RE: Hormetic Effects of Radiation should not be limited to cancer

[john cameron <jrcamero@wiscmail.wisc.edu>]

  Eric Goldin wrote: ,

	 "In the discussion of hormetic effects, some folks say that 

'a low level of radiological stress may stimulate the immune system.' 

Is there any

laboratory evidence to support such a claim?  In other words, any measure

of changes to hormones, immunoglobulin levels, lymphocyte counts, tumor

suppressor increases,... anything that would contribute to a beneficial

effect (that exceeds the downside)?"

	We must continue to admit our ignorance of health effects of 

ionizing radiation. Lack of identifying a specific agent to explain 

improved health from low dose rate radiation does not mean that it 

doesn't exist. Biology is not as simple as physics and chemistry. 

While there is much we don't know in the hard sciences, our ignorance 

in biology is comparable to the knowledge of the hard sciences in the 

middle ages.

	You must keep in mind that the unscientific LNT assumption 

has greatly hampered the search for beneficial effects of ionizing 

radiation. The adoption of the linear assumption has been as harmful 

to progress in this field as the assumption 400 years ago that the 

earth was the center of the universe was to understanding the solar 

system. At that time it was the dogma of the Catholic Church which 

slowed scientific progress. Now it is the LNT dogma of the ICRP.

	It seems particularly inappropriate  that the ICRP, a private 

organization that selects its own members, to do so much harm to 

understand health effects of low dose rate radiation. For example, 

DOE's low dose research funds are limited to look for radiation risk, 

not radiation health effects. Most radiation biology research has 

been to look for cancer rather than to look for beneficial effects.

	There is much evidence that low doses of radiation are 

beneficial but not proof or the description of  proven mechanism. I 

would not refer to low dose rates as a "radiological stress". 

Radiation levels up to about 0.2 Gy/y exist in nature and all life 

evolved in its presence. For the same reason I would not refer to the 

essential trace elements, which are all poisonous as producing 

stress.  Nobody refers to "hormetic effects" of  trace elements. 

Their value is never questioned. In most cases each of the essential 

trace elements is related to a specific biological function, such as 

iron is needed for our blood. Without it we become anemic. However, 

vitamins are also hormetic. Many of the vitamins have health benefits 

that are less easy to explain by a simple mechanism. I read an 

abstract recently that predicted that in the U.S. about 47,000 lives 

are shortened each year because of lack of Vitamin D from sunlight.

	If  the data from the nuclear shipyard worker study (NSWS) 

and the 100-year study of British radiologists are to be believed we 

can predict that many millions of U.S. lives are shortened by lack of 

ionizing radiation. The 28,000 nuclear shipyard workers with the 

highest doses are living nearly three years longer than their 

age-matched and job-matched controls. That is 16 std dev better than 

the 32,500 controls! Nobody is even looking for the scientific 

explanation for the increased longevity.

	The 100-year study of British radiologists shows that  during 

the 100 years they never had any life shortening compared to other 

MDs  in the UK. The UK radiologists who entered the field between 

1955-1979 have a death rate from non-cancer 36% lower than other MDs. 

(p<0.001).  These data are very convincing that there is a beneficial 

effect. These benefits have been ignored because of the general 

belief in LNT, even by many radiation scientists who are aware of the 

facts, i.e., members of NCRP. See NCRP Report No. 136 on LNT which 

ignores the NSWS data (p. 129).

	None are so blind as those who will not look at the facts. We 

need a double blind study, such as I proposed in: Cameron, J.R. Is 

radiation an essential trace energy? Physics and Society 

http://www.aps.org/units/fps/newsletters/2001/october/a5oct01.html

	The LNT assumption was "dead in the water" at the time it was 

adopted in 1977. Evans, R.D. (1974) Radium in man Health Physics 27, 

497-510 showed that the radium dial painters had a threshold of 1,000 

rad (200 Sv) to the skeleton for the induction of bone cancer. Above 

2,000 rads the incidence of bone cancer was far from linear. That is, 

LNT was contradicted by both having a high threshold and not being 

linear. In 1973 Frigerio, N.A., Eckerman, K.F. and Stowe, R.S. (1973) 

Carcinogenic Hazard from Low-Level, Low-Rate Radiation, Part I, Rep. 

ANL/ES-26. Argonne Nat. Lab showed that the six states with the 

highest background had a cancer death rate 15% lower than the average 

for all states.  That report was never published!

	I do not like the term "hormesis"-"beneficial" is much more 

understandable.  We don't refer to aspirin as being hormetic. It is 

not yet understood why it helps in so many different situations. Low 

dose rate radiation deserves equal consideration.  If it were not for 

the invention of nuclear weapons I doubt if we would have the present 

distortion of health effects of low dose rate radiation.

	Eric also wrote: "The flip side of the argument, that low 

levels of radiological stress have a deleterious effect, does have 

support in molecular radiation biology and tissue culture studies 

down to pretty low levels."  That is not evidence of deaths of 

animals or humans that have defence mechanisms.

	I know of no solid data to show a death caused by a radiation 

dose less than about 500 mGy acute and much higher if it is chronic. 

The British radiologists after 1920 never had a statistically 

significant excess of cancer compared to other MDs. Where is the 

evidence that low dose rates cause cancer. Cancer is so variable that 

it is impossible to find deleterious effects from low doses. The 

evidence for increased longevity from low dose rate radiation is 

statistically robust.  I think the most beneficial effect of low dose 

rate radiation is the reduction in deaths from non-cancer (i.e., the 

NSWS and the 100 year study of British radiologists).

	I hope some of the above gives you a better understanding of 

our present distorted attitude about radiation risk  and benefits at 

low dose rates. 

Best wishes,

John Cameron







-- 

John R. Cameron (jrcamero@wisc.edu)

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