Home > Science > Commentary on the LA Times Series on Autism

Commentary on the LA Times Series on Autism

Posted by Autism Speaks scientific advisory board member Irva Hertz-Picciotto, PhD, MPH. As an epidemiologist at the University of California-Davis MIND Institute, Hertz-Picciotto studies exposures to environmental chemicals, their interactions with nutrition and pregnancy and their effects on prenatal and early child development.

Alan Zarembo’s series on autism in the LA Times  covers a great deal of territory and has brought to light a wide range of personal stories that exemplify the complexity of issues surrounding autism diagnosis, treatment choices and effectiveness, impact on families and population incidence. Zarembo should be commended for the substantial work he has done researching inequities in the delivery of services. Of notable concern, he has put a spotlight on what appear to be serious racial and ethnic disparities in the California Department of Developmental Services (DDS) system and the provision of therapies. If his figures are correct, this result should stimulate an analysis of how to right this situation and ensure that appropriate opportunities are made available to all families with affected children.

Zarembo has also highlighted adults living with an autism spectrum disorder (ASD) but diagnosed late in life. We have too long overlooked the struggles faced by adults with autism as they try to find ways to be productive, live independently and connect with others.

My remaining comments pertain to Zarembo’s conclusions about the rise in autism diagnoses and the role of environmental factors. First, he is right that there is substantial variability in rates of diagnoses in different regions, and that we should not confuse diagnoses with the actual incidence of disease. Not all persons who meet criteria have been correctly diagnosed, and the degree to which this is true has likely changed over time.

Nevertheless, impressions are not the same as a scientific analysis. Zarembo has not demonstrated that the rise is purely social and cultural.  My colleague Lora Delwiche and I published the first quantitative analysis of how much of the increase in diagnosed cases in California could be explained by artifacts (changes in diagnostic criteria, earlier age at diagnosis and inclusion of milder cases).1 We used California state data that provided statistics over many years and found that the numbers simply do not add up. In other words, the actual increase has been far larger than these artifacts could have produced. Combining our results with those of another research team, it appears that about half of the increase in diagnoses in California is due to changes in diagnostic criteria or practices.2 These results left about a three-fold increase unexplained as of 2007. And autism diagnoses in California have continued to rise both in areas with low rates and in areas with high rates. Zarembo is interested in explaining the geographic variation, but the explanations for variation spatially are not necessarily the explanations for variation over time.

These statements were particularly misleading:

“No study points to an environmental reason for the worldwide explosion in cases over the last two decades.

Given the slow pace of genetic change in large populations, genes can’t account for the surge either.

That suggests the explanation for the boom lies mainly in social and cultural forces, notably a broader concept of autism and greater vigilance in looking for it.”

The logic that leads from the first two sentences to the third involves huge assumptions.

How many studies have been done of environmental causes? Very few!  And of these, most were extremely poor studies involving very small samples or lacking individual-level data. Is it surprising we’ve uncovered few leads?  The funding for environmental factors has been paltry – somewhere around $40 to $60 million over the last 10 years, while more than $1 billion has been spent on studying autism genetics.  To imply that environmental factors can be dismissed and that only social/cultural factors should be pursued is nonsensical.

It should be noted, however, that if anyone is looking for “one” environmental factor to explain the increase, they will certainly be disappointed. It doesn’t exist. Autism is far too complex. Moreover, to the extent the increase is due to diagnostic differences over time, we need to find explanations both for the increasing numbers of diagnoses and for the autism that has been around “all along.” In fact, data are emerging about quite a number of environmental factors. In 2011, major papers were published supporting contributions from maternal nutrition around the time of conception (here and here), traffic-related air pollution, and season of conception.3-6 Earlier papers indicated associations with pesticides  (here and here) and air pollution.7-9

One concern raised about the increase in diagnoses is a type of ‘inflation’ from inclusion of a growing number of high-functioning persons whose diagnosis is more likely to be Asperger syndrome than classic autism. This may apply to some studies of changes over time, but in our analysis of CHARGE study data, most of the cases were low functioning.10 This would likely be true for the majority of persons with ASD served by the California Department of Developmental Services (DDS), because in order to qualify for state services, they must have “significant functional limitations” in three areas of major life activities. This requirement would exclude most of those who are higher functioning.

With regard to genetics, Zarembo’s article leaves out the most current information: the largest and most statistically robust study of twin pairs found that 38 percent of concordance is due to shared genetics with 58 percent due to shared environmental factors (most likely prenatal and perinatal).11 This result completely overturns the widespread assumption, based on a number of previous small studies, that the causes of autism are overwhelmingly heritable, or genetic. Unfortunately, most analyses of twins make the incorrect assumption that genes and environment do not interact to influence risk for disordered brain development. This interaction is real, and one study has already shown a whole class of genes that primarily affect development in children whose mothers had not taken prenatal vitamin supplements during the months preceding and immediately following conception. 3

In summary, Zarembo’s investigative journalism provides unusual depth into difficult aspects of autism occurrence and the social policies that bear on the lives of affected families. He has raised several critical challenges facing the autism community. What was lacking from his series is a more balanced view of the role environment likely plays and the need to advance the agenda of discovering modifiable causative factors.

Autism Speaks is one of a few organizations that have begun to turn in this direction. I look forward to a continued strong commitment by Autism Speaks and others willing to support and significantly expand the scientific research aimed at identifying and understanding environmental contributions to autism, factors driving increased prevalence and ways to intervene so as to eliminate or lower human exposure levels. This will be the fastest road to reducing the occurrence of ASD in the next generation.

1             Hertz-Picciotto I, Delwiche L. The rise in autism and the role of age at diagnosis. Epidemiology 2009;20: 84-90.
2             King M, Bearman P. Diagnostic change and the increased prevalence of autism. Int J Epidemiol. 2009; 38:1224-34.
3             Schmidt, R J, et al. Prenatal vitamins, one-carbon metabolism gene variants, and risk for autism. Epidemiology 2011;22:476-85.
4             Cheslack-Postava K, Liu K, Bearman PS. Closely spaced pregnancies are associated with increased odds of autism in California sibling births. Pediatrics 2011;127:246-53.
5             Volk HE, Hertz-Picciotto I, Delwiche L, Lurmann F, McConnell R. Residential proximity to freeways and autism in the CHARGE study. Environ Health Perspect 2011;119: 873-7.
6             Zerbo O, Iosif AM, Delwiche L, Walker C, Hertz-Picciotto I. Month of conception and risk of autism. Epidemiology 2011;22:469-75.
7             Roberts EM, et al. Maternal residence near agricultural pesticide applications and autism spectrum disorders among children in the California Central Valley. Environ Health Perspect. 2007;115:1482-9.
8             Eskenazi B, et al. Organophosphate pesticide exposure and neurodevelopment in young Mexican-American children. Environ Health Perspect 2007;115:792-8.
9             Windham G, Zhang L, Gunier R, Croen L, Grether J. Autism spectrum disorders in relation to distribution of hazardous air pollutants in the San Francisco Bay Area. Environ Health Perspect. 2006; 114(9):1438-44.
10           Hertz-Picciotto, I. et al. The CHARGE study: an epidemiologic investigation of genetic and environmental factors contributing to autism. Environ Health Perspect. 2006;114: 1119-25.
11           Hallmayer, J. et al. Genetic heritability and shared environmental factors among twin pairs with autism. Arch Gen Psychiatry. 2011(68):1095-102.

  1. Janice Miller
    January 3, 2012 at 8:32 am

    Thank you.

  2. María Lujan
    January 3, 2012 at 10:50 am

    Thank you very much Dr Irva Hertz-Picciotto, for your constructive and balanced analysis of this series. I am the mom of a child diagnosed with aSD with multiple Concomitant medical problems environmentally related- postnatal- living outside USA,and I appreciate very much your work.
    Hope you have a very happy New year 2012.

  3. michelle p.
    January 3, 2012 at 11:00 am

    Have they ever thought of testing for toxic mold in the homes of children diagnosed with this disease?

  4. 2asdmom
    January 3, 2012 at 11:08 am

    Thank you for this post. We live in a toxic world, and to say that autism is purely genetic or a result of societal/cultural influences, is way too simplistic.

    • Grandma
      January 3, 2012 at 2:11 pm

      I agree….and lets just say it is genetics…well then what has happened to make our genes to have gone so out of line as to alter lives into an Autistic state of being?

  5. Katie Wright
    January 3, 2012 at 1:35 pm

    Very said Dr. Hertz-Pinchero!
    I was astonished that such a poorly researched piece w/ gross factual inaccuracies was published by the “LA TImes.” Zarembo’s was an opinion piece, belonging on the Op-Ed page, rather than a news story.

    Zarembo implied that middle class ASD parents are greedy on behalf of their children and are somehow shortchanging poor families. Pitting ASD families against each other is absurd and cruel. Believe me, our families don’t make the rules here- if we did the system would be far more equitable and just!

    I think all “LA Times” subscribers affected by autism should take a moment and e-mail the editor. ASD families are not the enemy here. No one wants their child to need these services.

  6. Sarah
    January 3, 2012 at 1:57 pm

    Thank you Dr. Hertz-Picciotto.

    It is a shame that our children have a “psychiatric” diagnosis and not the “body/metabloic” diagnosis they deserve.

    No one is saying “better diagnosising” for skyrocketing rates in other diseases: type ONE diabetes, allergies, asthma, childhood cancers (adult cancers too for that matter), etc., etc.

    Thank you, thank you, thank you.

  7. Grandma
    January 3, 2012 at 2:08 pm

    What about the fact that the only vaccine studies that have been done, have been done by the pharmaceutical companies themselves. No independent studies that I know of have ever been done. I have a 6 year old grandson diagnosed with Autism… I have been there every step of the way and there is no way you can convince me that his vaccines did not play a role. Within hours of his 4 yr old booster he regressed back 2 years!

    • Gramma Mary
      January 4, 2012 at 6:20 pm

      Gramm I truly believe you are right on target with the vaccines my grand daughter was perfectly growing and functioning as a neur-typical, until mmr vaccine then regressed and was diagnosed with asd, gramma too.

    • Paul G. King, PhD
      January 5, 2012 at 12:05 am

      In the USA, the Geiers, Geier DA and Geier MR (with other independent researchers in occassion) have done more than a dozen peer-reviewed independent studdies that implicate vaccines, including the MMR vaccine and vaccines containing Thimerosal as causal factors for neurodevelopmental, including “autism”, and or the developmental disorders. In South America Dorea, JG has published independent studies and several researchers in Poland have published independent studies implicating Thimerosal-preserved vaccines as possible factors.

      In addition, recently e-mails have come to light indicating that at least one, if not all, of the CDC-sponsored studies on the vaccine-autism link published findings that the authors knew were contrary to the facts that both the incidence and prevalence of “autism” dropped after the Thimerosal-preserved vaccines were removed from the Danish vaccination program.

      If you do appropriate searches using the advances Google Scholar search engine and the NIH search engine PubMed, you should be able to find these and several more studies and, for some of them, actually download the full article.

      Hopefully, this response will encourage you to do your own on-line research.

  8. January 3, 2012 at 9:14 pm

    I wonder if the plastic that all our food is wrapped /bottled in could be impacting on the increase in ASD. Thirty or so years ago food came wrapped in paper and liquids in glass bottles. The increase appears to coincide with the birth of our children’ children.
    Does food in contact with plastic and polystyrene absorb something in the makeup of this man made product it is encased in?

  9. January 4, 2012 at 12:17 pm

    Dr. Hertz-Picciotto and her colleagues King/Bearman in the other study uncovered HALF of the reasons for the increases in cases while barely batting an epidemiological eyelash. But now she wants to ‘move on’ and find out what environmental factors caused the other 3 fold increase over the last 20-30 years. Why on earth would we not roll up our sleeves and look deeper into the undeniably large percentages of autism increases ’caused’ by other social/legal/educational factors like IDEA and the major changes that the laws have caused in the educational system’s treatment of disability education? You cannot look at increases in autism rates and begin to search for environmental issues until you look at all the major societal issues that make it up.

    But to clarify, just because this could something that existed before 1980/1990 and has been ‘discovered’ does NOT mean that it should not be investigated for environmental causes. If simply clarifies the ‘when’ of the things to look at.

    BTW, as far as Zarembo’s piece is concerned, I was left a little cold, being a parent of two autistic children. While the piece did not lambaste parents for fighting for services for their children, the implication was that we were often getting much more than our children need. I assure Mr Zarembo, that most all parents are getting much LESS than what their children need, and often they are getting pitifully little of what their child’s bare minimum requirements are. These are not bratty kids in search of a label, but kids with REAL issues who will benefit greatly from these accommodations…

  10. another dad
    January 4, 2012 at 1:03 pm

    Thank you Dr Irva Hertz-Picciotto for taking the time to correct the LA Times. While I appreciate the press highlighting serious issues families face raising a child (or children) with autism – I don’t appreciate playing down the prevalence. Thank you for citing facts not myths.

    The only way we can address the issue is to be truthfull about the first fact; the numbers.

    Now if only the CDC would release updates on the reality and care enough to do a census on all those affected.

  11. Katie Wright
    January 4, 2012 at 2:56 pm

    I agree w Liv. Parent portrayal ridiculous. Someone please tell me what great state is generously handing out all these wonderful state paid for services and I will move there! In the meantime most families are fighting for the bare minimum.

  12. kaitlin
    January 4, 2012 at 5:56 pm

    Thank you SO MUCH for posting this response to the L.A. Times article. I was so upset after reading it, I really didn’t know what to do. I knew the data was twisted to spin a story because I knew of many of the studies you listed in your response. I felt like he took a direct jab at the autism community, which is already so vulnerable. Really, thank you! We needed an honest advocate to respond in this way for us. I really appreciate what you have done here.

  13. shaun
    January 6, 2012 at 2:20 am

    It does cost money to provide much needed services. It does cost money to help individuals. It cost money for just about everything in life.No surprise right, So why all the fuss when it comes down to spending it on individuals who need this help early on in life so they have a better chance of experiencing a productive life.To deprive and penny pinch out of support is inhuman and unGodlike, Do you think the kids and families are living their dream with the support money received.? No we are coping and stressing in more ways than most can imagine.To deny us the truth and set barriers from attaining services will only make us stronger,,you cannot cover up and ignore the situation so do the right thing.Karma goes a long way,

  14. Theresa Giglio
    January 31, 2012 at 7:04 am

    Mr. Zarembo’s article concerned me because it is misleading with his assertion that parents fueled the sky rocketing cost of Autism. He seems to have picked just the right quotes to back his agrument that maybe there are a lot of children out there getting unneeded therapy. As an educator, I think we may notice if we are treating children who don’t need it. In my many years of experience, I have seem children make great fast progress and maybe the label was not right but the therapy was helpful for the children. So, maybe the question is how do we treat and support families and children to meet their unique needs?

  1. January 9, 2012 at 7:34 pm

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