REPRODUCIBILITY OF MEASUREMENT OF RESTING ENERGY-EXPENDITURE IN PREPUBERTAL GIRLS

We determined the reproducibility of measuring resting energy expendit ure (REE) and the effect on REE of speeding the night before testing a t home compared with in a clinical research center. We studied 19 prep ubertal girls aged 6.0-10.1 y with a mean weight-for-height of 108% of ideal. REE was measured for 30 min with a metabolic monitor after 12 h of fasting on three consecutive mornings during two different hospit alizations 6 wk apart. The initial REE measurement of each hospitaliza tion was obtained on admission and the second and third measurements w ere performed during the 3-d hospitalization. Energy intake was ad lib itum and was recorded while the children were in the research center. Body composition was determined twice with dual-energy X-ray absorptio metry. No significant effect on REE of day within visit was found acro ss visits. There was no significant difference between the initial REE measurement and the second and third measurements. The mean REEs for the two hospitalizations were highly correlated. The mean CV in intrai ndividual REE (ie, all six measurements) was 5.8% and was unchanged wh en adjusted for fat-free body mass (FFM) or body weight. The mean CV i n interindividual REE decreased when adjusted for FFM or body weight. Because REE was highly reproducible, a single measurement can suffice for energy expenditure studies in girls aged 6-10 y. Admission to a cl inical research setting is not necessary for a reliable determination of REE.