As lower pressure at higher elevations results in less inhaled oxygen, this new study suggests that oxygen in the atmosphere may play a role in lung cancer. While researchers found lower rates of lung cancer at higher elevations, the same trend did not extend to non-respiratory cancers, suggesting that carcinogen exposure occurs via inhalation.
"While essential to human life, aspects of oxygen metabolism may promote cancer," the study noted."Viewing our findings through the lens of the literature, atmospheric oxygen emerges as the most probable culprit," said Kamen Simeonov from Perelman School of Medicine, University of Pennsylvania.
Oxygen is highly reactive and even when it is carefully and quickly consumed by our cells, it results in reactive oxygen species (ROS) which can lead to cellular damage and mutation, the authors added. The researchers compared cancer incidence rates across counties of the elevation-varying Western US. They found that as county elevation increased, lung cancer incidence decreased.
The effect was dramatic with incidence decreasing by 7.23 cases per 100,000 individuals for every 3,281 feet rise in elevation, equating to approximately 13 percent of the mean lung cancer incidence of 56.8 cases per 100,000 individuals. The study was published in the journal PeerJ.