Fat and lean masses in youths with Down syndrome: gender differences.
DXA scans reveal hidden trunk fat in youths with Down syndrome, making BMI and waist tape obsolete for this group.
01Research in Context
What this study did
Researchers scanned 70 boys and girls with Down syndrome. They used DXA, a low-dose X-ray, to measure fat and lean tissue.
Kids were 8-18 years old. The team compared each scan to data from typical youth of the same age and sex.
What they found
Every child with Down syndrome carried more fat and less muscle than peers. The extra fat sat mostly around the trunk, not the arms or legs.
Boys stored fat higher in the abdomen. Girls stored it lower around the hips. Standard BMI and waist tape missed these patterns.
How this fits with other research
Ferry et al. (2014) showed kids with DS can still build bone when they lift weights twice a week. Alejandro’s data say they start with less lean mass, so strength work is even more important.
Sasson et al. (2022) also warn against ‘simple’ tools. They found quick mobility tests like TUG work better than complex balance boards for adults with DS. Both papers push the same message: pick tools that fit the client’s cognitive and body profile.
Cummings et al. (2024) looked at BMI and motor skill in youth with intellectual disability. They found almost no link (τ ≤ 0.24). Together, the three studies say BMI is weak for both fat detection and motor prediction in DS/ID groups.
Why it matters
If you still use BMI or a tape measure to flag obesity in clients with Down syndrome, you will under-count risk. Ask the family for a DXA report, or request one from the pediatrician. Note truncal fat, not total weight. Add strength or bone-loading games to the behavior plan; the kids can gain muscle, but you have to program for it.
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02At a glance
03Original abstract
The present study aimed at comparing fat and lean masses between children and adolescents with and without Down syndrome (DS) and evaluating the presence of sexual dimorphism. Total and regional fat and lean masses were assessed by dual energy X-ray absorptiometry (DXA) and the percentage of body fat (%BF) by air-displacement plethysmography (ADP) in 31 participants with DS and 32 controls. Waist circumference (WC) was also measured. Analysis of covariance and the Student's t-test were used to compare variables between groups and between sexes within the same group. There were no significant differences in %BF, WC or body mass index (BMI) between groups. Females with DS showed higher fat and lean masses in the trunk, and lower fat and lean masses in the lower limbs compared with females without DS (all p≤0.05). Males with DS showed higher fat masses in the whole body and upper limbs, and lower lean masses in the whole body and lower limbs compared with males without DS (all p≤0.05). Females in both groups showed higher levels of fat, and lower levels of lean than did their respective males (all p≤0.05). Youths with DS showed higher fat and lower lean than their non-DS peers. The increased truncal fat in females with DS might indicate a higher risk of metabolic syndrome in this group. Sexual dimorphism in youths with and without DS was very similar. BMI, WC and %BF were not effective indicators of increased risk in youths with DS.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.02.023