Saturday, May 28, 2016

ALS and Environmental Pollutants

A recent study raises the possibility that exposure to certain environmental pollutants may contribute to the development of ALS (amyotropic lateral sclerosis, a degenerative nerve disease.) The authors of the study measured the concentrations of more than a hundred specific environmental pollutants in the blood of patients with ALS, using normal persons as controls. They found that the concentrations of some of the pollutants were significantly higher in the blood of patients with ALS than in normal patient controls. The authors concluded that certain environmental pollutants "may represent modifiable ALS disease risk factors."

It's a good study, but we need to be careful not to read too much into it. The data did not prove that environmental pollutants cause ALS. In fact, the data didn't really prove anything at all; they only revealed that an association exists between ALS and environmental pollutants. And as we know, an association does not prove causation. The authors' choice of the word "may" in their conclusion was deliberate and accurate.

And yet, this is still a very important finding because it gives us a possible clue to ALS that could be pursued by future scientific studies. Can the findings in this study be confirmed by other researchers? Are there any animal models that develop neurological conditions similar to ALS, and if so, is their condition made worse by exposure to environmental pollutants under strictly controlled conditions in the laboratory? Do any of these pollutants affect the biochemistry or development of embryonic nerve cells grown under laboratory conditions?

There's a lot more to do before we know for sure whether environmental pollutants contribute to the development of ALS. This current study represents a starting point.

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