High Altitude Risks

A vacation spent in the mountains, if there’s intense physical exertion combined with the effects of cold temperature, can result in an increased risk of heart attack, especially in the first couple of days.  That’s perhaps not too surprising.  However, there’s a hidden risk involved in living at higher altitudes, as reported in the American Journal of Psychiatry – suicide.

University of Utah scientists first reported a possible relationship between high altitude and suicide in 2009, which they thought might be related to a high level of gun ownership.  The present study explored the association further, together with the role played by other possible risk factors for suicide – gun ownership, depression, and loneliness. 

Data from the national Geospatial-Intelligence Agency and NASA were used to calculate elevation for US counties in 4 mountainous western states – Utah, Colorado, Montana, and Nevada.  Age-adjusted suicide rates, population density, and gun-ownership data for the counties were obtained from the US CDC.   

Analyses showed a significant positive correlation between suicide rate and county elevation, with a correlation coefficient (r) of 0.51.  Both firearm and non-firearm suicide rates were also positively correlated with average county elevation (r=0.41 and r=0.32, respectively.  The scientists conclude that high altitude is a significant independent risk factor for suicide.  Gun ownership is less of a suicide risk factor at high altitude, although there are likely to be plenty of guns in the western mountain dwellings.  Population density, as a surrogate for loneliness, is a risk factor, but less significant.

How does altitude have this effect?  The researchers speculate that it may be due to physiological changes, such as metabolic stress or a mild reduction in oxygen concentrations.  But first it’s necessary to see if mental illness (especially depression) is more common at high altitudes; or if mood is dependent on a sustained level of environmental oxygen.  An interesting subject for study.