According to Gemini, radiation related cancer rates aren't higher in high elevation cities like Quito or La Paz... Shouldn't they be too? Airliners fly a lot higher but people live in these 24x7.
High altitude Equatorial populations and air crew exposures are different beasts. A 10h flight close to the North Pole is like living in Quito for almost a month. The type of dosage (bursts x contínuous) also matters as the body can probably accommodate more easily, but that's just me saying. Then add natural selection to that mix that should have helped prepare high-altitude populations residents for those living conditions, which will heavily skew the data. Finally, the cosmic shower has lost a lot of energy from 12,000m to say 2,500m, so the "hit" is not the same. It all may end up having an exponential effect reducing cancer rates...
So a flight attendant that clocks ~700h a year, that's roughly 5 years of living in Quito in a year of flying in Sieves. Now, given that the air crew studies are not all that conclusive yet, take high-altitude populations at 5x less exposure and all these other factors I've mentioned, and they will end up having an even lower chance of showing up in any cancer studies.
