Several months ago, a commenter at Respectful Insolence, was wringing her hands over "one in six American children are now considered developmentally disabled", and was implying the high number was new and was caused by vaccination.
"Developmentally Disabled" sounds horrible and scary, doesn't it? Like a child who will never learn, or never live independently in adulthood?
The facts are otherwise.
The source of the "one in six" is a paper in Pediatrics, Boyle et al. (2011) Trends in the Prevalence of Developmental Disabilities in US Children, 1997–2008 Pediatrics. 2011 Jun;127(6):1034-42. Epub 2011 May 23. doi: 10.1542/peds.2010-2989)
From the abstract (emphases added):
Participants and Methods:We used data on children aged 3 to 17 years from the 1997–2008 National Health Interview Surveys, which are ongoing nationally representative samples of US households. Parent-reported diagnoses of the following were included: attention deficit hyperactivity disorder; intellectual disability; cerebral palsy; autism; seizures; stuttering or stammering; moderate to profound hearing loss; blindness; learning disorders; and/or other developmental delays.
Screening for and remediating learning disorders are my areas of expertise. I would say the one in six figure (16.6%) is possibly low. Dyslexia is classed as a developmental disability. Some dyslexia experts put the actual prevalence rate at up to 20%.
It would be a great day for children in America if all students were screened for dyslexia at the end of kindergarten, so that appropriate remediation could begin immediately. Of course, instituting such a course of action would mean a rise in both incidence and prevalence. What a terrible thing! Not.
The change in incidence and rise in prevalence of autism has been widely discussed previously (for starters, see Steven Novella at Neurologica).
The incidence and prevalence of ADHD are well, contentious. The prevalence rates vary from about 6% to over 15% on a state-by-state basis. As the CDC notes:
...because of the evolution of the case definition and differences in how the case definition is operationalized, there is disagreement as to prevalence and precise characteristics of children with the disorder.Due to the lack of a single, consistent, and standard research protocol for case identification, variable and disparate findings have been noted in the literature.
What's the take-away message here? For Kelly, lara, and others who use the "one in six" headline as a prompt for fears of vaccines, I fear it won't do much. Evidence-resistant ideologies don't change much in response to facts...
For everyone else, when you see the "one in six" figure, now you know what it refers to, and now you know why it isn't a fearful figure.
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