Reports of increased prevalence rates of autism, likely due to multiple factors, has resulted in a search for potential environmental causes. Questions of the relationship to vaccine administration came about in part because symptoms of autism are identified during late infancy and toddlerhood, and a temporal relationship with immunizations is noted in some cases, 22,81. A paper published in 2001 8 developed a hypothesis relating symptoms of mercury intoxication to symptoms of autism. Meta-analysis completed by Ng and colleagues 74 of 2 studies concluded that there was not enough evidence to show that hair mercury level was lower in autistic children than typical. A number of epidemiologic studies have failed to confirm a link between use of thimerosal as a vaccine preservative and elevated autism prevalence 21,44,45,61,64,73,79,81,88,100,102,103,106. Despite the lack of scientific evidence of a link between the exposure to ethyl mercury in thimerosal (the mercury containing preservative used in vaccines that has been largely eliminated in the US since 2001), chemical chelation treatments are a popular intervention. Chelation is theprocess of administering either DMPS (2,3-dimercaptopropane-1-sulfonate) or DMSA (2,3-dimercaptosuccinic acid) to bind heavy metals such as mercury and facilitate elimination from the body.
There are no controlled studies that examine the safety or efficacy of prescription or nonprescription chelation regimens for children with autism. More importantly, there have been deaths reported from inappropriate use of a chelator, EDTA, from hypocalcemia 10. Proponents of this therapy suggest that mercury is poorly eliminated by children with autism and that it interferes with immune function and other biochemical systems.
Child Adolesc Psychiatr Clin N Am. 2008 October ; 17(4): 803–ix.doi:10.1016/j.chc.2008.06.004.
Complementary and Alternative Medicine Treatments for Children with Autism Spectrum Disorders
Susan E. Levy, M.D.a,a and Susan L. Hyman, M.D.b,b
- Clinical Professor of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia
- Associate Professor of Pediatrics, University of Rochester School of Medicine, Golisano Children's Hospital at Strong