Deconstructing radiation hormesis

This paper explores some factors that may explain why the possibility of hormesis has not been embraced by the radiation protection community. If shown to be sustainable, hormesis might ameliorate several serious issues plaguing radiation protection including the high economic cost of environmental regulatory compliance and public fear of radiation exposure. Some but not all analyses of data from various sources, including the Japanese survivors of the atomic bombs and residential radon studies, suggest that low levels of ionizing radiation may be beneficial to human health. The evidence, however, has not been viewed as compelling for the following reasons: (1) Data in support of radiation hormesis in human populations is limited and much of it is based on re-evaluation of selected epidemiological data that has been used to test a different hypothesis; (2) Hormetic effects are weak and inconsistent, and are subject to large statistical uncertainties as is the case for carcinogenic effects at small doses; (3) A consensus is lacking on how hormesis should be defined and quantified; and (4) It is unclear how hormesis can be incorporated into the regulatory framework when beneficial health effects exceed the requirement for protection of health.