Deployment-Related Lung Disorders
Military deployed from World War II through the Vietnam War have had enough time for respiratory disorders with both short and long latencies to manifest. More recent deployments over the past 13 years to Iraq, Kuwait, Afghanistan, and other regions in southwest Asia (SWA) have been associated with a unique spectrum of respiratory disorders. The long-term respiratory effects of SWA deployments are unknown. This review will discuss deployment-related lung cancer and then focus primarily on the emerging respiratory disorders related to SWA deployment and case examples of deployment-related lung disease.
As the number of recent veterans in the VA health care system increases, primary care providers (PCPs) and specialists are increasingly faced with questions about potential hazards of deployment, referring patients to the VA Airborne Hazards and Open Burn Pit Registry, and evaluating patients with new-onset respiratory symptoms following deployment. Previous reviews and white papers have offered recommendations for evaluation and management; however, little has been reported in the form of case examples of patients with deployment-related lung disorders and their clinical course.1,2
Deployment-Associated Lung Cancer
Lung cancer is the leading cause of cancer death in the U.S. and around the world.3 Lung cancer in the U.S. causes more deaths than does the combination of breast, prostate, colon, and rectal cancers. Lung cancer is the second most common cancer and causes more deaths than does any other cancer in the VHA.4 Most cancers with an environmental cause have a significant latent period of decades between the exposure and cancer incidence. Thus, although lung cancer risk is relatively low in active-duty military personnel, the rate of lung cancer in VA patients is nearly double that of the general population, suggesting causes associated with military service.5
Tobacco
The main cause of lung cancer is tobacco smoking, which accounts for 85% to 90% of lung cancer in the U.S. The latent period between initiation of tobacco smoking and lung cancer incidence is typically ≥ 30 years. Military service has long been associated with tobacco smoking, due to past practices that included the provision of free cigarettes, the availability of cigarettes at reduced cost, smoking breaks, perceived relief from both stress and boredom, and social factors.6 More recently, the adverse effects (AEs) of smoking on health and readiness have been appreciated, and many incentives encouraging tobacco smoking have been eliminated. In 2009, the Institute of Medicine called for a tobacco-free military, and both the Secretary of the Navy and Secretary of Defense have seriously considered this change.7
The additional effect of deployment on smoking has been reported.8 The longitudinal Millennium Cohort study compared several smoking measures between 55,021 deployers and nondeployers who completed both baseline (acquired July 2001-June 2003) and follow-up questionnaires (acquired June 2004-January 2006). Smoking initiation affected 2.3% of deployers and 1.3% of nondeployers; smoking resumption showed a similar pattern with an increase of 39.4% compared with 28.7%. The overall prevalence of smoking increased 44% among nondeployers and 57% among deployers. Those never smokers exposed to combat were 60% more likely to initiate smoking compared with noncombat deployers. Thus, it is clear that tobacco smoking should be considered a deployment-related exposure that contributes to lung cancer risk.
Asbestos
In 1955, Doll published an analysis associating asbestos exposure with risk for lung cancer.9 Many naval veterans and shipyard workers had asbestos exposure, resulting in a spectrum of asbestos-related diseases, including bronchogenic cancer.10
Depleted Uranium
Depleted uranium was used in munitions during the first Gulf War and more recently during military operations in SWA as a part of Operation New Dawn (OND), Operation Iraqi Freedom (OIF), and Operation Enduring Freedom (OEF). Because of concerns of military personnel having complex exposure to depleted uranium, including via inhalation, the VA established the Depleted Uranium Surveillance Program, which has followed a cohort of service members exposed to inhaled depleted uranium during friendly fire in 1991. No significant differences between individuals with high urinary uranium levels and low urinary uranium levels were found in self-reported respiratory symptoms and pulmonary function testing (PFT). Additionally, 20 years after exposure to depleted uranium, there was no statistically significant difference of low-dose chest computed tomography (CT) evidence of lung cancer in these 2 groups.11
Mustard Gas
Mustard gas is considered a definite lung carcinogen.12,13 Both long-term, low-dose and short-term, high- intensity exposures are known to cause human lung cancer.14 Mustard gas was first widely used in warfare in World War I. Mustard gas was used in training for World War II; training accidents resulted in acute toxicity even in lower exposures. It was later used as a chemical warfare agent in the Iran-Iraq conflict in the late 1980s and early 1990s. It is estimated that about 4,000 U.S. service members have been acutely exposed to high concentrations of mustard gas. Sulfur mustard may be incorporated into improvised explosive devices, and there is concern that troops in Iraq have been exposed to this agent in sites previously used for manufacturing and storage.15
