http://www.cnn.com/2012/02/15/health/air-pollution-stroke-heart-attack-risk/index.html?hpt=he_c2
In this article Health.com is claiming that the increase in traffic related air pollution may be increasing strokes and heart attacks in individuals. They derived this from comparing almost 2,000 stroke cases to the day to day levels of air pollution. Health.com states in the article on CNN, that the chance of having a stroke is 34% higher after a day spent in moderate air quality, rather than good. I believe that this claim lacks the support of one or more of the six principles of scientific thinking. One major scientific thinking principle that should have been considered in this claim is the ruling out rival hypotheses. The article is giving readers one explanation; therefore, many are automatically assuming it is correct. Many readers need to realize there are other possible explanations or causes for these strokes and heart attacks. The article did state that they looked at the medical records of the patients in the stroke cases they evaluated. This was done before this claim was stated, but there are other explanations that would also fit these findings that may not be on individual's medical records. There could be causes that were never tested in those individuals or explanations that have not yet been thought of.
Another scientific thinking principle that does not support this claim is the Occam's Razor. When looking at other explanations of heart attacks and strokes like the blockage of an artery or the burst of a blood vessel, they seem like much simpler explanations. These explanations not only seem simpler, but also do a better job of accounting for the result of a stroke.
Can air pollution really increase health factors?
No TrackBacks
TrackBack URL: http://blog.lib.umn.edu/cgi-bin/mt-tb.cgi/180225
I believe that articles like this (especially ones that claim to have done a study and claim to have some sort of internal validity) is one of the reasons why knowing the 6 principles of scientific thinking comes in handy. Good for you that you could point some out.
I find the statistic that someone has a 34% increased chance of having a stoke on in a moderate air versus good air quality environment hard to believe. One thing that the researchers might want to consider is the fact that more than ever there have been better air quality standards. It's a bit of a stretch but it's possible that having bad air quality forces us to make changes in the way we handle pollution. In turn that will have an effect on the quality of life in the future (although these results may take a long time to show up)
I agree with your conclusion that this article is making an unscientific claim. Along with the two that you mentioned I think that two other principles also relate. First, how can we be sure that the two are not a mere correlation and that strokes and heart attacks occur when larger amounts of air pollution from traffic are present? There can easily be another factor causing both of these like an increase in activity on holidays that leads people with lots of cholesterol clogging their arteries to have strokes and heart attacks. This would also explain the increased traffic pollution because people may drive their vehicles to stores or events on days when they are more active.
The second principle is extraordinary claims. I think that everyone will agree that pollution has to go a long way to cause a heart attack. After all their would have to be some way for the air particles to find their way past all of the body's defense systems and into the blood stream to begin clogging the arteries. Then, you would have to somehow show that the stroke or heart attack was indeed caused by these pollution particles. This would require some extraordinary evidence.