Autistic Children May Retain Mercury

The study provides the strongest clinical evidence to date supporting the theory that mercury exposure is tied to autism, a finding that is not a surprise to coauthor by Mark Blaxill, a director of Safe Minds, (Sensible Action For Ending Mercury-Induced Neurological Disorders). This nonprofit parents' organization was founded to investigate the continuing risks to infants and children of exposure to mercury from medical products, including thimerosal in vaccines.

Blaxill, along with scientists Amy Holmes, MD and Boyd Haley, PhD, assessed mercury exposure levels among 94 autistic children and compared them with levels in 45 normally developing children in a control group. They found higher prenatal and postnatal exposures to mercury in the autistic group.

Then the team took a new approach to measuring mercury distribution in the study subjects during infancy. They collected the first lock of baby hair that had been taken years earlier from each child to determine its mercury content.

In a result that appears surprising at first, they found that the autistic hair mercury levels were only a fraction of that found in the hair of the control group.

"Our findings might seem counterintuitive," says Blaxill, "but if you take into account the higher exposures of the autistic children, you quickly see that these reduced hair levels suggest that less mercury was being excreted by these babies."

"This is because mercury must be in the blood in order to be taken up by the hair follicle," Blaxill reasoned, "and mercury must be in the blood in order to be eliminated from the body. If it's not in the hair, then it is not in the blood. And if it's not in the blood to be eliminated, more mercury is retained and available to cause neurological damage in infants who subsequently develop autism."

The researchers found relatively high levels of mercury in the hair of normal infants. These levels appear to be a direct result of the number of mercury containing amalgam fillings in the mother, as well as the mother's fish consumption, during pregnancy.

Many popular fish species contain high levels of mercury. These results appear consistent with the fact that mercury levels in women of childbearing age are already high. Infant vaccines containing thimerosal can then push vulnerable children over the edge, Blaxill says.

Blaxill's results are similar to those in a study published this spring by Mark Geier, MD, PhD and David Geier, in the "Journal of American Physicians and Surgeons." The Geiers evaluated doses of mercury from thimerosal containing childhood immunizations in comparison to U.S. Federal Safety Guidelines and the effects of increasing doses of mercury on the incidence of neurodevelopment disorders and heart disease.

This study showed that children received mercury from this source in excess of the Federal Safety Guidelines for the oral ingestion of methylmercury. Their analyses showed increasing relative risks for neurodevelopment disorders and heart disease with increasing doses of mercury. The Geiers say their study provides "strong epidemiological evidence for a link between mercury exposure from thimerosal-containing childhood vaccines and neurodevelopment disorders."

But the American Academy of Pediatrics takes issue with the Geiers' findings, saying, "No scientific data link thimerosal used as a preservative in vaccines with any pediatric neurologic disorder, including autism."

For parents who may be concerned about vaccinating their infants, the American Academy of Pediatrics says that all routinely recommended infant vaccines currently sold in the United States are free of thimerosal as a preservative and have been for more than two years.

Once considered a rare disorder with an incidence of only one to three per 10,000 births, autism now is found in 20 to 40 children per 10,000 births and "clusters" of one per 150 births have been reported in New Jersey and California, SafeMinds says.

No one knows exactly what causes autism, according to the Centers for Disease Control (CDC), but "scientists think that both genetic and environmental factors might play a role," the agency said, adding that parental actions do not cause children to have autism.

The CDC is doing several ongoing studies of children with autism and is assisting four states to conduct their own studies. One CDC study tracks the number of children with autism spectrum disorders and four other disabilities in a five county area in metropolitan Atlanta, Georgia. To date the studies have not come to any conclusions.

People with autism might not make eye contact and might just want to be alone, the CDC says. They might have trouble understanding other people's feelings or talking about their own feelings. Some autistic children might not like to be held or cuddled, or might not seem to notice when other people try to talk to them. Others might be very interested in people, but not know how to talk, play, or relate to them.

People with autism might repeat actions over and over again, and they might have trouble if family routines change.

Children with autism develop differently from other children. Children without autism develop at about the same rate in areas of development such as motor, language, cognitive, and social skills, but children with autism might have large delays in language, social, and cognitive skills, while their motor skills might be about the same as other children their age. They might be very good at things like putting puzzles together or solving computer problems, but not very good at some things most people think are easy, like talking or making friends.

About 40 percent of children with autism do not talk at all.

Sallie Bernard, executive director of Safe Minds says the Blaxill study provides the clearest proof to date, "that small differences in mercury exposure and detoxification ability can drive huge differences in the brain development of small children."

Based on the results of the mercury in hair research, Safe Minds is calling for the National Institutes of Health to implement and fund the Institute of Medicine's research recommendations on thimerosal, mercury and neuro-developmental disorders, including autism.

Safe Minds wants the CDC to make available its internal data from vaccine safety records available to independent researchers in order to investigate the role of thimerosal in causing neurodevelopmental disorders in children exposed to vaccines containing thimerosal.

The organization wants the CDC to be removed from any supervisory role in vaccine safety research. "Such research should be undertaken by independent researchers without ties to the CDC or to vaccine manufacturers," Safe Minds says.

Safe Minds is calling for the Food and Drug Administration to issue an immediate recall of all thimerosal-containing vaccines.

The FDA and the World Health Organization should require the immediate production of thimerosal-free formulations and the investments in sterile production required to make these vaccines safe, the organization says.

"Recent studies sponsored by vaccine health officials that have attempted to reassure parents about the safety of so-called low dose mercury exposures from vaccines have completely failed to assess individual sensitivity to this neurotoxin, Bernard said. "It only takes one child in 100 to have reduced excretion capacity and you can have an epidemic of neurological disease on your hands."

Safe Minds is asking the Bush administration to hold a summit on what it calls "the autism epidemic," and to encourage large-scale investigation into the environmental causes of autism, "a public health crisis that dwarfs the threats from infectious diseases like SARS and the West Nile virus," the organization says.