Tylenol (Also) Doesn't Cause Autism

"We've got a lot of stupid people in this country running things." -- Donald Trump (a.k.a., Exhibit A)

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For some time Donald Trump's pet charlatan, Bobby Kennedy, has been claiming he'd get the answer to the mystery of what causes autism this month. Yesterday, he claimed to deliver. Although his alleged culprit, Tylenol, might have surprised those of us expecting him to blame vaccines, the soundness of his claim did not.

At all.

Believe it or not, actual scientists have already considered the question of whether Tylenol taken during pregnancy might increase the chances of the child becoming autistic, and have answered that question in the negative.

While there may not be mountains of evidence on the question for Bobby Kennedy to ignore as he does with vaccine safety, there is ample evidence, and it is solid.

One study in particular stands out, as detailed in an X thread by epidemiologist Eric Feigl-Ding. It's the same article my apolitical wife (who is a physician and has a PhD in bioscience, as do I) found when I told her about yesterday's announcement. We both agreed that that study shows that there isn't a link between pregnant women taking Tylenol and autism. (This is also the case with with another, similar study that Feigl-Ding mentions in his thread.)

But don't take my word for it. The paper, which sampled nearly 2.5 million children, found no link and concludes:

Acetaminophen use during pregnancy was not associated with children's risk of autism, ADHD, or intellectual disability in sibling control analysis. This suggests that associations observed in other models may have been attributable to familial confounding.

The paper is linked above, but Feigl-Ding's thread is a good, quick walkthrough, and he plans to post a debunking on his Substack in the near future.

In the meantime, here are some highlights from the walkthrough.

• A crude unadjusted analysis found only a preliminary 5% risk, but once you adjust for family by matching using sibling controls (who didn't get autism), the even tiny 5% risk vaporizes to 0%.
• There is also no dose-response (higher dose, higher risk) relationship either. A higher dose of acetaminophen did not find a higher risk than a lower dose or medium dose pattern. This also suggests a lack of causality usually.
• The above study was in Sweden. Meanwhile, did another study find the same phenomenon? Yes, in a Norwegian study, where once you adjust the acetaminophen-autism analysis by family sibling analysis, then the association goes away to a very non-significant null. Also, short term acetaminophen use under 29 days had no increase risk in either type of analysis.
• For those wondering my background - I have a doctorate in Epidemiology (and another doctorate in Nutrition) and was a faculty and researcher for 15+ years at Harvard, and was a whistleblower during the Vioxx drug safety debacle versus Merck.

Incidentally, Feigl-Ding's Substack appears to be a good resource for anyone rightly concerned about the fact that, as Donald Trump ironically admits, we have "a lot of stupid people in this country running things." When one of those things is the agency tasked with setting safety and effectiveness standards for drugs, it pays more than usual to look elsewhere than the government for advice.

-- CAV