New-Onset Asthma and Combat Deployment: Findings From the Millennium Cohort Study

Abstract

Recent reports suggest US military service members who deployed in support of the recent conflicts in Iraq and Afghanistan have higher rates of new-onset asthma than those who did not deploy. However, it is unknown whether combat experiences, in addition to deployment, contribute to new-onset asthma risk. This study aimed to longitudinally determine the risk factors for developing asthma, including combat deployment (categorized as deployed with combat experience, deployed without combat experience, or nondeployed), among participants in the Millennium Cohort Study from 2001 to 2013. A total of 75,770 participants completed a baseline survey and at least 1 triennial follow-up survey on deployment experiences, lifestyle characteristics, and health outcomes. Complementary log-log models stratified by sex were used to estimate the relative risk of developing asthma among participants who reported no history of asthma at baseline. In models with adjustments, those who deployed with combat experience were 24%–30% more likely to develop asthma than those who did not deploy. Deployed personnel without combat experience were not at a higher risk for new-onset asthma compared with nondeployers. Further research is needed to identify specific features of combat that are associated with greater asthma risk to inform prevention strategies.

Respiratory Health after Military Service in Southwest Asia and Afghanistan. An Official American Thoracic Society Workshop Report

“…Case series describing the evaluation of symptomatic military personnel do not note any single etiology, emphasizing the importance of a comprehensive clinical assessment, but asthma has been a common finding (References 8 and 75 and S. D. Krefft, workshop presentation of unpublished data). This is consistent with epidemiologic findings from the Millennium Cohort Study that demonstrate an increased risk of new-onset asthma (by self-report) related to combat exposure during deployment ( 9 ) and the observational findings in which approximately half of the deployed persons discharged with asthma after deployment did not have a previous known diagnosis ( 10 ). Nonetheless, a number of questions remain regarding the drivers of increased healthcare use for respiratory conditions and potential under- and overdiagnosis of specific conditions.…”

“…There was also no statistical association in this analysis with self-reported incident asthma, chronic bronchitis, or emphysema. Subsequent and longer follow-up of a larger number of Millennium Cohort Study participants followed through 2013 ( n = 77,770) revealed an increased risk of respondent-reported new onset of health professional–diagnosed asthma for those with deployment-related combat experience compared with those who did not deploy ( 9 ). The RR of new-onset asthma was similar for men (RR, 1.30; 95% CI, 1.14–1.47) and women (RR, 1.24; 95% CI, 1.05–1.46) after adjustment for multiple covariates that included smoking, body mass index (BMI), rank, branch, and post-traumatic stress disorder status.…”

Faculty Opinions recommendation of Respiratory Health after Military Service in Southwest Asia and Afghanistan. An Official American Thoracic Society Workshop Report.

“…Case series describing the evaluation of symptomatic military personnel do not note any single etiology, emphasizing the importance of a comprehensive clinical assessment, but asthma has been a common finding (References 8 and 75 and S. D. Krefft, workshop presentation of unpublished data). This is consistent with epidemiologic findings from the Millennium Cohort Study that demonstrate an increased risk of newonset asthma (by self-report) related to combat exposure during deployment (9) and the observational findings in which approximately half of the deployed persons discharged with asthma after deployment did not have a previous known diagnosis (10). Nonetheless, a number of questions remain regarding the drivers of increased healthcare use for respiratory conditions and potential under-and overdiagnosis of specific conditions.…”

“…There was also no statistical association in this analysis with selfreported incident asthma, chronic bronchitis, or emphysema. Subsequent and longer follow-up of a larger number of Millennium Cohort Study participants followed through 2013 (n = 77,770) revealed an increased risk of respondent-reported new onset of health professional-diagnosed asthma for those with deployment-related combat experience compared with those who did not deploy (9). The RR of newonset asthma was similar for men (RR, 1.30; 95% CI, 1.14-1.47) and women (RR, 1.24; 95% CI, 1.05-1.46) after adjustment for multiple covariates that included smoking, body mass index (BMI), rank, branch, and post-traumatic stress disorder status.…”

“…We also considered reports based on Veterans Health Administration (VHA) encounters for health care, suggesting that former deployers may be more frequently diagnosed with obstructive lung disease, particularly asthma (7). In addition, we reviewed case series describing the clinical assessment of postdeployment dyspnea, and we considered Millennium Cohort Study data relevant to postdeployment asthma as well as other abnormalities (8)(9)(10). Of particular note, constrictive bronchiolitis and other small airway abnormalities have been reported in lung biopsies from case referral series (11).…”