Can inhaled oxygen cause cancer? Lung cancer rates fall dramatically with increasing elevation in the Western U.S

The ancient physician/alchemist, Paracelsus, said: "The dose makes the poison.” According to a new study published in PeerJ, even oxygen may fall prey to the above adage. While essential to human life, aspects of oxygen metabolism may promote cancer. Capitalizing on the inverse relationship of oxygen concentration with elevation, researchers found lower rates of lung cancer at higher elevations, a trend that did not extend to non-respiratory cancers, suggesting that carcinogen exposure occurs via inhalation.