A new study by researchers at Children's Hospital of Philadelphia (CHOP), the University of Pennsylvania and six other centers reveals that children with developmental delays, including autism spectrum disorder (ASD), are up to 50 percent more likely to be overweight or obese compared with the general population.
The findings were published online by The Journal of Pediatrics.
This is the first large study to demonstrate that young children with ASD or developmental delays are at an equally high risk of developing obesity. Among children with ASD, those with a higher degree of impairment and more severe symptoms were found to be at even greater risk of developing obesity by age five.
The study included nearly 2,500 children between the ages of two and five years old. This age group is especially relevant, since it is an important window for early obesity prevention.
The research was conducted as part of the Study to Explore Early Development (SEED). The multisite study analyzed 668 children with ASD, 914 children with developmental delays or disorders and 884 children from the general population who served as controls. Children's heights and weights were measured during clinical visits, and ASD severity was measured using the Ohio State University Global Severity Scale for Autism.
The study showed that children with ASD were 1.57 times more likely to be overweight or obese than the general population. Children with developmental delays were 1.38 times more likely to be overweight or obese. The risk for obesity was even more pronounced in children with severe ASD symptoms, as they were 1.7 times more likely to be classified as overweight or obese than children with mild ASD symptoms.
"These findings make it clear that monitoring these children for excess weight gain at an early age is critical, and that prevention efforts should be expanded to include not just children with ASD, but those with other developmental diagnoses, as well," said Susan E. Levy, MD, MPH, the study's lead author and medical director of the Center for Autism Research at CHOP.
Although increased obesity in children with ASD has been reported in other studies, this study is the first to examine if children with other developmental disabilities are also at increased risk for developing obesity. Also, the researchers examined connections between excess weight gain and the presence of other medical, behavioral, developmental, or psychiatric conditions.
"We need more research to understand why these children are more likely to develop obesity, and which children are at the highest risk," said Levy. Other medical conditions are especially common among children with ASD, and the authors note that these may play a role in excess weight gain. Possible factors include endocrine disorders, genetic disorders, gastrointestinal symptoms, medication-associated side effects, sleep disturbances, or rigid food choices, among others.
The research findings may shed light into possible mechanisms underlying the increased obesity risk in children with ASD, which may offer targets for early intervention. The authors suggest that clinicians monitor children who receive a diagnosis of ASD or developmental delays/disorders for signs of excess weight gain, and that they provide specific guidance for their parents in an effort to prevent obesity. Parents should discuss with their medical caregiver any concerns they have about their child who may be showing signs of obesity.