Hormone responsible for higher risk of obesity in Down syndrome

Children with Down syndrome have higher level of a hormone leptin which may contribute to higher risk of obesity, according to researchers at Children’s Hospital of Philadelphia and the University Of Pennsylvania School Of Medicine.

The researchers studied 35 children aged four and 10 with Down syndrome and 33 of their siblings from Philadelphia area. The researchers intentionally did not include severely obese children in the study, in order to focus on risk factors for obesity before obesity occurred.

The researchers found that the children with Down syndrome had higher body mass index, a higher percentage of body fat and higher level of leptin compared to their siblings. The higher levels persisted even when the researchers adjusted for the effect of percentage of body fat, suggesting that differences in body composition did not account for the difference in Leptin levels.

“The normal role of leptin is to suppress appetite and regulate body weight,” said senior author Nicolas Stettler, M.D., MSCE, a pediatric nutrition specialist at The Children’s Hospital of Philadelphia. “In general, obese people have higher levels of leptin, which suggests that they have some leptin resistance-their bodies do not respond to the hormone properly. Because Down syndrome is a chromosome disorder, children with Down syndrome may have a genetic predisposition to more severe leptin resistance.”

Sheela N. Magge, M.D., M.S.C.E., a pediatric endocrinologist at Children’s Hospital, the first author of the study, stressed that more research remains to be done on this question, as the reasons are yet uncertain why patients with Down syndrome are at higher risk of obesity. “Although the study had an advantage in including siblings as a control group, because this decreases the influence of different environments on children with or without Down syndrome, the sample size was limited, so larger studies are necessary. However, our findings may point to a useful approach to understanding why obesity often occurs in Down syndrome.”

The National Institutes of Health, the Penn-Cheyney Export Center, the National Down Syndrome Society, the Juvenile Diabetes Research Foundation, and the Lawson Wilkins Pediatric Endocrinology Society all provided support for this study. Dr. Stettler and Dr. Magge’s co-authors were Virginia A. Stallings, M.D., and Kristen O’Neill, M.S., of Children’s Hospital; and Justine Shults, Ph.D., of the University Of Pennsylvania School Of Medicine. Stettler, Magge, and Stallings also have appointments at the Penn School of Medicine.