[ RadSafe ] Scientists discover possible radiation and heartdisease link

[John Jacobus]

Of course, not everything is as easy to determine at first examination.
   
  From http://www.cancer.org/docroot/NWS/content/NWS_1_1x_Radiation_to_Left_Breast_Take_Care_of_Your_Heart.asp
   
          Radiation to Left Breast? Take Care of Your Heart    More Coronary Artery Disease Seen With Radiation to Left Breast            Article date: 2006/10/01                     Summary: Radiation for breast cancer may affect the heart when treatment is given to the left breast, doctors from the University of Pennsylvania report. Writing in the Journal of Clinical Oncology, they say women who have radiation to the left breast are more likely to develop coronary artery disease than those who get radiotherapy in the right breast. Consequently, women who require left-breast radiation should be especially vigilant about reducing their other risks for heart disease, the researchers say

   
   
  AND at http://www.nci.nih.gov/cancertopics/treatment/breast/radiation-and-heart
   
          Radiation Therapy for Breast Cancer Now Less Risky for Heart    
  Summary
The risk of death from heart disease caused by radiation therapy for breast cancer has declined steadily over the past 25 years, according to a new study. 
  . . .
   
  

"Philippe J. Duport" <pduport at uottawa.ca> wrote:
  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 





+++++++++++++++++++
"Part of human nature resents change, loves equilibrium, while another part welcomes novelty, loves the excitement of disequilibrium. There is no formula for the resolution of this tug-of-war, but it is obvious  that absolute surrender to either of them invites disaster."
-J. Bartlet Brebner 

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com
       
---------------------------------
Never miss a thing.   Make Yahoo your homepage.