Yesterday, Trump announced that vaccines and Tylenol cause autism. I saw this because the NYT had a headline that said something like “Trump falsely claims autism linked to Tylenol.” And I get why they said this; He also linked vaccines to Autism, which has been credibly refuted over and over. However, from my reading of the literature, this is not true of Tylenol. And while I’m not saying it’s proven that Tylenol causes autism (because that’s not really how science works), what I am saying is, based on my reading of the literature, there may be a link between Tylenol and Autism and it should be studied.
The Literature
Here is what I’ve read:
From a study out of the Barcelona Institute for Global Health:
The proportion of children having borderline/clinical symptoms ranged between 0.9 and 12.9% for ASC and between 1.2 and 12.2% for ADHD. Results indicated that children prenatally exposed to acetaminophen were 19% and 21% more likely to subsequently have borderline or clinical ASC (OR = 1.19, 95% CI 1.07-1.33) and ADHD symptoms (OR = 1.21, 95% CI 1.07-1.36) compared to non-exposed children. Boys and girls showed higher odds for ASC and ADHD symptoms after prenatal exposure, though these associations were slightly stronger among boys. Postnatal exposure to acetaminophen was not associated with ASC or ADHD symptoms. These results replicate previous work and support providing clear information to pregnant women and their partners about potential long-term risks of acetaminophen use.
This study out of WPLab (which, should be taken with a grain of salt given their whole thing is studying autism and acetaminophen):
A systematic review revealed that the use of APAP in the pediatric population was never tracked carefully…. We concluded that available evidence demonstrates that early exposure to APAP causes neurodevelopmental injury in susceptible babies and small children.
This one with authors from UCLA, Harvard, Mt. Sanai, and UMass:
Of these, 27 studies reported positive associations (significant links to NDDs), 9 showed null associations (no significant link), and 4 indicated negative associations (protective effects). Higher-quality studies were more likely to show positive associations. Overall, the majority of the studies reported positive associations of prenatal acetaminophen use with ADHD, ASD, or NDDs in offspring, with risk-of-bias and strength-of-evidence ratings informing the overall synthesis.
And finally this out of the University of Texas Health Science Center San Antonio (though again, take with a grain of salt as the sample size seems to be very small)
Our previous case-control study showed that use of acetaminophen at age 12–18 months is associated with increased likelihood for ASD (OR 8.37, 95% CI 2.08–33.7). In this study, we again show that acetaminophen use is associated with ASD (p = 0.013).
Conclusion
Now to be fair, I’m sure this is by no means comprehensive, just what I’ve find in my ChatGPTing and googling and there is at least one study out of The Karolinska Institute which controls for another possible confounding variable and finds that there’s no link. So, I am by no means saying that it’s proven that Autism and Acetaminophen are linked. What I am saying is that there are enough studies from varied and respected institutions suggesting that there may be and it’s reasonable to proceed with caution when it comes to Tylenol and ask for more studies. To say that it’s proven isn’t right, but I don’t think it’s right to say it’s disproven either (that’s also just not how science works). This is what Tom Wright-Piersanti wrote for the New York Times this morning:
For years, scientists have studied a possible link between pregnant mothers’ use of acetaminophen, the active ingredient in Tylenol, and neurological conditions like autism and A.D.H.D. The findings are complex. Some studies suggest a link; others do not. None have found proof of a causal relationship.
So while it’s reasonable to be cautious and fund more research in this field, what’s absolutely not reasonable is for the President and HHS secretary to hold a news conference announcing definitive proof that Tylenol causes Autism. And unfortunately, the President and the Nutjob probably did more to hurt the cause of Autism research by doing this, than by just leaving things alone and letting the scientists fight it out. There’s nothing worse than introducing politics into science.
Also
I do want this Substack to be about more than politics. That’s honestly part of why I haven’t been writing, been trying to develop a habit and topics, etc. But I had already done this research since I have a small child and felt I could meaningfully add to the conversation.