Rate of Autism Without Intellectual Disabilities Is Rising
March 07, 2023
By: Sherri Alms
Researchers at Rutgers University recently reported that, between 2000 and 2016, autism rates among children without intellectual disabilities rose by five times— from 3.8 per 1,000 to 18.9 per 1,000 in the New York-New Jersey metropolitan area. Rates among children with intellectual disabilities more than doubled – from 2.9 per 1,000 to 7.3 per 1,000. The research team used data from four counties included in the New Jersey Autism Study.
“One of the assumptions about [autism] is that it occurs alongside intellectual disabilities. This claim was supported by older studies suggesting that up to 75% of children with autism also have intellectual disability,” said Josephine Shenouda, an adjunct professor at the Rutgers School of Public Health and lead author of the study, in an article on the Rutgers website. However, the Rutgers research team found that two in three autistic children in the Rutgers study did not have any intellectual disability. More research is needed to specify the precise causes, she said.
“Better awareness of and testing for [autism] does play a role,” said Walter Zahorodny, associate professor at the Rutgers New Jersey Medical School and senior author on the study in the Rutgers article. “But the fact that we saw a 500 percent increase in autism among kids without any intellectual disabilities – children we know are falling through the cracks – suggests that something else is also driving the surge.”
Autism rates also increased overall, tripling among children in New York and New Jersey, the NBC News article noted. This mirrors findings for the country as a whole. One in 44 children had been diagnosed with autism by age 8 in 2018, compared to 1 in 150 in 2000, as reported by the Centers for Disease Control and Prevention.
The causes for the increase are not clear. Dr. Shenouda said in an article on the NJ.com website that environmental factors may play a role. Other experts believe the rate has remained more or less stable and that identification has gotten better. Stephen M. Kanne, director of the New York-Presbyterian Center for Autism and the Developing Brain, pointed out that researchers and clinicians have a better understanding of autism and how to diagnose it. “So we’re identifying more people with the disorder appropriately, and that creates the rise in prevalence that really does account for the lion’s share of what you’re seeing.”
Wendy Fournier, president of the National Autism Association, believes it’s a combination of both, as she said in a U.S. News & World Report article. “There is greater public awareness of early signs of autism, making parents more likely to address developmental concerns with their doctors, and actual prevalence rates are continuing to rise at alarming rates year after year.”
Similar to previous findings linking autism prevalence to race and socioeconomic status, the Rutgers study showed that, while they have narrowed, disparities still exist. According to the study, black children without intellectual disability were 30% less likely to be diagnosed with autism compared with white children. Children in affluent areas were 80% more likely to be identified with autism without intellectual disability compared with children living in underserved areas.
Dr. Shenouda said that the study’s findings highlight a need for early screening, identification, and intervention. “Because gains in intellectual functioning are proportionate with intense intervention at younger ages,” she noted. “it’s essential that universal screening is in place, especially in underserved communities.” She estimated that only about half of children in the United States are being screened, according to the NBC News article.
Sherri Alms is the freelance editor of The OARacle, a role she took on in 2007. She has been a freelance writer and editor for more than 20 years.