Low dose radiation is healthy!

What has cholesterol-heart disease theory and anti nuclear power environmentalism got in common?  It turns out - a lot!      8-:)

I came across a fascinating conference presentation by Philippe Duport on low level radiation in Ottawa University, January 2002.

Basically, turns out that radiation level between 10 to 1000 times stronger than the typical sea level natural background,  reduces the risk of cancer and extends the lifespan!   Some slides:

Note: 0.2Gy (Gray) is 20rad which is a rather high dosage (lethal dose for humans is 100rad), see also Wiki.

30% lung cancer reduction after 0.15Gy dose.

28% longer lifespan in mice at 35 and 70 times the natural background radiation!

Human cancer studies show a similar risk reduction, for example British radiologists have a lesser risk (by about 30%) than their non-radiologist colleagues.  Similar situation with Canadian radiation workers, 12% and 26% lower SIR (Standardized Incidence Ratio) of cancer in women and men, respectively,  28 and 35% lower cancer mortality rate (SMR=Standardized Mortality Rate) in women and men, respectively,  38 and 41% lower all causes mortality rate (SMR=Standardized Mortality Rate) in women and men, respectively (see slides 36,37).  It is interesting to note that the total mortality rate decreases more with (low level) radiation exposure than the cancer mortality, indicating that the protective effect of low level ionizing radiation against many other causes of death (cardiovascular?)  may be even stronger than against cancer!

The next slides illustrates the effect of rising natural radiation level with altitude above the sea level (due to cosmic ray effect).

High elevation = higher radiation = less cancer!

Similar map appears when plotting cancer incidence maps versus natural radiation map due to radon emission from the ground.

More Radon = more radiation = less cancer!

Conclusions (slides 45,46):

• Ionizing radiation is part of life.
• Sources of ionizing radiation are naturally everywhere, in food, air, water and our body.
• Life appeared and evolved in a radioactive environment.
• At environmental levels, there is no evidence of increased risk with increased dose, even when annual doses exceed current dose limits for radiation workers
• In fact, there are indications of decreased risk of cancer and non-malignant diseases at doses and dose rates well above current regulatory limits for the public and the workers.
• Populations in high background areas tend to have less cancers than those in low background areas.
• Low dose radiation is used in medicine: radon spas, cancer treatment and prevention.

This is supported by many other sources, studies and statistics, for example, see Figure 3 at  http://radiation-hormesis.com/

Optimum health = 100 times higher radiation than typ background!

------
Refs:

http://radiation-hormesis.com/

http://www.lowdose.uottawa.ca/projects.htm

http://www.lowdose.uottawa.ca/publications_files/Facts%20about%20low-dose%20radiation%20effects.ppt

http://stan-heretic.blogspot.ca/search?q=hormesis