Autism is higher in rainy counties of Washington, Oregon and California. Are you kidding?

by James Hubbard, M.D., M.P.H.

This new study, relating autism to increased precipitation, is a classic “scare of the day” news story.  You will see it everywhere.  Some people will latch onto it as a factual cause of autism, but you will never hear if it is disproven.  Don’t get me wrong.  The researchers should publish it.  It is interesting, but it is a starting point and nothing more.

We know little about causes or risk factors for autism.  So you have to start somewhere looking for clues.  The researchers started with a hypothesis that there could be some environmental trigger.  They scoured state records in Washington, Oregon and northern California, looking for autistic children 6 to 12 years old.  Then they looked at where the child was living and how much precipitation that area got when the child was under age 3. They found that more autistic children grew up on the rainy side of the states. (In case you didn’t know, it rains a lot on the coastal side of these areas, but much less east of the mountain range in the middle.)

But what does that really mean? Rain causes autism?  Nature is against us?  A few years back researchers found that more men with prostate cancer had undergone a vasectomy.  Later studies found it was just a coincidence.  So why do cross-sectional studies like this in the first place?

Because it is a starting point.  Was it some chemical pollutant in the rain that triggered this? Future studies will analyze the rain; scientists will research pollutants to see if there is any known cause for concern (maybe from past animal studies), and someone will see if any other area is exposed to these pollutants–and if there is an increase in autism there, also.  The researchers speculated it could be that the children on the rainy side stayed inside more, so studies may look at chemicals in the house, lack of sunshine and vitamin D, and even amount of TV viewing.

And then it could be a coincidence, with no cause and effect at all.  The researchers did account for race, per capita income and population, but there are many other variables that could account for the regional increased incidence, such as:

  • Is there a genetic tendency?
  • Did people with autistic children move to or from the area for some reason?  Most of the major cities are on the rainy, west coast side which means more referral centers and support.
  • Is autism diagnosed the same in different areas?  It is a clinical diagnosis (no one test can concretely prove “this is autism”).  Some have speculated that a tendency to be more liberal with making the diagnosis may be part of the dramatic rise in the overall number of U.S. cases.
  • Do the regional agencies, where the researchers gather their data, differ in how they report autism?

The authors acknowledge at the end of their paper that “further research focused on establishing whether such a trigger exists and on identifying it is warranted.”  Autism is devastating to families.  Most would do anything to avoid it.  But I wouldn’t move to the desert just yet.

Does anyone have comments on autism, speculation on causes, or comments about studies like this?

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8 Responses to “Autism is higher in rainy counties of Washington, Oregon and California. Are you kidding?”

  1. Mark Salinas Says:

    Something to consider…San Francisco is near Silicone Valley, Oregon is near Portland. Is their an increase in autism with a more technical individual”geek genes”? I don’t believe coincidence implies causality. Interesting post!

  2. James Hubbard, M.D., M.P.H. Says:

    Good point, Mark. There are so many possibilities.

  3. TB--Milwaukee Says:

    It seems in WI lots more cases of autism near Lake Michigan. I don’t know what to think of it all, but it does get you thinking.

    TB–Milwaukees last blog post..Staying Healthy While Not Feeling Well

  4. James Hubbard, M.D., M.P.H. Says:

    It sure does, TB. I hope we can get to the bottom of this.

  5. Emily Hagen Says:

    Fascinating stuff…I grew up in Washington and Oregon so this article really caught my eye. I agree…there are so many other factors that could be involved, you really can’t pinpoint the cause without taking into account all other risk factors. Great post!

  6. James Hubbard, M.D., M.P.H. Says:

    True Emily. I am glad they are working on the cause and risk factors, but they have a long way to go.

  7. Dan Says:

    Thoughts Regarding Autism Spectrum Neurodevelopmental Disorders

    Of these rare neurological disorders, Autism is the most common. The autism spectrum reflects the broad range of symptoms in which the names of these autism disorders have been given their own name for their disorder.
    Autism is a disability that is suspected to be caused possibly by a brain development disorder of unknown etiology. Others suspect the cause is some sort of neurological dysfunction- possibly with a genetic predisposition. Autism is about 3 times more common in males than females as well, and it is unclear as to why this occurs.
    Usually, symptoms of the disease present themselves before the toddler reaches the age of three. Before Autism was more understood, others inaccurately labeled autistic people as childhood schizophrenia or as having a psychosis or mental retardation.
    Symptoms of the autistic patient included limited or dysfunctional social and personal or intimate relationships with others, their intelligence is affected, and the autistic person typically is adverse to change. Also, the autistic person tends to be compulsive and prefers to be alone. They lack eye contact as much as physical contact with other people.
    Out of over two dozen diagnostic criteria utilized for these disorders, eight must be present to be considered autistic, according to the DSM. As with all passive developmental disorders, the person expresses language, social, and behavioral difficulties.
    Treatment includes what are called psychotropic medications that delay the progression of the disorder, as well as relieve some of the symptoms of one who is autistic. Behavioral therapy is common as a treatment regimen as well. Boys get Autism much more than girls.
    Then there is the controversy between many who claim that thimerosal- a preservative containing mercury, which is a neurotoxin that was used in vaccines until 2001, was the catalyst for autism in children.
    Over 5000 lawsuits have been filed because of this belief, and some have been successful for the plaintiff. Yet most agree the correlation between thimersal and autism is void of scientific merit. Furthermore, the cases of autism have not decreased since the preservative was discontinued in 2001.
    Aside from Autism, the other four passive developmental disorders are known as autism spectrum disorders.
    Asperger’s Syndrome is more common than autism, and the symptoms are milder, as there is minimal delay in language abilities, if at all. What is expressed with Asperger’s syndrome is mild autistic symptoms. In time, the patient may express atypical personality disorders, though.
    While intelligence is within normal limits with the Asperger’s patient, social interactions and abilities preset difficulty for such a patient. As with Autism, medications and behavioral therapy are treatment regimens with one with this syndrome
    Rett’s Syndrome or disorder presents with not only atypical behavior, but also suffers from restricted physical growth and movement. There is cognitive and social impairment as well. The disorder affects mostly girls, and the cause is due to a gene mutation.
    Childhood Disintegrative disorder is rare, and is 10 times less common than autism. The disorder has a late onset with mild autistic symptoms. The disorder affects mostly boys, and regression is sudden and possible with this disorder. Skills lost with this disorder may be language, social, self-care, as well as play or motor skills. Decreased function or impairment with this disorder may include social skills and behavioral flaws. Central Nervous System pathology is a suspected cause of this disorder.
    Finally, there are passive development disorders that are not otherwise specified. This may include atypical autism, for example. Yet as with the rest of types of these disorders, the symptoms vary in their frequency and intensity, as well as the range of abilities of these developmental disorders vary widely as well.
    Medicinal treatment is believed to be not necessary for the management of all of those who may have autistic spectrum disorders. Depending on the patient’s health care provider, medications may be prescribed by their doctor to manage any affective disorders autistics may present in an acute or chronic nature. However, cognitive and behavioral therapy prove to be most beneficial for all the different types of Passive Development Disorders that exist for reasons yet to be defined.
    Dan Abshear

  8. Thank you, bloggers! (Plus: New health, mom and Boomer sites to discover.) Says:

    [...] The Fight for Fitness: Fighting for a Healthier and Happier Lifestyle, “Good Stuff I Read This Week” (linked to autism in rainy counties post) [...]

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