Causation

 In The Politics of Autism, I discuss various ideas about what causes the condition.

• Contrary to the lies of Trump and RFK Jr., vaccines do not cause autism.
• Genetics plays an important role.
• Much of the reported increase reflects greater awareness and broadening of diagnostic criteria.
• Beyond that, there is uncertainty about how much true prevalence has increased, and what might be causing such an increase.

Emily Baumgaertner at NYT:

More than 100 genes have been associated with autism, but the disorder appears to result from a complex combination of genetic susceptibilities and environmental triggers.

The C.D.C. has a large-scale study on the risk factors that can contribute to autism, and researchers have examined dozens of potential triggers, including pollution, exposure to toxic chemicals and viral infections during pregnancy.

Some research suggests that babies born to older parents — particularly an older father — may be at increased risk of autism. Other studies hint that premature birth or low birth weight could be associated with autism, which is often linked to high oxidative stress.

The idea that such factors could also be involved in the overall rise in autism is convincing to Juergen Hahn, a professor at Rensselaer Polytechnic Institute who studies the computational systems biology of autism, given that both the number of children surviving premature birth and the average age of new parents are rising.

But testing a hypothetical driver of autism would mean controlling for the endless list of other influences on early development and following the child well into adulthood, when some people now receive their diagnosis.

“These are very complicated studies to conduct, especially if you want statistical certainty, and there are no easy answers,” Dr. Hahn said. “Sometimes we just have to say we don’t know. And that always gives people room for speculation.”

...

Researchers also point to the influence of social media as “one of the biggest unrecognized factors driving the explosion of autism diagnoses,” Dr. Baron-Cohen said. Platforms like Reddit, he said, became a space “where people who might wonder if they or their child were autistic could communicate with each other and feel a new sense of belonging and identity,” he said.

Still, for Catherine Lord, a psychologist at the University of California, Los Angeles, who has developed diagnostic tools and longitudinal studies for autism, the math just isn’t working.

“Some of it is clearly from greater awareness and broader inclusion,” she said. But even if those are the biggest factors driving the surge, and even if biological and environmental factors are contributing as well, she said, “it seems a little far-fetched to think that all of these add up to the increase.”

She is confident, though, from copious data in both the United States and abroad, that heightened autism prevalence does not correspond to childhood immunizations.

“Whatever it is,” she added, “it’s not vaccines.”

Here is a long. growing, and probably incomplete list of other correlates, risk factors, and possible causes that have been the subject of serious studies: 

1. Inflammatory bowel disease;
2. Pesticides;
3. Air pollution and proximity to freeways;
4. Maternal thyroid issues;
5. Autoimmune disorders;
6. Induced labor;
7. Preterm birth;
8. Fever;  
9. Birth by cesarean section;
10. Anesthesia during cesarean sections;
11. Maternal and paternal obesity;
12. Maternal diabetes;
13. Maternal and paternal age;
14. Grandparental age;
15. Maternal post-traumatic stress disorder;
16. Maternal anorexia;
17. Smoking during pregnancy;
18. Cannabis use during pregnancy;
19. Antidepressant use during pregnancy;
20. Polycystic ovary syndrome;
21. Infant opioid withdrawal;
22. Zinc deficiency;
23. Sulfate deficiency;
24. Processed foods;
25. Maternal occupational exposure to solvents;
26. Congenital heart disease;
27. Insufficient placental allopregnanolone.
28. Estrogen in the womb;
29. Morning sickness;
30. Paternal family history;
31. Parental preterm birth;
32. Antiseizure meds
33. Location of forebears
34. Lithium
35. Aspartame
36. BPA
37. Brain inflammation
38. Maternal asthma
39. Infertility
40. Ultraprocessed foods
41. Household chemicals
42. Parental psychiatric disorders
43. Fluoride
44. Fatty acids in umbilical cord blood
45. Maternal inflammation during pregnancy