Tuesday, October 23, 2007

More on Nuclear Power Plant Worker Cancer Studies

I was mistaken in stating there have been no studies on American nuclear power plant workers - the truth is that there are VIRTUALLY no studies. The attached is the largest to date, done by Columbia University.

It found an excess of leukemia deaths, solid cancer deaths, and arteriosclerotic heart disease deaths for workers employed during 1979-1997 for 15 nuclear utilities.

But there are problems:

1. The excesses aren't statistically significant, since the numbers are small (26 leukemia deaths, 368 solid cancer deaths)

2. Only deaths, not cases are examined. Workers are more likely to have access to good medical care that can help them to survive cancer. Studying cancer cases is much more revealing than deaths.

3. Workers who work less than 18 years may not have had enough exposure. I suspect they include even those who worked for a brief timeat nuclear plants.

4. The average age of workers at the end of follow up is 45 years, an age when cancer rates are still relatively low. It often takes much longer than that for cancer to manifest.

5. The healthy worker effect is a big issue. They compare actual worker deaths with expected (the entire population). That's not a fair comparison, since workers are much healthier than the general population.

This is a large study of workers at Canadian nuclear power plants. Elevated mortality rates of leukemia and solid tumors were found (although just borderline statistical significant).

This article suffers from the problems I stated before, but they should be taken with great concern. The literature has no other studies of U.S. nuclear power plant workers, other than a very small one of Calvert Cliffs in Maryland.

I hope this helps.

Joe Mangano
Advisory Board

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