Summary: The prevalence of 4-year-old children being diagnosed with autism spectrum disorder in New Jersey increased by 43% within a four-year span. Researchers determine the prevalence rate of ASD is one in 35, according to a new report from the CDC and Rutgers University.
Source: Rutgers University
A new report by the Centers for Disease Control and Prevention, which uses research by Rutgers University, shows a significant increase in the percentage of 4-year-old children with autism spectrum disorder in New Jersey.
The study found the rate increased 43 percent from 2010 to 2014 in the state.
The report, released April 11, found that about one in 59 children has autism. New Jersey’s rate was the highest of the states studied: one in 35. That puts the national rate of autism at 1.7 percent of the childhood population and New Jersey’s autism rate at 3 percent.
New Jersey is known for excellent clinical and educational services for autism spectrum disorder, so the state’s higher rates are likely due to more accurate or complete reporting based on education and health care records, the researchers said. Similar studies were conducted in Arizona, Colorado, Missouri, North Carolina, Utah and Wisconsin.
Walter Zahorodny, an associate professor of pediatrics at Rutgers New Jersey Medical School who directed the New Jersey portion of the study, called the results “consistent, broad and startling.” The analysis of this young group of children shows U.S. autism rates are continuing to rise without plateauing.
“It’s very likely that the next time we survey autism among children, the rate will be even higher,” he said.
The researchers analyzed information from the health and special education records of 129,354 children who were 4 years old between 2010 to 2014 and 128,655 children who were 8 years old in that time period. They used the guidelines for autism spectrum disorder in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders-IV for their primary findings.
Across the network, the researchers found the prevalence of autism spectrum disorders ranged from a low of 8 per 1,000 children in Missouri to a high of 28 per 1,000 children in New Jersey. The average was 13 per 1,000 children. The disorder is about two times more common among boys than girls and white children are more often diagnosed than black or Hispanic children.
Although the estimates are not representative of the country as a whole, they are considered the benchmarks of autism spectrum disorder prevalence, Zahorodny said.
The age that children received their first evaluation ranged from 28 months in North Carolina to 39 months in Wisconsin. The researchers discovered that children with an intellectual disability or other condition were more likely to be evaluated earlier than age 4, which gives them an advantage.
“Children who are evaluated for autism early – around their second birthday – often respond better to treatment than those who are diagnosed later,” Zahorodny said. “However, it appears that only the most seriously affected children are being evaluated at the crucial time, which can delay access to treatment and special services.”
The average age of diagnosis – 53 months – has not changed in 15 years.
“Despite our greater awareness, we are not effective yet in early detection,” he said. “Our goal should be systematic, universal screening that pediatricians and other health providers provide at regular visits starting at 18 months to identify autism as soon as possible.”
The researchers can’t explain why autism rates have increased across the United States. Factors associated with a higher risk include advanced parental age (children of parents over age 30 have heightened risk), maternal illness during pregnancy, genetic mutations, birth before 37 weeks gestation and multiple births.
“These are true influences exerting an effect, but they are not enough to explain the high rate of autism prevalence,” said Zahorodny. “There are still undefined environmental risks that contribute to this significant increase, factors that could affect a child in its development in utero or related to birth complications or to the newborn period. We need more research into non-genetic triggers for autism.”
Patti Verbanas – Rutgers University
The image is credited to Nick Romanenko / Rutgers University.
Original Research: Open access.
Christensen DL, Maenner MJ, Bilder D, et al. “Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 4 Years — Early Autism and Developmental Disabilities Monitoring Network, Seven Sites, United States, 2010, 2012, and 2014”. MMWR Surveill Summ 2019;68(No. SS-2):1–19. doi:10.15585/mmwr.ss6802a1
Prevalence and Characteristics of Autism Spectrum Disorder Among Children Aged 4 Years — Early Autism and Developmental Disabilities Monitoring Network, Seven Sites, United States, 2010, 2012, and 2014
Problem/Condition: Autism spectrum disorder (ASD) is estimated to affect up to 3% of children in the United States. Public health surveillance for ASD among children aged 4 years provides information about trends in prevalence, characteristics of children with ASD, and progress made toward decreasing the age of identification of ASD so that evidence-based interventions can begin as early as possible.
Period Covered: 2010, 2012, and 2014.
Description of System: The Early Autism and Developmental Disabilities Monitoring (Early ADDM) Network is an active surveillance system that provides biennial estimates of the prevalence and characteristics of ASD among children aged 4 years whose parents or guardians lived within designated sites. During surveillance years 2010, 2012, or 2014, data were collected in seven sites: Arizona, Colorado, Missouri, New Jersey, North Carolina, Utah, and Wisconsin. The Early ADDM Network is a subset of the broader ADDM Network (which included 13 total sites over the same period) that has been conducting ASD surveillance among children aged 8 years since 2000. Each Early ADDM site covers a smaller geographic area than the broader ADDM Network. Early ADDM ASD surveillance is conducted in two phases using the same methods and project staff members as the ADDM Network. The first phase consists of reviewing and abstracting data from children’s records, including comprehensive evaluations performed by community professionals. Sources for these evaluations include general pediatric health clinics and specialized programs for children with developmental disabilities. In addition, special education records (for children aged ≥3 years) were reviewed for Arizona, Colorado, New Jersey, North Carolina, and Utah, and early intervention records (for children aged 0 to <3 years) were reviewed for New Jersey, North Carolina, Utah, and Wisconsin; in Wisconsin, early intervention records were reviewed for 2014 only. The second phase involves a review of the abstracted evaluations by trained clinicians using a standardized case definition and method. A child is considered to meet the surveillance case definition for ASD if one or more comprehensive evaluations of that child completed by a qualified professional describes behaviors consistent with the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) diagnostic criteria for any of the following conditions: autistic disorder, pervasive developmental disorder–not otherwise specified (PDD-NOS, including atypical autism), or Asperger disorder (2010, 2012, and 2014). For 2014 only, prevalence estimates based on surveillance case definitions according to DSM-IV-TR and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) were compared. This report provides estimates of overall ASD prevalence and prevalence by sex and race/ethnicity; characteristics of children aged 4 years with ASD, including age at first developmental evaluation, age at ASD diagnosis, and cognitive function; and trends in ASD prevalence and characteristics among Early ADDM sites with data for all 3 surveillance years (2010, 2012, and 2014), including comparisons with children aged 8 years living in the same geographic area. Analyses of time trends in ASD prevalence are restricted to the three sites that contributed data for all 3 surveillance years with consistent data sources (Arizona, Missouri, and New Jersey).
Results: The overall ASD prevalence was 13.4 per 1,000 children aged 4 years in 2010, 15.3 in 2012, and 17.0 in 2014 for Early ADDM sites with data for the specific years. ASD prevalence was determined using a surveillance case definition based on DSM-IV-TR. Within each surveillance year, ASD prevalence among children aged 4 years varied across surveillance sites and was lowest each year for Missouri (8.5, 8.1, and 9.6 per 1,000, for 2010, 2012, and 2014, respectively) and highest each year for New Jersey (19.7, 22.1, and 28.4 per 1,000, for the same years, respectively). Aggregated prevalence estimates were higher for sites that reviewed education and health care records than for sites that reviewed only health care records. Among all participating sites and years, ASD prevalence among children aged 4 years was consistently higher among boys than girls; prevalence ratios ranged from 2.6 (Arizona and Wisconsin in 2010) to 5.2 boys per one girl (Colorado in 2014). In 2010, ASD prevalence was higher among non-Hispanic white children than among Hispanic children in Arizona and non-Hispanic black children in Missouri; no other differences were observed by race/ethnicity. Among four sites with ≥60% data on cognitive test scores (Arizona, New Jersey, North Carolina, and Utah), the frequency of co-occurring intellectual disabilities was significantly higher among children aged 4 years than among those aged 8 years for each site in each surveillance year except Arizona in 2010. The percentage of children with ASD who had a first evaluation by age 36 months ranged from 48.8% in Missouri in 2012 to 88.9% in Wisconsin in 2014. The percentage of children with a previous ASD diagnosis from a community provider varied by site, ranging from 43.0% for Arizona in 2012 to 86.5% for Missouri in 2012. The median age at the earliest known ASD diagnosis varied from 28 months in North Carolina in 2014 to 39.0 months in Missouri and Wisconsin in 2012. In 2014, the ASD prevalence based on the DSM-IV-TR case definition was 20% higher than the prevalence based on the DSM-5 (17.0 versus 14.1 per 1,000, respectively).
Trends in ASD prevalence and characteristics among children aged 4 years during the study period were assessed for the three sites with data for all 3 years and consistent data sources (Arizona, Missouri, and New Jersey) using the DSM-IV-TR case definition; prevalence was higher in 2014 than in 2010 among children aged 4 years in New Jersey and was stable in Arizona and Missouri. In Missouri, ASD prevalence was higher among children aged 8 years than among children aged 4 years. The percentage of children with ASD who had a comprehensive evaluation by age 36 months was stable in Arizona and Missouri and decreased in New Jersey. In the three sites, no change occurred in the age at the earliest known ASD diagnosis during 2010–2014.
Interpretation: The findings suggest that ASD prevalence among children aged 4 years was higher in 2014 than in 2010 in one site and remained stable in others. Among children with ASD, the frequency of cognitive impairment was higher among children aged 4 years than among those aged 8 years and suggests that surveillance at age 4 years might more often include children with more severe symptoms or those with co-occurring conditions such as intellectual disability. In the sites with data for all years and consistent data sources, no change in the age at earliest known ASD diagnosis was found, and children received their first developmental evaluation at the same or a later age in 2014 compared with 2010. Delays in the initiation of a first developmental evaluation might adversely affect children by delaying access to treatment and special services that can improve outcomes for children with ASD.
Public Health Action: Efforts to increase awareness of ASD and improve the identification of ASD by community providers can facilitate early diagnosis of children with ASD. Heterogeneity of results across sites suggests that community-level differences in evaluation and diagnostic services, as well as access to data sources, might affect estimates of ASD prevalence and age of identification. Continuing improvements in providing developmental evaluations to children as soon as developmental concerns are identified might result in earlier ASD diagnoses and earlier receipt of services, which might improve developmental outcomes.