Is body mass index a useful measure of excess body fatness in adolescents and young adults with Down syndrome?
Article first published online: 14 SEP 2012
© 2012 The Authors. Journal of Intellectual Disability Research © 2012 John Wiley & Sons Ltd, MENCAP & IASSID
Journal of Intellectual Disability Research
Volume 57, Issue 11, pages 1050–1057, November 2013
How to Cite
Bandini, L. G., Fleming, R. K., Scampini, R., Gleason, J. and Must, A. (2013), Is body mass index a useful measure of excess body fatness in adolescents and young adults with Down syndrome?. Journal of Intellectual Disability Research, 57: 1050–1057. doi: 10.1111/j.1365-2788.2012.01605.x
- Issue published online: 23 SEP 2013
- Article first published online: 14 SEP 2012
- Accepted 12 July 2012
- body fatness;
- body mass index;
- Down syndrome;
Background To determine the validity of body mass index (BMI) to identify excess fatness in youth with Down syndrome (DS).
Methods Using the Centers for Disease Control and Prevention (CDC) growth reference, we defined overweight (≥85th percentile) and obesity (≥95th percentile) based on participants' age- and sex-specific BMI z-scores, calculated from measured height and weight. Percentage body fat was measured by dual-energy X-ray absorptiometry. We determined sensitivity, specificity, positive predictive value, negative predictive value and efficiency of BMI percentiles to identify excess adiposity relative to elevated percentage body fat cut-offs developed from the Pediatric Rosetta Body Composition project in 32 youth (20 boys/12 girls), ages 13–21 years with Down syndrome.
Results For adolescents with Down syndrome using the cut-off points of 95th percentile for BMI (obesity), sensitivity and specificity were 71% and 96% respectively. Positive predictive value was 83% and negative predictive value was 92%. Overall efficiency was 91%. Sensitivity and specificity for BMI cut-offs above the 85th percentile (overweight) were 100% and 60% respectively. The positive predictive value was 41% and negative predictive value was 100%. Overall efficiency was 69%.
Conclusion On the whole, the obesity (≥95th percentile) cut-off performs better than the overweight cut-off (85th–94th percentile) in identifying elevated fatness in youth with DS.