Thursday, February 11, 2016

Rummaging Through the Stacks

Where the radiation level is greater, cancer risk is invariably less. [Nambi and Soman. Further observations on environmental radiation and cancer in India, Health Physics, submitted in 1990, unpublished.]

Presenting the evidence of radiation hormesis has been the most daunting problem faced in writing this book; there is just too much of it. Luckey had more than 2,000 citations in his two books, and he estimates that this was about half of the data available in 1990. [Hormesis with Ionizing Radiation, CRC Press, Boca Raton, 1980; and Radiation Hormesis, CRC Press, Boca Raton, 1991.]

In the fifteen years since then, other researchers have become involved, and their research compounds the problem of "too much" evidence. Until of late there had been only a very few experiments designed to address the radiation hormesis hypothesis, and most of these involved non-vertebrates. [Even more rare are subambient (i.e., less than normal background) radiation experiments, which should show a degradation of biologic function when the target microbes are shielded from cosmic and other background sources. Two such experiments are described in Radiation Hormesis, pp. 211-23.]

The data available - which are the backbone of the argument I'm putting forth [While I have absolutely no reason to distrust the recent test reports that attest to the hormesis phenomenon, there is something very satisfying about examining data taken without any conceivable bias toward "the reverse effect." If there were any bias it was to ignore that which didn't fit the curve.] - are generally one of the following types:

  • Animal tests designed to find adverse effects of high levels of ionizing radiation but which happened to take measurements in the low-dose area in the course of the experiment; [According to Luckey, much of the low-dose data - which showed negative correlation of the dose-response relationship - was either ignored, omitted or simply deemed too unimportant to report.]
  • Japanese bombing survivors who were within a known distance of A-bomb detonations and whose exposures could be calculated; [There is considerable controversy about exposures, particularly in Hiroshima, with many researchers believing the data analysis understates the radiation dosage. One problem is related to some data still not being available to investigators - even after more than fifty years!]
  • Statistical evidence on workers in nuclear power plants and weapons manufacturing facilities; and
  • Populations that live in various areas with background radiation up to eighty times the U.S. average.

It would be wonderful if there were carefully controlled experimental data on humans for all diseases over the complete radiation dosage range. To optimize the hormesis effect, it would be marvelous to have double-blind studies over long periods of time, with carefully controlled exposures and rates. But we don't have these things.