Autism Prevalence Rate

According to the Centers for Disease Control and Prevention (CDC) the national rate of children identified with Autism Spectrum Disorder is 1 in 54 children. This statistic is based on their evaluation of health and educational records of 8-year-old children in 2016 in 11 states, including New Jersey. New Jersey has the highest rate of autism in the nation: 1 in 32 children, or 3.1% of 8-year-old children. New Jersey’s prevalence continues to exceed and outpace other states.

Prevalence in 8-year-old children

About the rates

Since 2000 and for the eighth consecutive time, the CDC found autism prevalence in 8-year-olds increased in the United States and were the highest to date nationally and here in New Jersey.

  • Nationally, the prevalence of autism is 1 in 54 (1.85%).
  • Here in New Jersey, it is 1 in 32 (3.1%)*, 1 in 20 boys (5%), and 1 in 85 girls (1.2%).

*The rate is a slight increase from two years ago (1 in 34 or 2.9%)

More data from a younger subset

Since the study began 20 years ago, the Autism and Developmental Disabilities Monitoring (ADDM) Network has been reviewing records of 8-year-olds in New Jersey and across the country and issuing biannual reports on their prevalence findings.  The 2020 prevalence report is from records reviewed in 2016.

In 2014, some of the states, including New Jersey, began studying 4-year-olds. Also issued biannually, the 2016 findings on 4-year-olds released with this report offer a snapshot at an earlier point in time and, therefore, provide a means to monitor progress toward key initiatives such as ages of screening, evaluation, and diagnosis.

Why the increase and why is New Jersey the highest?

The New Jersey study’s lead investigator, Dr. Walter Zahorodny, an Associate Professor at Rutgers New Jersey Medical School, suggests the higher rate in New Jersey is likely due to more people knowing about autism and referring children to experts to document their concerns. These detailed reports then provide the investigators a more complete picture of children’s challenges and possible diagnoses. Without as many reports, “other states could be underestimating the rate of autism,” he stated.

Certainly, greater awareness and public health education by the government and advocacy groups like Autism New Jersey and our partners contribute to the increase. New Jerseyans also have more access to diagnostic services, so more children are evaluated.

Drivers of prevalence are likely to involve gene/environment interactions, not merely to reflect better awareness which cannot fully explain the increase. Known risk factors such as prematurity, low birth weight, multiples, and advanced maternal age could contribute to the higher prevalence rate. For example, New Jersey has a much higher rate of births to women over the age of 35. The Department of Health’s Autism Registry Brief outlines these risk factors for autism and how New Jersey compares to the national averages.  The 2020 report also sheds light on the effects of the 2013 changes in diagnostic criteria. In fact, the current diagnostic criteria (DSM 5) yields lower prevalence rates as measured in 4-year-olds here in New Jersey (2.5% vs 3.1%).

Other notable takeaways

Race/Ethnicity:  Improved screenings closing racial gap 
Historically in New Jersey, black and Hispanic children were diagnosed less often and at later ages than their white peers. For the 2014 cohort in New Jersey and the first time ever, there were no racial disparities as the prevalence in each ethnic group was nearly identical, demonstrating that public awareness about autism has reached and has galvanized minority communities. In fact, in the 2016 cohort of 4-year-olds, autism prevalence was highest among Hispanic children (3.2%) and may be declining or plateauing in white children.

Nationally, disparities in the evaluation and diagnosis of ASD across racial backgrounds continue to persist. For example, children with ASD from black and Hispanic communities were less likely to receive a professional evaluation before 36 months. Nationally, the differences between black and white children decreased in most sites from previous reports, but remained notable for Hispanic children.

Gender:  4 of 5 are boys
Consistent with previous national and New Jersey findings, boys were identified at a rate four times that of girls.

IQ:
Among New Jersey children who had IQ scores available, 25% also have an intellectual disability. This percentage is consistent with national figures (33%). Also, more children with average or above average IQ are identified as having autism.

Age of Diagnosis:  Progress towards identifying earlier
Even though ASD can be diagnosed as early as age 2, most children were not diagnosed with ASD by a community provider until ages 3 to 5, depending on how ASD presented. This 2020 study revealed that more children are being evaluated and identified at younger ages. Eighty-four percent (84%) of 4-year-olds were screened in 2016 compared to 74% in 2014. The goal remains to diagnose ASD as early as possible to ensure children have access to intensive, evidence-based treatment.

For more information

Links to the CDC’s full report, the snapshot of the New Jersey results, additional findings and detailed analysis can be found below.