If you look at enough variables, you WILL find a correlation with whatever you are looking at.
Key paragraph:
Vinyl flooring is commonplace in Sweden, where only about 1 percent of homes have carpeted floors. But it is uncommon in U.S. bedrooms, so it may not be related to autism among American children. However, carpeting contains other contaminants, including pesticides and brominated flame retardants, which have been found to harm brain development in animal tests.
This makes me very suspicious, because it smacks of "our unusual theory does not bear out when we look at another country, so we will come up with another unusual theory to explain the effect there".
Also, while I am not familiar with Sweden, there are other places where vinyl/carpet flooring versus wood/tile correlates with socioeconomic factors.
In fairness, that handwaving is from Sciam's writers; the study itself is quoted on page 1, expressing caution against drawing conclusions: 'The data are far from conclusive. They are puzzling, even baffling, and not readily explicable at this time. However, because they are among the few clues that have emerged about possible environmental contributions to autistic disorders, we believe that they should be weighed carefully and warrant further study.'
If their insight is correct, it may be significant. Other data (eg the link about smoking in this article, and many other sources) suggest a degree of heritability, as well as noticing the correlation with asthma, which condition is also thought to be heritable. Although modern vinyl flooring may be low in phthalate emissions, they may well have been higher in the past. I grew up with linoleum in a lot of the house, and well remember its characteristic smell (along with those of vinyl car seats and a bunch of other plastics which were widespread in the 1970s). While I certainly wouldn't draw conclusions from that about having ADD - factors like parental smoking are likely to have played a more significant role - it's worthy of further study.
Even they aren't saying anything about linoleum...
"Infants or toddlers who lived in bedrooms with vinyl, or PVC, floors were twice as likely to have autism five years later, in 2005, than those with wood or linoleum flooring.
You're being uncharitable to the researchers. They have no theory for why they found this correlation - they weren't even looking for it. They noticed something unusual in their data, they reported it and invited further investigation. That's the responsible thing to do.
I think it was the Scientific American compilation that leaves a bad taste in one's mouth. They repeatedly quote "this is only preliminary, don't draw conclusions!" then finish the paragraph by drawing conclusions...
"The scientists were surprised by their finding, calling it 'far from conclusive.' Because their research was not designed to focus on autism, they recommend further study of larger numbers of children to see whether the link can be confirmed."
That's the money quote in the interesting submitted article.
The finding is quite intriguing, and I wonder how it will filter through the varied opinion-makers in the autism-issues blogosphere.
After edit: You're welcome for the link to Peter Norvig's article. As regular readers here know, it is one of my favorite links to post in comments here on HN. My further comment on the submitted article in this thread is that its second page refers to an increase in autism in California. Statements that autism has increased in recent decades are controversial,
because diagnostic criteria have changed over the same period, so how much real increase in the actual condition there has been may be much less than the increase in recorded diagnoses.
This is the most worst piece of a bad article:
"Rates of autism in California have increased seven-fold since 1990, a recent study found. Because genetics do not change that quickly, scientists suspect that chemical pollutants are probably playing a role. But there have been few studies attempting to pinpoint which chemicals, or combination of chemicals."
How could they not mention that the diagnostic criteria for autism changed over that time period? In addition to it getting slapped on shy kids, it's become a socially acceptable word for what used to be called mental retardation.
Agreed. I was surprised by this similar sentence in the article, stating that autism "has increased dramatically in children over the past 20 years."
Such an important component of the article shouldn't be misstated like that. That really should be written as "the number of children diagnosed with autism has increase dramatically over the past 20 years."
That's a crucial point. I wonder why that angle keeps getting overlooked when there are studies that support and explore it so well. Are the scientists dropping the ball? Are the writers?
One danger in any quotes about autism statistics is that sometimes folks use autism as shorthand for "autism spectrum disorders", which includes much more mild things like Asperger's syndrome. Plus, one could argue that some of the things they classify as "bad" within that "range" are actually good things. For example, I've noticed that the rise in so called autism or ASD roughly correlates with the rise of the Internet and web usage. Perhaps something about the web and our increased use of it has brought out a much more nerdy aspect of many people's brains, a wider swath of people than previously had engaged in nerd/geek/Asperger's-like behaviors and thought processes. That could explain the "cause" rather than some dramatic increase in some biological/chemical factor. Maybe it's just a social/intellectual shift.
It's sad, but my first thought at seeing yet another weak "link" between something and autism was, "well, better to have wacko parents shield their children from PVC floors than from vaccines."
>'It's sad, but my first thought at seeing yet another weak "link" between something and autism was, "well, better to have wacko parents shield their children from PVC floors than from vaccines."'
I guess you'd call me a wacko parent then.
When we were offered the swine flue vaccine I looked at the medical literature as, to my mind, using an untested (long-term tests) vaccine against an unknown risk seemed a bit chancy.
My research showed that there were associated with one of the factors (Thiomersal) apparent risks of elevating occurrence of autism. I ruled out the risk based on the evidence from the USA that removal of this factor over the last few years had not lead to a consequential reduction in the number of children suffering from autism. This seemed sufficient evidence for me to rule out the link and go on to look at the other constituents.
Once an intial, if now discredited, link between the chemical factor and autism was established, lacking refuting evidence, it doesn't seem "wacko" to me to exercise caution. A large part of this is that the vaccines have been successful in reducing incidence of the once common diseases making them known smaller risks to weigh against the then unknown risk of inducing autism.
The evidence in the OP shows a correlation. Phthalates certainly interact in negative ways with human biology already and so are a good thing to test - if I were fitting a floor I'd be more inclined to something phthalates-free given this result.
So, you'll depend on the rest of the world to vaccinate so you can benefit from herd immunity and not chance the impossible odds that anti-vaccine conspiracy theories are correct?
No, maybe not a wacko, just selfish and uninformed. Vaccine preventable diseases coming back. Children are dying at the hands of the anti-vaccine movement.
>So, you'll depend on the rest of the world to vaccinate so you can benefit from herd immunity
It's easy to make a remark about "anti-vaccine conspiracy theories" now that we have evidence to show - but to expect me or anyone else simply to trust the medical establishment has not erred in creating a new vaccine is too much.
Selfish? My children have both been immunised for the standard spread of common [childhood] disease in my country using the established vaccines. The swine flu vaccine was offered to us the week before vaccination was stopped - the reports were already in that it had been vastly overstocked, that vaccination wouldn't be effective against next seasons mutations, that other countries had ceased immunisation, that there were barely any new cases being reported, that it was far less virulent than expected and in addition I had a strong suspicion that our youngest (the only one offered the vaccine) had actually had the virus already. FWIW I've also donated to charities that make medical interventions such as vaccination of children.
Uninformed? I've attempted to ascertain the risks involved in the vaccines offered to us. Most have been widely tested over several years but the swine-flu virus had not; as you saw I did rely on past empirical data to establish some of the risk factors.
I am in no way part of an "anti-vaccine movement" I'm simply trying to use available knowledge to reduce the risk of harm to my own family.
This does bring us back to the question of selfishness - I would let others be guinea pigs first before risking the health of my own children. Part of the problem is that from an immunological perspective you can expect a lot of deaths from a vaccine and still make the call that to save the population it's better to vaccinate.
Do you really believe that I was risking the lives of other children by not immunising against swine flu in January of this year? ( http://news.bbc.co.uk/1/hi/wales/south_east/8645477.stm shows there were no further deaths in reality in my region).
> the article talks about scientific rigorous way to test something.
The article is about a specific study. It does not 'talk about scientific rigorous way to test something.' Nowhere in my post did I mention that we should all abandon the scientific process, or just disregard it when we 'believe' something different than what the results say.
>Infants or toddlers who lived in bedrooms with vinyl, or PVC, floors were twice as likely to have autism five years later, in 2005, than those with wood or linoleum flooring.
Wood flooring is more expensive than vinyl, so.....really, maybe its just an indicator of economic status...
I recall reading more than a few articles about a strong positive correlation between socioeconomic status and autism diagnosis rate.
What I've never seen addressed in any of the underlying studies, was whether the rate could be determined to be tied to prevalence of condition or prevalence of diagnosis.
Given the "flavor of the month" status that Autism Spectrum Disorders have attained, I'm very skeptical that the socioeconomic link is anything more than the same helicopter parenting that seemed to lead the explosion of attention disorder diagnoses and prescription rates.
I didn't mean to imply autism was caused by economic status. What I meant to say is its probably a fair assumption that families of different means would consume a vast range of different products in many forms. Finding one study linking something as common as vinyl is not a good indicator. I'd bet you'd find the same correlation with upscale automobiles....
If there is a positive correlation between higher socioeconomic status (especially in the last 10-20 years) and a higher autism diagnosis rate, I have a theory to explain it. My pet theory is that as the rise of the Internet and Web has placed higher economic demand for people with certain kinds of mental skills and thought processes (programmers, computer hardware designers, etc.), and that class of people has generally risen in wealth, and also in marriage suitability (more money, success, greater attraction to women, etc.) that then causes those kinds of people to be more likely to have kids, and thus you see a spike in kids who inherited those mental traits from their parents -- I'm guessing mostly from the father, assuming my theory is right.
It could be a combination of that effect plus the rise in widespread Internet usage, and the massive increase in "geek out" behavior that has caused in the general population (surfing the web, clicking on every little link, web forums, text messaging, etc. all the kinds of things that a hyper-focused nerdy or Asperger's like person would be more likely to engage in).
Vinyl flooring isn't cheap, floor boards are usually already there and sand paper isn't that expensive. A rug is a lot cheaper than vinyl were I am - perhaps very thin vinyl tiles would be cheap but vinyl requires a very flat starting surface so you need floorboards, hardboard, levelling compounds and then the vinyl on top. Most people can use sand paper but laying a levelled floor needs skills.
It's also been linked to asthma, allergies, endocrine disruption, obesity and diabetes. The federal government recently banned them in children's toys.
So even if this study turns out not to hold up, you should keep this stuff away from kids. The other worrisome chemical in plastic is BPA.
I've heard of a study that found a link between U.K. nuclear power plant sites and cancer ... including ones they were only thinking about placing a plant in.
Key paragraph:
Vinyl flooring is commonplace in Sweden, where only about 1 percent of homes have carpeted floors. But it is uncommon in U.S. bedrooms, so it may not be related to autism among American children. However, carpeting contains other contaminants, including pesticides and brominated flame retardants, which have been found to harm brain development in animal tests.
This makes me very suspicious, because it smacks of "our unusual theory does not bear out when we look at another country, so we will come up with another unusual theory to explain the effect there".
Also, while I am not familiar with Sweden, there are other places where vinyl/carpet flooring versus wood/tile correlates with socioeconomic factors.