrinsic alteration of the RMR. Further studies are needed to clarify the possible role of the visceral fat in modulating the energy balance in PCOS.