Sunday, 31 January 2016

More Sloppy Science and Autism

Steroid inhaler (left)  and  B2AR agonist Salbutamol/Ventolin  (right)

Here is a perfect example of more sloppy science being applied to autism.

The headline reads:

Anti-Asthma Drugs Taken During Pregnancy Associated With Autism Risk

When really it should read:-

Poorly Controlled Asthma Associated With Autism Risk

The US study used data from Denmark to suggest that increased use of asthma rescue inhalers by pregnant mothers was associated with increased autism in the child.  This was clearly suggesting that the drug might lead to autism.

The study looked at mothers with asthma who had a repeating prescription for a ß-2-andrenergic receptor (B2AR) agonist drug (the blue rescue inhaler).

Children with mothers who filled their B2AR agonist prescriptions from 90 days before the estimated conception date all the way until their birth date were considered to be exposed to the drug. If a prescription was not filled throughout that entire period, the children were not considered to be exposed

Asthma Control

I know a fair amount about autism, but I also know about asthma.

Almost everyone with asthma has a long term therapy to control the disease, like a steroid inhaler, and then a short term therapy to deal with flare-ups when the asthma gets out of control.

The usual short term therapy is a ß-2-andrenergic receptor agonist drug, like Salbutamol (Ventolin).  This is the blue rescue inhaler.

If your asthma is well controlled, you need your short term therapy less often.

I am forever throwing away my son’s date-expired Ventolin inhalers that are way more than half full.  I do buy new Ventolin inhalers, but that does not mean they ever get used.

Sign of asthma under control  -  throwing away date-expired 
                                                       Salbutamol/Ventolin inhalers

Sign of asthma out of control -   throwing away empty 
                                                       Salbutamol/Ventolin inhalers

So all this study showed is that the mothers with less well controlled asthma had a higher chance of having a child with autism.

Since this was a study in Denmark, where there is no significant under-class of poor people or poorly educated people (unlike the UK or USA), we can probably say that the people with the less well controlled asthma were the ones with more severe asthma.

We can then note that asthma is an auto-immune disease, like diabetes, thyroid diseases, rheumatoid arthritis etc.   It is hardly surprising that the more severe the auto immune disease in the mother the higher the chance of autism in the child.

If the mother has any kind of auto-immune disease, or, because it is genetic and epigenetic, if her parents or grandparents do/did, she has an elevated risk of a child with autism. 

If she was remarkably well informed, she could choose to mitigate this elevated risk, by minimizing the other risk factors.

Not surprisingly, gestational diabetes is also found to increases autism risk.

Just as the public is being made aware of what factors increase the risk of cancer, and has the choice of minimizing exposure to them, the same will become true for autism.  Most of the knowledge already exists for both cancer and autism.

Since people are not rushing out to become vegetarian, give up alcohol (and smoking) and ride a bicycle to work (while inhaling no pollutants, or being knocked down) cancer rates will continue to rise and, for a different set of reasons, so will autism incidence.  


Salbutamol/Ventolin does not cause autism and might just save your life.

A family history of auto-immune disease and an exacerbation of an auto-immune disease during pregnancy will increase the likelihood of a child developing autism.  But there are many other risk factors involved.

There are people writing and reviewing autism research with PhD’s, even from Ivy League Universities, who are far less bright than you might imagine.

1 comment:

  1. From:
    Croen, Lisa A. et al. “Prenatal Exposure to β2-Adrenergic Receptor Agonists and Risk of Autism Spectrum Disorders.” Journal of Neurodevelopmental Disorders 3.4 (2011): 307–315. PMC. Web. 1 Feb. 2016.

    "Prenatal exposure to any B2AR occurred at a similar rate among children with autism and control children. Asthma treatment with B2AR agonists during pregnancy does not explain our previous observation of increased ASD risk among asthmatic mothers. There is a suggestion that maternal exposure to terbutaline for greater than 2 days during the third trimester of pregnancy could be associated with elevated autism risk—however, larger studies are needed. Should this association be confirmed, it would provide further contraindication to maintenance tocolysis with B2ARs and also raise interesting questions about late pregnancy mechanisms and exposures to be considered in autism risk factor research."

    Here is the link to full article:

    Compare the authors for more fun (or not).




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