According to CNN – Study: ADHD Linked to Pesticide Exposure

[Patte Rosebank]

http://www.cnn.com/2010/HEALTH/05/17/pesticides.adhd/index.html?hpt=T2Study

My brother sent me the link to this story. Despite the headline, the study merely “suggests” a link.

The story is followed (naturally) by the usual mix of comments from people who don’t believe ADHD exists at all and that all those kids need is some harsh discipline, those who believe it does exist but can be cured without medications if people would just eat organic foods only, and those who know it’s a genuine medical disorder because they either have it themselves or have kids who do.

Considering how many people throughout history appear to have had ADHD, and that so many of them lived at a time when pesticide use was not as widespread as it is now, I’m inclined to say that the study is bollocks, or at least that the announcement of the results is extremely premature. ADHD is genetic, though certain external factors (such as the multitasking, multimedia, overstimulated world we now live in) can make the symptoms appear to be worse. Maybe pesticides fall into that category, or maybe they don’t. It’s way too early to tell. And it may very well be that ADHD isn’t actually more prevalent than it was; it’s just being diagnosed more often and more accurately.

Even as someone who sucked at math and science, I can spot some serious flaws in the study.

A study of 1139 people really isn’t all that big a sample, considering the world is home to over 6 billion people. Also, the sample consisted only of children “from across the USA”. What about all the adults? And what about people in other developed and non-developed countries?

Note that the testing consisted of a single urine sample from each child, so the study didn’t consider whether the pesticide levels in the samples were a constant or a singular occurrance. They didn’t put one group on more fresh produce and one group on less of it, and then test them over time. They just looked at things as they were on a one-time visit. So how can they claim that the results prove (or even “suggest”) the truth of their hypothesis? (I may have sucked at science, but I still remember the scientific method.)

Plus, the ADHD diagnosis was based on symptoms reported by the parents of each child, NOT on actual testing of each child for ADHD. This is hardly scientific evidence that the kids have ADHD. (***Devil’s Advocate Alert***) If it appears that the kids who consumed the most fresh fruit & vegetables had more ADHD symptoms, maybe those kids are more upper-middle-class with parents who can afford to buy more fresh produce. And upper-middle-class parents tend to be more likely to assume that their kids’ problems with school and discipline are due to ADHD, and to just get their kids a Ritalin prescription. Lower-class American families can’t afford to buy as much fresh produce, and without health insurance, they certainly can’t afford to keep taking their kids to the doctor for Ritalin prescriptions. So maybe that’s why the kids who ate more fresh produce seemed to be more likely to have ADHD.

Even the scientist who headed up the study admits that it’s hardly definitive, based on the limitations of the study. She acknowledges that, while it suggests that pesticides may increase the risk of ADHD, far more research is needed, on a long-term basis. Other scientists agree with her on that point.

And yet, CNN trumpets the story as a huge medical breakthrough with the headline, “ADHD Linked to Pesticide Exposure”…

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[Anonymous]

Nevermind the fact that it’s just ONE story. *rolls eyes* I hate this kind of thing.

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[Tim]

I did a lot of work a while back, trying to get a local pesticide bylaw. Being a chemist by training was very helpful in this and something that I concluded was that although some pesticides such as the organophosphate insecticides were clearly a problem because of their nature — they are poisons — other pesticides such as some of the common herbicides weren’t so obviously a direct problem for human health. The difference is that insects and other members of the animal kingdom share a lot of biochemistry with us while plants share less.

However, I also became aware of how many chemicals we are all exposed to that are man made and quite recent — post war mostly. While absolutely pure 2,4-D may not be harmful to any thing but your weeds, the commercial product contains impurities that are not tested along with other chemicals, each with their own impurities, that make it possible to spray the stuff and make it more effective. If you looked hard enough you could find hundreds of chemicals in the mixture and few have received any scrutiny. And, even if we screen out the obvious poisons, what about the long term effects of the others that we can only guess at? Rick Smith and Bruce Lourie document the issue in their book. Here is the web site: http://slowdeathbyrubberduck.com. I think this is a huge problem and one very hard to study because no one is unexposed so a true control group for a study is impossible to find.

So, what about ADHD? There is a clear link with cigarette smoking during pregnancy, which is a chemical exposure for the foetus. As for the chemical soup we live in? We may never know for certain.

Let me throw out something for thought. ADHD is clearly a disability in our culture but there is some evidence that it may have some evolutionary advantage in our previous hunter gatherer life. I don’t know if I would want to hang my hat on the idea but this web site http://borntoexplore.org/hunter.htm is an interesting read.

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[Anonymous]

Maybe they can cause it, but that wouldn’t explain the millions of people throughout history who clearly had ADD even before pesticides existed.

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[Patte Rosebank]

Now the Toronto Star has picked up the story and posted it on its Health website, with nearly as much fanfare as the CNN version. And no opportunity to call attention to the rather obvious flaws in the study.

I wonder if Dr. Jain would write a rebuttal letter to the Star…

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[Anonymous]

Oh, great. And I though being from Camp Gagetown was bad enough already…

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[Anonymous]

I was under the impression that pesticides are used LESS now (or in a lower intensity) than they were several decades ago. (Hence the return of things like bedbugs)

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[Patte Rosebank]

Of course, for a truly natural, safe pesticide, they could just plant marijuana through the fields. Most insect pests can’t stand the smell of it, so they stay away. My grandfather was a farmer, and back in the old country, many farmers controlled pests this way. When he came to Canada, he had to use chemical pesticides, which contributed to the lung cancer that killed him…and to the cancers that killed many of the barn cats who roamed around the shed where the spraying equipment and chemicals were kept.

Unfortunately, marijuana is illegal here and in the USA, so (a) the plants would quickly be stolen by people wanting to smoke them, and/or (b) the cops would quickly seize the plants and arrest the farmers.

While I have never, and would never, smoke a joint, I do believe that the conspiracy theorists are right about the real reasons that pot is illegal.

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