As many as one in 90 children are today being diagnosed with autism--and autism research continues to focus almost exclusively on genetics. In its January/February 2010 issue (posted now at: www.emagazine.com), E-The Environmental Magazine looks at another factor that may be driving up autism rates--environmental toxicity.
Richard Lathe, Ph.D., a molecular biologist who wrote Autism, Brain, and Environment says that since the 1980s, autism rates "have gone up at least tenfold. It indicates that it can't just be genetic--it must be environmental."
One of the difficulties in tracking autism--and its causes--is the degree of variability in the disorder. In its more severe forms, autism affects social interaction and communication and leads to the development of intense habitual interests. Often, after a year of seemingly normal interaction, autistic kids will fail to respond to stimuli, make eye contact or turn at the sound of their name. They may not talk readily, or they may repeat themselves incessantly. They are likely to follow compulsive behavior, such as shaking their hands, stacking objects or repeating daily activities the exact same way each day. The treatment is years of intensive--and expensive--therapy.
Much speculation has surrounded the role of vaccines in triggering autism--specifically vaccines preserved with mercury-containing thimerosal (no longer widely used, except in flu vaccines)--but there have been limited studies on the effects of other environmental toxins, such as mercury from fish, air pollutants like lead and sulfur dioxide, water pollutants like arsenic and pharmaceuticals, and environmental toxins like phthalates (plasticizers), Bisphenol-A (used in some plastic water and baby bottles) and flame retardants known as polybrominated diphenyl ethers or PBDEs, which are used in everything from electronics equipment to plastics and furniture.
"These chemicals are everywhere," says Michael Merzenich, Ph.D., a neuroscientist at the University of California San Francisco. "They've looked at levels of contamination from PBDEs in the Polar Regions and there are significant airborne levels everywhere. You really can't escape them."
The research that is taking up the environmental challenge is uncovering surprising answers--particularly in relation to the link between heavy metal toxicity and autism. Some of this research focuses on porphyrins: chemicals that increase in the blood in response to heavy metal toxicity. It turns out that autistic kids have more porphyrins in their blood following chelation--a detoxifying process--than do typical kids.