Is body mass index a useful measure of excess body fatness in adolescents and young adults with Down syndrome?

UMMS Affiliation

Intellectual and Developmental Disabilities Research Center; Department of Pediatrics; Shriver Center



Document Type


Medical Subject Headings

Adolescent; Anthropometry; Body Composition; *Body Mass Index; Down Syndrome; Female; Growth Charts; Humans; Male; Obesity, Abdominal; Overweight; Predictive Value of Tests; Reproducibility of Results; Sensitivity and Specificity; Young Adult


Mental Disorders


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. Wiley and Sons Ltd, MENCAP and IASSID.

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Citation:Bandini LG, Fleming RK, Scampini R, Gleason J, Must A. Is body mass index a useful measure of excess body fatness in adolescents and young adults with Down syndrome? J Intellect Disabil Res. 2013 Nov;57(11):1050-7. doi: 10.1111/j.1365-2788.2012.01605.x. Epub 2012 Sep 14. PubMed PMID: 22974061; PubMed Central PMCID: PMC4019440. Link to article on publisher's site

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