Background radiation impacts human longevity and cancer mortality: Reconsidering the linear no-threshold paradigm

BACKGROUNDThe current linear-no-threshold paradigm assumes that any exposure to ionizing radiation carries some risk, thus every effort should be made to maintain the exposures as low as possible. Here, we examined whether background radiation impacts human longevity and cancer mortality.\n\nMETHODSOur data covered the entire US population of the 3139 US counties, encompassing over 320 million people. The data on background radiation levels, the average of 5-year age-adjusted cancer mortality rates, and life expectancy for both males and females in each county, was extracted using publicly available tools from official sources, and analyzed with JMP(R) software.\n\nRESULTSWe found for the first time that life expectancy, the most integrative index of population health, was approximately 2.5 years longer in people living in areas with a relatively high vs. low background radiation ([≥] 180 mrem/year and [≤] 100 mrem/year, respectively; p < 0.005; 95% confidence interval [CI]). This radiation-induced lifespan extension could to a great extent be associated with the decrease in cancer mortality rate observed for several common cancers (lung, pancreas and colon cancers for both genders, and brain and bladder cancers for males only; p < 0.05; 95% CI).\n\nCONCLUSIONSExposure to a high background radiation displays clear beneficial health effects in humans. These hormetic effects provide strong evidence for re-considering the linear no-threshold paradigm, at least within the natural range of low-dose radiation.