01 April 2011

Altitude Sickness Vulnerability Overwhelmingly Genetic

Robert Roach, who directs the Altitude Research Center at the University of Colorado, performed a similar test last year, taking 28 research subjects to a simulated altitude of 16,000 feet by putting them in a special chamber that mimics the effect of a low-oxygen environment. A blood test, screening for those six genetic elements, was able to predict with 96% accuracy which of the 28 would fall ill.

From here.

The military wants to know so that it can predict which soldiers will be most impaired when deployed rapidly to a high altitude situation, so it is funding the research, replicating the study described above with 140 subjects, and if it is successful, having a mass production "Acute Mountain Sickness Prediction Kit" for the military in place by 2014.

Military models indicate at least 25% of unacclimatized troops parachuting into a battlefield at 10,000 feet—and more than 80% of troops fighting at 13,200 feet—will get altitude sickness. One military study of a prolonged operation in the high mountains of Afghanistan found 14% of troops evacuated for medical treatment didn't have combat injuries—they had altitude sickness. Uncounted others, not sick enough to merit rescue by helicopter, were huddled in base camps while their units went out fighting, said Dr. Muza, the Army research physiologist. In most cases, acute mountain sickness dissipates within three days as the body adjusts to the elevation, though in severe cases, it can linger or lead to fatal complications. . . .

Projections for proportion of unacclimatized troops who will get sick at high altitudes.

10,000 feet – 25-35%
11,500 feet – 50-60%
13,200 feet – 80-90%
14,800 feet – 90-100%

Source: Stephen Muza, U.S. Army Research Institute of Environmental Medicine. . . .

While the military is funding the new research, a predictive blood test could also be marketed to the public, Dr. Roach said. That could benefit Colorado's ski industry, which says up to 40% of its visitors come down with mountain sickness. The Institute for Altitude Medicine in Telluride, Colo., estimates the illness damps spending at mountain resorts by $200 million a year, as afflicted tourists don't much feel like shopping, skiing or dining out.

The fact that this trait is so overwhelmingly predicted by genetics is itself surprising.

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