Autism May Be More Common Than Once Thought: Study
By Keith Mulvihill
SOURCE:Yahoo News; Journal of the
American Association 2001;285:3093-3099,3141,3142.
6/26/01
NEW YORK (Reuters Health) - While there have been conflicting reports on whether autism rates are on the rise, a new UK study indicates that pervasive developmental disorders (PDDs) like autism and Asperger syndrome are more common than previously believed.
"PDD is not as rare as once thought. Thirty years ago, we had a narrow view of autism, and we estimated the rate to be four or five children out of every 10,000 children,'' lead researcher Dr. Eric Frombonne of King's College in London told Reuters Health.
However, Frombonne's team found in a study of children in Staffordshire, England, that the rate of autism was about 17 children for every 10,000--or about four times higher than previous estimates. The findings are published in the June 27th issue of the Journal of the American Medical Association (news - web sites).
"With a better understanding of the disorder, and especially the fact that there is a spectrum of problems with somewhat milder forms, the rates are much higher,'' Frombonne explained.
With PDDs like autism or Asperger syndrome, Frombonne points out, there are a range of developmental impairments that occur in communication and language. For instance, children may be significantly delayed in speaking or mute with no ``compensatory gestures.'' Others may have ``odd ways'' of speaking such as talking ''at'' people rather than to them, Frombonne noted.
Children may also have problems with social interaction, showing little interest in others, failing to make eye contact or displaying little emotional response to interactions.
In their study, Frombonne and colleague Dr. Suniti Chakrabarti evaluated 15,500 children between the ages of 2.5 to 6.5 years. They estimated the prevalence of PDDs overall to be 63 children for every 10,000.
Specifically, they put the autism prevalence at nearly 17 children for every 10,000. The prevalence for other PDDs was about 46 per 10,000 children.
Ultimately, the researchers say, these findings may have implications for the screening and diagnosis of PDDs.
"We have evidence that early intervention improves the outcome, and as our study shows that PDD can be reliably screened and diagnosed at an early age, the findings suggest that intensive screening programs for PDD in preschoolers should be established,'' Frombonne told Reuters Health.
As for why his team found PDDs to be more common than previous estimates, Frombonne said that ``we used a case definition which is broad enough to capture all the presentations of PDD along the spectrum.''
"Second,'' he added, "we used intensive case finding techniques and were proactive to identify cases in the community at an early age. Third, we used modern diagnostic assessment tools.''
Frombonne also noted that his findings concur with those of a recent Centers for Disease Control and Prevention (news - web sites) study in Brick Township, New Jersey.
"Chakrabarti and Frombonne have corroborated that PDDs are not rare among preschool children,'' Dr. Susan L. Hyman and colleagues at the University of Rochester School of Medicine and Dentistry in New York write in an accompanying editorial.
"Given the limitations of current knowledge,'' they add, ''valuable data sets such as these should be used to increase understanding of the characteristics of young children with PDDs as well as to determine the current prevalence.
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