"A 2008 peer-reviewed study in the Annals of Neurology, for example, found that TCE is “a risk factor for parkinsonism.” And a 2011 study echoed those results, finding “a six-fold increase in the risk of developing Parkinson’s in individuals exposed in the workplace to trichloroethylene (TCE).”"
It doesn't strike me as fair to dismiss studies like the ones quoted (from the article) as simple correlations.
> It doesn't strike me as fair to dismiss studies like the ones quoted (from the article) as simple correlations.
I didn't see the particular studies and I am not dismissing them out of hand, but I've seen a lot of studies, lost a lot of battles against all sorts of unsound statistical analysis. When I taught Intro Stats, I had no trouble finding examples of what not to do to illustrate in class: Just look at the front page of the campus newspaper which seemed intent on filling pages with bogus "studies".
Again, I am not calling this one[1] bogus, but I am going to point out that study seems to consist solely of finding people who have Parkinson's and have worked around the chemical.
It doesn't strike me as fair to dismiss studies like the ones quoted (from the article) as simple correlations.