Study challenges drug's role in autism
By Jia-Rui Chong, Los Angeles Times Staff Writer
5:15 PM PST, January 7, 2008
The prevalence of autism in California children continued to rise after many vaccine manufacturers started to remove the mercury-based preservative thimerosal in 1999, suggesting that the chemical was not a primary cause of the disorder, according to a study released Monday.
The analysis found that from 2004 to 2007, when exposure to thimerosal dropped significantly for 3- to 5-year-olds, the rate continued to increase in that group from 3.0 to 4.1 per 1,000 children.
"If mercury exposure in vaccines was a major cause of autism, then the number of ... affected kids should have diminished once they were no longer exposed to thimerosal," said Dr. Robert Schechter, lead author of the study and a medical officer at the state Department of Public Health. "That is not what we found."
The study, published in the Archives of General Psychiatry, is the latest in a series that has investigated the connection between thimerosal and autism. The majority have found no association.
But the latest findings failed to convince some parents and advocacy groups that have long blamed mercury, a neurotoxin, for the disorder.
"This study presents a greatly over-simplified explanation of a very complex problem," said Claire Bothwell, chairwoman of the board at the National Autism Association, which works on behalf of families with autism. "Rising numbers do not confirm that thimerosal never had a role."
These advocates make me want to scream. They either do not understand the science or they are simplifying the standard caveats in scientific research. I fear the desire to blame someone, anyone, for autism is leading some groups and individuals to reach statistically implausible
Maybe thimerosal and other factors are triggers for a genetic predisposition. Maybe. But that is a huge maybe.
Let's be brutally honest: the only people likely to benefit from blaming mercury are lawyers and a handful of "experts" (using the term loosely) promoting alternative therapies.
No, drug companies are not always honest. There have been and are catastrophic conditions caused by exposure to various chemicals in medications. I am not about to claim the drug companies should be trusted. Unfortunately, any testing is going to be paid for by the
drug companies — you can't bill taxpayers for every drug test. Such testing should be done by government and university labs, paid for via special patent fees.
I have no doubt some environmental factors are at work, but I also think way too much attention is being given to a single suspect... one that looks increasingly unlikely based on statistical epidemiology. It's time to start looking for other environmental agents, from pesticides to heavy metals in drinking water, and stop suffering from tunnel vision.
Better diagnostic criteria, improved awareness of autism, and other factors are merging to create an increase in the "autism rate" in the United States. We must admit causal factors are only a part of the increase.