Is Autism prevalence increasing?
It’s complicated. Learn the facts direct from top scientists..
The Claim:
CNN reported that Autism in the US is increasing. Is this true for the US and globally? If so, what is the cause?
The Metafact Expert Consensus:
Debatable +53% (16/30 answered ‘Yes’) as of July 31, 2018
Snapshot of expert answers of “Likely” or above
Emeritus Professor Uta Frith of Cognitive Development from University College London :The prevalence of autism — the number of cases diagnosed at any age, has increased hugely, but prevalence is not the same as incidence, — the number of cases born with autism. There is no reason to believe that the incidence of autism has increased. An increase in the prevalence of cases was inevitable given the recognition that the classic definition of autism was too narrow and there was a whole spectrum of autism. (see full answer)
Dr Richard Solomon, Pediatrician from Michigan specialising in Autism Spectrum Disorders: As a developmental pediatrician who has cared for literally thousands children with autism spectrum disorders (ASD), I have been watching the ASD trends over the last 20 years. I believe that there is both an increase in prevalence and an increase in incidence…Time will help to sort out the ‘prevalence vs incidence’ debate but what’s clear is that 2% of boys have ASD (see full answer)
Dr Kevin Becker, a geneticist at the National Institutes of Health: It is generally agreed that that the number of diagnoses of the autisms is increasing. …[However] there is clearly no increase in genetically determined cases, these have remained stable at <15% and tend to be more severe. Of the >85% of non-genetic cases (which tend to be less severe) are most probably environmentally determined.
So in my view, NO increase in genetically determined cases of autism, YES in increase of apparent cases due to expanding clinical definitions of the disease and increased awareness, and LIKELY increases in environmentally triggered cases of autism… [For environmental triggers] I favor inflammatory/autoimmune alterations in prenatal and neonatal life, possibly related to microbiome/dysbiosis/antibiotic effects and/or inadequate microbiome immune priming in early life…. although Vitamin D, air pollution, and acetaminophen can dysregulate immune function as well. (see full answer).
Snapshot of expert answers of “Unlikely” or below
Michael Levy, M.D., Ph.D., chief of pediatric neurosurgery at Rady Children’s Hospital-San Diego: A difficult question to answer.The Autism and Developmental Disabilities Monitoring (ADDM) Network estimates the prevalence of Autism Spectrum Disorder among children aged 8 years who reside within specific ADDM sites in the US.
ADDM estimated prevalence for 2014 was 16.8 per 1,000 children (11 sites).
ADDM estimated prevalence for 2008 was 11.3 per 1,000 children (14 sites).
ADDM estimated prevalence for 2006 was 9.0 per 1,000 (11 sites).
ADDM estimated prevalence for 2002 was 6.4 per 1,000 children (13 sites).
The 2014 date was found to vary widely when stratified by geographic area, sex, and level of intellectual ability… Though the overall ASD prevalence estimates are progressively higher, it must be understood that the ADDM sites do not provide a representative sample of the US and should not generalized to all children. (see full answer)
Eric J. Fombonne M.D., Epidemiologist, Oregon Health & Science University: If the question simply asks: is today’s prevalence higher than yesterday’s prevalence, the answer is ‘Yes’, without question. In the US, this would be illustrated by CDC estimates that have risen from 0.7% to 1.68% in cohorts of children born from 1992 to 2006. The same upward trend in prevalence has been reported in the last 40 years in all countries where prevalence was reported at different time points.
If the question means: is there an ‘epidemic’ of autism (the usual implicit meaning of the question), then the answer is: not sure. Any prevalence estimate can be biased in either directions. Thus, if many children were ‘missed’ in prior surveys (prevalence was underestimated) who are now identified in more recent ones (the downward bias gets reduced), the prevalence would clearly increase without the need to invoke an ‘epidemic’ (a true increase in the incidence of the disorder). Did that happen? Yes, without a doubt. (see full answer)
Professor Terry Brugha, Autism Epidemiologist, University of Leicester: in Three separate studies of adults and the elderly in England, show the tiny (largely statistically not significant) fall off in rates of autism (a 1% drop in prevalence for each extra year of age) simply does not fit with the suggested increases in rates coming from US studies on children.The latest US report from the CDC which your enquirer may have picked up on shows further increases in REPORTED diagnoses of autism in children aged 8, which is NOT evidence of a change in prevalence. (see full answer)
These expert answers originally published at metafact.io. Any media inquiries contact us here.
