There may be an epidemic of autism diagnoses in the nation, but child-count data collected by the U.S. Department of Education are not the way to prove it, says a researcher at the University of Wisconsin-Madison.
The Individuals with Disabilities Education Act requires states to track children by disability type and report the data to the department. Since 1993, when autism was first included, it has been on the rise.
Paul T. Shattuck, a postdoctoral fellow at the university鈥檚 Waisman Center, which studies neurological disorders, says in a study that the number of children diagnosed with autism-spectrum disorders has increased at the same time the number of children diagnosed with mental retardation and learning disabilities has declined. Such a phenomenon is known as diagnostic substitution, he said.
鈥淭here鈥檚 no consistency whatsoever among states and schools鈥� on how autism is defined, he said in an interview. 鈥淐hild-count data was never intended as a public-health monitoring device.鈥�
Some autism organizations have derided Mr. Shattuck鈥檚 work as shoddy, and possibly tainted by the pharmaceutical industry. Safeminds, a Tyrone, Ga., group that believes mercury-based preservatives in vaccines cause autism, said in an April 3 press release that diagnostic substitution has been rejected in other studies, and that autism research should focus on more valid databases than Education Department data.
Mr. Shattuck defended his research and said he does not have ties to the drug industry.
The debate has fired up online discussion groups about autism, as supporters of Mr. Shattuck鈥檚 study accuse his opponents of drumming up a link between mercury and autism as a strategy for winning future lawsuits.
Mr. Shattuck agrees that more-valid databases should be used to discuss whether autism is indeed on the rise. In his study, published in the April issue of Pediatrics, he takes no position on whether there鈥檚 any link between autism and environmental factors or vaccines.
Whether or not autism cases are at epidemic levels, he said, the increasing number of children with autism 鈥渄o present a very real challenge for schools.鈥�
