LAST month health officials in California announced two staggering pieces of news. The first was that the number of Californian children diagnosed with autism has nearly doubled in just four years. The second was that nobody knows why.
If ever confirmation were needed that we are in the midst of a deeply mysterious epidemic, this surely is it. Are genes involved? Almost certainly, but which genes, nobody can say 鈥� and a population鈥檚 genetic make-up does not change in four years, not even in California. Is there something in the water/air/food chain? Possibly, but experts have yet to form a consensus on any leading culprits. They cannot even agree on whether autism is surging or merely doctors鈥� ability to diagnose it.
Faced with this explanatory void it is no wonder that parents with autistic children seek answers in theories outside the mainstream. The UK has had the MMR debate. In the US and Canada thousands of parents have filed lawsuits claiming a link between autism and a mercury-based preservative called thimerosal found in certain childhood vaccines.
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So far, governments and mainstream institutions have tended to react to such claims with all the sensitivity and ingenuity of thought police, or else have only confused matters. Three years ago research by the US Centers for Disease Control suggested thimerosal exposure could be correlated with an increased risk of neurodevelopmental conditions, including autism. These days the CDC says that analysis was flawed.
Into this charged arena comes a controversial new study suggesting children with autism may be unable to excrete mercury normally (see 鈥淭oxic metal clue to autism鈥�). Clearly it is preliminary and the result, even if it can be replicated, falls well short of supporting a specific link with mercury in vaccines. There are other ways in which fetuses and infants can be exposed to mercury, and plenty of facts that do not square with the vaccine link. The UK, for instance, saw a surge in autism in the 1980s and 1990s, yet there has been no increase in British children鈥檚 exposure to the additive since the 1950s.
But even if vaccines have nothing to do with it, the broader idea that some autistic children may 鈥� and the stress is on may 鈥� have some sort of abnormality in their handling of mercury, and perhaps other toxic metals, has to be worth thorough investigation.