Schneeberg Study Criticisms

[precura.martin@T-ONLINE.DE (Dr. Karl Martin)]

Dear Jim,



in your last mail to radsafelist you brought to attention an article about the 

German Health Spa in Schlema. Schlema belongs to our study area. It is very 

close to Schneeberg and has a population highly exposed to indoor radon in the 

past.



Your problems with the Schneeberg Study:



1. Retrospective cases (and controls)

Cases went back to the 1950s. (The study area with high indoor radon exposure 

has a small population only - about 25.000 for Schneeberg and Schlema together. 

To collect a significant number of non-smoking female cases you cannot rely on 

incident cases to conduct a risk analysis. Therefore the approach with 

retrospective cases was needed). These cases where collected from the local 

cancer registry. As you can see from our final report controls where collected 

from the same source with cancer illness with no known radon or smoking effect, 

which is different from lung cancer and free from metastases in the lung (see 

2.2 Definition of cases and controls).



Due to the high quality of the East German Cancer Registry (validated after 

reunification) the approach with retrospective cases is justified. The cancer 

cases where interviewed at the time of diagnosis in the local cancer registry 

collecting in unchanged forms from 1952 to 1998 all biographical information 

plus smoking behaviour, exposure at the workplace, results from medical 

diagnosis with type of cancer, histology etc. Only when questions for example 

regarding smoking where skipped, than next of kin had to be interviewed.



2. Radon exposure cases vs controls

The radon levels in the homes of cases and controls where measured for 30 years 

before diagnosis of cancer by one year measurements (see 3.2 Dosimetry - Radon 

gas measurements). For a subsample retro measurements where conducted (surface 

activity of glass sheets using Po-210 detectors by the Uni Gent/Belgium). The 

actual radon measurements could be validated by this method, confirming the 

stability of exposure levels over long time periods.



3. Power

The power in the exposure category of about 150 Bq/m³ is of course lower than 

over all catagories combined. (For more details see 4.2 Study power and 5.2 The 

influence of smoking on risk estimation). Besides future inclusion of more cases 

from the extended study area to increase confidence and power - non-smoking 

males and females - our argument regarding power in the lower exposure 

categories goes as follows (in the mean time):

When the risk estimations in miners and population studies that claim a lung 

cancer risk from low radon levels are true than the Schneeberg Study must have 

confirmed such results with a high enough power. This is not the case. So it is 

assumed that the results from the other studies confirming LNT might not be 

valid.



4. Exposure categorisation

In our study protocol no exposure categories where predetermined. When I 

mentioned that other categories where tried than published, it was just a 

response to your proposal to try three categories only to enhance cases per 

exposure category. The influence of even categories was tested in our final 

report (see table 19 Distribution of the probationers by percentiles of the 

cumulative radon exposure and OR) with no deviation from the overall results in 

table 17 and 18. 



5. Comparability of controls

>From radon measurements in the study area prior to the Schneeberg study we found 

a dependency of the indoor radon levels from birth cohorts. Older probationers 

had a greater probability to be highly exposed to radon than younger 

probationers. This is due to the fact that older probationers lived more 

frequent in the old part of the town (with very old houses) and younger 

probationers in the newly build part of the town after unranium mining started 

after WW II. To prevent an exposure bias the two categories of controls where 

introduced.  



Best regards, Karl

 



    



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