Re: Radon Health Hazard, Myth or Reality?

[John Goldsmith <gjohn@bgumail.bgu.ac.il>]

Eric:
     Your concern for socio-economic variables is sensible.  As it happens
there are at least 20 different miners populations studied (cited in Samet
"Radon and Lung Cancer", J. National Cancer Institute vol 81 pp745-757,
1989, see also BEIR IV report, 1988, )including 7 of uranium miners, 6 of
iron miners, and 7 from mining other materials.  All but one other (from
China's tin miners) were from U.S., Canada and Western countries.  Of the
nine groups with data sufficient for calculating the excess relative risk/100
working-level months, the Czech miners are third highest (1.9) and the
Chinese lowest (0.9). 
     There are socio-economic gradients in lung cancer, but they are
not likely to be confounders of  the impact of radon exposures in
underground miners. Some of the gradients are due to smoking, which is
an important contributor to the lung cancer rates.
     In comparison to Dr. Cohen, the authors, such as Samet and Radford
and Lundin and Whittemore and Jorgenson and Axelson, all of whom are
competent in epidemiology, have done most careful work in dealing with
confounding. All of them have dealt explicitly with smoking, for example,
which, with his data sources, was difficult for Dr. Cohen.               

  John Goldsmith
On Tue, 4 Nov 1997, Eric Denison wrote:

> A query for the Radsafe community:
> 
> At 02:34 AM 11/04/97 -0600, Dr. Goldsmith wrote:
> >Dr. Scribner:
> >     We start any appraisal with two widely accepted facts.
> >       I. Radon exposures are a large fraction of background radiation
> >from natural sources, and the exposures may vary with local geology,
> >housing, and possibly local meteorology.
> >       II.  Radon exposures occur occupationally to miners, and there
> >have been several convincing epidemiological studies relating dose to
> >probability of lung cancer.
> 
> Would any of you out there happen to know specifically where I could find
> the original Czech miner studies?  I'm particularly interested in looking
> at how (or whether) socioeconomic factors and personal habits were handled
> in the data analysis.
> 
> I have always had a bit of a problem with the idea of using data from a
> low-income (poverty-level?) single-occupation group from an Eastern Block
> nation to predict cancer risk for the entire spectrum of American
> lifestyles and locations.  For example, did the study address diet
> (probably much poorer than most Americans), availability of quality routine
> medical care and average life span (both probably much lower for the
> Czechs), and local environmental pollution (undoubtedly far greater than
> most of us here suffer)?  Dr. Cohen aparently took great pains to account
> for confounding factors in his recent studies here in the U.S.  I'm
> wondering how well the authors did on the study upon which so much of our
> regulation seems to be based.
> 
> Unless you feel that the info is desired by the whole group, please reply
> to my e-mail.  Thank you in advance for your assistance.
> 
> 
> 
> 
> 
> >     It follows that your question needs refinement concerning what kind
> >of health hazard and to whom.  I assume that you refer to the general
> >public, rather than to occupationally exposed miners and to risk of lung
> >cancer.
> >     The premise of community health hazard is partly based on
> >quantitative extrapolation of miner's occupational exposure to those
> >of the general population.  Recently some doubt as to the suitability of
> >direct extrapolation has arisen because of the demonstration of the
> >carcinogenic risk of silica exposure, a frequent co-exposure for miners.
> >In other words some of the excess cancer risks in underground miners is
> >associated with silica exposures and some to radon, and some to a
> >combination. (Assuming we are speaking of populations with equivalent
> >smoking exposure, since smoking is by far the most potent cause of lung
> >cancer.)     
> >      A number of general population studies of risk from
> >contemporary measurements of radon have been done, and meta-analyses 
> >are consistent with a small association with lung cancer.  The one
> >anomalous report is that of Dr. Bernard Cohen of the University of 
> >Pittsburgh, who by lumping together data from different types of studies,
> >finds a significant negative relationship of radon and lung cancer by 
> >County in the U.S.  Part of the problem is that the analysis depends on
> >the lung cancer data for the totality of the county residents and the
> >measurements are from a (usually) self-selected subset of households.
> >The self-selection favors the more suburban dwelling units, while lung
> >cancer is strongly associated with population desnity.
> >     Professor Cohen has made some of his data available, and I have
> >recently examined a subset obtained by EPA.  Briefly, the data for
> >counties in eight states with high radon levels in the EPA subset, show no
> >significant associations between log radon and lung cancer for males or 
> >for females.  (Lung cancer rates are age adjusted.)
> >     Health risks to the general population from background levels of 
> >radon are no myth, but except for the rare,unusually high residential 
> >exposures, the risks are small and difficult to detect.  
> >               John Goldsmith, M.D, M.P.H.  Professor of Epidemiology,
> >                gjohn@bgumail.bgu.ac.il  Ben Gurion University,
> >                  Beer Sheva Israel
> >
> >
> >
> Eric Denison <denison.8@osu.edu>
> Radiation Safety Technician
> Environmental Health & Safety
> The Ohio State University
>