Autism Has Increased 500% Over the Past 16 Years in New York, New Jersey

The study’s co-lead author suggests that these estimates are likely similar in other metropolitan areas in the US.

Autism Spectrum Disorder (ASD) is a pervasive developmental disorder that impacts communication, behavior, and social interactions.

Autistic people can also have intellectual disabilities along with autism. For example, during 2000 through 2002, estimates indicated that around 50% of autistic children also had intellectual impairments. However, a decade later, less than one-third of children with ASD had intelligence quotient (IQ) scores within the intellectual disability range.

What causes autism, besides certain genetic conditions, is largely unknown. What is known is that autism rates are increasing. According to the CDC, 2020 data indicates that about one in 36 children in the U.S. have ASD. In 2008, that number was one in 88, meaning the autism rate has more than doubled in the past 10 years.

Recently, scientists from Rutgers School of Public Health uncovered data that suggests the autism rate could be even higher, and autistic individuals without intellectual disabilities may be driving the increase.

Their findings were published on January 26 in the journal Pediatrics.

Scientists examine metro area autism rates

To conduct the study, researchers examined 2000 through 2016 cross-sectional data retrieved from the New Jersey Autism Study (NJAS) — which is part of the CDC’s Autism and Developmental Disabilities Monitoring Network (ADDM). After data analysis, the scientists identified 4,661 8-year-olds with ASD in the New York-New Jersey metropolitan area.

Among those identified, 1,505 (32.3%) had intellectual disabilities, and 2,764 (59.3%) did not have intellectual impairments. Looking into it further, the team found that between 2000 and 2016, the rate of autistic children with intellectual disabilities increased by 200%. In addition, the rate of autism in children without intellectual impairments showed a 500% increase.

Moreover, the study found that autistic Black children without intellectual impairments were 30% less likely to be identified than White children. What’s more, children without intellectual disabilities living in affluent areas were 80% more likely to be identified with ASD compared with children residing in underserved areas.

Josephine Shenouda, DrPH, MS, an Adjunct Professor of Biostatistics and Epidemiology at Rutgers School of Public Health and co-lead study author, told Healthnews, "Our estimates for the New York-New Jersey metro area are likely to be similar [to] estimates from other metro areas in the US."

She explained, "In New Jersey, we see many communities with autism rates at 5% or higher, and in a recent ADDM Network report, ASD rates of 4% were identified in San Diego, California." She continued, "We expect to see autism rates continuing to rise as identification of autism is improved. This study shows that even in an area with good resources and services, disparities in identification remain."

Why are autism rates increasing?

"We don’t know the factors that are driving autism prevalence," Shenouda said. "Better recognition of autism among children without intellectual disability is probably a factor, and while disparities in identification among underserved populations remain, it has improved over time." While numbers are increasing, so is research. Investigations around the country are ramping up in order to rule out unknown causes.

Whatever the reason, whether it be better recognition, genetic, or environmental influences, Shenouda suggests that, to a large degree, autistic individuals without an intellectual disability are driving the increase. "The number of children with autism is likely to continue increasing," she said.

Shenouda concluded, "The best way to address increasing autism and to effect disparities in autism identification is through universal autism screening during the toddler period."

The earlier detection is spotted, the better the care will be.