New estimates show that 61.8 million people around the globe have autism and that the developmental disability is among the most common health issues facing youth.

As of 2021, researchers found that 1 in 127 people worldwide were on the spectrum, according to findings published recently in the journal The Lancet.

Autism was twice as likely to affect males versus females and there was high prevalence among young people, with the condition ranking in the top 10 causes of non-fatal health burden for those under age 20, the study found.

The findings are based on a review of studies and data that was conducted as part of the Global Burden of Diseases 2021 Study, which is considered the largest scientific effort to measure the prevalence and impact of various conditions. The autism rate identified in the new study “substantially changed estimates” from the last version of the report in 2019, but the researchers attributed the increase to updates in their methodology, in particular excluding studies that were likely to undercount prevalence.

Researchers identified variances in prevalence by geography with autism affecting 1 in 163 people in tropical Latin America versus 1 in 65 people in the higher-income Asia Pacific region.

“There are many factors contributing to this wide range, including varying exposures to risk factors, cultural variation, behavioral norms, or screening tools and diagnostic tools being used in those locations, and also how people are responding to these surveys, or whether they even choose to respond or participate in the survey in the first place,” said Dr. Damian Santomauro, an affiliate assistant professor at the Institute for Health Metrics and Evaluation at the University of Washington who led the study. “Work is currently ongoing to explore ways to quantify and correct for these differences so we can paint the most accurate picture of the prevalence of autism globally.”

The latest estimates from the Centers for Disease Control and Prevention indicate that 1 in 36 American children are on the autism spectrum. That figure is based on data collected on 8-year-olds in 2020. By contrast the rate was 1 in 150 in 2000. Experts attribute the rise in diagnosis to greater awareness of the developmental disorder.

Those behind the new study say they hope their findings will prompt better policies and greater supports for individuals with autism around the world.

“The prevalence and health burden of autism persisted across the lifespan,” Santomauro said. “These findings highlight the need for early detection and lifelong supportive services for autistic individuals.”