Vascular "leaking" has a big effect on developing pulmonary/cerebral and overall edema. Vascular tone may be the key to controlling leaking of fluids to the outside of blood vessels, but again the question arises - genetic or environmental and is there a pharmaceutical solution. Consider that the higher you go, the less atmospheric pressure is exerted on your entire body - this also explains hypoxia. At higher elevation and lower atmospheric pressure, the reduced pressure diminishes passive distribution of oxygen into your blood via your lungs. A common misconception is there is less oxygen in air at increasing altitude. Although the air is less dense, the percentage of oxygen (21%) does not change in the atmosphere.
A completely different factor is the ability of the body to digest and utilize energy at different altitudes.
Guru of high altitude medicine, Dr. Peter Hackett is the man! The only conclusion I've ever come up with is the only constant in physiology is change!