ATLANTA, Nov. 13 (UPI) -- A new report from the Centers for Disease Control and Prevention shows a significant increase in the number of children diagnosed with autism spectrum disorder or another related developmental disability.
The study, published by the CDC as part of its National Center for Health Statistics Report, found that 1 in 45 children has been diagnosed with a disability on the autism spectrum, a large increase from the previous estimate of 1 in 68 children in 2014. Researchers were quick, however, to note the increase likely comes from a change in survey methods, including surveying parents and changes to questions.
"Challenges to estimating the prevalence of developmental disabilities include changing definitions and labeling practices over time, as well as the high probability of co-occurring conditions that fall under the umbrella term of developmental disabilities," researchers wrote in the report. "It is difficult to interpret trends in prevalence over time because of the possibility of 'diagnostic substitution,' whereby labeling practices might change and cause similar symptoms to be classified under different disabilities during different time periods."
CDC researchers contacted 35,000 households, asking parents of children age 3 to 17 a series of detailed questions on health conditions, functional limitations and healthcare utilization. In reordering questions and asking about ASD and other developmental delays, researchers sought what they believe to be a more true look at autism prevalence.
The 2014 survey showed 2.24 percent of children have ASD, a significant 1-point increase in prevalence over survey data collected between 2011 and 2013. The researchers noted the prevalence of other developmental delays experienced also dropped by a point, from 4.84 percent to 3.57 percent.
Researchers pointed to changes in diagnostic practice in recent years being responsible for some of the continued increase of diagnosis, as well as changing questions, which they believe helped parents give more accurate responses about their children.
"One in 45 is what we think is the most accurate parental report of autism to date," Benjamin Zablotsky, an epidemiologist at the NCHS, told NBC News. "I think within this report we found that the way that we ask the parents about autism spectrum disorder can have an impact on the way the parents respond to the question. We feel we are asking the question in a better way than before."