Children with autism spectrum disorder (ASD) are more likely to become obese compared to their typically developing peers. But until now, it has remained unclear why ASD children are at greater risk for developing obesity.

In a new study, researchers at the University of Pennsylvania School of Nursing (Penn Nursing) examined early life risk factors for obesity among children with ASD and those with developmental delays or disorders, as well as children from the general population.

The findings, published in the journal Autism, are among the first to show that children with ASD had the highest frequency of rapid weight gain during the first six months of life, which may put them at increased risk for childhood obesity.

“Healthy growth patterns during infancy, in particular, may carry special importance for children at increased risk for an ASD diagnosis, including high-risk populations such as former premature infants, younger siblings of children with ASD, children with genetic disorders that predispose to ASD and others,” said Tanja Kral, Ph.D., associate professor of nursing in the department of biobehavioral health sciences and lead author of the study.

The study also showed that mothers across all groups who were overweight or obese before pregnancy were almost 2.5 times more likely to have a child who was overweight or obese at ages 2-5. The risk for childhood obesity across all groups was also 1.5 times greater for mothers who exceeded the recommendations for weight gain during pregnancy.

“Helping mothers achieve a healthy pre-pregnancy weight and adequate gestational weight gain and fostering healthy growth during infancy represent important targets for all children,” Kral said.

The findings of the new study may shed light into potential mechanisms underlying the increased obesity risk in children with ASD and offer targets for early intervention.

In the United States, the percentage of children and adolescents affected by obesity has more than tripled since the 1970s, according to the Centers for Disease Control and Prevention (CDC). Data from 2015-2016 show that nearly 1 in 5 school age children and young people (6 to 19 years) in the United States has obesity.

In addition, a 2014 study of more than 6,000 children and teenagers on the spectrum revealed that they are more than twice as likely to be overweight and nearly five times as likely to be obese as their typical peers.

Source: University Pennsylvania School of Nursing