Leptin Levels among Prepubertal Children with Down Syndrome Compared with Their Siblings

Objectives

To compare levels of leptin and other obesity-related hormones in prepubertal children with Down syndrome (DS), a population at high obesity risk, and those in unaffected siblings to better understand the pathophysiology of obesity in children with DS.

Study design

This was a cross-sectional study of 35 children with DS and 33 control siblings, ages 4 to 10 years, with a fasting blood sample and anthropometric measurements to estimate body composition. Generalized estimating equations were used to account for the lack of independence between siblings.

Results

In addition to having higher body mass index and percent body fat, children with DS had higher leptin levels than unaffected siblings, even after adjustment for age, sex, race, and ethnicity (difference, 5.8 ng/mL; 95% CI, 2.4-9.3; P = .001) and further adjustment for percent body fat (difference, 2.7 ng/mL; 95% CI, 0.08-5.40, P = .04). Leptin and percent body fat were positively associated in both groups (P < .0001), but with a significantly greater positive association in the DS group, suggesting a significant effect modification (P < .0001).

Conclusions

This group of children with DS had increased leptin levels for percent body fat than their unaffected siblings. This difference may contribute to the increased risk for obesity in children with DS.

Abbreviations: BMI, Body mass index, DS, Down syndrome, DXA, Dual energy X-ray absorptiometry, GEE, Generalized estimating equations, HOMA, Homeostasis model assessment, IGF, Insulin-like growth factor, PWS, Prader Willi Syndrome, QUICKI, Quantitative insulin sensitivity check index