MercolaWatch:On Environmental Factors for Autism -- Part 2

This is the second of a two-part response to a recent mercola.com speculating on environmental causes for autism. This part briefly responds to his mention of vaccines, phthalates and gut flora.

Vaccines

Vaccines: A 2011 review of the peer-reviewed published studies on autism (going all the way back to 1943) revealed numerous documented cases of autism caused by encephalitis following vaccination.5

His footnote 5 links to an article in the Journal of Immunotoxicology by Dr. Helen Ratajczak. As a reference for her views outside of the journal, there is an interview with her from "vactruth" where she supports the notion of vaccines as a cause of Shaken Baby Syndrome. Reading the study, the internal reference "citing" the government as admitting that encephalitis following vaccination is actually a reference to the anti-vaccine site "Child Health Safety". I think most people would agree that blog references like that don't quite belong in a scientific study ("review article" or not). In any case, the reference is to the fact that the vaccine court has awarded damages in some cases where encephalopathy appeared to follow vaccination. Keep in mind that the vaccine court is not a scientific body and their standard of evidence is, rightfully, lower than what would be required in a scientific study.

That said, according to the CDC there may be very rare cases where someone with an underlying mitochondrial disease (which can have autism-like symptoms) affecting their brain might have it triggered by vaccines. But they point out that there are not actually studies that demonstrate this, as it is so rare.

To bring up the link with encephalopathy is highly misleading.

There are many potential vaccine-related culprits, including the use of toxic adjuvants [...] any one of which could induce autoantibodies to be formed that may attack self-structures such as the myelin that coats the nerves, disrupting neurological development and function.

Sounds great, how about citing some research to that affect? However, just as with homeopathy, there seems little reason to attempt to find "what" in vaccines is causing autism, as there is no evidence that vaccines are a significant factor in autism and autism-like disorders. I've actually spent more time than I should on this particular topic given how much content is already out there refuting the links to autism and vaccines.

Phthalates

Phthalates: Research from 2009 discovered that infants who lived in homes with vinyl floors were twice as likely to have autism five years later, compared to those with wood or linoleum flooring ...

His source for this is essentially a 2009 Scientific American article discussing this study. It was based on a survey of 4779 children, but the researchers note in the conclusion of the study (but also in the SA article):

In this study, we did not expect, or even intend to search for, an association between PVC ?ooring and ASD. The study was not designed speci?cally to address ASDs, and con?rmation would require further efforts. Nevertheless, we believe the data warrant publication at this time because, so far, we lack con?rmed environmental contributions to the etiology of autism despite considerable searching.

As best I can tell, it's a legitimate early study that may represent an actual causal link. There are a couple of other studies on Google Scholar indicating the potential link between phthalates and autism, but I didn't find any systematic reviews yet. Unless I've been totally fooled (very possible), Mercola has managed to score a possible one here.

Autism and gut flora?

The Autism-Gut Connection You May Not Have Heard About

Neurologist Dr. Natasha Campbell-McBride recently shared a common thread that may be linking these and other environmental factors together, namely brain toxicity stemming from gut toxicity, otherwise known as Gut and Psychology Syndrome (GAPS). She cured her own son of autism using an all-natural treatment involving dietary changes and detoxification [...]

In her research, Dr. Campbell-McBride discovered that nearly all of the mothers of autistic children have abnormal gut flora, which is significant because newborns inherit their gut flora from their mothers at the time of birth. Establishing normal gut flora in the first 20 days or so of life plays a crucial role in the maturation of your baby's immune system. Babies who develop abnormal gut flora are left with compromised immune systems, putting them at higher risk for suffering vaccine reactions.

If your baby has suboptimal gut flora, vaccines can become the proverbial "last straw" â€" the trigger that "primes" his/her immune system to develop chronic health problems.

Smells quite a bit like the disproved hypothesis of Andrew Wakefield. At no point does Mercola link to a study on "GAPS", instead referencing a book by Dr. Campbell-McBride. Based on the various articles that mention her, her "evidence" seems to be simply the patients she has seen at her clinic (she's a pediatrician), not any formal study. It's not clear why she is so well-versed on the gut flora of her patients (neither of my daughters' "gut flora" has been tested, nor have my wife's as far as I know). And always a good sign for sound science, the site for information about GAPS helpfully sells you things right on the home page. She has in fact trademarked the term "GAPS".

Conclusion

The vaccine-autism hypothesis is bunk until the anti-vaccine folks can manage to mount any sort of evidence that actually links autism to vaccines. Continuously looking for different things "in" the vaccine that are the cause are pointless until that time. Phthalates seem like they could actually be a contender for some children, but it seems unlikely to explain the bulk. Mercola does not even attempt to provide evidence of the gut flora link, and the main proponent of it does not even pretend to cite evidence on her site, so there is currently no reason to take that hypothesis seriously.