The latest survey on childhood autism now estimates that one in 40 children in the United States has the disorder. This represents 2.5 percent of kids age 3 to 17, or 1.5 million individuals. The results of the parental survey were released by Pediatrics, a child-focused medical journal. In contrast, the latest study on autism prevalence by the Centers for Disease Control and Prevention released earlier this year found that one in 59 children have autism. This was based on data from 2014.
The discrepancy in findings may be due to different methods used in each study. The Pediatrics survey was based on data collected in the 2016 National Survey of Children’s Health, which relied on parental reporting of the disorder. The survey collected information from 50,000 parents of children under the age of 18, and the Pediatrics study counted all reports of children who had been diagnosed with autism spectrum disorder and currently held that diagnosis.
According to CNN, the results of the CDC study are verified by health and education records, while estimates like those in the Pediatrics study are not. However, according to the chief science officer of Autism Speaks, Thomas Frazier, the one-in-40 result is consistent with the findings of similar surveys, saying that the number is “generally consistent with previous parent surveys and other direct prevalence studies where researchers directly screen for and attempt to identify autism.”
The authors of the study in Pediatrics also noted that the 2016 study used updated data collection methods and re-worded questions compared to previous surveys. It has been theorized that the rising prevalence of autism is due to better diagnostic methods rather than increasing rates of the disorder. In other words, there may not be more kids with autism, just fewer who are left undiagnosed.
That being said, Frazier believes that the CDC’s findings are likely more accurate than those of parental surveys.
“What is happening is that these studies use methods that are a bit more liberal and inclusive than the CDC’s methods,” said Frazier.
However, he did add that he thinks the CDC’s numbers are “likely a bit conservative.” Frazier also believes that the prevalence of autism is increasing.
The Pediatrics survey also found that parents are reporting increasing difficulties getting the necessary health care for their autistic children.
“Though we’ve seen progress in recent years, this confirms what we know from our parents — that many children face unacceptable delays in getting a diagnostic evaluation, even after parents, teachers or other caregivers have recognized the signs of autism,” Frazier said.
According to Frazier, studies like the one published in Pediatrics are a way to help resolve these issues.
“Having prevalence estimates — even if there is some variation — helps us to advocate for improved screening, diagnosis, interventions and supports.”