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Monday, July 19, 2010

Autism and the Environment

The Examiner reports that Dr. Philip Landrigan of the Mount Sinai Medical Center told the Interagency Autism Coordinating Committee (IACC) about the need for more research into autism's environmental causes.

Landrigan is one of the leaders of the National Children’s Study, which is expected to identify causes of autism and many other childhood disorders and diseases. The study will “examine the effects of environmental influences on the health and development of 100,000 children across the United States, following them from before birth until age 21.”

Landrigan has been investigating the effects of environmental toxicants on the development of children since the early 1970s when he determined that even very small levels of lead could affect cognitive ability.

His landmark work for the Centers for Disease Control and Prevention (CDC) resulted in the government banning lead from gasoline in 1976 and from paint in 1977, actions that decreased childhood lead poisoning in the U.S. by more than 90 percent.

Landrigan said genetic factors have only been proven to account for a small fraction of the cases of autism, raising the possibility that environmental causes are strongly associated with autism. Landrigan told the IACC that when the complex developing brain is interrupted by environmental insults such as lead, PCBs, or pesticides, it becomes extremely difficult if not impossible to repair.

It has been known for years that environmental toxicants are especially harmful to the developing brains of fetuses and infants, Landrigan said. A 1993 report by the National Academies Press, "Pesticides in the Diets of Infants and Children," stated that young children are not “little adults,” and they detoxify and excrete chemicals very differently than adults. It has also long been suspected that children with autism are more susceptible to environmental toxicants than other children.

In the April 2010 issue of Current Opinion in Pediatrics, Landrigan published “What causes autism? Exploring the environmental contribution,” and stated that “External exposures such as lead, ethyl alcohol and methyl mercury have been known to have an affect on the developing brain.” He wrote that a strong case exists for a link between environmental exposures in early pregnancy and autism, citing studies implicating certain prescription drugs such as Valproic acid and insecticides such as chlorpyrifos in the disorder.