Autism is a disease which may result from genetic and environmental factors. It includes a variety of syndromes termed neurobehavioral disorders. The symptoms include social disorders, communication problems, stereotyped behavior, sensory abnormalities, and delayed mental development. Toxic environmental exposures may be significant, such as heavy metals. Children with autism may not be able to detoxify their bodies of heavy metals.
This study evaluates autistic children for toxic exposure to mercury, lead, or aluminum by hair analysis. One hundred autistic children aged 2.5 to 15 years were studied and compared to 100 normal children who were friends and neighbors. Complete histories included details about maternal diet during the pregnancy (especially fish), and the mother’s amalgam* fillings. The children’s developmental histories were taken in detail. Questions were asked about pica (the habit of some children to eat old paint chips which may contain lead), the closeness of gasoline stations to the family homes, and the type of metal cooking pans used.
Hair analysis for metals was used as a measure of long-term toxic metal exposure. Hair was cut from the back of the head close to the skin and was cut in 1.5 to 2 cm. lengths. The hair samples were tested for lead, mercury, and aluminum.
Results showed that the hair levels of lead, mercury, and aluminum were significantly higher in the autistic group than in the normal controls. The mothers of the autistic group were significantly older than mothers of the controls. Autistic children were nursed for shorter periods than controls, and the autistic children with high mercury levels ate more fish than controls. Autistic children with high lead lived closer to gasoline stations than controls, and the children with high aluminum ate more food from aluminum pans than controls. Severity of autism was not related to the elevation of the metals on hair analysis.
CONCLUSION: Research results support a connection between autism and toxic metal environmental exposures. Toxic levels may be related to increased tendency to accumulate the metals or an inability to eliminate them.
NOTE: *Amalgam tooth fillings may contain mercury.
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