About a decade ago (even longer) there was a question posed as to whether thimerosal (a mercury containing preservative) in vaccines could increase the risk of autism. Many studies have been performed and the answer is no (for example, here).
Even though the question has been approached from multiple angles, research continues. A study out this week takes a look at blood mercury levels in the mother and newborn baby to see if they are correlated with later autism diagnoses in the baby.
California archives blood samples from pregnant mothers and blood spots (cards with a dried spot of blood) from newborns. A team looked at these samples to explore the question: are blood mercury levels in pregnant mothers or newborns correlated with autism.
Short answer: no.
Add this to a MIND Institute study from a few years ago , (Blood mercury concentrations in CHARGE Study children with and without autism) which showed no differences in blood mercury levels between ASD and non ASD preschool children when controlled for diet. And this study from Jamaica again showing no differences. So, while the authors in the recent study suggest a larger study would be valuable, I question whether resources would be wisely spent in that way.
The abstract is below of the new study is below:
Prenatal and early-life exposures to mercury have been hypothesized to be associated with increased risk of autism spectrum disorders (ASDs).
This study investigated the association between ASDs and levels of total mercury measured in maternal serum from mid-pregnancy and infant blood shortly after birth.
The study sample was drawn from the Early Markers for Autism (EMA) Study. Three groups of children who were born in Orange County, CA in 2000-2001 were identified: children with ASD (n=84), children with intellectual disability or developmental delay (DD) (n=49), and general population controls (GP) (n=159). Maternal serum specimens and newborn bloodspots were retrieved from the California Department of Public Health prenatal and newborn screening specimen archives. Blood mercury levels were measured in maternal serum samples using mass spectrometer and in infant bloodspots with a 213nm laser.
Maternal serum and infant blood mercury levels were significantly correlated among all study groups (all correlations >0.38, p<0.01). Adjusted logistic regression models showed no significant associations between ASD and log transformed mercury levels in maternal serum samples (ASD vs. GP: OR [95% CI]=0.96 [0.49-1.90]; ASD vs. DD: OR [95% CI]=2.56 [0.89-7.39]). Results for mercury levels in newborn blood samples were similar (ASD vs. GP: OR [95% CI]=1.18 [0.71-1.95]; ASD vs. DD: OR [95% CI]=1.96 [0.75-5.14]).
Results indicate that levels of total mercury in serum collected from mothers during mid-pregnancy and from newborn bloodspots were not significantly associated with risk of ASD, though additional studies with greater sample size and covariate measurement are needed.
Copyright © 2014 Elsevier Inc. All rights reserved.
By Matt Carey