Lung function abnormalities among service members returning from Iraq or Afghanistan with respiratory complaints

Longitudinal changes in lung function following post-9/11 military deployment in symptomatic veterans

RATIONALE

Exposure to burn pit smoke, desert and combat dust, and diesel exhaust during military deployment to Southwest Asia and Afghanistan (SWA) can cause deployment-related respiratory diseases (DRRDs) and may confer risk for worsening lung function after return.

METHODS

Study subjects were SWA-deployed veterans who underwent occupational lung disease evaluation (n = 219). We assessed differences in lung function by deployment exposures and DRRD diagnoses. We used linear mixed models to assess changes in lung function over time.

RESULTS

Most symptomatic veterans reported high intensity deployment exposure to diesel exhaust and burn pit particulates but had normal post-deployment spirometry. The most common DRRDs were deployment-related distal lung disease involving small airways (DDLD, 41%), deployment-related asthma (DRA, 13%), or both DRA/DDLD (24%). Those with both DDLD/DRA had the lowest estimated mean spirometry measurements five years following first deployment. Among those with DDLD alone, spirometry measurements declined annually, adjusting for age, sex, height, weight, family history of lung disease, and smoking. In this group, the forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) ratio declined 0.2% per year. Those with more intense inhalational exposure had more abnormal lung function. We found significantly lower estimated FVC and total lung capacity five years following deployment among active duty participants (n = 173) compared to those in the reserves (n = 26).

CONCLUSIONS

More intense inhalational exposures were linked with lower post-deployment lung function. Those with distal lung disease (DDLD) experienced significant longitudinal decline in FEV1/FVC ratio, but other DRRD diagnosis groups did not.

Impact of poor air quality while deployed on respiratory health: a systematic review

INTRODUCTION

British military personnel deploy internationally to areas with high levels of ambient air pollution. Air pollution can cause acute respiratory symptoms which lead to concern about potential long-lasting health effects. There is a requirement for evidence-based policy on chronic respiratory disease associated with military deployments to areas with poor air quality (AQ). This literature review examines the published evidence relating to the development of chronic respiratory disease in military personnel after exposure to poor AQ while deployed.

METHODS

A literature search was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Embase, MEDLINE and Global health databases were searched for English language studies published since 2014 examining the respiratory health of military personnel deployed to Southwest Asia since 2001. A quality appraisal of selected articles was conducted using the Critical Appraisals Skills Programme checklist and a descriptive review completed.

RESULTS

Eleven studies were found, eight of which had objective outcome measures. Two prospective cohort studies were included; the remainder of the data were retrospective.

CONCLUSION

High rates of respiratory symptoms are reported by personnel who deploy to areas of poor AQ, giving rise to high levels of concern. Spirometry testing has found mild deficits, mostly of an obstructive nature, in a third of those with ongoing symptoms post deployment. These have not been consistently linked with deployment length. An increased risk of asthma appears to be multi-factorial in aetiology and there is no evidence for an increased risk of chronic obstructive pulmonary disease or histological pathology post deployment. At present, there is no definitive evidence of chronic respiratory disease due to exposure to poor AQ while deployed. Further objective longitudinal studies are required to continue to investigate the association, diagnosis and management of those with ongoing symptoms.

Posttraumatic Stress Disorder Is Associated With a Decrease in Anaerobic Threshold, Oxygen Pulse, and Maximal Oxygen Uptake

BACKGROUND

Posttraumatic stress disorder (PTSD) has been linked to respiratory symptoms and functional limitations, but the mechanisms leading to this association are poorly defined.

RESEARCH QUESTION

What is the relationship between PTSD, lung function, and the cardiopulmonary response to exercise in combat veterans presenting with chronic respiratory symptoms?

STUDY DESIGN AND METHODS

This study prospectively enrolled military service members with respiratory symptoms following deployment to southwest Asia. All participants underwent a comprehensive evaluation that included pulmonary function testing and cardiopulmonary exercise testing. Pulmonary function test variables and cardiopulmonary response to exercise were compared in subjects with and without PTSD by using multivariable linear regression to adjust for confounders.

RESULTS

A total of 303 participants were included (PTSD, n = 70; non-PTSD, n = 233). Those with PTSD had a greater frequency of current respiratory symptoms. There were no differences in measures for airway disease or lung volumes, but patients with PTSD had a reduction in diffusing capacity that was eliminated following adjustment for differences in hemoglobin levels. Participants with PTSD had a lower anaerobic threshold (23.9 vs 26.4 cc/kg per minute; P = .004), peak oxygen pulse (19.7 vs 18.5 cc/beat; P = .03), and peak oxygen uptake (34.5 vs 38.8 cc/kg per minute; P < .001). No significant difference was observed in gas exchange, respiratory reserve, or effort at peak exercise between participants with and without PTSD.

INTERPRETATION

A diagnosis of PTSD was associated with a reduced anaerobic threshold, oxygen pulse, and peak oxygen uptake. This objective reduction in cardiopulmonary work is independent of baseline lung function, was not associated with abnormalities in gas exchange or respiratory reserve, and may be related to deconditioning.

Exercise-Induced Bronchoconstriction in Iraq and Afghanistan Veterans With Deployment-Related Exposures

INTRODUCTION

Acute exposure to high-levels of ambient fine particulate matter while exercising results in airway narrowing, but the long-term effects of repeated exposure on exercise-induced bronchoconstriction (EIB) are not well known. The goal of this preliminary study is to determine the rate of EIB among a sample of non-treatment seeking veterans deployed to Iraq and Afghanistan.

MATERIALS AND METHODS

Twenty-four veterans (median [interquartile range]: 35.0 [27.3, 45] years) without history of asthma volunteered for this study. Spirometry was assessed before and after a standardized exercise challenge. A positive EIB response was defined as an exercise-induced fall in forced expiatory volume in 1 second ≥10%. Secondary criteria (peak flow ≥10% or mid-expiratory flow ≥15%) were also considered as an estimate of probable EIB.

RESULTS

A positive EIB response was observed in 16.7% and probable EIB response was observed in 41.7% of our sample. Median deployment length to Iraq or Afghanistan was 13.0 [10.3, 17.5] months and the median time since deployment was 4.2 [2.7, 7.7] years. At the time of testing, veterans reported persistent cough (58.3%), wheeze (37.5%), and shortness of breath (37.5%). During deployment, veterans reported exposure to dust and sand (70.8%), smoke from burn pits (66.7%), vehicle exhaust (83.3%), and regional air pollution (26.0%) on most days or daily.

CONCLUSIONS

Approximately 17% of our sample of non-treatment seeking deployed Iraq and Afghanistan veterans demonstrated EIB, similar to the general population prevalence. However, persistent respiratory symptoms and alternative indices of probable EIB supports continued monitoring of this population.

Respiratory illness among Gulf War and Gulf War era veterans who use the Department of Veterans Affairs for healthcare

BACKGROUND

Veterans of the 1990-1991 Gulf War were exposed to a variety of toxic substances during their service that included several airborne hazards, but only a few small studies have assessed respiratory outcomes in Gulf War veterans. This paper presents population prevalence estimates and prevalence ratios of respiratory disease among Gulf War and Gulf War Era veterans who use VA healthcare.

METHODS

A total of 360,909 Gulf War deployed veterans and 323,638 Gulf War Era non-deployed veterans were included in the analysis. Ten-year period prevalence rates (PRs) for fifteen respiratory diseases were calculated for Gulf War and Gulf War Era veterans and period prevalence ratios comparing Gulf War veterans to Gulf War Era veterans were calculated.

RESULTS

The five respiratory conditions with the highest prevalence per 100,000 veterans across both Gulf War deployed and Gulf War Era non-deployed veterans (respectively) were: allergic rhinitis (8,400 and 8,041), chronic obstructive pulmonary disease (4,763 and 4,795), asthma (4,685 and 4,477), chronic airway obstruction (3,983 and 4,059), and chronic sinusitis (2,863 and 2,672). The adjusted PRs showed a small, but significantly increased, elevation in Gulf War-deployed compared to Gulf War Era non-deployed veterans for chronic bronchitis (PR 1.19; 95% CI 1.10, 1.28), emphysema (PR 1.11; 95% CI 1.01, 1.21), chronic airway obstruction (PR 1.09; 95% CI 1.07, 1.12), and chronic obstructive pulmonary disease (PR 1.09; 1.07, 1.11).

DISCUSSION

Gulf War veterans should continue to be monitored in the future to better evaluate the potential long-term consequences on respiratory health.

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

Since 2001, more than 2.7 million U.S. military personnel have been deployed in support of operations in Southwest Asia and Afghanistan. Land-based personnel experienced elevated exposures to particulate matter and other inhalational exposures from multiple sources, including desert dust, burn pit combustion, and other industrial, mobile, or military sources. A workshop conducted at the 2018 American Thoracic Society International Conference had the goals of: 1) identifying key studies assessing postdeployment respiratory health, 2) describing emerging research, and 3) highlighting knowledge gaps. The workshop reviewed epidemiologic studies that demonstrated more frequent encounters for respiratory symptoms postdeployment compared with nondeployers and for airway disease, predominantly asthma, as well as case series describing postdeployment dyspnea, asthma, and a range of other respiratory tract findings. On the basis of particulate matter effects in other populations, it also is possible that deployers experienced reductions in pulmonary function as a result of such exposure. The workshop also gave particular attention to constrictive bronchiolitis, which has been reported in lung biopsies of selected deployers. Workshop participants had heterogeneous views regarding the definition and frequency of constrictive bronchiolitis and other small airway pathologic findings in deployed populations. The workshop concluded that the relationship of airway disease, including constrictive bronchiolitis, to exposures experienced during deployment remains to be better defined. Future clinical and epidemiologic research efforts should address better characterization of deployment exposures; carry out longitudinal assessment of potentially related adverse health conditions, including lung function and other physiologic changes; and use rigorous histologic, exposure, and clinical characterization of patients with respiratory tract abnormalities.

Non-necrotizing granulomatous pneumonitis and chronic pleuritis in soldiers deployed to Southwest Asia

AIMS

Reports of respiratory illnesses among soldiers returning from Southwest Asia have been described. During deployment to Southwest Asia, soldiers are exposed to various respiratory hazards, including dust storms, smoke from burn pits and industrial air pollutants. A few studies have reported increased rates of constrictive bronchiolitis and asthma in these patients. We sought to expand upon the pathological findings in this cohort.

METHODS AND RESULTS

Lung biopsies from veterans of Southwest Asia were identified and re-reviewed. All patients had undergone pulmonary function tests and chest high-resolution CT imaging with no significant findings. Overall, 59 patients with a history of inhalational exposure to at least one of the following were identified: smoke from burn pit, dust storm and sulphur plant fire. Samples included video-assisted thoracoscopic lung biopsies (57 of 59, 96.6%) and cryobiopsies (two of 59, 3.4%). Patients were predominantly male (54 of 59, 91.5%) with an age range of 24-55 years (mean and median = 35). Non-necrotising, poorly formed granulomas were identified in 22 cases (22 of 59, 37.2%). The granulomas were mainly bronchiolocentric and were associated with chronic lymphoplasmacytic bronchiolitis, similar to hypersensitivity pneumonitis (HP). Pleural reaction in the form of focal chronic lymphocytic pleuritis and/or focal pleural adhesions were seen in 43 of 57 (75.4%) biopsies.

CONCLUSIONS

To our knowledge, this is the first study to report pleural reaction as well as features of HP in this population, suggesting that pleural reaction and HP may be part of the spectrum of Southwest Asia deployment-related lung diseases.

Combat zone exposure and respiratory tract disease

BACKGROUND

The impact of deployment to combat zones on the respiratory and sinonasal health of U.S. soldiers is an emerging public health concern. Retrospective studies have shown a correlation between deployment and development of post-deployment pathology, particularly of the aerodigestive system. Respiratory disease, including sinusitis, allergic rhinitis, and asthma, are commonly reported in soldiers deployed to the Middle East and Southwest Asia.

METHODS

Current literature pertaining to combat zone exposure and development of respiratory disease was retrieved using PubMed, Embase, Web of Science, and Google Scholar.

RESULTS

Several types of combat zone exposures exist that may play an influential role in the development of upper and lower respiratory tract diseases. Exposures including foreign dusts, harsh environments, particulate size, and close living quarters may play a causative role. The effect of combat zone exposures has been better examined for lower respiratory tract diseases; however, with the theory of the unified airway, the upper respiratory tract may also be involved. There is evidence that the upper respiratory tract is susceptible, with an increased risk for development of sinusitis and sinonasal disease; however, the quality of evidence of the present literature is generally low.

CONCLUSION

More research is necessary to determine a pathophysiologic mechanism between combat zone exposure and the development of sinonasal disease. Practicing otolaryngologists should be aware of the possibility of combat zone exposures that could contribute to rhinologic symptomatology.