Originally published Dec. 2009. Republished April 2, 2010 in recognition of Autism Awareness Day
Government researchers have documented a 57% increase in the prevalence of childhood autism, according to the latest official statistics from the Centers for Disease Control and Prevention. The CDC termed the epidemic an "urgent public health concern." (Though you may be surprised at some of the documented causes of autism clusters.)
Whereas the previous estimate, from 2002, put the rate of autism spectrum disorder at 1 in 150, new studies, of 8-year-olds in 11 states in 2006, put the rate at 1 in 110. While the autism rate for boys increased in nine states, the rate for girls increased in just four states monitored. There were also surprising differences between states, with the Florida's rate of autism (4.2 per 1,000) barely one-third the rate of that in Arizona and Missouri (12.1 per 1,000). (Some of this difference may be explained in the types of records reviewed, however, since only some states had access to both health and educational records.)
As recently as a decade ago, the autism rate was thought to be 1 in 500.
What is going on? Part of it the increase is an increase in diagnosis: Years ago, autism was recognized as a single, severe disease, whereas now it's recognized as a spectrum disorder, with a range of symptoms. But CDC researchers agreed that diagnosis alone did not account for the overall increase.
There's a general consensus that our genetic makeup predicts risk for autism, and that awareness about the disease has increased diagnosis for autism spectrum disorders... but there's also reason to believe that some triggers have yet to be identified. Is it something in the water? Something to do with parenting? Something we're eating? Almost certainly.
"Environmental mercury and other heavy metal exposure, contaminated water, pesticides, a greater reliance on antibiotics -- and even extensive television viewing by very young children -- have been cited by some as possible factors in mounting autism rates," E-The Environmental Magazine recently summarized. "Researchers at the American Academy of Pediatrics and other institutes have also identified flame retardants as possible culprits."
Everything from toxic waste sites to vinyl flooring is being investigated as a potential cause, with a proliferation of research, including the landmark Children's Health Study. (One suspected cause that has been largely discredited is the vaccine preservative thimerosal; anyway, mercury-based thimerosal has been removed from routine childhood vaccines, though it remains in flu and swine flu vaccines.)
Until a definitive cause -- or set of causes -- is identified, parents would be wise to reduce exposure to toxic chemicals during pregnancy and early childhood. The Daily Green recently asked children's health advocate Deirdre Imus, a 2009 Heart of Green Award winner, to offer tips for protecting your kids from toxic chemicals.
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