Fewer Deaths from Heart Disease at High Altitudes

University of Colorado and Harvard scientists have examined mortality rates of people living at higher altitudes in the USA, and reported their findings online in the Journal of Epidemiology and Community Health.

Data were obtained from analyses of death certificates from every county in the USA. Socio-economic factors, the amount of annual solar radiation, and the cumulative exposure to smoking were used to make necessary adjustments before estimating mortality rates for ischemic heart disease, stroke, chronic obstructive pulmonary disease (COPD) and cancers.

Counties situated above 1500 m (XY C feet) had people with longer life expectancy is and those within 100 m (XY C feet) of sea level; the differences were 1.2 to 3.6 years for men and 0.5 to 2.5 years for women.  . The top 20 counties with the highest life expectancy, including 11 for men and 5 for women, were located in Colorado and Utah at a mean elevation of almost 6000 feet above sea level. It's notable that Colorado is the fittest state and has the fewest deaths from heart disease amongst the US states.

High altitude living had a beneficial association with heart disease mortality and a harmful or negative association with COPD; these associations showed a "dose-response relationship", i.e. the greater the altitude the stronger the association. The beneficial effect of higher altitude on ischemic heart disease and the harmful effect on COPD tended to cancel each other out, so that there was no net effect on life expectancy in a statistical sense; however, the beneficial effect on ischemic heart disease was more pronounced.  There were no apparent relevant associations for stroke and cancers with altitude

It’s thought that the apparent effect of high altitude on ischemic heart disease is related to a lower oxygen environment, which has been postulated to turn on certain genes that may change the way heart muscle functions; these genes may also stimulate new blood vessel growth within heart muscle. An alternative explanation could be that increased solar radiation improves synthesis of vitamin D in the body. From a practical viewpoint, it’s possible these findings may suggest new treatments for improving heart health, although it will be necessary to avoid risking impaired respiratory health i.e. COPD.