Living at a high altitude lowers risk of deadly stroke

A new study has found that living at a high altitude may reduce the risk of a fatal stroke. The research, which was focused on people living in Ecuador, is the first of its kind to investigate the risk of stroke at four different elevations.

The experts analyzed the incidence of stroke-related hospitalization and death based on data from over 17 years and more than 100,000 stroke patients. 

The study revealed that people who lived at higher altitudes had a lower risk of stroke and stroke-related death. This protective effect was found to be strongest at an altitude between 2,000 and 3,500 meters.

Some of the most common health factors that contribute to stroke risk include smoking, high blood pressure, and a sedentary lifestyle. Altitude is an often overlooked factor that can also influence stroke risk. 

People must adapt to living at higher altitudes, where there is less oxygen available, but exactly how this may affect stroke risk remains unclear. In the Ecuadorian Andes, the wide array of altitudes presented researchers with a unique opportunity to investigate.

“The main motivation of our work was to raise awareness of a problem that is very little explored,” explained study lead author Professor Esteban Ortiz-Prado of the Universidad de las Americas.

“That is, more than 160m people live above 2,500 meters and there is very little information regarding epidemiological differences in terms of stroke at altitude.” 

“We wanted to contribute to new knowledge in this population that is often considered to be the same as the population living at sea level, and from a physiological point of view we are very different.”

The results of the analysis showed that people who lived at altitudes above 2,500 meters tended to experience stroke at a later age compared with those at lower altitudes. People who lived at higher altitudes were also less likely to be hospitalized or die as a result of a stroke. 

According to the researchers, the protective effects did not apply to people living at altitudes of over 3,500 meters.

While more research is needed to determine what underlies the relationship between high altitude and low stroke risk, one explanation may be that people who live at high altitudes (and have adapted to the low oxygen conditions) can more readily grow new blood vessels to help overcome stroke-related damage. 

The study is published in open-access journal Frontiers in Physiology. 

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By Chrissy Sexton, Earth.com Staff Writer