Here is just a partial list of correlates, risk factors, and possible causes that have been the subject of serious peer-reviewed studies:
• Air pollution and proximity to freeways;
• Maternal thyroid issues;
• Autoimmune disorders;
• Induced labor;
• Preterm birth;
• Birth by cesarean section;
• Maternal and paternal obesity;
• Maternal and paternal age;
• Maternal post-traumatic stress disorder;
• Smoking during pregnancy;
• Antidepressant use during pregnancy.
I also write: "If the science were not confusing enough, its coverage in the mass media has added another layer of murk. News reports hype tentative findings and weak correlations as “breakthroughs” in the quest for autism answers. "
The written press release was titled “Too Much Folate in Pregnant Women Increases Risk for Autism, Study Suggests.”
The subsequent headlines were similar: “Autism Linked to Overdose of Folate and Vitamin B12 During Pregnancy” (The Telegraph), “Study: Too Much Folate, B12 In Pregnant Women Can Multiply Autism Risk By 17.6” (CBS), “A Study Asks: Too Much Folic Acid a Cause of Autism?” (Fox News). I could go on.
At this point, though, the evidence is extremely premature. The findings have not been peer-reviewed or published in a journal; the press release referred only to a brief scientific abstract that is being presented at a conference this week.
It remains to be seen if the findings hold up to the scrutiny of peer review and, so, warrant publication in a medical journal. Even if they do, after that, the correlation would need to be seen again, and again, in multiple studies, before it could reliably be said to exist. Then, if it does exist, the challenge would be to attempt to figure out what drives those elevated levels in a person’s blood.