Study of Active Duty Military Personnel for Environmental Deployment Exposures: Pre- and Post-Deployment Spirometry (STAMPEDE II)

BACKGROUND: There is significant concern about the respiratory health of deployed military service members given the reported airborne hazards in southwest Asia, which range from geologic dusts, burn pit emissions, chemical exposures, and increased rates of smoking. There has been no previous comparison of pre- and post-deployment lung function in these individuals. METHODS: Military personnel who deployed to southwest Asia in support of ongoing military operations were recruited from the Soldier Readiness Processing Center at Fort Hood, Texas, from 2011 to 2014. The participants were asked to complete a brief survey on their respiratory health and perform both spirometry and impulse oscillometry studies at baseline with repeated survey and testing after deployment. RESULTS: Of the 1,693 deployed personnel who completed baseline examinations, 843 (50%) completed post-deployment testing. Post-deployment values demonstrated no statistical or clinical change in spirometry, with an increase in mean +/- SD FEV1 (% predicted) from 95.2 +/- 12.6 to 96.1 +/- 12.4 (P = .14), increase in mean +/- SD FVC (% predicted) from 95.9 +/- 11.8 to 96.4 +/- 11.9 (P = .32), and increase in mean +/- SD FEV1/FVC from 81.5 +/- 5.9 to 81.8 +/- 6.1 (P = .29). Impulse oscillometry values showed statistical improvement with reduction in resistance (at 5 Hz and 20 Hz) and reactance (at 5 Hz). The presence of pre-deployment obstruction, self-reported asthma, smoking history, or increased body mass index also did not change spirometry values after deployment. DISCUSSION: To our knowledge, this was the first prospective evaluation of deploying military by using spirometry as an indicator for the possible development of pulmonary disease related to environmental exposures. Pre-deployment testing with spirometry and impulse oscillometry was unable to detect any significant change. In those with abnormal spirometry pre-deployment or asthma history, there was also not identifiable change that indicated worsening lung function. CONCLUSIONS: Utilization of spirometry for the deploying military population had little benefit and did not identify individuals with lung disease after deployment. Routine use was not warranted before or after deployment in the absence of pulmonary symptoms.