Respiratory symptoms, lung function, and fraction of exhaled nitric oxide before and after assignment in a desert environment : a cohort study

BACKGROUND: Inhalation of small particulate matter (PM 2.5) may be associated with development of respiratory disease. Increased respiratory symptoms have been reported among military staff after service in countries with recurrent desert storms. OBJECTIVE: The aim was to investigate whether an assignment in a desert environment and exposure to desert storms are associated with negative effects on respiratory health. METHODS: In two cohorts of Swedish soldiers serving in Mali as part of the United Nations stabilization forces, examination with spirometry, determination of fraction of exhaled nitric oxide (FeNO), and a questionnaire including participant characteristics, symptoms, and exposure was performed before and after service. Ambient air sampling was conducted on-site. Paired t-test was used to compare pre- and post-variables on lung function data, FeNO and symptom level. RESULTS: Most indoor and outdoor air measurements of dust and silica were within the Swedish occupational exposure limit for PM2.5 and silica (<0.10-2.7 mg/m3 and <0.002-0.40 mg/m3, respectively) as well as for respirable dust and silica (0.056-0.078 mg/m3and 0.0033-0.025 mg/m3, respectively). In the subgroup of participants with reported exposure to desert storms during the stay in Mali, forced expiratory volume in 1 s (FEV1) was significantly lower after exposure than before the mission (mean litres (SD) 4.21 ± 0.66 vs 4.33 ± 0.72, p = 0.021). CONCLUSION: Exposure to a desert storm was associated with a decrease in FEV1. Exposure to small particulate matter may contribute to the development of respiratory disease and thus spirometry should be performed after occupational exposure to desert storms