The prevalence of autism spectrum disorder (ASD) among American kids appears to be undercounted. A new government study has revealed that as many as one in 45 kids has the condition characterized by impaired communication and social skills.

Results of the U.S. Centers for Disease Control and Prevention's (CDC) National Health Interview Survey conducted in 2014 showed that more than 2.2 percent of American children between three and 17 years old, or about one in 45, have autism.

From 2011 to 2013, the National Survey of Children's Health found that autism affects only 1.25 percent of kids, or one in 80 people. The CDC estimated the prevalence at 1.47 percent, or one in 68 people.

Experts offered possible reasons to explain the dramatic increase in the number of kids reported to have autism in the latest survey.

Katherine Walton, of the Ohio State University, said that the results suggest that parents now use different labels when describing their children.

Although the number of children who were diagnosed with autism increased, the number of children reported to have been diagnosed with other developmental delays dropped. The overall number of parents who reported of any developmental disability in their children also remained the same at 5.75 percent.

"What we call an autism spectrum disorder now is a much wider group of symptoms than what we called autism in the past so I think that captures a larger number of children that might have received other diagnoses in the past," Walton said.

Study author Benjamin Zablotsky, from CDC's National Center for Health Statistics, said there may have been changed in the way parents label their children which could possibly be attributed to changes in the way researchers interviewed them.

For the survey covering the years from 2011 to 2013, for instance, the surveyors asked parents if they were told by their doctor that their child had intellectual disability and then proceeded to asking them about any other developmental delays. Parents were also provided a list of conditions, which included arthritis, diabetes and autism, and were asked to tell surveyors, which, if any, of the condition their child had.

Instead of including autism in the list of other conditions, the latest survey included a question specific about ASD, which came after questions on intellectual disabilities and other developmental delays. This appeared to have resulted in some parents who might have previously selected "other developmental delays" to indicate an ASD diagnosis

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