Thu May 3, 5:01 PM ET
Mercury levels have no relationship to the development of autism, a developmental disorder whose cause remains unclear, according to a Canadian study published Thursday.
"In recent years, hypotheses have been raised concerning a possible relationship between mercury exposure and autism," said Eric Fombonne, head researcher and director of pediatric psychiatry at the Montreal Children's Hospital.
"Specifically, the concerns have been related to childhood thimerosal-containing vaccines, dental amalgams, and methylmercury in food," he said in a statement.
The research team examined mercury levels in hair and blood samples provided by autistic children and their mothers and concluded that the levels observed did not differ largely from those taken from children without autism.
The study also "demonstrated that there was no correlation between the mercury level and the severity of symptoms and level of functioning of autistic children."
Children with autism, a growing developmental concern which appears before age three, often avoid physical contact and communicate with gestures rather than speech.
A February study by the US Centers for Disease Control and Prevention suggested that autism is more common in the United States than previously believed, affecting one child in 150.
The Canadian study was performed on 71 autistic children and 75 children without the disorder.
Fombonne said the study's findings also implied that "chelation therapies, whereby heavy metals are removed from the body using specific compounds, are not useful in the treatment of autism."