Energy expenditure in obese children with pseudohypoparathyroidism type 1a

Abstract

ContextPatients with pseudohypoparathyroidism type 1a (PHP-1a) develop early-onset obesity. The abnormality in energy expenditure and/or energy intake responsible for this weight gain is unknown.ObjectiveThe aim of this study was to evaluate energy expenditure in children with PHP-1a compared with obese controls.PatientsWe studied 6 obese females with PHP-1a and 17 obese female controls. Patients were recruited from a single academic center.MeasurementsResting energy expenditure and thermogenic effect of a high fat meal were measured using whole room indirect calorimetry. Body composition was assessed using whole body dual energy x-ray absorptiometry. Fasting glucose, insulin and hemoglobin A1C were measured.ResultsChildren with PHP-1a had decreased resting energy expenditure compared with obese controls (P <0.01). After adjustment for fat free mass, the PHP-1a group’s resting energy expenditure was 346.4 kcals/day less than obese controls (95% CI [−585.5 to −106.9], P <0.01). The thermogenic effect of food, expressed as percent increase in postprandial energy expenditure over resting energy expenditure, was lower in PHP-1a patients than obese controls but did not reach statistical significance (absolute reduction of 5.9%, 95% CI [−12.2% to 0.3%], P = 0.06).ConclusionsOur data indicate that children with PHP-1a have decreased resting energy expenditure compared with obese controls and that may contribute to the development of obesity in these children. These patients may also have abnormal diet-induced thermogenesis in response to a high fat meal. Understanding the causes of obesity in PHP-1a may allow for targeted nutritional or pharmacologic treatments in the future.