The relationship between mercury and autism: A comprehensive review and discussion

Abstract

The brain pathology in autism spectrum disorders (ASD) indicates marked and ongoing inflammatory reactivity with concomitant neuronal damage. These findings are suggestive of neuronal insult as a result of external factors, rather than some type of developmental mishap. Various xenobiotics have been suggested as possible causes of this pathology. In a recent review, the top ten environmental compounds suspected of causing autism and learning disabilities were listed and they included: lead, methyl-mercury, polychorinated biphenyls, organophosphate pesticides, organochlorine pesticides, endocrine disruptors, automotive exhaust, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers, and perfluorinated compounds. This current review, however, will focus specifically on mercury exposure and ASD by conducting a comprehensive literature search of original studies in humans that examine the potential relationship between mercury and ASD, categorizing, summarizing, and discussing the published research that addresses this topic. This review found 91 studies that examine the potential relationship between mercury and ASD from 1999 to February 2016. Of these studies, the vast majority (74%) suggest that mercury is a risk factor for ASD, revealing both direct and indirect effects. The preponderance of the evidence indicates that mercury exposure is causal and/or contributory in ASD.

A Two-Phase Case-Control Study of Autism Risk Among Children Born From the Late 1990s Through the Early 2000s in the United States

“…A significant overall association between environmental Hg exposure during prenatal or infant periods and autism risk was found in a recently published meta-analysis (odds ratio=1.66 95% confidence interval=1.14–2.17) [18]. Finally, a recent critical review of the more than 90 studies published from 1999 to 2016 that examined the potential relationship between Hg and autism found that 74% supported the link [19]. By contrast, there are studies that did not link Hg exposure with the long-term risk of a child being diagnosed with autism, but these studies have been criticized for their potential methodological limitations [12] and potential conflicts of interest [20].…”

Exposure of children with autism spectrum disorders to mercury and polycyclic aromatic hydrocarbons

“…Mercury, then, has repeatedly been proposed as a cause of autism. A review of the literature by Kern [21] reveals that a large majority of the work (approx. 74%) under consideration took into account the role of mercury as a risk factor for ASD.…”

Fluoridation Practices - A Missing Link in the Vaccine Autism Connection?

“…Some studies implicate vaccines or thimerosal therein. One review found a high correlation between mercury exposure and autism (1). Another review totes "shifting hypotheses" in an unproven vaccine story (2).…”