Analysis of Prevalence Trends of Autism Spectrum Disorder in Minnesota

Abstract

We observed dramatic increases in the prevalence of autism spectrum disorder as a primary special educational disability starting in the 1991-1992 school year, and the trends show no sign of abatement. We found no corresponding decrease in any special educational disability category to suggest diagnostic substitution as an explanation for the autism trends in Minnesota. We could not assess changes in actual disease incidence with these data, but federal and state administrative changes in policy and law favoring better identification and reporting of autism are likely contributing factors to the prevalence increases and may imply that autism spectrum disorder has been underdiagnosed in the past.

Trends in Autism Prevalence: Diagnostic Substitution Revisited

“…Even when ''reverse'' diagnostic substitution was factored in, the net contribution of diagnostic substitution to the increase in autism prevalence was 10.1 per 10,000, or 32.9% of the total increase. This finding contradicts results from several studies where there was no evidence of diagnostic substitution (Gurney et al 2003;Newschaffer et al 2005). One explanation for this may be that we used individual-rather than group-level data.…”

Trends in Autism Prevalence: Diagnostic Substitution Revisited

“…Even when ''reverse'' diagnostic substitution was factored in, the net contribution of diagnostic substitution to the increase in autism prevalence was 10.1 per 10,000, or 32.9% of the total increase. This finding contradicts results from several studies where there was no evidence of diagnostic substitution (Gurney et al 2003;Newschaffer et al 2005). One explanation for this may be that we used individual-rather than group-level data.…”

Pervasive Developmental Disorders in Preschool Children: Confirmation of High Prevalence

“…Consistent with research (7,(13)(14)(15)(16) and review (4) data, the prevalence for all pervasive developmental disorders was near 60 per 10,000. Pervasive developmental disorder not otherwise specified was the most frequent subtype, and it occurred at about 1.7 times the rate of autistic disorder in the combined samples from the two surveys.…”

Parental Report of Health Conditions and Health Care Use Among Children With and Without Autism

“…Although the possibility of false positives and false negatives for ASD is likely, the study's prevalence estimate of autism at 53 per 10 000 children aged 3 through 17 years is reasonably consistent with the range reported in recent studies. 33,34 In addition, the weighted mean number of visits reported by parents for nonurgent care (preventive and nonemergency combined) of 3.46 among the children aged 3 through 17 years without autism in our study (data not shown) is also reasonably close to the 2.88 reported for children younger than 18 years in the National Ambulatory Medical Care Study. 35 In conclusion, the findings we report herein document an important pattern of high parent-reported rates of concurrent conditions and high health care use associated with childhood autism on a national scale that warrants systematic assessment in more specific detail, from the standpoint of health systems and effect on the family.…”

Trends in Autism Prevalence: Diagnostic Substitution Revisited

“…Even when ''reverse'' diagnostic substitution was factored in, the net contribution of diagnostic substitution to the increase in autism prevalence was 10.1 per 10,000, or 32.9% of the total increase. This finding contradicts results from several studies where there was no evidence of diagnostic substitution (Gurney et al 2003;Newschaffer et al 2005). One explanation for this may be that we used individual-rather than group-level data.…”

Pervasive Developmental Disorders in Preschool Children: Confirmation of High Prevalence

“…Consistent with research (7,(13)(14)(15)(16) and review (4) data, the prevalence for all pervasive developmental disorders was near 60 per 10,000. Pervasive developmental disorder not otherwise specified was the most frequent subtype, and it occurred at about 1.7 times the rate of autistic disorder in the combined samples from the two surveys.…”

Parental Report of Health Conditions and Health Care Use Among Children With and Without Autism

“…Although the possibility of false positives and false negatives for ASD is likely, the study's prevalence estimate of autism at 53 per 10 000 children aged 3 through 17 years is reasonably consistent with the range reported in recent studies. 33,34 In addition, the weighted mean number of visits reported by parents for nonurgent care (preventive and nonemergency combined) of 3.46 among the children aged 3 through 17 years without autism in our study (data not shown) is also reasonably close to the 2.88 reported for children younger than 18 years in the National Ambulatory Medical Care Study. 35 In conclusion, the findings we report herein document an important pattern of high parent-reported rates of concurrent conditions and high health care use associated with childhood autism on a national scale that warrants systematic assessment in more specific detail, from the standpoint of health systems and effect on the family.…”

Trends in Autism Prevalence: Diagnostic Substitution Revisited

“…Even when ''reverse'' diagnostic substitution was factored in, the net contribution of diagnostic substitution to the increase in autism prevalence was 10.1 per 10,000, or 32.9% of the total increase. This finding contradicts results from several studies where there was no evidence of diagnostic substitution (Gurney et al 2003;Newschaffer et al 2005). One explanation for this may be that we used individual-rather than group-level data.…”

Pervasive Developmental Disorders in Preschool Children: Confirmation of High Prevalence

“…Consistent with research (7,(13)(14)(15)(16) and review (4) data, the prevalence for all pervasive developmental disorders was near 60 per 10,000. Pervasive developmental disorder not otherwise specified was the most frequent subtype, and it occurred at about 1.7 times the rate of autistic disorder in the combined samples from the two surveys.…”

Parental Report of Health Conditions and Health Care Use Among Children With and Without Autism

“…Although the possibility of false positives and false negatives for ASD is likely, the study's prevalence estimate of autism at 53 per 10 000 children aged 3 through 17 years is reasonably consistent with the range reported in recent studies. 33,34 In addition, the weighted mean number of visits reported by parents for nonurgent care (preventive and nonemergency combined) of 3.46 among the children aged 3 through 17 years without autism in our study (data not shown) is also reasonably close to the 2.88 reported for children younger than 18 years in the National Ambulatory Medical Care Study. 35 In conclusion, the findings we report herein document an important pattern of high parent-reported rates of concurrent conditions and high health care use associated with childhood autism on a national scale that warrants systematic assessment in more specific detail, from the standpoint of health systems and effect on the family.…”