RE: New study finds multiple myeloma linked to radiation exposure

["Elizabeth M. Brackett" <brackett@bright.net>]

A quick search on the web yielded information from the NIH National Cancer Institute, which confirms your memory:

>>>>
> In 1994, an estimated 12,700 new cases of multiple myeloma were diagnosed in the United States (Boring et al., 1994). Multiple myeloma primarily affects older individuals. In the United States, the median age at onset is 67 for blacks and 71 for whites (Ries et al., 1994). Multiple myeloma is one of the few cancers that occurs twice as frequently in blacks as in whites. The annual incidence for 1987-91 was 11.1 cases per 100,000 for black men and 7.7 for black women, compared with 5.1 for white men and 3.3 for white women (Ries et al., 1994). U.S. blacks experienced the highest incidence of multiple myeloma in the world, while Asians and Hispanics had low rates (Parkin et al., 1992).
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It also goes on to cite several references linking radiation exposure to the disease:
>>>>
> Little is known about the etiology of multiple myeloma. Both environmental and genetic factors may play a role in the development of this cancer (Riedel et al., 1992). Exposure to ionizing radiation has been linked with multiple myeloma. The strongest associations have been noted for Japanese atomic bomb survivors (Shimizu, 1990), U.S. radiologists (Matanoski et al., 1975), and radium dial workers (Stebbings et al., 1984). Nuclear power plant workers may also be at an increased risk for developing multiple myeloma (Darby et al., 1988; Gilbert et al., 1989). Living near nuclear facilities, however, does not appear to be associated with myeloma occurrence (Jablon et al., 1990).
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A number of other causes are potential causes are also listed:
>>>>
> Numerous epidemiologic studies have reported a link between multiple myeloma and farming or agricultural work (Riedel et al., 1992). However, it is not clear whether pesticides, agricultural exhausts, chemicals, dusts, or a combination of these exposures are the responsible agents. Other nonspecific occupational exposures that have been associated with myeloma include metals, rubber, wood, leather, paint, and petroleum (Riedel et al., 1992). Workplace exposure to benzene, a chemical used in many manufacturing processes, may play a role in the development of multiple myeloma (Decoufle et al., 1983; Rinsky et al., 1987).
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At 03:06 PM 4/10/2000 -0500, you wrote:
>I don't know much about this, but I seem to recall that the average age of
>onset of this disease is listed as from 63 to 70 years old.  Also seems that
>other studies have shown the ratios stated between blacks/whites/male/female
>to be pretty much the same.  Is it possible that what was discovered is in
>reality exactly what you would expect to see in the general population?  I
>admit that I did not read the entire URL article, just what was included in
>the post so there may be information of which I am unaware.  I am sure that
>someone has the time or the information at hand to see if this is an
>increase in the rate from the general population. 
>

I'm curious as to how potential internal exposure was considered in the UNC study.  Did they simply exclude anyone who was ever monitored for internal exposure?  Studies such as these in the past have done a lot of hand waving when it came to internal dose because it was "too difficult to calculate" (the words from one of the researchers when I was working at ORNL).  While I don't disagree with the statement for the most part (a great deal of effort would be required at many sites to reconstruct the internal doses from the early days because of the lack of known intake dates, material classes, ...), it could certainly have a significant effect on the study's outcome if people  included in the study were simply classified as having a potential internal dose but no value quantified.  This is just a potential concern - it may be that all such people were excluded.

Liz Brackett


******************************
Elizabeth M. Brackett, CHP 
Sr. Health Physicist     
MJW Corporation, Inc.       
(330) 644-3757        
mailto:brackett@bright.net 
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