Body composition, energy expenditure, and energy intake in patients with Williams syndrome.

OBJECTIVE: To evaluate the body composition, resting energy expenditure (REE), and energy intake of adolescents and adults with Williams syndrome (WS) compared with matched healthy control subjects. METHODS: Body composition was determined by total body electrical conductivity and anthropometric measurements in six subjects with WS from the WS Clinic at Children's Hospital of Philadelphia and six healthy control subjects matched for age, height, and pubertal stage. REE was measured by open-circuit indirect calorimetry. Dietary intake was assessed by 3-day dietary records. RESULTS: Subjects with WS had similar anthropometric measurements to the control group except for a significantly lower percent body fat (17.1%+/-5.2% vs. 25.0%+/-6.7%). Dietary intake (measured in kilocalories per day) was similar between the two groups. REE was statistically higher by 155 kcal/day in the WS group after controlling for age, gender, and body composition. In addition, the WS group had a significantly higher percent predicted REE according to the World Health Organization equation, which adjusts for age, gender, and body weight. CONCLUSION: Adolescents and adults with WS have a similar dietary intake but a lower body fat than healthy control subjects. A higher REE may contribute to the thin body habitus and reduced total body fat stores of people with WS.

Differences in resting energy expenditure in prepubertal black children and white children.

OBJECTIVE: To evaluate differences in resting energy expenditure (REE) of black and white prepubertal children. SUBJECTS: The study subjects were 34 prepubertal children 5 to 12 years of age and weighing 90% to 206% ideal body weight. Girls represented 59% of the study subjects; 44% were white children and 56% were black children. METHODS: Fat-free mass (FFM), fat mass, and the percentage of body fat were determined by total body electrical conductivity. Fasting REE was measured by open-circuit indirect calorimetry. RESULTS: Although weight, height, FFM, fat mass, percentage of body fat, and age were similar between the ethnic groups (black vs. white children), the black subjects had a significantly lower REE (1312 +/- 38 kcal/day) compared with the white subjects (1524 +/- 43 kcal/day) after adjusting for age, gender, weight, FFM, and fat mass. Fat-free mass and ethnic group were the only significant predictors of REE (R2 = 0.70). CONCLUSION: Resting energy expenditure is significantly higher in this sample of white children compared with the black children after adjusting for body size and composition. Both FFM and ethnic background were significant determinants of REE in prepubertal children.

Resting energy expenditure in clinical pediatrics: measured versus prediction equations.

OBJECTIVE: To evaluate the use of resting energy expenditure (REE) prediction equations compared with measured REE in children referred for REE to aid clinical care. SUBJECTS: One hundred two patients, aged 0.2 to 20.5 years, 55% female, with a nutritional diagnosis of failure to thrive (76%), obesity (19%), or other (5%). METHODS: We measured REE by indirect calorimetry and compared with prediction equations: Food and Agriculture/World Health Organization/United Nations University (FAO/WHO/UNU) equation, Harris-Benedict (H-B) equation, and two equations from Schofield, one using weight (SCHO-WT) and one using weight and height (SCHO-HTWT). RESULTS: The SCHO-HTWT equation more closely predicted measured REE (100% +/- 19%), compared with the WHO equation (99% +/- 22%), the SCHO-WT equation, (99% +/- 21%), and the H-B equation (92% +/- 25%). The SCHO-HTWT equation was the best at predicting REE for obese subjects (95% +/- 17%), for those with failure to thrive (101% +/- 20%), and for children from birth to 3 years of age (101% +/- 23%). Nevertheless, the prediction equations closely predicted REE in only about 40% of subjects. CONCLUSION: These findings suggest that the SCHO-HTWT equation predicts REE in children with clinical nutritional problems better than equations that use weight alone. In view of the wide variability in REE measurements, however, we believe that REE should be measured in patients for whom knowledge of caloric expenditure is required for clinical care.