"Environmental, State-Level Regulatory Factors Affect Incidence of Autism & Intellectual Disability"

[proverbialwisdom]

4. Respectful Insolence critiques study, Dr. Sanjay Gupta, more.

http://scienceblogs.com/insolence/2014/03/14/autism-clusters-and-toxins/

Autism clusters and “toxins”
Posted by Orac on March 14, 2014

(Blather)

COMMENT:

March 14, 2014

The study isn’t solid proof of environmental influences on autism, but there’s virtually never solid proof of any influence of any environmental factor on anything where free-living humans are concerned. When you’re dealing with substances that humans consume voluntarily, the best you can get is prospective observational studies combined with animal studies. When substances that are consumed, breathed, etc. unintentionally are involved, especially when you do not assume that only one such substance has any effect, it may be that population-level studies are the best you can manage.

There are now an increasing number of studies that measure bisphenol A levels in individual pregnant women, for example, and correlate them with unwanted outcomes in the offspring. But you couldn’t possibly do such a study that measured exposures to every conceivable pesticide and plasticizer. Nor could you do one with millions of mothers, so participant numbers are relatively small and results easy to handwave away. Hence an alternative approach is the population-level study. Attempting not just to acknowledge that method’s real and significant limitations, but to dismiss all such studies altogether with scientistic claims that they constitute this or that Fallacy, is the behavior of someone who suspects that such studies may give results that will not suit his ideology.