A recent study conducted by Rutgers University has found that the number of cases of autism spectrum disorder (ASD) in the New York-New Jersey metropolitan area has increased by as much as 500% between 2000 and 2016.
Notably, the highest increase was among children without intellectual disabilities. This is in contrast to previous research which suggested that autism typically co-occurs with intellectual impairment.
The study, which was published in the journal Pediatrics, used biannual data from the New Jersey Autism Study to identify 4,661 8-year-olds with ASD in four New Jersey counties (Essex, Hudson, Ocean, and Union) during the study period. Of these, 32.3% had an intellectual disability, while 59.3% did not.
The researchers found that rates of ASD co-occurring with intellectual disability increased two-fold between 2000 and 2016, from 2.9 per 1,000 to 7.3 per 1,000. Meanwhile, rates of ASD with no intellectual disability jumped five-fold, from 3.8 per 1,000 to 18.9 per 1,000. The study’s lead author, Josephine Shenouda, said that better awareness of and testing for ASD does play a role in the increase, but that the 500% increase in autism among children without intellectual disabilities suggests that there is something else driving the surge.
The study also found that there are disparities in the identification of ASD based on race and socioeconomic status. Black children with ASD and no intellectual disabilities were 30% less likely to be identified compared to White children, while children living in affluent areas were 80% more likely to be identified with ASD and no intellectual disabilities compared to children in underserved areas. The researchers argue that addressing these findings could help close identification gaps and bring much-needed ASD services to lower-income areas.