Deployment exposures and long-term health risks: the shadow of war.
A legacy of 1990-1991 Operation Desert Shield/Desert Storm (DS/DS) was the realization that the public health toll of a military conflict is not known at the time of redeployment. Beyond combat-related deaths or injuries and disease nonbattle injury (DNBI) that occur during the conflict, concerns regarding delayed health effects resulting from environmental exposures may extend the medical mission for years after the conflict has ended. The operation was considered a victory with the surprisingly low total of 145 service members dying in combat and 225 lives claimed by nonhostile actions. (1) Nonetheless, over 60,000 individuals eventually sought an evaluation as part of registry programs open to DS/DS veterans and their families. (2,3) Widespread somatic symptoms such as pain, fatigue, rashes, and cognitive deficits were raised with concerns about their relationship to environmental exposures. Multiple expert boards and committees reviewed health consequences of service in the Gulf; none were able to define the medical nature and cause or causes of a "Persian Gulf War Syndrome," nor identify any cause and effect relationships between putative exposures and undefined illness. (1,3,4) The Institute of Medicine (IOM) and the Presidential Advisory Committee noted that registries established by Department of Defense (DoD) and the Veterans Administration (VA) to provide free medical evaluation to concerned Persian Gulf War veterans were not designed to answer epidemiological questions. Furthermore, available scientific evidence did not support a causal link between the symptoms/illnesses reported and exposures while in the Gulf to oil well fires, smoke, petroleum products, pesticides, chemical warfare agents, biological warfare agents, immunizations, pyridostigmine bromide, infectious diseases, or depleted uranium. However, the investigation of possible exposures of troops was considered "superficial and inadequate." (1) It was noted that very little personalized exposure information was available, thus it would be extremely difficult to define relevant control groups and obtain data for them. The lack of exposure data limited even the most expert and well-funded investigation to identify health outcomes linked to specific exposures or risk factors. (4) The General Accounting Office stated that:
Without accurate exposure information, the investment of millions of dollars in further epidemiological research on the risk factors or potential causes for veterans' illnesses may result in little return. (5)
The IOM noted that the victory in the Gulf was overshadowed by questions regarding long-term health and exposures that were known or possible for the deployed. (3) This understanding is the primary public health legacy of DS/DS, and resulted in the 2000 Institute of Medicine report, Protecting Those Who Serve: Strategies to Protect the Health of Deployed U.S. Forces (6) with recommended improvements.
DEPLOYMENT EXPOSURE ASSESSMENT
Presidential Review Directive 5 published in 1998 by the Clinton administration called protection of the health of our service members while deployed a "national obligation." (7) It directed DoD to:
... identify and minimize or eliminate the short and long-term health effects of military service, especially during deployments (including war) on the physical and mental health of veterans.
The IOM responded and recommended strategies to protect those who serve, including environmental exposure assessments in deployment locations. (6) They noted that the spectrum of health concerns was broadening from acute illness and injury due to pathogens and accidents to possible influences of low-level chemical exposures which can manifest in chronic illnesses years later. The IOM also noted that a useful management scheme must address all the threats that deployed forces face, so integration is particularly needed. In addition, "risk information must be presented in a way that permits rapid decisions to be made by field commanders with little pertinent expertise." (6) Necessary to this process are clear guidelines appropriate for deployed forces; a way to assess risk that takes into account competing risks and mission requirements. In addition, risk communication must occur on the ground. Sampling is conducted to answer questions, and those who are affected typically want to know the answers or they may draw their own conclusions. While the desire to disseminate all relevant exposure information to the affected group is strong, it is important to deliver it in an understandable way that causes neither unwarranted concern nor undue complacency.
Assessing acute risk is fairly straightforward, and the military developed both acute exposure guidelines and those considered protective for a one-year exposure for lower but continuous exposures. (8) "Dose" relates to the magnitude, duration, and frequency of exposure. During deployment, exposure concentrations may be variable over time. Some may be for a short period but at levels high enough to immediately affect health or even degrade the mission. Regarding lower concentrations and long-term health effects: concentrations above the long-term guidelines do not necessarily pose long-term risk if the levels are intermittent. However, there is rarely sufficient monitoring information to assess levels over time in dynamic locations since sampling episodes are brief. Therefore, health risk associated with these intermittent exposures is almost always uncertain and rarely actionable, unless the action is to conduct more sampling. This can be frustrating for preventive medicine personnel and for commanders who have to choose among courses of action. The risk matrix for operational risk management classifies risk in a table as green, amber, red, and black as the risk increases. (8) Gray (unclear results) is not in the matrix. While the IOM recommended risk communication down to the level of those exposed, the lack of clear risk and clear messages at this level interfered with this goal. In many cases, sampling was done at a unit level, but sent out of country for analysis. In most cases, a clear interpretation of the results was not available at the unit level, leaving the opportunity for inconsistent messages. According to the IOM, the acknowledgement of uncertainty does not erode trust and confidence in leaders; instead, it fosters confidence in the reliability of the information deemed to be more certain and valid. (6)
EXPOSURE TO AIRBORNE HAZARDS
Early into Operations Iraqi Freedom and New Dawn (OIF/OND), it was recognized that particulate matter (PM) was likely to be a ubiquitous hazard. (9) Shamal winds cause dust storms, and daily windblown dust, diesel exhaust, local pollution, and open burning were potential additional sources. It had been demonstrated that [PM.sub.2.5] levels (representing the respirable fraction of PM) in the region had been measured at twice the US National Ambient Air Quality Standards. Exposure to PM affects the health of children, the elderly, and those with cardiopulmonary disease. The risk of various adverse health outcomes increases with exposure concentration, and there is little evidence of a threshold below which no adverse health effects are expected. (9) The nature and probability of health effects are also dependent upon the size fraction, chemical composition, and the duration of exposure. In short, health effects were plausible, but there was a paucity of information as to the health effects of Southwest Asia (SWA) PM on a relatively young and healthy population. On the basis of concerns about the potential health effects, US Central Command (CENTCOM) approval was obtained to design and implement sampling to characterize and quantify the PM in the ambient environment at 15 deployment sites. (10)
While the sampling effort was remarkably successful given that the every sixth-day schedule was conducted at 15 sites and generated much information, it was difficult to tie the results to health effects. One epidemiological effort was a case-crossover study to evaluate the association between daily average [PM.sub.2.5] and [PM.sub.10] concentrations at the 15 sites and acute cardiovascular and respiratory medical visits. (11) Results were limited because the study lacked statistical power due to the paucity of health-outcome events, and since those that occurred were not always associated with a sampling day. Another used a retrospective cohort design to examine the association between time-weighted average [PM.sub.2.5] and [PM.sub.10] concentration and postdeployment cardiovascular or respiratory diagnoses in cohorts defined by deployment location. (12) No increased diagnoses rates with higher PM was found after adjustment for many confounding variables. The data were limited by potential exposure and outcome misclassification and by a relatively short follow-up period after deployment. In addition, it was recognized that base camps differ in other sources of potential airborne hazards such as industrial pollution, vehicles and fuel exposures, trash burning, and other individual contributions to respiratory or other effects. The Committee on Toxicology of the National Research Council reviewed the available sampling information and studies and concluded that it is indeed plausible that exposure to ambient PM in SWA is associated with adverse acute and chronic health effects. (10) However, the question of whether this was occurring remained. Later publications have looked at trends in respiratory conditions in the Army. (13,14) Others have demonstrated increases in symptoms and small increases in respiratory conditions postdeployment, particularly asthma. Those studies included comparisons such as those exposed to a sulfur mine fire (Mishraq), locations with high background pollution (Kabul), and locations with and without open trash burning. (15-17) Postdeployment respiratory effects of airborne hazards continue to be studied and are the subject of a recently published book. (18)
BURN PIT EMISSIONS
Once the perception of a health hazard exists, it is difficult to reassure individuals that the risk is low. Characterization of the deployed environment and health concerns of those deploying should be used to develop force protection measures and risk communication tools. Joint Base Balad (JBB) was one of the largest air bases in Iraq and was home at one point to 25,000 military, civilian and coalition personnel. Since 2003, burn pits or areas designated for burning trash were used to facilitate solid waste disposal at Balad. (19) In the absence of a waste disposal infrastructure, the options for expedient disposal of trash in operational environments are burial, incineration, or a combination of the two. Tactical security considerations often limited the options to incineration as it did at JBB. (20) Wind roses constructed by the Air Force 14th Weather Squadron demonstrated that prevailing winds carried smoke away from locations where personnel were located. However, black smoke was often visible rising from the burn site. Under some weather conditions, such as low winds and inversions, the smoke from the burn pit lingered over areas of the base, generating complaints and health concerns amongst service members from 2003 until open burning ceased in 2009. Air sampling conducted from summer 2004 to summer 2006 demonstrated the occasional presence of volatile organic compounds and polycyclic aromatic hydrocarbons and dioxins, all of which may be associated with the open burning of trash. (19) The potential health risk was estimated to be low, based on the limited detections in the small number of samples, but a more formal sampling plan was jointly developed. Four rounds of air sampling were completed; Spring and Fall 2007, Spring 2009, and Spring 2010. These air sampling efforts coincided with the introduction of initiatives to reduce exposure to burn pit smoke. Primary measures included the installation and operation of 4 solid waste incinerators and the start of a program to segregate waste, with emphasis on the elimination of plastic water bottles from the waste stream. Two incinerators became operational in May 2007, a third in April 2008, and the last during the summer of 2009. The JBB burn pit officially closed on October 1, 2009.
Risk assessments conducted using the results of the 4 aforementioned air sampling efforts estimated cancer risk in the range considered to be "acceptable" per the US Environmental Protection Agency standards, but some volatile organic compounds were measured at levels that might be associated with acute irritation. (19) These effects were consistent with health conditions reported by some personnel. It took some time for the reports to be published, and it is uncertain how well the findings were disseminated or understood by those with concerns. The VA requested assistance from the Institute of Medicine to assess air sampling data and risk assessment information from JBB. The IOM concluded that none of the individual chemicals were likely to be associated with adverse health outcomes, but that monitoring data suggests particulate matter from local and regional sources other than burn pits appeared to be of greatest concern. (21) Risk assessments do not address mixtures of chemicals and their potential for adverse effects. (20,22) The IOM was unable to conclude whether long-term health effects are expected from exposure to burn pit emissions. While this may be the state of the science, it does not reassure those who develop subsequent illness and might reasonably wonder if it is associated with the exposure. Congress addressed the issue in the fiscal year 2013 National Defense Authorization Act by requiring the VA to establish a registry for veterans with potential exposure to burn pits. (23) The DoD elected to expand this to service members. Participation is voluntary, and eligibility is based on deployment to OIF, Operation Enduring Freedom (OEF), and OND. Confirmation of potential exposure or deployment to specific camps or locations is not required as DoD was unable to specifically list dates and locations where trash was burned. While the actual health risk associated with burning trash may still be under study, service members, the media, and Congress viewed the billowing, thick smoke as demonstrating a lack of consideration for service members' health, which heightened the concern. Over 50,000 service members and veterans have signed up for this registry to date, and the IOM is currently assessing the data.
CHEMICAL WARFARE AGENT EXPOSURE
Exposure to chemical warfare agents (CWA), particularly nerve agents, was a major concern after the first Gulf War due to reports of alarms, the use of the pyrdostigmine bromide tablets as a nerve agent pretreatment, and lingering health concerns after the war. Due to this, a massive research effort to address effects of low-level chemical warfare agents (24) was undertaken. Once again, over a decade later, CWA exposure is also an issue of lingering concern. On October 14, 2014, the New York Times published an in-depth investigation, "The Secret Casualties of Iraq's Abandoned Chemical Weapons," (25) that initiated a landslide reaction and innovative response. The report alleged that from 2004-2011, American troops who deployed in support of OIF/OND:
... repeatedly encountered, and on at least 6 occasions were wounded by, chemical weapons remaining from years earlier in Saddam Hussein's rule.
The article noted that none of the exposed veterans were receiving long-term health monitoring. While this was not necessarily correct, there was no centralized tracking of these exposures and most of the exposure incidents were classified. The US Army Public Health Command (USAPHC) responded and by October 20, 2014, the USAPHC began contacting service member and veterans identified in the article; 17 Soldiers, 6 Marines, and 3 Sailors reported to have had symptomatic exposure to CWA, either sulfur mustard or nerve agent. The immediate task was to contact and interview these individuals and identify their exposure and their symptoms at the time, and to discuss current health concerns. Exposures for the 26 individuals occurred between 2003 and 2011, most typically from handling old leaking munitions. These munitions were either being transported for destruction, or handled during excavation, with a few exposures occurring during destruction. Mustard exposures may injure the skin (blisters), the eyes, and/or the respiratory tract depending on the dose and the route of exposure. Nerve agent exposure may cause miosis from vapor exposure to the eye, sweating, nausea, vomiting, muscle twitching, involuntary urination and defecation, or seizures and death as dose increases.
Beyond the original 26 individuals in the New York Times article, the USAPHC reviewed the medical records of individuals who were known to have been in the same unit of a previously identified exposed service member. In addition, in coordination with the Armed Forces Health Surveillance Center, a review of those who had identified exposure to a CWA on their Post-Deployment Health Assessment or Reassessment was initiated. By October 30, 2014, the DoD had established a toll-free hotline (1-800-497-6261) for service members and veterans to report potential chemical weapons exposure and seek a medical review. On November 7, 2014, the Under Secretary of Defense (Personnel and Readiness) designated the Army as lead agent for this response and directed the Army to develop and publish implementation guidance for the identification and evaluation of current and former service members who had CWA exposures during their deployment to Iraq in support of OIF/OND, to be executed by all branches. On March 20, 2015, the Under Secretary of the Army issued guidelines under which service members and veterans identified as possibly exposed to a chemical weapon were to be contacted by their military service, evaluated in a structured interview, and invited for a full medical examination if they had symptomatic CWA exposure. (26) The participants were also to be provided with documentation of their exposure and have their medical records updated. This information was to be shared with the VA to help veterans receive follow-up care or submit claims for potentially related medical conditions. The medical examinations are being conducted at Walter Reed National Military Medical Center and Secretarial Designee status is requested for those not on active duty so that invitational travel orders may be used to pay for travel and expenses. Progress through the process and dispositions are tracked for each individual in a special module of the Defense Occupational and Environmental Health Readiness System, access to which is available to the VA. In addition, dispositions, medical history, and physical examination are documented in the individual's electronic health record.
As of October 2015, there were approximately 7,000 service members or veterans in all phases of the process of evaluation for potential CWA exposure. At the time of this writing, roughly 150 individuals were identified with symptomatic CWA exposure, all of whom have been offered a medical examination. In the vast majority of cases, no evidence of symptomatic exposure is found, although an additional 62 current and former service members were authorized a medical examination upon plainly requesting one. To date over 100 individuals have completed the medical examination process and among the completed medical examinations, no significant correlation between acute CWA exposure and chronic health effects has been identified. Nearly all exposure effects were mild (C. P. B. unpublished data). A clear lesson developed from this effort: in some exposure scenarios, testing and or monitoring resulted in mixed results. Confirmatory testing was conducted in laboratories in the United States, but service members rarely learned of the results, and the results were classified. In many cases, service members were not sure about to what they had been exposed, and thus were not sure of the potential risk that might be associated with the exposure. This resulted in both anger and frustration. The most beneficial part of the effort was that many service members had the opportunity to ask questions and come away with a better idea of their future health risk.
As in previous conflicts, many personnel returning from deployment to Iraq and Afghanistan have concerns about environmental exposures and their potential health. Exposure assessments have helped to gauge the risk, but typically are insufficient to negate risk. Transparency regarding the use and limitations of the data collected, and communication of the risks to those it affects is recommended. (6) To support on-the-ground risk communication, the actions triggered by specific sampling results and the uncertainty surrounding these assessments should be identified prior to data collection. To the degree that results are inconclusive, it should be acknowledged that an "unclear risk" is not the same as "clear lack of risk." It is recognized that service connection and other issues complicate these matters. Operations Iraqi Freedom, Enduring Freedom, and New Dawn were the first military operations for which specific exposure scenarios have resulted in relatively early recognition of and response to concerns in the form of a registry or other process. Registries have been developed to allow individuals to come forth and report both exposure and health concerns. These initiatives will gather information that is potentially useful to service members and their healthcare providers, as well as public health professionals who are endeavoring to protect the health of deployed troops. Though there are structural limitations to the data (for example, self-reported exposures and outcomes, and limited generalizability to unenrolled personnel), registries can be used to generate hypotheses for further evaluation. That said, it is unlikely that any amount of environmental sampling will be sufficient to completely characterize environmental health risks and alleviate all future health concerns. Awareness, assessment, documentation, and early risk communication may help reassure those deploying, whom we are obligated to protect. In order to provide meaningful risk communication, we must know how the collected information will be used to assess risk, and how to clearly communicate it to those who have the right to know.
(1.) Presidential Advisory Committee on Gulf War Veterans' Illnesses. Special Report. Washington DC: US Government Printing Office; December 1996. Available at: http://www.gulflink.osd.mil/ gwvi/toc-f.html. Accessed March 23, 2016.
(2.) Gray GC, Hawksworth AW, Smith TC, Kang HK, Knoke JD, Gackstetter GD. Gulf War Veterans' health registries. Who is most likely to seek evaluation?. Am J Epidemiol. 1998;148(4):343-349.
(3.) Committee on the DoD Persian Gulf War Syndrome Comprehensive Clinical Evaluation Program. Evaluation of the U.S. Department of Defense Persian Gulf Syndrome Comprehensive Clinical Evaluation Program. Washington, DC: National Academies Press; 1996. Available at: http://www.nap.edu/read/9057/chapter/1. Accessed March 23, 2016.
(4.) Committee to Review the Health Consequences of Service During the Persian Gulf War Medical Follow-up Agency. Health Consequences of Service During the Persian Gulf War: Recommendations for Research and Information Systems. Washington, DC: National Academies Press; 1996. Available at: http://www.nap.edu/read/5272/chapter/1. Accessed March 23, 2016.
(5.) US General Accounting Office. Gulf War Illnesses: Improved Monitoring of Clinical Progress and Reexamination of Research Emphasis are Needed. Washington, DC: US Government Accountability Office; June 23, 1997. Report GAO/NSAID-97-163. Available at: http://www.gao.gov/assets/230/224299. pdf. Accessed March 23, 2016.
(6.) Institute of Medicine. Protecting Those Who Serve: Strategies to Protect the Health of Deployed U.S. Forces. Washington, DC: National Academies Press; 2000:47. Available at: http://www.nap.edu/ read/9976/chapter/8#47. Accessed March 23, 2016.
(7.) Executive Office of the President. A National Obligation --Planning for Health Preparedness for and Readjustment of the Military, Veterans, and Their Families after Future Deployments. Washington, DC: Executive Office Presidential Review Directive 5; August 1998:8,19. Available at: http:// clinton5.nara.gov/textonly/WH/EOP/OSTP/NSTC/ html/directive5.html. Accessed April 1, 2016.
(8.) US Army Public Health Command. Technical Guide 230: Environmental Health Risk Assessment and Chemical Exposure Guidelines for Deployed Military Personnel. Aberdeen Proving Ground, MD: US Army Public Health Center (Provisional). 2013. Available at: https://phc.amedd.army.mil/ PHC%20Resource%20Library/TG230.pdf. Accessed March 23, 2016.
(9.) Weese CB, Abraham JH. Potential health implications associated with particulate matter in deployed settings in Southwest Asia. Inhal Toxicol. 2009;21:291-296.
(10.) Abraham JH, Baird CP. A case-crossover study of ambient particulate matter and cardiovascular and respiratory medical encounters among US military personnel deployed to Southwest Asia. J Occup Environ Med. 2012;54(6):733-739.
(11.) Abraham JH, DeBakey SF, Reid L, Zhou J, Baird CP. Does Deployment to Iraq and Afghanistan affect respiratory health of US military personnel?. J Occup Environ Med. 2012;54(6):740-745.
(12.) National Research Council. Review of Department of Defense Enhanced Particulate Matter Surveillance Program Report. Washington, DC: National Academies Press; 2010. Available at: http://www. nap.edu/catalog/12911/review-of-the-department-of-defense-enhanced-particulate-matter-surveil lance-program-report. Accessed March 23, 2016.
(13.) Baird CP. Respiratory disease and deployment: What do we know? What do we think?. US Army MedDep J. July-September 2011:80-86.
(14.) Abraham JH, Clark LL, Sharkey JM, Baird CP. Trends in rates of chronic obstructive respiratory conditions among US military personnel 2001-2013. US Army Med Dep J. July-September 2014:33-43.
(15.) Baird CP, DeBakey S, Reid L, Hauschild VD, Petruccelli B, Abraham JH. Respiratory health status of US Army personnel potentially exposed to smoke from 2003 Al-Mishraq sulfur plant fire. J Occup Environ Med. 2012;54(6):717-723.
(16.) Armed Forces Health Surveillance Center. Epidemiological Studies of Health Outcomes Among Troops Deployed to Burn Pit Sites. Silver Spring, MD: Armed Forces Health Surveillance Center; 2010. Available at: http://fhp.osd.mil/pdfs/100604_ FINAL_Burn_Pit_Epi_Studies.pdf. Accessed March 23, 2016.
(17.) Sharkey JM, Abraham JH, Clark LL, Rohrback P, Ludwig S, Hu Z, Baird CP. Postdeployment respiratory health care encounters following deployment to Kabul, Afghanistan: a retrospective cohort study. Mil Med. 2016;181(3):265-271.
(18.) Baird CP, Harkins DK, eds. Airborne Hazards Related to Deployment. Fort Sam Houston, TX: Borden Institute; 2015.
(19.) Vietas AJ, Taylor G, Rush V, Deck A. Screening Health Risk Assessment, Burn Pit Exposures, Balad Air Base, Iraq and Addendum Report. Aberdeen Proving Ground, MD: US Army Center for Health Promotion and Preventive Medicine; May 2008. USACHPPM 47-MA-08PV-08; AFIOH IOHRS-BR-TR-2008-0001. Available at: http://www. dtic.mil/cgi-bin/GetTRDoc?AD=ADA493142. Accessed March 23, 2016.
(20.) Weese CB. Issues related to burn pits in deployed settings. US Army Med Dep J. April-June 2010:22-28.
(21.) Institute of Medicine. Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan. Washington DC: National Academies Press; 2011. Available at: http://www.iom.edu/Reports/2011/Long-Term-Health-Consequences-of-Exposure-to-Burn-Pits-in-Iraq-and-Afghanistan. aspx. Accessed March 23, 2016.
(22.) Weese CB. Review of the Institute of Medicine report: long-term health consequences of exposure to burn pits in Iraq and Afghanistan. US Army Med Dep J. July-September 2012:43-47.
(23.) Dignified Burial and Other Veterans' Benefits Improvements Act of 2012. Pub L No. 112-260, 126 stat 2417.
(24.) Somani S, Romano JA. Chemical Warfare Agents: Toxicity at Low Levels. Boca Raton, FL: CRC Press. 2001.
(25.) Chivers CJ. The secret casualties of Iraq's abandoned chemical weapons [archives]. New York Times. October 14, 2014. Available at: http://www. nytimes.com/interactive/2014/10/14/world/mid dleeast/us-casualties-of-iraq-chemical-weapons. html. Accessed March 23, 2016.
(26.) Under Secretary of the Army. Memorandum: Iraq Chemical Warfare Agent Exposure Review Implementation Guidance. Washington, DC: US Department of the Army; March 20, 2015. Available at: https://assets.documentcloud.org/documents/1694786/chemguidelines.pdf. Accessed March 23, 2016.
Dr Baird is Manager, Environmental Medicine Program, US Army Public Health Center (Provisional), Aberdeen Proving Ground, Maryland.
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|Title Annotation:||PUBLIC HEALTH CHALLENGES|
|Publication:||U.S. Army Medical Department Journal|
|Date:||Apr 1, 2016|
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