The Relationship Between Baseline Exhaled Nitric Oxide Levels and Acute Mountain Sickness

Background: Acute mountain sickness (AMS) is a common disabling condition observed in people ascending to high altitudes. However, a simple predictive test for AMS is not known. The aim of this study was to assess the relationship between baseline exhaled nitric oxide (FENO) and AMS occurrence. Methods: Eighty healthy lowland Chinese adults were recruited for this study. FENO was measured at baseline, as well as 6 and 24 hours after arrival in Tibet. The standard Lake Louise Score (LLS) consensus symptoms questionnaire was used to assess the incidence and severity of AMS. Results: Individuals with a high LLS (>3) had higher FENO levels at baseline and after arrival in Tibet than people with a low LLS (<= 3) (baseline: 22.9 +/- 6 11.9 versus 16.7 +/- 6.4; 6 hours: 26.2 +/- 16.7 versus 17.9 +/- 5.7; 24 hours: 24.9 +/- 13.1 versus 16.3 +/- 1.7; all P < 0.01). Evaluation of risk factors revealed that female gender, diabetes and not smoking were associated with a high AMS score (all P < 0.05), but that hypertension showed no association (P > 0.05). Conclusions: This prospective observational study suggests that baseline FENO levels may be positively correlated with AMS in healthy Chinese lowlanders.