Abstract
Aim. Risk factors for occupationally-related acute mountain sickness (AMS) remain unclear and could impact workplace prevention efforts. We wished to examine smoking-related risk factors for AMS as these could present a target for intervention.
Methods. We studied workers at a gold mine operating at 4000 meters above sea level. All newly hired workers during a four-year period (2009-2012) were tracked for any AMS event (predominantly mild to moderate symptoms) leading to an acute care assessment on site during the first 12 months of work. At pre-employment examinations at 700 meters, we ascertained smoking intensity and measured forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC), defining COPD as a ratio <0.70. We used Cox regression analysis to estimate the hazard ratio (HR) for AMS associated with COPD and cigarettes per day (CPD) currently smoked.
Results. In the first year of employment, 46 episodes of AMS occurred in the cohort (N=569, aged 34.1 ± 7.6 years), an 8% annual incidence. Of those studied, 34 (6%) had COPD and 253 (44%) were current smokers (8.1 ± 4.2 CPD among smokers). Adjusting for age, sex, and place of residence, both COPD (HR 2.47; 95%CI 1.01-6.04) and CPD (HR 1.83 per 10 cigarettes; 95%CI 1.07-3.13) were associated with AMS.
Conclusions. Airflow obstruction, which likely partly reflects chronic cigarette smoking, and current smoking intensity are each associated with increased risk of occupationally-related AMS.
Clinical Relevance: Smoking status should be considered in assessing AMS risk for persons in whom a high altitude challenge is anticipated.
- © 2014 ERS