Rocketdyne Radiation Study

["Otto G. Raabe" <ograabe@ucdavis.edu>]

September 12, 1997
Davis, CA

Dear RadSafers:

You will soon be hearing more in the news about a new report out of UCLA
entitled: "Epidemiologic Study to Determine Possible Adverse Effects to
Rocketdyne/Atomics International Workers from Exposure to Ionizing
Radiation" by H. Morgenstern et al., UCLA School of Public Health. It
claims to show "that occupational exposure to ionizing radiation among
nuclear workers at Rocketdyne/AI has increased the risk of dying from
cancer of the blood and lymph systems." It also claims that other types of
cancer such as lung cancer and cancers of the "upper-aerodigestive tract"
are indicated to be caused by low level exposures to ionizing radiation
above 10 mSv. 

Among the list of the "Advisory Panel" are some well known anti-nuclear
types including Dan Hirsch (Committee to Bridge the Gap), Alice Stewart,
Robert Goble, and Greg Wilkinson.

The most important finding has been discarded by the authors. That finding
is that "...THE MORTALITY RATES FOR ALL CAUSES...WERE LOWER FOR MONITORED
ROCKETDYNE/AI WORKERS THAN FOR EITHER THE GENERAL U.S. POPULATION OR THE
NIOSH POPULATION OF OTHER WORKER COHORTS." They attribute this to
Rocketdyne workers being healthier than the general population. This is the
so-called "healthy worker effect" which is a common finding in studies of
nuclear workers. In general, people who have worked in the nuclear field
anywhere in the U.S. have not had higher death rates from any causes than
the general U.S. worker, and often show lower death rates from cancer, as
in the Rocketdyne study.

In the Rocketdyne study there is no actual control for confounding causes
of mortality such as smoking and alcohol consumption, although they claim a
subset of the study group for which smoking patterns were known did not
suggest that there were more smokers in the exposed group. This possibility
was not disproved, however. Overall, the statistical power of this study is
weak.

The cancers that they pull out of the data as showing radiation trends are
very selective. The "upper-aerodigestive tract" cancer association with
radiation exposure suggests a random observation since that strange
grouping of cancers is not know to be a mark of radiation exposure. It is a
mark of tobacco use, alcohol consumption, and excessive consumption of
spicy food. None of these possibilities can be ruled out by this study. In
addition, they do not appear to have shown a dose-response relationship for
those effects they attribute to radiation exposure. 

We should wonder why they did not report those cancers whose occurrence was
much lower in the "exposed" workers, if any.

This is a weak study that will no-doubt produce a lot of press. 

Otto

 
		*****************************************************
		Prof. Otto G. Raabe, Ph.D., CHP
                [President, Health Physics Society, 1997-1998]
		Institute of Toxicology & Environmental Health (ITEH)
		     (Street address: Old Davis Road)
		University of California, Davis, CA 95616
		Phone: 916-752-7754     FAX: 916-758-6140
		E-Mail: ograabe@ucdavis.edu
		******************************************************