Intermittent work at high altitude: a new epidemiological situation

A review of the epidemiological features of a new labour condition, namely, working intermittently at high altitude, is presented. A retrospective study was designed to compare mine employees living and working at 4,600 m and undergoing chronically intermittent exposure to high altitude with a similar group of workers at sea level, during 2 years. Overall 91,500 medical consultations were analysed and classified according to ICD-10. Results showed six annual consultations per individual and an excess of consultations of 3.3 for the high altitude group. Most of the morbidity groups had an excess of consultations and higher incidence (p < 0.001) at high altitude. Upper respiratory tract problems accounted for the main burden (54%), being predominantly acute and inflammatory diseases. Also, acute mountain sickness remained steady over time, and the consultation excess was significant for high blood pressure. This study sets an epidemiological baseline for further research as well as for decision making on the health and economic issues related to mining at high altitude.