title: Risk determinants of acute mountain sickness in trekkers in the Nepali Himalaya: a 24-year follow-up.
abstract: 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.
authors.affiliation: Division of Emergency Medicine, University of Utah, Salt Lake City, UT. Electronic address: marion.mcdevitt@hsc.utah.edu.
authors.forename: Marion
authors.initials: M
authors.lastname: McDevitt
authors.affiliation: Division of Emergency Medicine, University of Utah, Salt Lake City, UT.
authors.forename: Scott E
authors.initials: SE
authors.lastname: McIntosh
authors.affiliation: Division of Health Sciences, University of Nevada, Reno, NV.
authors.forename: George
authors.initials: G
authors.lastname: Rodway
authors.affiliation: Department of Biomedical Informatics, School of Medicine, University of Utah, Salt Lake City, UT.
authors.forename: Jitsupa
authors.initials: J
authors.lastname: Peelay
authors.affiliation: School of Nursing, University of Utah, Salt Lake City, UT.
authors.forename: Doug L
authors.initials: DL
authors.lastname: Adams
authors.affiliation: Institute of Sports Sciences, and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Switzerland.
authors.forename: Bengt
authors.initials: B
authors.lastname: Kayser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000532:Altitude Sickness / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009051:Mountaineering / Q000706:statistics & numerical data*; D009390:Nepal / Q000453:epidemiology; D012307:Risk Factors; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Nepal; acute mountain sickness; altitude; prevalence; tourism; trekking