Objectivity

["Les Crable" <lescrable@HOTMAIL.COM>]

Jim Muckerheide,



If your postings are to be perceived with at least a hint of objectivity, 

try posting abstracts on both sides of the issue such as these.  I see 

Tomasek's study did not match cases to controls by smoking status either.  

It looks like they dependent on multivariate analysis like Field.





Radiat Environ Biophys 2001 Sep;40(3):207-11



Microdosimetric calculation oCent Eur J Public Health 2001 Aug;9(3):150-3



Study of lung cancer and residential radon in the Czech Republic.



Tomasek L, Muller T, Kunz E, Heribanova A, Matzner J, Placek V, Burian I, 

Holecek J.



National Radiation Protection Institute, Srobarova 48, 100 00 Prague, Czech 

Republic. ltomasek@suro.cz



Epidemiological evidence of lung cancer risk from radon is based mainly on 

studies of men employed underground in mines where exposures are relatively 

high in comparison to indoor exposure. Risk from residential radon can be 

estimated from occupational studies. Nevertheless, as such extrapolations 

depend on a number of assumptions, direct estimation of the risk is needed. 

The present study of lung cancer mortality was designed as a follow-up of a 

population (N = 12,004) in a radon prone area of the Czech Republic covering 

the period 1960-1999. Information on vital status and causes of death were 

obtained mostly from local authorities and from the national population 

registry. Exposure estimates were based on one year measurements of radon 

progeny in most houses of the study area (74%). Exposures outside the area 

(16%) were based on country radon mapping. Mean concentration of 509 Bq/m3 

is higher than the country estimate by a factor of 5. By 1999, a total of 

210 lung cancers were observed, somewhat more than the nationally expected 

number (O/E = 1.10) in comparison to generally low numbers corresponding to 

cancers other than lung (O/E = 0.81). The excess relative risk per standard 

radon concentration (100 Bq/m3) was 0.087 (90% CI: 0.017-0.208). This value 

is consistent with risk coefficients derived in other indoor studies. The 

present follow-up demonstrated that increased incidence of lung cancer 

depends linearly on exposure in terms of average radon concentration in the 

course of previous 5-34 years. Adjustment for smoking did not substantially 

change this estimate, although the risk coefficient for non-smokers (0.130) 

was higher in comparison to that for ever smokers (0.069), but not 

statistically different.f absorption fraction and the resulting dose 

conversion factor for radon progeny.





-----------------

Nikezic D, Yu KN.



University of Kragujevac, Faculty of Science, Yugoslavia.



It is an established fact that radon progeny can induce lung cancers. 

However, there is a well-known discrepancy between the epidemiologically 

derived dose conversion factor for radon progeny (4 mSv/WLM) and the 

dosimetrically derived value (15 mSv/WLM) (mSv is a unit of the dose while 

WLM is a unit of exposure to radon progeny). Up to now there is no 

satisfactory explanation to this. In the present study we propose that 

microdosimetry will help reduce the discrepancy significantly. The ICRP 

Human Respiratory Tract Model (HRTM) has been applied to calculate the 

effective dose conversion factor. All parameters have been kept at their 

best estimates. Modifications were made in the calculation of the absorbed 

fractions of alpha particles. In contrast to the ICRP approach where the 

energy has been considered to be deposited in the layer containing the 

sensitive cells, we used a microdosimetric approach in which the alpha 

particles deposit their energy only in the nuclei of sensitive cells. This 

modification alone has lowered the dose conversion factor by about one-third 

(from 15 mSv/WLM down to approximately 10 mSv/WLM).



Les Crable







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