A study has been making the rounds on social media claiming an association between prenatal exposure to pesticides and the risk of autism and developmental delay. This means that I am getting asked by many people what the study actually shows. Spoiler alert – not much. But let’s break it down.
Autism spectrum disorder (ASD) is a neurological disorder involving brain development resulting in decreased communications among neurons in the brain and characterized by reduced social ability. Our current scientific understanding is that ASD is largely a genetic disorder. While environmental factors cannot be ruled out, it seems that genes are the primary factor. It’s reasonable to search for environmental risk factors, but so far none have been clearly established.
Those who feel there likely is an environmental factor also tend to believe that there is an autism epidemic – that the incidence of autism is increasing in a way that is not easily explained by genetics, and therefore suggests and environmental factor. While it is uncontroversial that the number of ASD diagnoses has been increasing over the last two decades, this does not necessarily mean that the true incidence of ASD has been increasing.
The evidence actually shows that diagnostic substitution, broadening of the definition of ASD, and increased surveillance account for much of the increased recorded incidence. It’s possible that changes in diagnostic behavior entirely accounts for the apparent increase. It’s also possible that a subset is due to a true increase, but that has not been clearly established.
This still leaves us with the conclusion that an environmental factor is possible in ASD, but not necessary.
What does this current study show? The study in question is a case-control study using data from the CHARGE study and data about pesticide use in California. A case-control study is a retrospective epidemiological study. It looks at two or more populations based upon whether or not they have a condition, in this study there are three groups – ASD, developmental delay (DD) and typical. The groups are then compared based on exposure to a potential risk factor to see if it is correlated with the condition.
In this study the authors looked at proximity to pesticide use prior to conception and during each trimester of pregnancy. They concluded:
“This study of ASD strengthens the evidence linking neurodevelopmental disorders with gestational pesticide exposures, and particularly, organophosphates and provides novel results of ASD and DD associations with, respectively, pyrethroids and carbamates.”
Orac has already reviewed this study and I agree with his assessment – this conclusion is not justified by the data presented.
First, there is a fatal flaw in the study design . . .
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Autism cure promoters are people who claim they “cure” people with autism.
The claims made by these people are very conversational, both in their claims about autism and it’s causes, and what they say can cure autism.
Now there are a lot of different things I have noticed about autism cure promoters, but I’ve narrowed it down to five different things.
So here are five things I’ve noticed about autism cure promoters:
5. They’re closely aligned with the anti-vaccination movement.
Autism cure promoters and the anti-vaccination movement are pretty much like peas in a pod. Anti-vaccers often promote these so called “therapies” that the autism cure promoters claim can cure a person with autism, and autism cure promoters also tend to publish on their websites anti-vaccination movement propaganda, mainly in the form of claims that certain chemicals in vaccines can cause autism.
Some of these promoters also like to use certain words that the anti-vaccination movement also uses inorder to sell their therapies to people with autism or have autistic children, such as “vaccine damage”, “vaccine injury”, or “autism epidemic”.
They also ignore the fact that such words are not only incorrect and misleadinf, but very insulting to people with autism. Ofcourse they’re not actually promoting their therapies towards people with autism, they’re really promoting them towards parents of children who have autism and just want their kids to be normal.
4. They exploit the fears and desires of parents with autistic children.
For some parents when a child is diagnosed with autism it can be devastating to them, and the fact that there is no way to cure autism can make that devastation to them even worse. Then comes along someone who claims they can do things that the medical industry cannot do and can “cure” their child of autism, and if they don’t know any better they may take that person up on their offer.
A person who is misinformed about what autism is and what causes autism, mixed with both the fear of what will happen to their child and how their life will turn out due to their autism, combined with their desire to have a “normal” child, would be very temped by someone whom claims they can cure their child of autism and give them a chance at a normal life and be willing to pay whatever price they can inorder to do so.
The people who are promoting these so called autism cures know this and know that they can exploit these fears and desires to sell people products and services that scientific research has concluded are useless at curing autism.
3. They’re trying to give a simple solution to a complex issue.
Autism is a neurological disorder, and like all neurological disorders it’s complex without any simple solutions.
Autism cure promoters try to make it look like autism is caused by toxins in the body, and that by removing these toxins a person whom has autism one can be cured of autism.
While some toxins can cause neurological disorders, all legitimate scientific research has shown that autism isn’t one them.
While the actually cause of autism is still technically unknown, most scientists who study autism agree that it’s . . .