Thanks to the California Air Resources Board, I now know about "oxidative stress." Perhaps many or all of the persons who are reading these words have known about oxidative stress for years. I just found out.
According to Doctor Victoria Dunckley, M.D., oxidative stress means (or is associated with) inflammation. Click on the "oxidative stress" link, above, to get her views on oxidative stress and the brain. Wikipedia has a more involved explanation of oxidative stress.
At any rate, I did discover "oxidative stress" as an interesting subject because I subscribe to periodic bulletins from the California Air Resources Board, or ARB. I like to keep informed about important environmental issues, and this is certainly one reason I subscribe. I actually used to be a member of the ARB, too, so you might also say I do it for "old times' sake."
In an email bulletin I received on the morning of July 15th, the ARB highlighted a presentation that was being given that afternoon in Sacramento. Unfortunately, I couldn't attend, or even watch the webcast, but I do think I got the gist:
Numerous epidemiological and toxicological studies have demonstrated that exposure to ambient PM is associated with increased heart and lung disease and death; however, little is known about the effects of PM exposure on the central nervous system. This study took advantage of a multicity project sponsored by the Health Effects Institute to compare central nervous system impacts among sites with different source contributions to ambient PM. Brain tissue from transgenic mice exposed for 6 months to concentrated ambient fine particles (CAPs) in cities with very different pollutant source profiles was examined.
In essence, the studies presented gave some indication that exposure to fine particle air pollution leads to inflammation in the brain. That's "oxidative stress." You can get more on this topic by clicking on this link.
When I used to go to the ARB meetings in Sacramento, I almost always drove (ironically causing more air pollution as I did). Necessarily, I parked in the ARB's parking lot, and can say that one bumper sticker that was not uncommon on vehicles in that particular parking lot always gave me a kick:
Remember When Sex Was Dirty And The Air Was Clean?
Even I am not that old!
The latest studies do seem to confirm what the ARB has been saying for years: air pollution is bad for you!
In fact, it can inflame your brain!
http://drdunckley.com/2010/09/17/oxidative-stress-and-the-central-nervous-system-if-this-brain-could-talk-part-i/
Well, maybe... The study doesn't establish a causal relationship.
ReplyDeleteI tend to rely on the Sniff Test: if it smells bad, it's not good for you. This applies to the actions of legislative bodies as well as air quality.
You can read the full report by Michael Kleinman here:
ReplyDeletehttp://www.arb.ca.gov/research/apr/past/08-306.pdf
Notice this has not been peer reviewed. The conclusions are not well supported by the evidence. It's probably possible to measure oxidative stress caused by CAPs reaching the brain, but this paper shows no such thing. I doubt any such effect is relevant to human health unless you live in a very polluted area, like Xingtai.
Basically, he put a bunch of caged mice in 5 different locations. Then, he measured proteins in their brains. The most significant change was in the Seattle group, with the least CAP pollution. Inverse dose response leads me to suspect these results are due to confounding factors like age.