Access to letter - healthy Worker Effect

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Jim,  The letter is available free online.  Bill Field





http://www.iop.org/EJ/S/1/NIO935000/K3dFfKElZYXWBrQgZRwcP

g/abstract/0952-4746/22/1/104



LETTER TO THE EDITOR



Healthy worker effect

Dear Sir



Whilst I appreciate the concerns that Barrie Skelcher 

may have with regard to the healthy worker effect (HWE), 

may I assure him that it is not fundamental to 

understanding the risks from radiation exposure. Not 

only is the HWE much quoted, it is a much studied and 

multifaceted phenomenon in occupational epidemiology. It 

is a bias induced by comparing the worker population 

with the national population, often resulting in lower 

than expected SMRs and/or SRRs, and is not peculiar to 

occupational studies of nuclear workers. As these 

comparisons are known to be subject to bias, the SMRs 

and/or SRRs must be interpreted with caution. The 

evidence for a statistical association between health 

outcome and exposure arises, however, out of the trend 

tests. These tests are `internal', i.e. they are not 

dependent on any external population and hence are 

unaffected by the HWE.



If Barrie accepts the Popperian philosophy that 

hypotheses cannot be proved right but can only be 

discredited, then, to cast doubts on the utility of the 

linear non-threshold (LNT) hypothesis it is necessary to 

show that either the dose response is non-linear at low 

doses and/or that there is a threshold below which there 

is no dose response. Because radiation-induced diseases 

do not leave a `marker' to distinguish them from non-

radiation induced diseases, epidemiological studies are 

unlikely to invalidate the LNT hypothesis in the 

foreseeable future. Barrie may note that this argument 

does not depend on the existence of the HWE. If a study 

does not find any detrimental effects on health 

resulting from radiation exposure, the HWE cannot 

therefore be `wheeled out' to explain this so called 

anomaly with the LNT hypothesis. The reasons that some 

studies are unable to demonstrate a dose response is 

more to do with the power of the study. The power of the 

study is dependent on such factors as the number of 

participants in the study, the number of years that they 

have been followed up for and, of course, the exposures 

that the participants have encountered.



Yours faithfully,



Dave McGeoghegan





> Friends,

> 

> Do you have the following ref?

> 

> J Radiol Prot 2002 Mar;22(1):94

> Healthy worker effect.

> McGeoghegan D.

> Publication Types: 

> *    Letter

> 

> Thanks.

> Jim Muckerheide

> 

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