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Reference ranges for body composition indices by dual energy X-ray absorptiometry from the Bone Mineral Density in
Babette S Zemel1, John A Shepherd2, Struan F A Grant3
1Division of Gastroenterology, Hepatology and Nutrition, The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
Insights
New dual energy X-ray absorptiometry (DXA) reference ranges for pediatric body composition were developed. These ranges, based on a diverse, low-obesity cohort, reveal differences compared to NHANES data, aiding accurate interpretation of child growth and health.
Area of Science:
- Pediatric Endocrinology
- Body Composition Analysis
- Public Health Nutrition
Background:
- Accurate body composition assessment is crucial for evaluating child growth, energy stores, and the effects of diseases and interventions.
- Current US pediatric reference ranges (NHANES) include a significant proportion of children with obesity (≥95th BMI percentile).
Purpose of the Study:
- To establish dual energy X-ray absorptiometry (DXA)-based pediatric reference ranges for body composition.
- To utilize a diverse cohort with a lower prevalence of obesity from the Bone Mineral Density in Childhood Study (BMDCS).
Main Methods:
- Secondary analysis of a longitudinal, prospective cohort study of healthy children aged 5-19 years across 5 US centers.
- Whole body DXA scans were performed annually, with generated reference ranges for lean soft tissue mass index (LSTM Index) and fat mass index (FMI).
- Sex and age-specific equations were developed to adjust body composition Z-scores for height Z-scores.
Main Results:
- 9846 scans from 2011 diverse participants (51% female, 22% Black, 17% Hispanic, 48% White, 7% Asian/Pacific Islander) with 6% obesity.
- NHANES and BMDCS reference curves were similar at the median, but NHANES showed higher +2 SD LSTM Index and FMI.
- Subgroup differences in appendicular LSTM Index-Z and FMI-Z were observed, becoming smaller after adjusting for height Z-score.
Conclusions:
- Developed reference ranges supplement limited normative data for pediatric body composition.
- The BMDCS cohort offers a valuable resource with an obesity prevalence comparable to current BMI charts.
- Recognizing subgroup differences is essential for accurate interpretation of pediatric body composition results.
Background:
Body composition assessment aids evaluation of energy stores and the impact of diseases and interventions on child growth. Current United States pediatric reference ranges from the National Health and Nutrition Examination Survey (NHANES) include 20% of children with obesity, body mass index of ≥95th percentile.
Objectives:
This study aimed to develop dual energy X-ray absorptiometry (DXA) based reference ranges in a diverse cohort with low-obesity prevalence from the Bone Mineral Density in Childhood Study (BMDCS).
Methods:
This is a secondary analysis of a longitudinal, prospective, observational cohort. Healthy children (height and BMI within 3rd to 97th percentiles, ages 5-19 y at enrollment), from 5 United States centers were measured annually for ≤7 visits. Whole body scans were acquired using Hologic scanners. A subsample underwent repeat measurements to determine precision. We generated reference ranges for appendicular and total lean soft tissue mass index (LSTM Index), fat mass index (FMI), and other body composition measures. Resulting curves were compared to NHANES and across subgroups. Sex and age-specific equations were developed to adjust body composition Z-scores for height Z score.
Results:
We obtained 9846 scans of 2011 participants (51% female, 22% Black, 17% Hispanic, 48% White, 7% Asian/Pacific Islander, and 6% with obesity). Precision (percent coefficient of variation) ranged from 0.7% to 1.96%. Median and-2 standard deviation curves for BMDCS and NHANES were similar, but NHANES +2 standard deviation LSTM Index and FMI curves were distinctly greater than the respective BMDCS curves. Subgroup differences were more extreme for appendicular LSTM Index-Z (mean ± SD: Asian -0.52 ± 0.93 compared with Black 0.77 ± 0.87) than for FMI-Z (Hispanic 0.29 ± 0.98 compared with Black -0.14 ± 1.1) and were smaller for Z-scores adjusted for height Z-score.
Conclusions:
These reference ranges add to sparse normative data regarding body composition in children and adolescents and are based on a cohort with an obesity prevalence similar to current BMI charts. Awareness of subgroup differences aids in interpreting results.
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