Autism and Environmental Toxins

Explore recent research addressing the links between autism and environmental toxins.

Age-dependent lower or higher levels of hair mercury in autistic children than in healthy controls.
Majewska MD, Urbanowicz E, Rok-Bujko P, Namyslowska I, Mierzejewski P.
Acta Neurobiol Exp (Wars). 2010;70(2):196-208.

In this study, 91 autistic Polish children are compared to 75 age- and sex-matched non-autistic children with respect to: demographic, perinatal, clinical and developmental measures, parental age, birth order, morphometric measures, vaccination history, and hair mercury content. The authors find that autistic children have a significantly greater prevalence of adverse reactions after vaccinations and abnormal development than non-autistic children-between 45% and 80% of autistic children experienced developmental regress. They also find that autistic children significantly differ from healthy peers in the concentrations of mercury in hair: younger autistic children had lower levels than their non-autistic peers, while older children had higher levels than their respective controls. These results suggest that autistic children differ from non-autistic children in metabolism of mercury, which seems to change with age.

Contributions of the environment and environmentally vulnerable physiology to autism spectrum disorders.
Herbert MR.
Curr Opin Neurol. 2010 Apr;23(2):103-10.

This review presents a rationale and evidence for contributions of environmental influences and environmentally vulnerable physiology to autism spectrum disorders (ASDs). The author concludes that prevalence, genetic, exposure, and pathophysiological evidence all suggest a role for environmental factors in the inception and lifelong modulation of ASD; this supports the need for seeking targets for early and ongoing medical prevention and treatment of ASD.

Hepatitis B vaccination of male neonates and autism diagnosis, NHIS 1997-2002.
Gallagher CM, Goodman MS.
J Toxicol Environ Health A. 2010;73(24):1665-77.

This cross-sectional study uses weighted probability samples obtained from National Health Interview Survey 1997-2002 data sets and finds that U.S. male neonates vaccinated with the hepatitis B vaccine prior to 1999 (from vaccination record) had a threefold higher risk for parental report of autism diagnosis compared to boys not vaccinated as neonates during that same time period. Nonwhite boys bore a greater risk.

Level of Trace Elements (Copper, Zinc, Magnesium and Selenium) and Toxic Elements (Lead and Mercury) in the Hair and Nail of Children with Autism.
Lakshmi Priya MD, Geetha A.
Biol Trace Elem Res. 2010 Jul 13. [Epub ahead of print.]

The authors assess the levels of trace elements and toxic elements in the hair and nail samples of autistic children and to evaluate whether the level of these elements could be correlated with the severity of autism. In autistic subjects, they observe significant elevation in the concentration of copper, lead and mercury, and significant decrease in the concentration of magnesium and selenium, which could be well correlated with their degrees of autistic severity.

Proximity to point sources of environmental mercury release as a predictor of autism prevalence.
Palmer RF, Blanchard S, Wood R.
Health Place. 2009 Mar;15(1):18-24. [Epub 2008 Feb 12.]

The authors use autism count data from the Texas Educational Agency and environmental mercury release data from the Environmental Protection Agency to determine if proximity to sources of mercury pollution in 1998 were related to autism prevalence in 2002. The authors find that for every 1000 pounds of industrial release, there was a corresponding 2.6% increase in autism rates and a 3.7% increase associated with power plant emissions. Also, for every 10 miles from industrial or power plant sources, there was an associated decreased autism Incident Risk of 2.0% and 1.4%, respectively.

Toxicity Biomarkers in Autism Spectrum Disorder: A Blinded Study of Urinary Porphyrins.
Kern JK, Geier DA, Adams JB, Mehta JA, Grannemann BD, Geier MR.
Pediatr Int. 2010 Jul 4. [Epub ahead of print.]

Using control groups that are age- and gender-matched to children diagnosed with an autism spectrum disorder (ASD), the authors' results suggest that the levels of mercury-toxicity-associated porphyrins are higher in children with an ASD diagnosis than in their peer controls. Although the pattern seen is characteristic of mercury toxicity, the influence of other factors, such as genetics and other metals cannot be completely ruled-out.

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