Children with developmental delays — including autism — are nearly 50 percent more likely than other kids to become overweight or obese at young ages, according to a new study.

The findings come from what researchers say is the first large study to show an equally high risk of obesity among those with autism and other developmental delays.

The study of kids ages 2 to 5 included 668 with autism, 914 diagnosed with developmental delays or disorders and 884 typically-developing children. All of the participants had their height and weight measured and information was gathered about their medical, behavioral and developmental histories from records, interviews and questionnaires.

Those with autism were 1.57 times more likely to be overweight or obese, according to findings published recently in The Journal of Pediatrics. The risk for youngsters with developmental delays was 1.38 times higher.

Moreover, researchers found that the risk for obesity varied even among those on the spectrum, with children displaying severe symptoms of autism 1.7 times more likely to be overweight or obese than others with more mild symptoms of the developmental disorder.

“We need more research to understand why these children are more likely to develop obesity, and which children are at the highest risk,” said Susan E. Levy who led the study and is medical director of the Center for Autism Research at the Children’s Hospital of Philadelphia.

Levy and her colleagues noted that other medical conditions common among those with autism like gastrointestinal and sleep issues as well as side effects from medications and rigid food choices may play a role.

Given the increased risk for weight problems among children with developmental disabilities, the researchers said that clinicians treating young kids in this population should pay special attention to their weight and give parents specific information about how to prevent obesity.

“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,” Levy said.