Remarks about the LNT-hormesis discrepancy and Cohen's theory on indoor radon

Adaptive and stimulating effects of ionizing radiation occur at near natural doses. The phenomenon is known in literature as 'hormesis' but this disagrees with the linear no-threshold hypothesis on the dose effect relationship. Radiation hormesis goes beyond the notion that radiation has no deleterious effects at small doses; it is considered that at small doses there exist new effects beneficial to the organism. The LNT theories assume that there is no threshold below which the harmful effects, in linear proportion to the dose, cease to appear. Several recent Cohen's papers have reported strong negative association between home indoor radon and lung cancer risk. Following the average radon concentration in homes for 1,601 U.S. counties, the discrepancy of these data with prediction of the linear no-threshold theory LNT found by Cohen is about 20 standard deviations. Most epidemiologists have considered this fact to be spurious because no case-control study on this subject has exhibited a similar strong negative association. There are different opinions among scientists that have been widely discussed about the testing of the linear no-threshold theory with ecological data pointing out some factors responsible for this discrepancy. In this paper a critical analysis and presentation of different views on the validity of the ecological epidemiology and 'the hormesis' reported by Cohen is made. Also we will present new data and results of some recent case-control studies. (author)