Acute mountain sickness in Iranian trekkers around Mount Damavand (5671 m) in Iran

Background.-Many trekkers up Mount Damavand run the risk of developing acute mountain sickness (AMS); however, not much is documented concerning the incidence of AMS and its related factors within this population. Objective.-We designed this study to determine the incidence and risk factors for AMS in trekkers around Mount Damavand in Iran. Methods.-Symptoms of AMS and the contributing factors were assessed in the course of 6 weeks in summer 2000. Standard Lake Louise questionnaires were administered to 459 subjects, all of whom were trekkers. The questionnaires were filled out in 3 steps, first at 2900 in and then during both ascent and descent at 4200 m. Results.-The overall incidence of AMS was 60.8%. The incidence was higher in residents who lived at an altitude less than 600 in, amateur trekkers, those with a previous history of AMS, those with a history of AMS at ascent to Damavand, and those with night ascents (6 Pm to midnight). Incidence was weakly dependent on rate of ascent (from 2900 m up to 4200 in in less than 4 hours) and sleep at 4200 in. No significant association was found between AMS and sex, age, body mass index, height, weight, smoking, weight of knapsacks, or the spent time in the shelter (at 4200 in). Conclusions.-We conclude that the incidence of AMS is high in Iranian trekkers ascending Mount Damavand. Some of the contributing factors are preventable, so we suggest considering an educational program for trekkers to high altitudes in Iran.