Children from low-income families, girls, and 3- to 5-year-olds showed the steepest increases in autism rates, according to a large CDC study. The researchers also found 1 in 5 children were diagnosed with a developmental disability. The authors cited earlier detection and awareness as contributors to the increases. But experts said the paper offered no evidence for those explanations, called for a “greater sense of urgency to understand” what’s behind the large increases.
The percentage of U.S. children diagnosed with a developmental disability rose sharply between 2019 and 2024, with reported cases of autism increasing by more than 40% and ADHD also climbing substantially, according to a new study published in Pediatrics.
In 2023-2024, an estimated 20.45% of children ages 3 to 17 — roughly 1 in 5 — were diagnosed with at least one of five developmental disabilities, up from 16.73% in 2019-2020, a 22.2% increase in just five years.
Autism showed the largest increase, rising 42.4%, with the steepest increases reported among 3- to 5-year-olds and children from families living below 200% of the federal poverty level.
Researchers from the Centers for Disease Control and Prevention’s (CDC) National Center for Health Statistics analyzed data from the 2019-2024 National Health Interview Survey, a nationally representative household survey that includes detailed health interviews with families in their home or by phone.
Toby Rogers, Ph.D., social & economic research fellow at the Brownstone Institute, told The Defender that the “truly alarming” findings were solid, based on a large sample size and a detailed dataset.
He called the lead author, Benjamin Zablotsky, Ph.D., “a titan in the field of autism prevalence research.”
However, Rogers told The Defender that he was “struck by the cowardice of the study’s discussion section and conclusions.”
In their discussion of the data, the authors said the study didn’t investigate what drove the substantial increases, but that changes in diagnostic criteria and clinical practices, and increased awareness among parents and across society may explain the increased prevalence.
“The conclusion that these increases ‘could be related to earlier detection and awareness’ is speculation that is not grounded in any strong evidence presented in the paper, autism researcher Cynthia Nevison, Ph.D., told The Defender.
Nevison, who recently published a study in California that found comparable rising rates, said the CDC researchers could have acknowledged that the numbers may also reflect true increases in autism — and that “distinguishing those alternative explanations is an urgent public health research priority.”
The study examined data from 2019-2024. “A lot of toxicological factors changed during that time period,” Rogers said. He cited more onerous vaccine mandates in California, New York and other blue states; more shots added to the childhood vaccine schedule and recommended for pregnant women; and the COVID-19 shots, which were given to the most Americans for the first time.
