March 11, 2021

Youth with ASD have higher body mass index: study

Vanderbilt researchers have concluded that children with autism spectrum disorder (ASD) tend to have higher body mass index (BMI) percentiles when compared to youth with typical development.

Vanderbilt researchers have concluded that children with autism spectrum disorder (ASD) tend to have higher body mass index (BMI) percentiles when compared to youth with typical development.

Their findings confirm previous research that suggests youth with ASD may be at heightened risk for weight-related health concerns.

Blythe Corbett, PhD

The study, led by Blythe Corbett, PhD, professor in the Department of Psychiatry and Behavioral Sciences and investigator with the Vanderbilt Kennedy Center, was completed simultaneously with another study led by Corbett, which found that on average, girls with ASD experience the onset of puberty significantly earlier than their peers.

“In this study, we demonstrated that youth with ASD had higher BMIs when compared to typically developing children,” Corbett said.

“The findings are a significant concern, as it’s now been replicated by several different samples and labs.”

ASD is primarily considered a psychosocial diagnosis, defined by difficulties in social communication and interaction, but the study’s results suggest that there may be a physical aspect to ASD as well.

“When we think about autism spectrum disorder, we immediately think about things like social interaction and communication. We need to consider the child as a whole, including both their social and physical worlds,” Corbett said.

While BMI is not a diagnostic tool, it is considered a proxy of percentage of body fat and is a fair predictor of cardiovascular risk.

In addition to physical consequences, the social consequences of a higher BMI can include stigma or bullying, to both of which children with ASD may be particularly vulnerable.

Corbett recommends all parents — not just those of children with ASD — encourage their children to eat more fruits, vegetables and healthy grains.

“However, many adolescents on the spectrum tend to have more limited diets in terms of the types of foods they will eat based on taste, texture or even color,” she said.

This may require parents of children with ASD to be creative with snacks and meals.

Another recommendation for all children, but particularly for youth with ASD and higher BMIs, is physical activity. “Children with autism tend to be more sedentary, and we need to help them become more physically active,” said Corbett. “We need to encourage them to join sports teams and try to set up play dates at the park instead of at home.”

Corbett stresses the importance of identifying youth that are having health concerns during adolescence so they can be set on a healthy course early on in life.

“It’s important to make sure our children are not only growing cognitively and socially, but growing healthily in terms of their natural physical development, too,” she said.