Update on body composition and bone density in children with Prader-Willi Syndrome

Aim: To compare body composition in children with Prader-Willi syndrome (PWS) not naïve to growth hormone (GH) with obese and lean controls.

Methods: Participants included 12 children with PWS, 12 children with obesity (body fat percentage >95th percentile for age and sex) and 12 lean children (body fat percentage <85th percentile for age and sex) matched by age and height. Fat mass, lean mass, bone mineral content (BMC), bone mineral density (BMD) and BMD z-score for total body, hips and lumbar spine were obtained through dual X-ray absorptiometry.

Results: PWS had higher fat percentage in the legs (p = 0.04) but similar leg fat mass (p = 1.00) compared to obese. PWS exhibited lower lean mass in the body (p = 0.04) and legs (p = 0.02) than obese, but similar to lean (p = 1.00 and p = 0.89, respectively). PWS had lower hip BMC (p < 0.01), BMD (p < 0.01) and BMD z-score (p < 0.01) compared to obese but similar to lean. No other differences were found between PWS and obese (p > 0.05 for all).

Conclusions: Children with PWS not naïve to GH present differences in fat and lean mass distribution compared to obese controls. BMC and BMD appear unaffected by PWS, except at the hips.