Send to

Choose Destination
Wilderness Environ Med. 2014 Jun;25(2):152-9. doi: 10.1016/j.wem.2013.12.027.

Risk determinants of acute mountain sickness in trekkers in the Nepali Himalaya: a 24-year follow-up.

Author information

Division of Emergency Medicine, University of Utah, Salt Lake City, UT. Electronic address:
Division of Emergency Medicine, University of Utah, Salt Lake City, UT.
Division of Health Sciences, University of Nevada, Reno, NV.
Department of Biomedical Informatics, School of Medicine, University of Utah, Salt Lake City, UT.
School of Nursing, University of Utah, Salt Lake City, UT.
Institute of Sports Sciences, and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland.



Exposure to altitude may lead to acute mountain sickness (AMS) in nonacclimatized individuals. We surveyed AMS prevalence and potential risk factors in trekkers crossing a 5400-m pass in Nepal and compared the results with those of 2 similar studies conducted 12 and 24 years earlier.


In April 2010, 500 surveys were distributed to English-speaking trekkers at 3500 m on their way to 5400 m, of which 332 (66%) surveys were returned complete. Acute mountain sickness was quantified with the Lake Louise Scoring System (LLSS, cutoff ≥3 and ≥5) and the Environmental Statistical Questionnaire III AMS-C score (ESQ-III, cutoff ≥0.7). We surveyed demographics, body mass index (BMI), smoking habit, rate of ascent, awareness of AMS, and acetazolamide use.


Prevalence of AMS was 22%, 23%, and 48% (ESQ-III ≥0.7, LLSS ≥5, and LLSS ≥3, respectively) lower when compared with earlier studies. Risk factors for AMS were younger age, female sex, higher BMI, and smoking habit. Forty-two percent had elementary knowledge about the risk and prevention of AMS. Forty-four percent used acetazolamide. Trekkers took longer to climb from 3500 to 5400 m than in earlier studies.


Prevalence of AMS continued to decline over a period of 24 years, likely as a result of slower ascent and increased use of acetazolamide. The AMS risk factors of younger age, female sex, and high BMI are consistent with prior studies. Awareness of risk and prevention of AMS remains low, indicating an opportunity to better educate trekkers and potentially further reduce AMS prevalence.


Nepal; acute mountain sickness; altitude; prevalence; tourism; trekking

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center