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Re: Access to letter
The complete text is available on-line at
http://www.iop.org/EJ/S/3/362/yoE3aewPM8E7wusW.hYaTw/abstract/0952-4746/22/1/104
It is copied here:
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
Bernard L. Cohen
Physics Dept.
University of Pittsburgh
Pittsburgh, PA 15260
Tel: (412)624-9245
Fax: (412)624-9163
e-mail: blc@pitt.edu
On Mon, 8 Apr 2002, muckerheide wrote:
> 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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