Assessing energy requirements in women with polycystic ovary syndrome: A comparison against doubly labeled water

Context: Weight loss is prescribed to offset the deleterious consequences of polycystic ovary syndrome (PCOS), but a successful intervention requires an accurate assessment of energy requirements. Objective: Describe energy requirements in women with PCOS and evaluate common prediction equations compared with doubly labeled water (DLW). Design: Cross-sectional study. Setting: Academic research center. Participants: Twenty-eight weight-stable women with PCOS completed a 14-day DLW study along with measures of body composition and resting metabolic rate and assessment of physical activity by accelerometry. Main Outcome: Total daily energy expenditure (TDEE) determined by DLW. Results: TDEE was 2661 6 373 kcal/d. TDEE estimated from four commonly used equations was within 4% to 6% of the TDEE measured by DLW. Hyperinsulinemia (fasting insulin and homeostatic model assessment of insulin resistance) was associated with TDEE estimates from all prediction equations (both r = 0.45; P = 0.02) but was not a significant covariate in a model that predicts TDEE. Similarly, hyperandrogenemia (total testosterone, free androgen index, and dehydroepiandrosterone sulfate) was not associated with TDEE. In weight-stable women with PCOS, the following equation derived from DLW can be used to determine energy requirements: TDEE (kcal/d) = 438 2 [1.6∗Fat Mass (kg)] + [35.1∗Fat-Free Mass (kg)] + [16.2∗Age (y)]; R2 = 0.41; P = 0.005. Conclusions: Established equations using weight, height, and age performed well for predicting energy requirements in weight-stable women with PCOS, but more precise estimates require an accurate assessment of physical activity. Our equation derived from DLW data, which incorporates habitual physical activity, can also be used in women with PCOS; however, additional studies are needed for model validation.