Smoking increases the risk of acute mountain sickness

We aimed to ascertain risk factors for acute mountain sickness (AMS) in miners exposed to chronic intermittent high altitude conditions.

All new hires (2009-2012) for mine employment (4000 m above sea level) were followed up for 12 months after first ascent. Demographics, physiologic data, and cigarette smoking were assessed at preemployment screening. Mine site clinic care for AMS defined incident events. Cox regression analysis estimated risk of AMS associated with smoking and selected covariates.

There were 46 AMS cases among 569 individuals during the first 12 months of employment. Adjusted for age, sex, and altitude of permanent residence, cigarettes smoked per day before hiring were prospectively associated with AMS (hazard ratio [HR], 1.9; 95% CI, 1.1 to 3.2 per 10 cigarettes smoked). This risk was higher in the subset of workers with less demanding physical work (n=336; HR, 3.3; 95% CI, 1.7 to 6.3), whereas among those with more physically demanding jobs (n=233), smoking was not associated with increased risk (HR, 0.6; 95% CI, 0.1 to 2.3).

In workers newly hired to work at high altitude, smoking increases the likelihood of AMS, but this effect appears to be operative only among those with less physically demanding work duties.