A Prospective Investigation of Newly Reported Respiratory Illness among Military Personnel Deployed to Iraq and Afghanistan

Background: Deployments to Iraq and Afghanistan may expose troops to environmental conditions adversely affecting respiratory health. An increased prevalence of postdeployment respiratory illnesses were reported among 1991 Gulf War veterans. New-onset respiratory illness following deployments to the current conflicts remains unclear.

Methods: Participants are from the 21-year longitudinal Millennium Cohort Study. We examined self-reported new-onset respiratory outcomes in the following categories: (1) respiratory symptoms (persistent or recurring cough or shortness of breath), (2) chronic bronchitis or emphysema, (3) asthma, (4) asthma with respiratory symptoms, and (5) any of the aforementioned respiratory illnesses. Logistic regression was used to evaluate the association of respiratory illness with cumulative deployment length compared to nondeployed participants, after adjusting for confounders.

Results: After exclusions, 47,875 participants were available for analyses, 24% of whom deployed leaving a robust comparison population of nondeployed personnel. The proportion of new-onset respiratory outcomes in deployed versus nondeployed individuals were as follows: any respiratory illness (14 vs. 10%), respiratory symptoms (14 vs. 10%), emphysema or chronic bronchitis (1.2 vs. 1.2%), asthma (1.0 vs. 1.2%). and asthma with respiratory symptoms, (3.1 vs. 5.3%). Participants with more cumulative days deployed were at elevated risk for new-onset respiratory symptoms and new-onset of any respiratory illness when compared to non-deployed personnel and those who deployed for less time.

Conclusions: Greater cumulative deployment length was positively associated with newly reported respiratory symptoms and illness. Because certain outcomes may have longer latency, longitudinal investigation for new-onset respiratory symptoms will further elucidate respiratory illnesses potentially associated with military service.