Fat and lean masses in youths with Down syndrome: gender differences.

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.

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.

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.

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.

This study used dual-energy X-ray absorptiometry and air-displacement plethysmography to compare 31 youths with Down syndrome to 32 peers. Overall, youths with Down syndrome carried higher fat mass and lower lean mass than their peers.

Body composition also varied by sex. Females with Down syndrome showed higher fat and lean mass in the trunk and lower amounts in the lower limbs, while males showed higher whole-body and upper-limb fat with lower lean mass. So body shape ranges widely, and not every child fits one stereotype.

Standard screening missed these differences. Body mass index, waist circumference, and percent body fat did not differ significantly between groups, so they were not effective indicators of the elevated risk seen on DXA.

The increased truncal fat in females is a concern because it is associated with metabolic syndrome. For clinicians, the practical message is to look beyond BMI and use direct body-composition measures when assessing health risk in this population.