Home > Science > The Search for Environmental Influences on Autism Risk Expands at IMFAR 2010

The Search for Environmental Influences on Autism Risk Expands at IMFAR 2010

As the emphasis on a role for environmental factors in autism continued to grow at this year’s International Meeting for Autism Research (IMFAR), so did the list of candidate environmental risk factors under study. Among the many factors discussed at the meeting were hazardous air pollutants, assisted reproductive technologies, medications given during pregnancy and childbirth, maternal infections, smoking, nutritional factors, maternal stress, and chemicals such as flame retardants.

Several studies presented by researchers at the latest International Meeting for Autism Research (IMFAR) suggested that a variety of environmental factors likely contribute to the risk of developing autism.  This year, as the emphasis on the role for environmental factors in autism continued to grow, so did the list of candidate environmental risk factors under study. Among the many factors discussed at the meeting were hazardous air pollutants, assisted reproductive technologies, medications given during pregnancy and childbirth, maternal infections, smoking, nutritional factors, maternal stress, and chemicals such as flame retardants.  Many of the projects were funded by Autism Speaks or Autism Speaks-funded researchers, including those leading the Early Autism Risk Longitudinal Investigation (EARLI) study the International Collaboration for Autism Registry Epidemiology.

Epidemiological data presented at IMFAR 2010 supported a link to autism for some environmental factors while ruling out a link for others.   Two of the exposures found to be associated with autism were gestational diabetes in pregnancy and medical interventions related to assisted reproductive technology, specifically ovulation induction or in vitro fertilization. Other exposures, such as smoking, prenatal stress, and hazardous air pollutants in Southern California were not found to be associated with an increased risk for autism or differences in autism severity.   Many of the findings presented by researchers were considered preliminary and will require replication with larger samples.

Not all risk factors will impact everyone equally, and researchers at the conference found that the effects of some early environmental exposures, such as maternal infection during pregnancy, were dependent on the particular individuals being exposed.  For example, maternal bacterial infection during pregnancy was more likely to increase risk for autism when the infant was born prematurely or have low birth weight infants.  Additional “high risk” groups may include children who spent time in neonatal care units as infants either due to low birth weight or gestational age.  Further research needs to be carried out to validate and extend these findings, helping to better identify particularly susceptible – or perhaps even protected – subgroups.  Moreover, although these epidemiological studies have found a link between these specific factors and autism risk, beyond replication of the data it will be important to address the biological mechanisms through which the candidate environmental factors are operating, including the role of genetic variation in vulnerability to specific environmental factors.  As one example, using samples available through Autism Speaks’ genetic data base, AGRE, researchers found variations in the sequences for genes related to the oxidative stress response.  These gene mutations may impact the ability of a person to metabolize toxins.

To hasten discovery of environmental risk factors through epidemiological studies, Autism Speaks partnered with the National Institute of Environmental Health Sciences to facilitate the creation of a network of over 35 researchers involved in a dozen studies that collect biosamples and other data related to gene / environment interactions in ASD. It is hoped that the establishment of a network of researchers with common goals, challenges and needs, will facilitate advances in this field through collaborative efforts that could provide larger data sets.  Researchers in the new network met together for the first time at this year’s IMFAR.  “We are thrilled to be partnering with the National Institute of Environmental Health Science to promote collaboration among epidemiologists studying environmental risk factors for autism,” commented Autism Speaks’ Chief Science Officer, Geri Dawson, Ph.D.   “We hope this new collaborative effort will help us identify strategies for accelerating research on environmental factors, what are the needed tools and gaps, and what are the most important questions we should be addressing.”  For more on this network, read Dr. Geri Dawson’s summary of IMFAR.

One specific environmental factor that was particularly highlighted among the IMFAR presentations this year was BDE-47, a chemical in the class of poly-brominated diphenyl ethers, or PBDEs, which are flame retardants used in plastics and consumer electronics.  Scientists reported that peripheral blood cells treated with BDE-47 show an increased production of a cytokine called IL-6, which has previously been linked to autism-like behaviors in mice.   Following up on this study, researchers from the same institution found behavioral deficits were induced by pre- and post- natal exposure to BDE-47, including spatial learning and perseverative behaviors.  Another study at the conference focused on the interaction between exposure to BDE-47 and certain genetic risk factors, finding that deficits caused by BDE-47 were more severe in the presence of a mutation that effected expression of MeCP2, the gene that causes Rett Syndrome, a neurodevelopmental disorder related to autism.  Finally, although an epidemiological study did not find increased levels of BDE-47 in children that had already been diagnosed with autism, a follow-up study using a prospective design to study “at-risk” infants is underway to determine possible critical windows of exposure during development.  Therefore, in the case of BDE-47, the neurobiological mechanisms of action are in the process of being identified.  However, further epidemiological research is needed to determine if this exposure is specifically associated with an outcome of autism.

While these findings are interesting, how do scientists convey important research findings related to risk for autism when there is still uncertainty regarding their meaning for individual families affected by autism?  This was the topic of a special IMFAR symposium this year titled “Ethics of Communicating Scientific Risk,” led by Craig Newschaffer, Ph.D. and Michael Yudell, Ph.D. from Drexel University.  Families rely on scientific research to establish the credibility and reliability of findings, and on advice from professionals regarding whether and how they should change their behavior to modify risk.   Discussions at the symposium centered around making sure to keep in mind the prevalence of the risk factor in the general population – how common it is – and whether the benefits of exposure outweigh the risks.   Because families primarily seek information from autism care providers, such experts should be receiving training on how to evaluate findings and communicate them effectively.  Overall, this symposium and the discussions to follow will provide a framework for scientists, clinicians, autism providers and the media to more effectively convey information in an ethical and responsible way.

Find more  information about the broad range of environmental exposures being studied through Autism Speaks support.

  1. Katie Wright
    June 10, 2010 at 4:43 pm

    I appreciate AS is trying to pay attention to this very important and neglected research subject.
    However, there is nothing of substance here and not a thing that would help the hundreds of thousands of sick ASD kids, who are most likely to have a highly environmentally triggered form of ASD.
    Listed risk factors include: smoking, stress, air pollutants, small or preterm babies and IVF. With the exception of IVF, all these risk factors have been well established for many years. As a typical Mom of a child of an ASD child, I have never smoked, did not use IVF, wasn’t under stress and did not have a preterm baby. We have to do better than this list of stock risk factors.

    It is good AS is studying flame retardants. Everyone should STOP using/ buying flame retardant kids pjs now. Never ever buy those clothes. The fact flame retardants are possibly dangerous has also been known for some time. When my son was born 8 yrs ago never bought traditional pjs but used organic t shirts or jumpers.
    Is it a joke that a meeting on communicating the “Ethics of Scientific Risks” was held without any parents of environmentally affected kids??I also find title somewhat condescending. Of course you should communicate risks, scientists should not be filtering information for the public. It is not your right to decide what parents should know and not know. ASD parents are intelligent people who deserve to know all the risks and make their decisions accordingly. Advising parents not to buy flame retardant clothes, use unsafe plastics or have selective early C sections is the responsible thing to do. What on earth is the down side to this?

    We need to actively research ASD populations re coal burning power plants, why Tylenol is the worst pain reliever to give babies (it depletes glutatione), and naturally the effect of up to 24 toxic adjuvants on a newborns immune system. It is scary that there has been virtually no research on this subject.

    Regarding the environment we need to look aggressively at factors we have the possibility to change vs. bad things we have to live with- massive toxic mercury emissions from China to CA. Lets get adjuvant research going.

    • Mom standing Up For Our Rights
      June 13, 2010 at 8:18 pm

      Why are they still refusing to admit to the world they screwed up and purposely gave our innocent babies vaccinations that contain desasterous fatally catistrophically large poisonous amounts of mercury especially in the MMR? They should be held accountable to forcing us to vaccinate when they didn’t even vaccinate their own because they known??? And why are they still wasting tax payers money of frivalous attempts to find the real cure is it because they been sitting on it all this time wanting to reap the medical profits underneath the table??? Didn’t they know GOD was going to catch up with them and reveal the REAL truth??? God have mercy on their souls because judgement day is near for the severety of what they’ve done to so many innocent babies that we watched and suffered with them so much… Now is their chance to make right and fear our GOD’s vengeance and anger in great risk of loosing their souls for all they had done, don’t you think???

      And I think I speak for All who had suffered especially the Ones that can’t speak for themselves…

  2. Sarah
    June 12, 2010 at 9:13 am

    I second Katie on that.

  3. Meaghan
    November 10, 2011 at 11:09 am

    “Is it a joke that a meeting on communicating the “Ethics of Scientific Risks” was held without any parents of environmentally affected kids??”

    Katie, are you a scientist? If not, then I don’t see how you could be qualified to attend, and in fact, your comment here proves that to me. You need to consider that scientists aren’t filtering information for the benefit of parents or large companies, but simply wary of publishing information without enough conclusive scientific evidence, lest we forget the vaccination scare, which it is obviously you parents have not. Are you aware that the information which caused the whole vaccination issue was based on ONE study, and since then there have been many replications receiving opposite results. Given this information, it is clear that evidence of vaccinations causing autism were inconclusive (not to say it doesn’t deserve more research). The entire world is searching for causes to autism, and it is clear that they are striving to mitigate the suffering of both children with autism and their parents, however publishing unfounded information will only scare the public. FOR A STUDY TO BE SCIENTIFICALLY RELEVANT IT MUST BE REPEATED MANY TIMES. Which is why NEW information on “risk factors that have been well established for many years” was presented. Research (specifically on humans) takes decades. I understand your struggle, but stop looking for someone to blame.

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