Dr. Andrew Zimmerman of Massachusetts General Hospital for Children and colleagues at The Johns Hopkins Bloomberg School of Public said questions remain as to whether changes in diagnosis of an autism spectrum disorder are due to true etiologic differences -- risk factors contributing to the cause of a disease -- or shifts in diagnostic determination.
The researchers analyzed data from a phone survey in 2007 and 2008 of 92,000 parents of U.S. children across three developmental stages -- children ages 3-5 and 6-11, and adolescents ages 12-17.
More than 1,300 said their child had a past or current diagnosis of an autism spectrum disorder, but in 453 of those cases, children had been diagnosed by a doctor of having a disorder -- but parents said the children did not have a disorder anymore.
The results identified co-occurring conditions that distinguish groups currently diagnosed with an autism spectrum disorder from groups with past but not current diagnoses of autism spectrum disorder.
Children with learning disability, delayed development, epilepsy and anxiety tended to continue to be classified as having autism spectrum disorder. Children or teens with early hearing problems were less likely than similarly affected older children to be considered autistic.
The findings are published in the journal Pediatrics.