RE: Epidemiology of Multiple Myeloma at Four DOE Sites

[L_K_II_Les_Aldrich@RL.gov]

A video version of this study was in circulation almost 2 years ago.  The
overall result of the study that I saw when I reviewed the data was that the
controls had a higher level of cancer than the subjects.  It was, to me
(admittedly not an expert in cancer research) a clear picture of hormesis in
action.  The author had to look long and hard to find any support for his
preconceived answer that low levels of radiation cause cancer.  Only by
dividing the subjects by age group was he able to show "an increase" in
cancer.  If you know the answer you want, it is usually possible to massage
your data until you find a sub-group that has that answer.  That's good for
getting more federal money to do more study, but it leaves a bad taste in my
mouth when a researcher comes to a conclusion, based on part of his data,
that is contrary to the conclusion seen when all data is considered.

My opinion only.

Les Aldrich
l_k_ii_les_aldrich@rl.gov 

> -----Original Message-----
> From:	Susan Gawarecki [SMTP:loc@icx.net]
> Sent:	Monday, April 10, 2000 9:12 AM
> To:	Multiple recipients of list
> Subject:	Epidemiology of Multiple Myeloma at Four DOE Sites
> 
> Some information on radiation-related health effects I thought might be
> of interest to the list.
> 
> --Susan Gawarecki
> 
> Epidemiology of Multiple Myeloma at Four DOE Sites 
> Department of Epidemiology 
> University of North Carolina at Chapel Hill 
> 
> An epidemiological study of multiple myeloma among Department of Energy
> (DOE) workers. Multiple myeloma is a cancer of the blood-forming
> tissues, affects primarily older people, and is often fatal. The study,
> which began in October
> of 1993, consisted of a feasibility phase, a protocol development phase,
> and an implementation phase. The final report was submitted to the
> funding agency, the National Institute for Occupational Safety and
> Health (NIOSH), in March of
> 1997. 
> 
> Ionizing radiation is an accepted cause of multiple myeloma and most
> other types of cancer. This study was requested by NIOSH because of
> previous reports of associations of multiple myeloma with radiation
> exposures of workers at the
> Hanford site. The new study was intended to include more cases of the
> disease, better evaluation of radiation doses, and measurement of other
> occupational exposures not available in the Hanford studies. 
> 
> Facilities were chosen for inclusion in the study based on their age,
> size, type of operations, and availability of basic records assembled
> for past epidemiological studies. Those records included employee
> rosters and information on causes
> of death. These data formed the basis for choosing cases - workers who
> died with multiple myeloma - and a random sample of controls who lived
> to be as old as the cases. Because multiple myeloma is rare, four
> facilities were chosen in
> order to identify a sufficient number of cases for statistical analysis. 
> 
> We identified 98 multiple myeloma deaths and 391 age-matched controls
> from a combined roster of 115,143 workers hired before 1979 at Hanford,
> Los Alamos National Laboratory, Oak Ridge National Laboratory, and the
> Savannah
> River site, and followed for vital status through 1990 (1986 for
> Hanford). Information on prior work history, smoking, medical x-rays,
> and exposure to physical and chemical agents was derived from personnel,
> medical, industrial hygiene and health physics records. 
> 
> The study compared exposure histories of cases and controls to
> investigate whether certain occupational exposures were relatively more
> common among cases. Results of these comparisons were expressed in terms
> an epidemiological measure
> called the odds ratio. The odds ratio is an estimate of the ratio of the
> disease rate among workers with a particular characteristic compared to
> those without the characteristic. An odds ratio of 1.0 indicates that
> disease occurrence is the
> same among people with and without the characteristic; an odds ratio of
> 2.0 would indicate that people with the characteristic have twice the
> rate of disease as those without. We also calculated a measure of the
> precision of the odds
> ratios called the 95% confidence limit (95% CI). This statistic is an
> indication of the stability of the odds ratio. 
> 
> We attempted to determine whether workers had been exposed to a variety
> of chemical and physical agents that might be causes of multiple
> myeloma, including solvents, metals, welding fumes, asbestos, ionizing
> and non-ionizing radiation. With
> the exception of external penetrating radiation, for which most longer
> term workers had at least some badge data, information on exposures to
> specific chemical and physical agents was not sufficient to assign a
> quantitative exposure
> estimate or even to determine with a high degree of certainty whether or
> not a worker was exposed. We calculated odds ratios for many factors
> although we believe that the results are not very interpretable due to
> the poor measurement of
> exposures. With the exception of the estimated whole body dose from
> ionizing radiation, other factors were not clearly in excess among cases
> compared to controls. 
> 
> External penetrating ionizing radiation was measured by individual
> dosimeters. Whole body radiation dose was constructed by adding annual
> external radiation doses and estimates of doses from tritium. Although
> tritium is an internal
> radiation exposure, it was routinely counted with external dose because
> it irradiates the body uniformly. Neutron doses were included using
> quality factors employed at the facilities, which varied from 8 to 20.
> Tritium and neutrons comprised only a small fraction of whole body dose
> estimates. 
> 
> Total cumulative radiation doses were similar between cases and
> controls. However, doses received at ages 45 and above were associated
> with an average 7% per 10 mSv (one rem) increased risk of multiple
> myeloma, adjusted for age, race, sex, facility, period of hire, birth
> cohort, monitoring for internal radionuclide contamination, and external
> radiation received prior to age 45. The 95% confidence limit for this
> estimate was 1-13%. For exposure at ages 45 and above, the
> odds ratio for workers with cumulative doses of 50 mSv (5 rem) or
> greater compared to workers with cumulative doses of less than 10 mSv
> was 4.34 (95% CI 1.46-12.90). 
> 
> The association of multiple myeloma with radiation doses at older ages
> is consistent with findings from some epidemiological studies of cancer
> among workers and theoretical expectations that older people are more
> sensitive to a
> variety of carcinogens. These findings and other studies of nuclear
> workers have implications for radiation protection standards for workers
> and the general public. 
> 
> For a copy of the final report of this study write to:
> Health-related Energy Research Branch, National Institute for
> Occupational Safety and Health, Robert A. Taft Laboratories, 4676
> Columbia Parkway, Mailstop R-44, Cincinnati, OH 45226-1998
> -- 
> ==================================================
> Susan L. Gawarecki, Ph.D., Executive Director
> Oak Ridge Reservation Local Oversight Committee, Inc.
> 136 S Illinois Ave, Ste 208, Oak Ridge, TN 37830
> Phone (865) 483-1333; Fax (865) 482-6572; E-mail loc@icx.net 
> ==================================================
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