Acute Mountain Sickness Impact Among Travelers to Cusco, Peru


  • Part of the data in this manuscript was presented at the 12th Conference of the International Society of Travel Medicine.

Corresponding Author: Miguel M. Cabada, MD, Calle Rubens 199, Lima-41, Peru. E-mail:



Increasing numbers of travelers are visiting high altitude locations in the Andes. The epidemiology of acute mountain sickness (AMS) among tourists to high altitude in South America is not well understood.


A cross-sectional study to evaluate the epidemiology, pre-travel preparation, and impact of AMS among travelers to Cusco, Peru (3,400 m) was performed at Cusco's International Airport during June 2010. Foreign travelers, 18 years or older, staying 15 days or less, departing Cusco were invited to participate. Demographic, itinerary, and behavioral data were collected. The Lake Louise Clinical score (LLCS) was used to assess AMS symptoms.


In total, 991 travelers participated, median age 32 years (interquartile range 25–49), 55.5% female, 86.7% tourists, mostly from the United States (48.2%) and England (8.1%). Most (76.7%) flew from sea level to Cusco and 30.5% visited high altitude in the previous 2 months. Only 29.1% received AMS advice from a physician, 19% recalled advice on acetazolamide. Coca leaf products (62.8%) were used more often than acetazolamide (16.6%) for prevention. AMS was reported by 48.5% and 17.1% had severe AMS. One in five travelers with AMS altered their travel plans. Travelers older than 60 years, with recent high altitude exposure, who visited lower cities in their itinerary, or used acetazolamide were less likely to have AMS. Using coca leaf products was associated with increased AMS frequency.


AMS was common and adversely impacted plans of one in five travelers. Acetazolamide was associated with decreased AMS but was prescribed infrequently. Other preventive measures were not associated with a decrease in AMS in this population. Pre-travel preparation was suboptimal.