Autism cases increased 500% in the New York - New Jersey area

According to a new study conducted by Rutgers University researchers, the number of children with autism in the New York–New Jersey region has increased by as much as 500 percent in 16 years, according to an institutional press release. Researchers said the uptick is driven largely due to awareness and new diagnoses of autistic children with average or above-average intellect.

What is Autism Spectrum Disorder (ASD)?

Autism Spectrum Disorder (ASD) is a developmental disorder that impacts an individual verbally, behaviorally, and socially. It is called a "spectrum" disorder because it affects individuals differently and to varying degrees. Since there is no exact medical test, determining ASD can be challenging. Some do not receive a diagnosis until they are adolescents or even adults.

For the study, researchers examined data from the New Jersey Autism Study (NJAS) between the years 2000 and 2016. They identified 4,661 8-year-olds with ASD in four New Jersey counties - Essex, Hudson, Ocean, and Union.

Autism doesn't necessarily overlap with intellectual disability

Among those identified with autism, 1,505 (32.3 percent) had intellectual disabilities, and 2,764 (59.3 percent) did not have intellectual impairments. The team also found that the rate of autistic children with intellectual disabilities increased 200 percent in 16 years- from 2.9 per 1,000 to 7.3 per 1,000. In contrast, the rates of ASD with no intellectual disability jumped up to 500 percent, from 3.8 per 1,000 to 18.9 per 1,000.

The study adds to a growing body of research that suggests that autism does not necessarily overlap with intellectual disability.

"One of the assumptions about ASD is that it occurs alongside intellectual disabilities," said Josephine Shenouda, an adjunct professor at the Rutgers School of Public Health and lead author of the study published today (January 26) in the journal Pediatrics. "This claim was supported by older studies suggesting that up to 75 percent of children with autism also have intellectual disability."

"What our paper shows is that this assumption is not true. In fact, in this study, two-in-three children with autism had no intellectual disability whatsoever," said Prof. Shenouda.

The new study also found an association between ASD prevalence and racial disparities. Historically, Black and Hispanic children have been diagnosed with autism at lower rates than white children.

The new analysis showed that among children without intellectual disabilities, Black children were 30 percent less likely than white children to be diagnosed with autism. However, the gap has narrowed among children with intellectual disabilities.

Higher detection rates could be due to better diagnoses

Researchers said that some of these detections were due to better recognition of the disorder in the diagnostic process.

"Better awareness of and testing for ASD does play a role," said Walter Zahorodny, associate professor at the Rutgers New Jersey Medical School and senior author of the study. "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."

Researchers emphasized that there is a need to understand better autism diagnoses and intellectual disabilities now more than ever. They recommended all toddlers be screened for autism during routine checkups at their pediatricians to ensure that autistic children — especially those without intellectual disabilities — don't fall through the cracks.

The study was published in the Journal of Pediatrics.

Study abstract:

Background: Intellectual ability predicts functional outcomes for children with autism spectrum disorder (ASD). It is essential to classify ASD children with and without intellectual disability (ID) to aid etiological research, provide services, and inform evidence-based educational and health planning.

Methods: Using a cross-sectional study design, data from 2000 to 2016 active ASD surveillance among 8-year-olds residing in the New York-New Jersey Metropolitan Area were analyzed to determine ASD prevalence with and without ID. Multivariable Poisson regression models were used to identify trends for ASD with ID (ASD-I) and without ID (ASD-N).

Results: Overall, 4661 8-year-olds were identified with ASD. Those that were ASI-I were 1505 (32.3%) and 2764 (59.3%) were ASD-N. Males were 3794 (81.4%), 946 (20.3%) were non-Hispanic Black (Black), 1230 (26.4%) were Hispanic, and 2114 (45.4%) were non-Hispanic white (white). We observed 2-fold and 5-fold increases in the prevalence of ASD-I and ASD-N, respectively, from 2000-2016. Black children were 30% less likely to be identified with ASD-N compared with white children. Children residing in affluent areas were 80% more likely to be identified with ASD-N compared with children in underserved areas. A greater proportion of children with ASD-I resided in vulnerable areas compared with children with ASD-N. Males had higher prevalence compared with females regardless of ID status; however, male-to-female ratios were slightly lower among ASD-I compared with ASD-N cases.

Conclusions: One-in-3 children with ASD had ID. Disparities in the identification of ASD without ID were observed among Black and Hispanic children as well as among children residing in underserved areas.