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autism epidemic Eric Fombonne autism-epidemic epidemiology omnibus experts science
shared by Tero Toivanen on 26 Mar 09
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A new paper from Eric Fombonne is in electronic print at the journal Pediatric Research.
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Pervasive Developmental Disorders, including Autistic Disorder, Asperger Disorder, Pervasive Developmental Disorder Not Otherwise Specified, and Childhood Disintegrative Disorder.
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For autistic disorder, Fombonne says: The correlation between prevalence and year of publication was statistically significant and studies with prevalenceover 7/10,000 were all published since 1987. These findings point towards an increase in prevalence estimates in the last 15-20 years.
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recent autism surveys have consistently identified smaller numbers of children with AS than those with autism within the same survey.
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How much lower is difficult to establish from existing data, but a ratio of 3 or 4 to 1 would appear an acceptable,
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We therefore used for subsequent calculations an estimate of 6/10,000 for AS, recognizing the strong limitations of available data on AS.
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Eight studies provided data on childhood disintegrative disorder (CDD). Prevalence estimates ranged from 0 to 9.2/100,000.
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The upper-bound limit of the associated confidence interval (4.0/100,000) indicates that CDD is a very rare condition, with about 1 case to occur for every 103 cases of autistic disorder.
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Current evidence does not strongly support the hypothesis of a secular increase in the incidence of autism but power todetect time trends is seriously limited in existing datasets.
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Whilst it is clear that prevalence estimates have gone up over time, this increase most likely represents changes in the concepts, definitions, service availability and awareness of autistic-spectrum disorders in both the lay and professional public.
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The possibility that a true change in the underlying incidence has contributed to higher prevalence figures remains, however, to be adequately tested.