The Centers for Disease Control and Prevention (CDC) estimates that between two and six per 1,000 children have an autism spectrum disorder, or somewhere between one in 500 to one in 150. The risk is three to four times higher in males than females.
Autism is an extremely complex disorder, the causes of which are the subject of great debate among experts and laypeople alike. While many experts say that autism can be caused by genetic and environmental factors alike, it remains unclear which factor plays a bigger role in the onset of the disorder.
But these findings provide little additional information on the various mechanisms of the disorder. Rather, said Dr. Sessions Cole, director of the Division of Newborn Medicine at the Washington University School of Medicine in St. Louis, Mo., the study highlights the potential shortcomings of using the M-CHAT checklist to screen young children for autism.
"This report is more about the high false positive values of autism screening tools like the M-CHAT in extremely preterm infants than it is about the causes of autism," he said. "I think providing parents with anticipatory guidance is always a good idea. The problem is that the tool used to provide such a warning should be reasonably accurate -- that is, have a high positive predictive value."
Still, others said the M-CHAT test provides doctors and parents alike with useful information about their child's cognitive function and development. And Dr. Nancy Minshew, professor of psychiatry and neurology at the University of Pittsburgh, said that the test's use as an "early warning" for a possible increase in autism risk could, indeed, be useful.
"Knowledge is helpful and leads to interventions to promote social communication and social contact," she said.