Medline 6/1/2018 JAMA 2/1/2018
The prevalence of autism spectrum disorder (ASD) in US children and adolescents seems to have stabilized, a new analysis suggests.
On the basis of data from the large population-based National Health Interview Survey (NHIS), the estimated prevalence of ASD ranged from 2.24% to 2.58% among US children and adolescents aged 3 to 17 years from 2014 to 2016, with no statistically significant increase during the 3 years.
The study was published online January 2 in a research letter in JAMA.
Although there was "no statistically significant increase over the study period, it may be preliminary to conclude firmly about the trends in autism rates, according to the present study," Wei Bao, MD, PhD, from the University of Iowa, Iowa City, told Medscape Medical News.
"Our study was based on data over only 3 years," he noted. "Such a short duration is usually not sufficient to draw a conclusion on the trend. Long-term trends in autism should be reassessed later."
Table. NHIS: Estimated ASD Prevalence 2014 to 2016
Years Estimated ASD Prevalence (95% Confidence Interval)
2014 2.24% (1.89% to 2.59%)
2015 2.41% (1.98% to 2.84%)
2016 2.58% (2.14% to 3.01%)
They found that the prevalence of ASD was higher in boys than girls (3.54% vs 1.22%) and lower in Hispanic children (1.78%) than in non-Hispanic white (2.71%) and non-Hispanic black children (2.36%).
"Previous surveys have reported a steady increase in ASD prevalence in US children over the past 2 decades," Dr Bao and colleagues note in their article. "However, the most recent estimate from the Autism and Developmental Disabilities Monitoring (ADDM) Network for the first time reported a plateau in ASD prevalence (1.46%) in 2012, after documenting a continuous increase from 0.67% in 2000 to 1.47% in 2010," they point out.
"It may not be a good idea to directly compare the estimates in our study with the previous ADDM estimates, because there are obvious methodological differences in the study design," said Dr Bao.
"Specifically, the present study was based on a nationally representative sample of children aged 3 to 17, while the ADDM collects data from the health and special education records of 8-year-old children at 11 selected sites," he said. Also, the NHIS is based on parent reports of physician diagnoses, whereas the ADDM is based on clinician review of education or healthcare evaluations.
Continued monitoring of the prevalence and changes in risk factors for ASD is warranted, the researchers conclude.
The study had no specific funding. The authors have disclosed no relevant financial relationships.
JAMA. Published online January 2, 2018. Abstract