Doctors ponder the environmental causes of autism

Perri Klass, MD, wrote an article in today’s New York Times puzzling over the possible environmental causes of autism.

Parents of children with autism often ask pediatricians like me about the cause of the condition, and parents-to-be often ask what they can do to reduce the risk,” she wrote. “But although there is more research in this area than ever before, it sometimes feels as if it’s getting harder, not easier, to provide answers that do justice to the evidence and also offer practical guidance.

Research is suggesting that an individual’s genes matter, but environmental exposures are also apparently causes of autism. A recent twin study, published in July in the Archives of General Psychiatry, had a surprising finding–that fraternal twins were much more likely to both have autism than had been expected.

“The implication is that something in their common gestational or early childhood experience may have contributed to this similarity,” wrote Dr. Klass.

This new direction, evaluating environmental contaminants, has so far produced little fruit in research. Researchers have looked at some prenatal exposures and found correlation with a few things, like rubella infection during pregnancy, and two drugs, thalidomide and valproic acid, according to Dr. Klass. Phthalate exposure before birth also correlates with social difficulties later, though cause has not been proven. Phthalates are chemicals used to soften plastics. Conversely, taking prenatal vitamins at the time of conception apparently lessens the risk of autism.

I’m hoping to see more research on these environmental contaminants, focusing on the ones that changed a lot in about 1990, a birth year when the epidemic began in earnest. A biggie: vaccines, whose numbers and frequencies started going way up in about 1990. There is so much about vaccines that hasn’t been tested yet. Another biggie: plastics additives. Plastics became a lot more useful, because of these additives, in about 1990, so our exposures went way up.  These include phthalates, BPA, and plenty of others I am sure.


Phyllis Wheeler

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