Cancer mortality in six lowest versus six highest elevation jurisdictions in the u.s.
Sherman College of Chiropractic, Spartanburg, SC.
Low levels of background radiation exist around us continuously. These levels increase with increasing land elevation, allowing a comparison of low elevations to high elevations in regard to an outcome such as cancer death rates. The present study compares archived cancer mortality rates in six low versus six high elevation jurisdictions. The study also compares mortality rates for all causes, heart disease, and diabetes in low versus high elevation jurisdictions in an effort to see if other mortality outcomes are different in low versus high elevations. Statistically significant decreases in mortality, with very large effect sizes, were observed in high land elevation for three of the four outcomes, including cancer. One possible explanation for the decreased mortality in high elevation jurisdictions is radiation hormesis. Another possible explanation, at least in the case of heart disease mortality, is the physiologic responses that accompany higher elevations regarding decreased oxygen levels. Since this is an ecological study, no causal inferences can be made, particularly when viewpoints on possible effects of low level radiation are diametrically opposed. Further research is indicated.