New Study Finds Childhood Autism Rates in Jersey Are Double National Estimates
Autism affects about 1 in 28 children, or about 3.6% of children in metropolitan areas of the Garden State.
The study was based on children enrolled in public schools in 2016 in a four-county area: Essex, Hudson, Ocean, and Union counties. The surveillance covered 76 populous and diverse urban and suburban school districts.
By Jill Escher
A new study of New Jersey children born in 2008— and who are currently about 13 years old —shows autism prevalence for that age group to be about double the national estimates previously published by the Centers for Disease Control (CDC). The CDC has reported a nationwide prevalence of about 1 in 54 children born that year, or 1.85%, but this study estimates autism affects about 1 in 28 children, or about 3.6% of children in metropolitan areas of the Garden State.
The study was based on children enrolled in public schools in 2016 in a four-county area: Essex, Hudson, Ocean, and Union counties. The surveillance covered 76 populous and diverse urban and suburban school districts.
Some regions were found to have a strikingly higher prevalence than 3.6%, including about 7% of all children in Toms River. The study also found significant variation in ASD prevalence by race/ethnicity, socioeconomic status (SES), and school district size. The highest prevalence was in mid-SES communities, contrary to expectation. Prevalence among Hispanic children was lower than expected. The study was published today in the journal Autism Research.
It is often speculated that service-seeking migration has artificially inflated autism prevalence in New Jersey, but lead investigator Walter Zahorodny, PhD, who has examined such factors in the past, disagrees. "I think in-migration plays a minor role in the absolute level of prevalence," he says. "Definitely migration is not a primary driver."
The methods involved active case finding from multiple sources at the county and school district levels. In Phase 1, researchers determined ASD diagnosis, autism special education classification information and/or documented indication of one or more specific ASD-associated behavior. In Phase 2, the cases were refined. Clinician reviewers satisfying specialized CDC training and reliability criteria used standardized scoring and case definition procedures to confirm ASD cases. The ASD case definition was satisfied if (1) behaviors documented in abstracted professional evaluations met the DSM-5 criteria as specified by the surveillance case definition and/or (2) if abstracted information disclosed an ASD diagnosis by age 8.
Of the children identified as having ASD, 94% received special education services. About 75% of the children had IQs above 70, though the distribution of those scores was unaddressed. The male:female ratio followed historical trends, at about 4:1, or even higher in some areas.
The reasons for the dramatic growth in autism in the U.S., or the higher rates in New Jersey, are not understood. In metro regions, Dr. Zahorodny noted that we are already seeing between 3-5% autism rates in cohorts born after 2010. Dr. Zahorodny also stressed there is no evidence that awareness is the driver of increasing ASD diagnosis and prevalence.
Future CDC investigations will use a conservative approach to identifying ASD cases, relying on existing diagnoses and special ed classifications, and not active case-finding like that used in this study, which will likely result in lower reported autism rates in some areas.
Reference:
Shenouda, J., Barrett, E., Davidow, A. L., Halperin, W., Silenzio, V. M. B., & Zahorodny, W. (2021). Prevalence of autism spectrum disorder in a large, diverse metropolitan area: Variation by sociodemographic factors. Autism Research, 1–10. https://doi.org/10.1002/aur.2628
