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

Marion McDevitt, Scott E. McIntosh, George W Rodway, Jitsupa Peelay, Doug L. Adams, Bengt Kayser

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Objective 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. Methods 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. Results 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. Conclusions 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.

Original languageEnglish (US)
Pages (from-to)152-159
Number of pages8
JournalWilderness and Environmental Medicine
Issue number2
StatePublished - 2014
Externally publishedYes


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

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Emergency Medicine
  • Medicine(all)


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