Scientists now believe oxygen can trigger the deadly disease and they have fresh research to back it up.
The new data suggests the way our bodies process oxygen could be carcinogenic – or likely to cause cancer.
Researchers discovered the correlation between the caner and the gas by tracking the disease in people who live at various altitudes.
They found that those who live in regions further above sea level are less likely to have lung cancer.
Kamen Simeonov, from the University of Pennsylvania, and Daniel Himmelstein, of the University of California, compared the rates across 250 western counties in the US.
Their research states that cases of lung cancer fell by 7.23 cases per 100,000 people for every 1,000 metre rise above sea level.
It also claimed that if the entire population of the US live in San Juan County – some 3,470 metres above sea level – then there would be 65,496 fewer cases every year.
The scientific duo also stated their research factored in sunlight and pollution to their calculations.
Adding: "Viewing our findings through the lens of the literature, atmospheric oxygen emerges as the most probable culprit.
"Overall, our findings suggest the presence of an inhaled carcinogen inherently and inversely tied to elevation."
source Daily star.uk
