[ RadSafe ] Scientists discover possible radiation and heartdisease link

Mon Mar 10 13:01:25 CDT 2008

John,

The Darby's paper you mention shows a positive association between
radiation exposure and cardiovascular disease.  However, the link is
tenuous: the odds ratio for all years of follow-up is 1.04 (confidence
interval 1.00 - 1.08).

Conversely, a study comparing French nuclear to non-nuclear workers
shows an odds ratio = 0.88 (0.76 - 1.02) for cardiovascular diseases.
(Gros et al. Occup Med 52(1): 35-44, 2002) - Note this is an internal
study: all workers belong to the same company, no so-called healthy
worker effect).

An internal study of French electricity nuclear workers shows a SMR of
0.50 (0.40 - 0.62) for cardiovascular diseases (comparison to the
general population). The same study a strong influence of the
socio-economic status (SES)on cardiovascular (SMR = 0.35 in the high SES
group, SMR = 0.91 (3 times more) in the low SES group). (Rogel et al. Am
J Indust Medicine Vol 47:72-42, 2005) 

Also, thoracic doses are relatively high in breast cancer radiotherapy
(breast dose can exceed 30 Gy - Preston et al, Radiation Research
158:220-235, 2002.  Extrapolating the risk of cardiovascular disease
from high to low doses and dose rates might imply undue confidence in
dose-effect linearity...  

The risk increase in Darby's paper is small compared to the risk
reduction in nuclear workers.  Before accepting the small increase in
Darby's paper, one should also be certain that SES factors, which have a
strong impact on cardiovascular risk, have been duly taken into account.

Philippe Duport
Institute of the Environment
University of Ottawa  

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of John R Johnson
Sent: March 5, 2008 13:40
To: Fred Dawson; srp-uk at yahoogroups.com
Cc: radsafe at radlab.nl
Subject: Re: [ RadSafe ] Scientists discover possible radiation and
heartdisease link

Fred

There is a link between radiation and cardiovascular disease. See Darby
et 
al (BMJ Vol. 326, pp256-257, 2003) and our poster at the IRPA-11
meeting.

John
***************
John R Johnson, PhD
CEO, IDIAS, Inc.
4535 West 9th Ave
604-676-3556
Vancouver, B. C.
V6R 2E2, Canada
idias at interchange.ubc.ca

----- Original Message ----- 
From: "Fred Dawson" <fred-dawson at blueyonder.co.uk>
To: <srp-uk at yahoogroups.com>
Cc: <radsafe at radlab.nl>
Sent: Tuesday, March 04, 2008 8:53 AM
Subject: [ RadSafe ] Scientists discover possible radiation and heart 
disease link

> Guardian reports
>
> http://www.guardian.co.uk/world/2008/mar/04/nuclear.nuclearpower
>
> A study of nearly 65,000 nuclear industry workers over more than 60
years
> has found a possible link between high radiation exposure and heart 
> disease.
>
>
> The finding was particularly surprising since there is no established
> biological mechanism that would explain how radiation exposure might
cause
> heart disease. However, the research team stressed that its analysis
could
> not rule out other factors that could explain the link, such as 
> work-related
> stress or irregular shift patterns.
>
> The team studied 64,818 workers at the Sellafield, Springfields, 
> Chapelcross
> and Capenhurst nuclear sites. Some of the workers began work in the 
> industry
> as far back as 1946, and 42,426 were exposed to radiation as part of
their
> job.
>
> When the researchers compared workers occupationally exposed to
radiation
> with those who were not, they did not find any difference in the
number of
> cases of heart disease and stroke. However, when they split the
> radiation-exposed workers into groups with different levels of
exposure
> (based on readings from radiation-monitoring badges worn by all staff)

> they
> did see a disparity.
>
> Those workers who were exposed to the highest levels had a slightly
lower
> life expectancy due to an increased probability of heart disease and
> strokes. "We see a higher mortality for those workers with the highest

> level
> of operation exposure," said Prof Steve Jones of Westlakes Scientific
> Consulting, the private company hired by British Nuclear Fuels and the
> Nuclear Decommissioning Authority to carry out the research.
>
> The team stressed that because the analysis was carried out 
> retrospectively,
> it could not be sure that the findings ruled out other factors that
could 
> be
> responsible for the results. "We can't show whether it's a consequence
of
> that exposure or whether it's due to something else," said Jones.
>
> However, he added that if radiation were the cause, then the workers
who
> have experienced the highest levels of exposure have roughly a 73%
chance 
> of
> surviving until they are 70, compared with a 75% chance if they had 
> received
> no exposure at all.
>
> The findings will have little relevance for workers joining the
industry
> today, according to the team. "I don't think it's a big issue for
nuclear
> workers at present or in the future because the exposure levels are so

> low,"
> said the report's co-author Michael Gillies. In the 1960s, workers
were
> exposed to up to a radiation dose of 12 millisieverts per year
compared 
> with
> around one millisievert per year now.
>
> The most highly exposed workers received a radiation dose around five
to 
> 10
> times less during their entire working lives than survivors of the
atomic
> bomb dropped on Hiroshima in 1945.
>
> In any case, workers in the nuclear industry are generally much
healthier
> than the general population, despite the health risks they may face at

> work.
> By comparing their sample with the average for the local population,
the
> team found that the mortality rate of nuclear workers is 20% lower.
>
> The team reported its findings today in the International Journal of
> Epidemiology.
>
> ======================
>
> Fwp_dawson at hotmail.com
>
>
>
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