Evidence Builds for Link between Mercury and Autism

Though Dr. Mark Geier and David Geier have published extensively on the effects of Thimerosal, the mercury-containing compound used as a preservative in childhood vaccines that was demonstrated to increase the risk for developing autism spectrum disorder (ASD), their recent work into the risks of mercury exposure continues to generate insightful and impactful results. Though we know mercury to be toxic to humans—international conferences have been held to limit its use and exposure to humans—the case for mercury’s association with ASD has been somewhat slow to take hold. The Geiers’ continued research efforts may change that.

In their paper, “Hair Toxic Metal Concentrations and Autism Spectrum Disorder Severity in Young Children,” published in the International Journal of Environmental Research and Public Health, the Geiers provide us with even more reason to heed their earlier assertions of a link between ASD and toxic metals like mercury, and offer up a deeper analysis of how this exposure can influence the severity of ASD.

The Geiers used the prolific research of other scientists in the field as a foundation for their “Hair Toxic Metal Concentrations and Autism Spectrum Disorder Severity in Young Children” paper.  Over 40 research articles from various investigators had found that children with ASD maintain higher concentrations of toxic metals in their hair than children without ASD. These metals included arsenic, cadmium, lead, chromium, aluminum, nickel, cobalt, tin, uranium and manganese, though most research had focused on mercury concentrations. Researchers had also observed that when metal toxicity in an ASD child’s hair and nails increases, so too do their ASD symptoms, as measured using the CARS autism assessment. Of note, children with moderate to severe autism were more significantly impacted by these higher levels than children with mild autism.

With this information in hand, the Geiers sought to determine if there was a correlation between high levels of toxic metals in hair and more severe symptoms of autism by conducting a study of moderate to severe ASD subjects between the ages of 1 and 6. Using the widely-accepted and well-established CARS autism assessment and the CLIA-approved laboratory Doctor’s Data to analyze subject hair samples, the Geiers collected data about each subject’s CARS rating and toxic metal concentrations. Upon pairing hair toxicity with corresponding CARS data, a significant correlation was found to exist between higher concentrations and more severe symptoms of ASD. When graphed, increasing levels of toxicity corresponded to increasing CARS scores (higher CARS scores indicate more severe symptoms). Though a variety of toxic metals were tested, only mercury showed a strong correlation to severe symptoms of ASD. The Geiers have therefore shown that not only do children with ASD maintain higher levels of mercury, but the quantity of this mercury actually parallels the severity of their symptoms. In other words, an even stronger case has been built for mercury’s link to autism.

The study also observed relationships between ASD brain pathology and effects on brains intoxicated with mercury, and found numerous parallels. This again suggests a significant link between the presence of mercury and ASD. The many parallels identified between ASD brain pathology and the effects of mercury intoxication include neuro-inflammation, dysfunction of the mitochondria, microtubule degeneration, and decreased blood flow.  In total, 17 similar behaviors were identified in both brain conditions. These parallels suggest to researchers that either mercury is a causal factor of ASD, or that it works in conjunction with other toxic elements to cause ASD. Either way, we’ve once again been shown that mercury is a contributing factor in this increasingly-prevalent neurodevelopmental disorder.

 

Is Thimerosal Getting a Fair Trial? A Closer Look at Pro-Vaccine Research

Even though scientific research aims to uncover truths, sometimes findings aren’t always an accurate reflection of “the truth.” This could be the result of unintentional human errors, misguided methodologies, or the omission of important results. In the case of Thimerosal, an organic-mercury based compound that was used as a preservative in childhood vaccines, the truth about its health risks now seems obscured by new flawed studies.

Thimerosal gained attention in the United States after a wide array of research found a link between Thimerosal-containing vaccines (TCVs) administered during early childhood and a higher risk for developing neurodevelopmental disorders like autism. Though Thimerosal was subsequently recommended to be removed from all vaccines by the US Public Health Service and American Academy of Pediatrics in 1999, it can still be found in some flu vaccines, which are administered to many pregnant women, infants, and children each year in the United States.

The CDC argues that Thimerosal is in no way attributed to neurodevelopmental diseases like autism, despite the fact that a study conducted by the CDC itself found a nearly 8-fold increase in autism rates when infants received Thimerosal-containing vaccines. In total, there have been over 160 different studies that have found Thimerosal to be harmful.

So we wonder: is Thimerosal getting a fair trial?

One reason to doubt the fairness of the Thimerosal debate is the fact that the six papers the CDC cites as evidence that Thimerosal is safe were all conducted, funded, or cosponsored by the CDC itself. In his 2014 paper “Methodological Issues and Evidence of Malfeasance in Research Purporting to Show Thimerosal in Vaccines is Safe,” Dr. Mark Geier assesses each of the six studies that the CDC has used as proof there is no link between autism and TCVs.

What did Geier find?

  • A paper published by Madsen et al. in 2003 argued that the rates of autism in Denmark actually increased when Thimerosal was removed from vaccines. However, the paper had a major flaw in its methodology. Researchers first calculated the number of those who had received TCVs and developed autism based on data collected solely from inpatient visits, yet then calculated the number of those with autism after TCVs were banned based on data from both inpatient and outpatient visits; this made it appear as if cases increased after TCVs were banned, when in fact the researchers simply looked at a larger pool of data.
  • The CDC’s Stehr-Green et al. study in 2003 provides inaccurate information about TCVs because it compare the correlation of TCVs and autism between three different countries (the U.S., Sweden, and Denmark), without acknowledging the presence of influential factors like varying quantities of Thimerosal and a reliance on a small sample population.
  • The Hviid et al. study, also conducted in 2003, states that populations that received TCVs were not at an increased risk of developing autism. However, the study’s sample population included children as young as 1 year of age, an age at which most are too young to start showing signs of autism. The study therefore could not accurately determine that actual number of children who received TCVs and developed autism.
  • In 2004, the Andrews et al. study found that TCVs resulted in a lower risk for developing neurodevelopmental disorders, yet the study evaluated data from children that experienced significantly different vaccination schedules and were diagnosed based on different criteria. Further, all subjects were given the same follow up times; in other words, if the subject didn’t develop a disorder within a standard amount of time, no correlation was reported. However, we know that disorders can appear at any time in an individual’s life, which means that using a standard follow up time is ineffective. This research is also based on subjects from the UK who received lower quantities of Thimerosal in TCVs than children did in the U.S.
  • The CDC’s 2003 Verstraeten et al. study stated there was no relationship between Thimerosal and cases of autism after studying data from the Vaccine Safety Datalink, yet the paper (which only published findings on the fifth of the study’s five phases) inexplicably did not include any actual data to back this claim. Interestingly, the first phase of the study (which was only published internally), found that infants who were exposed to more than 25 micrograms of Mercury were 7.6 times more likely to develop autism. The following phases of the study employed manipulative methodologies that were able to drop this figure to just 1.69.
  • 2010’s Price study found that pre-natal and infant exposure to TCVs presented no significant risk for developing autism. Yet, this conclusion was based on a matching methodology that resulted in flaw known as overmatching, as matching variables were in fact significant predictors of exposure. Further, the study also did not report that it found that prenatal exposure to Thimerosal resulted in an 8.73 increase in risk for regressive autism.

Each of the six primary studies the CDC cites as evidence that Thimerosal doesn’t increase the risk for autism have significant flaws in methodology and reporting. Therefore, it seems that if the debate about Thimerosal is to be fair, research cited to support arguments should at the very least be founded on sound approaches.