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Introduction

The involvement of the National Academies of Sciences, Engineering, and Medicine (the National Academies) with issues regarding the health impacts associated with burn pit emissions resulting from military operations began with a 2009 request from the Department of Veterans Affairs (VA) to examine the evidence regarding long-term effects from exposure to burn pits in the Iraq and Afghanistan theaters and to evaluate the feasibility and design issues surrounding an epidemiologic study of exposed veterans (IOM, 2011). While the statement of task for that study specified using Joint Base Balad in Iraq as an example of a location with high burn pit exposure, the committee responsible for conducting it extended the task to include all military personnel deployed to Iraq and Afghanistan who may have experienced exposure. Using peer-reviewed literature and data provided by the Department of Defense (DoD) and VA to examine the long-term health effects of exposure to burn pits, the 2011 report committee concluded that there was limited but suggestive evidence of an association between exposure to combustion products and reduced pulmonary function. However, it determined that there was inadequate or insufficient evidence of an association between exposure to combustion products and cancer, respiratory diseases, circulatory diseases, neurologic diseases, and adverse reproductive and developmental outcomes in the populations studied (service members, firefighters, and incinerator workers).

That Institute of Medicine (IOM) committee recommended that a tiered approach be applied to conducting an epidemiologic study that would characterize exposures and account for other sources of air pollutants in the ambient environment. The three tiers of the recommended study were characterized by the decreasing specificity of exposure and would answer different research questions. That committee suggested that the first tier be focused on determining whether proximity to burn pit operations at Joint Base Balad increased the risk of adverse health outcomes, using data such as dates of deployment, duties on base, and location of housing relative to the burn pit, and taking into account wind-dispersion models to assess individual exposure to Joint Base Balad burn pit emissions. The second tier would address whether the installation of incinerators at Joint Base Balad between 2008 and 2010 had reduced the incidence of disease or intermediate outcomes by evaluating chronic health outcomes in those deployed before and those deployed after the burn pit was shut down, factoring in the increased use of incinerators over those 2 years. The third tier would be an examination of whether deployment at Joint Base Balad during full burn pit operation increased the risk of adverse health outcomes compared with deployment elsewhere in Iraq or Afghanistan or with no deployment, taking into account the fact that the burn pit emissions occurred in the presence of particulate matter and other pollutants from other sources. With this approach, that committee concluded that a study of health effects resulting from exposure to burn pit emissions would be feasible, but the

committee also realized that a study’s ability to produce useful and actionable results would depend on it having a well thought-out design, thorough exposure assessment, and careful follow-up.

VA published preliminary plans formulated in response to the conclusions and recommendations contained in the 2011 report in a February 4, 2013, posting in the Federal Register (Federal Register, 2013). To address the need for further study of the long-term health effects of exposure to airborne hazards in Iraq and Afghanistan, VA proposed to (1) design appropriate studies that would incorporate objective measures such as clinical exams, (2) establish an independent oversight mechanism, and (3) conduct a cohort study to assess potential long-term effects related to burn pit emissions in the context of other ambient exposures. The cohort study would involve a population-based prospective study that would include baseline and repeated clinical examinations with sufficient follow-up to address the potential long-term health effects of deployment to Iraq and Afghanistan as well as potential burn pit exposure.

At around the same time (on January 10, 2013), Congress passed and the President signed Public Law 112-260,¹ § 201 of which directed VA to establish an open burn pit registry within 1 year after enactment. Appendix A of this report provides an excerpt of the law calling for the current study. The law directed the Secretary of VA to coordinate with DoD to establish and maintain an open burn pit registry for eligible individuals who may have been exposed to toxic airborne chemicals and fumes caused by open burn pits. It specified that the registry should include information that would be necessary to ascertain and monitor the health effects of members of the armed forces exposed to toxic airborne chemicals and fumes caused by open burn pits. The law instructed VA to develop a public information campaign to inform eligible individuals about the registry and to periodically notify eligible individuals of significant developments in the study and treatment of conditions associated with exposure to toxic airborne chemicals.

Section 201(b)(1) of the law directed the Secretary to enter into an agreement with an independent scientific organization to prepare a report that addressed several issues related to the establishment and conduct of the registry and use of its data.

THE COMMITTEE’S CHARGE AND APPROACH TO ITS TASK

In accordance with the directive contained in § 201(b)(1) of Public Law 112-260, VA entered into an agreement with the National Academies to form an expert committee to perform an assessment of the registry created by the law, which it named the Airborne Hazards and Open Burn Pit (AH&OBP) Registry. The committee’s statement of task is shown in Box 1-1.² In brief, it directs the committee to conduct an analysis of data collected by the registry in the initial months of its operation and to offer observations and recommendations regarding its operation and best use of the data it collects.

The committee convened by the National Academies included experts in epidemiology, environmental and occupational health, exposure assessment, military and veteran’s health, statistics, survey methodology, and toxicology. It initially comprised eight members, who held three in-person meetings between March and August 2015. These meetings included a presentation by VA staff to present and elucidate their charge to the committee and an information-gathering workshop that is detailed in the section below. Three more members were added in late 2015 to supplement the committee’s expertise. That expanded committee met three additional times in person and twice by phone over 2016 to consider evidence and write its report.

INFORMATION GATHERING

Several activities were undertaken to develop the scientific foundation for the report’s findings, conclusions, and recommendations. These included gathering material from the peer-reviewed literature; requesting informa-

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¹Title II–Health Care, Public Law 112-260, Establishment of Open Burn Pit Registry, § 201 (January 10, 2013).

² Note that the Statement of Task refers to the Institute of Medicine (IOM). As of March 2016, the Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine continues the consensus studies and convening activities previously undertaken by the IOM.

tion directly from VA and from experts in the field; examining other pertinent published literature, government documents and reports, testimony presented to Congress, surveys, and exposure and diseases registries; attending professional meetings and educational events; and consulting relevant National Academies reports. In particular, the committee found a great deal of relevant background information on such topics as the use of military burn pits and the state of the literature regarding the health effects of exposure to combustion products in genera—and to burn pit emissions in particular—in the 2011 IOM report Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan, some results of which are touched on in the following section. Details concerning these topics may be found in that report.

Prior National Academies Reports Regarding Burn Pit Exposures and Health Outcomes

Three previous National Academies reports examined health outcomes related to specific exposures that occurred during deployment to Southwest Asia,³ including exposures from or related to burn pit emissions. They are briefly summarized below.

The third volume of the report series Gulf War and Health contained a comprehensive review of the literature addressing the association between exposure to fuels, combustion products, and propellants present in the 1990–1991 Gulf War theater and health outcomes (IOM, 2005). Combustion products were defined as “smoke from fires, exhaust from burning fuels, and products of other combustion sources” (p. 39), and it was noted that these are also constituents of air pollution in general. The committee responsible for that report classified its findings into a set of categories adapted from the scheme used by the International Agency for Research on Cancer (IARC, 2006). It stated that

Responding to a request from the U.S. Army, the National Academies formed an expert committee to review a report (Engelbrecht et al., 2008) that summarized the results of DoD’s Enhanced Particulate Matter Surveillance Program (EPMSP) (NRC, 2010). EPMSP was an effort to characterize and quantify particulate matter in the ambient environment at 15 sites⁴ in the Persian Gulf Region over 12 months in 2006–2007. This committee was also asked, among other tasks, to consider whether and how such data and other information collected by the U.S. Army Center for Health Promotion and Preventive Medicine (CHPPM) might be put to use in assessing the health outcomes of deployed personnel. It commended the effort but found that the design and conduct of the EPMSP limited its usefulness in health studies. The committee concluded that it was plausible that exposure to ambient pollution was associated with adverse health outcomes but that the interpretation of the information collected in theater was encumbered by uncertainties regarding the actual exposures, the small number of study subjects, and the limited amount of exposure data. It recommended that “[a] more complete inventory of all major sources of ambient pollutants and potential emissions in the theater should be constructed before assessment of health effects to ensure that all relevant pollutants are monitored” (p. 9).

Of particular relevance for the current report, the previously mentioned report Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan summarized the health effects associated with exposures to 51 pollutants that were detected in air samples taken at Joint Base Balad in Iraq in 2007 and 2009 (IOM, 2011). There were a number of potential sources of these, and that committee concluded that burn pits were not a major source

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³ VA defines the Southwest Asia Theater of operations to include the following locations: Iraq, Kuwait, Saudi Arabia, Bahrain, Gulf of Aden, Gulf of Oman, Oman, Qatar, and the United Arab Emirates; the waters of the Persian Gulf, Arabian Sea, and Red Sea; and the airspace above these regions.

⁴ The 15 sites were in the following countries: Djibouti (one), Afghanistan (two, in Bagram and Khowst), Qatar (one), United Arab Emirates (one), Iraq (six, in Balad, Baghdad, Tallil, Tikrit, Taji, and Al Asad), and Kuwait (four, in northern, central, coastal, and southern Kuwait).

of many of them. Furthermore, some key air pollutants were not assessed, including ozone, carbon monoxide, nitrogen dioxide, and sulfur dioxide or other chemicals associated with combustion such as hydrogen cyanide.

Because there were few studies on exposures of military populations to burn pits, that committee expanded its literature review to include toxicologic studies. It also looked at studies of surrogate populations whose members had occupational or residential exposures to combustion products, such as firefighters, incinerator workers, and those living near an incinerator. The committee used a weight-of-evidence approach to determine the strength of the association between exposure to combustion products and each health outcome. Three major classes of chemicals detected at Joint Base Balad—polychlorinated dibenzo-p-dioxins and dibenzo-p-furans, polyaromatic hydrocarbons, and volatile organic compounds—and particulate matter have been associated with a wide array of long-term health effects in many organs and organ systems, including the adrenal glands, blood, lungs, liver, kidneys, stomach, spleen, and cardiovascular, respiratory, reproductive, and central nervous system (IOM, 2011).

However, the 2011 report concluded that there was “inadequate/insufficient evidence of an association between exposure to combustion products and cancer, respiratory disease, circulatory disease, neurologic disease, and adverse reproductive and developmental outcomes in the populations studied” (IOM, 2011, p. 7). It did find limited or suggestive evidence of an association between exposure to combustion products and reduced pulmonary function in the study populations, but it was unable to determine whether the long-term health effects are likely to result from service members exposed to emissions from burn pits—specifically the one in operation at Joint Base Balad—because high ambient concentrations of particulate matter from both natural and anthropogenic sources likely modified the effects, but could not be accounted for or adjusted in the analyses. Therefore, that committee concluded that the long-term health risk of airborne, burn pit, and other related exposures was not clearly defined. The report stated that none of the individual chemical constituents of the combustion products emitted from the burn pit appeared to have been present at concentrations high enough to be responsible for any of the adverse health outcomes. However, it was also noted that “the possibility of exposure to mixtures of those chemicals raises the potential for health outcomes associated with cumulative exposure to combinations of the constituents in burn pit emissions” (p. 8). Moreover, given the limitations of the literature, the information “might not provide a comprehensive picture of the risks posed to military personnel from burn pit emissions” (IOM, 2011, p. 103).

Registry Data Analysis Efforts

In order to conduct the analysis of the initial months of data collected by the AH&OBP Registry, the National Academies contracted with Westat, Inc., a statistical survey research corporation. The data made available by VA—which did not contain any personally identifiable information—were delivered to Westat in January 2016, and its staff conducted work under the direction of the committee. Neither committee members nor National Academies staff had any access to the data—they received summary statistics and analysis results only.

Separately, VA contracted directly with Westat to conduct a series of analyses of AH&OBP Registry data under VA’s direction which resulted in three reports (Gasper and Kawata, 2015; VA, 2015a,b) and a publication in the Journal of Occupational and Environmental Medicine (Liu et al., 2016). The committee used these as references but emphasizes that the VA–Westat efforts were entirely independent of the committee’s work, covered time periods that were different than the data made available for the committee’s analyses, and used additional data sources that were not made available to the committee.

Some information requested by the committee was not released because of VA protocols regarding the management of data that VA considered to be personally identifiable information and the protection of the privacy of registrants and the security of the information VA was providing. These protocols limited the committee’s ability to fully address its charge.

Summary of the Committee’s Workshop

As part of fulfilling its statement of task, the committee held a workshop to assist in information gathering which informed discussions throughout this report. It heard from presenters with knowledge of veterans health issues related to airborne hazards and open burn pits, in-theater burn pit exposures characterization, military

environmental health registries, and also from veterans and veteran service organizations with perspectives on burn pit exposure effects. A roundtable of veterans—including those who had been deployed to bases with burn pits—and family members of veterans offered their views and engaged in dialogue with the committee members.

The workshop agenda is reproduced in Appendix B. Copies of speakers’ written presentations are posted to the National Academies website,⁵ and highlights of this information are summarized below.

John Kolivosky, PE, provided an overview of an in-theater ambient air monitoring program. Mr. Kolivosky was the project lead on a burn pit assessment conducted in the Deployment Environmental Surveillance Program at the Army Institute of Public Health, and he provided the committee with details on how the effort was conducted and on the data that were collected. The operation of air sampling devices was the responsibility of Army Preventive Medicine personnel. They would conduct site surveys to identify potential exposure to airborne hazards and collect 24-hour time-composite samples using Environmental Protection Agency methods or the equivalent. The samples were sent out of theater to a laboratory for analysis and archived in the Defense Occupational Environmental Health Readiness System. Some 20,000 samples are in the database; most of these were taken within the boundaries of bases. Particulate matter (PM)—both PM₁₀ and PM_2.5⁶ —as well as heavy metals and volatile organic compound levels were measured at various times. Mr. Kolivosky indicated that there were a number of challenges associated with operating air sampling equipment in theater that limited the ability to collect good data. He and his colleagues have since published two papers on the results of the air monitoring effort (Blasch et al., 2016a,b).

Maj Charlie Toth, U.S. Air Force, PE, spoke about environmental sampling at the Balad Air Base.⁷ Maj Toth focused on his knowledge of the design of the burn pit study sampling plan for the site and on personal observations from the actual collection of samples and subsequent report. The sampling plan was a joint effort with the Army CHPPM and Air Force Institute for Occupational Health. The goal was to quantify worst-case effects of exposures to the open burn pits. The intent of investigators was to gather this information while waste incinerators were still in place and the exposure was still comparable to what the exposed population had experienced. Maj Toth described his experience as an environmental engineer tasked with collecting samples near Balad Air Base and the resulting report published from the data gathered (CHPPM and AFIOH, 2009). Between January and May 2007, samples were collected to assess the levels of dioxins, furans, polycyclic aromatic hydrocarbons, volatile organic compounds, and PM₁₀ particulates. Maj Toth suggested that having a dedicated sample team or providing more training for the use of the instruments could have improved the collection of samples. During his time in theater, Maj Toth said he recalled seeing items including plastics, metal/aluminum cans, rubber, chemicals such as paints and solvents, petroleum, oil, lubricant products, munitions, unexploded ordnance, wood waste, and incomplete combustion by-products in burn pits with jet fuel (JP-8) being used as the accelerant. The report summarizing this work noted that the actual number of final samples collected was relatively small and that 15% of the samples were rejected because of damage from shipping or failed pumps. The report’s findings did not include input or verification from members of the team involved in the collection of data, which led, in Maj Toth’s view, to flaws and misinterpretation of information.

John Rinker, CIH, discussed information developed in his master’s thesis, “Retrospective Geospatial Modeling of PM10 Exposures from Open Burning at Joint Base Balad, Iraq” (Rinker, 2011), and provided the committee with an understanding of what data were gathered with respect to burn pit emissions and exposures. The intent of his study was to create an exposure-zone map using spatially interpolated particulate air sampling point data from Joint Base Balad and exposure contours from dispersion model outputs. He concluded that source-specific individual exposures could be estimated with his dispersion model and information on subjects’ time-activity patterns.

Gary Gackstetter, DVM, PhD, and Tomoko I. Hooper, MD, briefed the committee on lessons learned from other health registries and the Millennium Cohort Study. Drs. Gackstetter and Hooper are part of the research team conducting the Millennium Cohort Study, a prospective longitudinal epidemiological research effort intended to evaluate the impact of military exposures, including deployment, on long-term health outcomes. While it was not

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⁵ See http://www.nationalacademies.org/hmd/Activities/Veterans/VABurnPitRegistry/BurnPitRegistryWorkshop.aspx (accessed February 9, 2017).

⁶ PM_2.5 refers to airborne particles 2.5 microns in diameter and smaller, while PM₁₀ refers to particles between 2.5 and 10 microns in diameter.

⁷ Balad Air Base was renamed Joint Base Balad in June 2008. It reverted to Balad Air Base in December 2011 when the Iraq Air Force assumed responsibility for it.

specifically established for the purpose of examining exposures and health outcomes related to service in Iraq and Afghanistan, its original mandate envisioned the possibility of such studies, and 61% of the more than 200,000 participants in the study have deployed there, and the information obtained from them has been used to investigate burn pit-related issues (Gray et al., 2002; Smith et al., 2009, 2012). They presented background information on the Millennium Cohort and offered their perspectives on the utility of registries versus prospective epidemiologic studies in research on health outcomes in military populations. (Chapter 2 addresses the Millennium Cohort Study in a discussion of populations whose health outcomes could be compared with results generated by the AH&OBP Registry.)

Anthony Szema, MD, an adjunct professor at Stony Brook University and clinical assistant professor at Hofstra University, provided a perspective on the AH&OBP Registry and on registries in general as a tool for gathering information on the health of veterans. He presented his views on the limitations of the AH&OBP Registry and on topics the questionnaire does not address such as spirometry, allergy skin testing, contact dermatitis to metals and chemicals, gastroesophageal reflux disease, and lung biopsies. Dr. Szema suggested that some exposure questions were limited or absent, for example questions about dust in containerized housing units, JP-8 jet fuel, grinding metals, and asbestos. He contrasted the AH&OBP questionnaire with information gathering on the BurnPits360. org website.

A number of points were raised in the roundtable discussion that concluded the workshop. CPT (ret.) LeRoy Torres of the U.S. Army Reserve spoke to the committee via a Web link from his home. He related his experience serving at Camp Anaconda,⁸ his exposure to the burn pit that operated there, and his subsequent health problems. Rosie Torres, the executive director of Burnpits 360°, which was established by her and CPT Torres, presented information on the registry that the organization maintains on its website. Ms. Torres suggested that the AH&OBP Registry include an open field that would allow the self-reporting of symptoms and allow family members of deceased eligible persons to submit information. Peter Sullivan of The Sergeant Thomas Joseph Sullivan Center echoed the suggestion that the registry be open to submission of information on deceased service members and veterans and added that mortality data should be collected for those already enrolled in the registry. He indicated that it was important for registry data to be used not only for research but also for improvements in clinical diagnosis, treatment, and prevention. Daniel Sullivan of The Sergeant Thomas Joseph Sullivan Center suggested that it would be useful for VA to involve veterans, their families, and advocacy organizations concerned with burn pit exposure issues in their outreach and education activities surrounding the registry. Representatives of three veterans service organizations—Adrian Atizado of Disabled American Veterans (via teleconference), Thomas Berger, PhD, and Rick Weidman of Vietnam Veterans of America, and Carlos Fuentes of Veterans of Foreign Wars—highlighted reports of difficulties encountered by some eligible persons in registering for and completing the questionnaire. They said that participants they had heard from had found that the online system would sometimes freeze and that some had encountered problems with correcting and supplementing the list of locations where they had served. The multiple formal and informal names used for some bases and difficulties in spelling location names were identified as particular problems. Furthermore, comments were offered that VA had not done a good job in encouraging people who did not have exposure to burn pits or were not experiencing health problems to fill out the registry questionnaire.

The committee is deeply grateful to the participants in the workshop. All of the information presented was factored into the committee’s considerations whether or not any particular piece of information is explicitly mentioned here.

Recent Epidemiologic Studies of Military Personnel Exposed to Burn Pits

The committee’s statement of task directed it to use established and previously published epidemiologic studies to provide recommendations regarding the most effective and prudent means of addressing the medical needs of eligible individuals with respect to conditions that are likely to result from exposure to burn pit emissions. To accomplish this, a targeted review was conducted of epidemiologic studies published since the last National Acad-

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⁸ Later called Joint Base Balad.

emies review of such work in Long Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan (IOM, 2011).

The literature search was limited to epidemiologic studies of long-term health outcomes (not acute⁹ or short-term) experienced by service members and veterans of the 1990–1991 Gulf War, the stabilization period (1992–September 2001), and post-9/11¹⁰ (Operation Enduring Freedom [OEF], Operation Iraqi Freedom [OIF], and Operation New Dawn [OND]), which were published in or after 2010 through January 2016 and were not cited in the 2011 IOM report. Search terms included “open burn pit,” “military or veterans,” and “environment or occupational or war exposure.” The committee did not include or review studies of populations exposed to other sources of burning materials, such as firefighters and incinerator workers. Multiple databases including Embase, Medline, Scopus, Web of Science, Cochrane Database of Systematic Reviews, PubMed Systematic Reviews, PubMed, and ProQuest were searched. The committee also searched other sources such as the Defense Technical Information Center database, and reports released by VA, RAND Corporation, DoD, the Government Accountability Office, and the Congressional Research Service.

The literature search identified 23 studies of potential relevance regarding the long-term health consequences of exposure to burn pit emissions in Southeast Asia, specifically Iraq and Afghanistan. The committee reviewed the titles and abstracts of each study, and omitted those publications that described case reports, acute outcomes, or populations of civilians or refugees in the Persian Gulf region, as well as studies that focused on treatments and meeting abstracts. For each of the remaining studies, the full text was obtained, reviewed, and discussed by the committee. Since the literature search was conducted, the committee became aware of one additional publication that presented an analysis of AH&OBP Registry questionnaire data (Liu et al 2016); it is described elsewhere in the report. After exclusions, eight publications remained for review. All studies were conducted using U.S. service members. Five publications reported on new epidemiologic studies (Abraham et al., 2014; Jones et al., 2012; Powell et al., 2012; Sharkey et al., 2015; Smith et al., 2012) and three publications were reviews (Abraham et al., 2015; Falvo et al., 2015; Morris et al., 2011). The five publications of new epidemiologic studies are discussed below and summarized in Table 1-1. Although literature reviews are cited in the discussion below, they were not of primary concern to the committee because they offer no original data.

Four publications looked specifically at proxies of burn pit exposure (Abraham et al., 2014; Jones et al., 2012; Powell et al., 2012; Sharkey et al., 2015; Smith et al., 2012). Two publications (Abraham et al., 2014; Sharkey et al., 2015) reported updated results from an earlier study conducted by the Armed Forces Health Surveillance Center (AFHSC et al., 2010) and three published additional analyses (Jones et al., 2012; Powell et al., 2012; Smith et al., 2012) of a study by the Naval Health Research Center using data from the Millennium Cohort Study (AFHSC et al., 2010). Three publications focused on respiratory outcomes (Abraham et al., 2014; Sharkey et al., 2015; Smith et al., 2012), and one each focused on autoimmune diseases (Jones et al., 2012) and chronic multisymptom illness (Powell et al., 2012). No new studies examined outcomes of cardiovascular conditions.

Respiratory Outcomes

Two publications reported on additional follow-up data for a study of respiratory conditions conducted by the Armed Forces Health Surveillance Center (AFHSC et al., 2010). The original report was central to the IOM’s review of the health effects associated with burn pit exposure at Joint Base Balad (IOM, 2011). The AFHSC et al. (2010) study examined medical encounters of Army and Air Force personnel 36 months after deployment to Joint Base Balad or Camp Taji (with burn pits), Camp Beuhring or Camp Arifjan (without burn pits), or the Republic of Korea (urban air pollution and PM exposure) from 2005 to 2007. Personnel who served within 3 miles of burn pits were considered exposed (15,908 at Joint Base Balad and 2,522 at Camp Taji) and were compared with 51,299 personnel at bases without burn pits and 237,714 personnel in the United States who had not deployed as of April 2006.

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⁹ The committee defined acute outcomes as those that manifested within 6 months of exposure.

¹⁰ Operation Enduring Freedom (OEF; October 7, 2001–December 28, 2014); Operation Iraqi Freedom (OIF; March 19, 2003–August 31, 2010); Operation New Dawn (OND; September 1, 2010–December 15, 2011); Operation Freedom’s Sentinel (January 1, 2015–present)—the most recent U.S. mission in Afghanistan—the purpose of which is to focus on training, advising, and assisting Afghan security forces (Torreon, 2015).

TABLE 1-1 Epidemiologic Studies of Military Personnel Exposed to Burn Pits Published Since Long-Term Health Consequences of Exposure to Burn Pits in Iraq and Afghanistan (IOM, 2011)

Incidence rates for medical encounters (defined by International Classification of Diseases, Ninth Revision [ICD-9] codes) that occurred within 36 months of April 2006 at military medical facilities were reported. Overall, the incidence rates of health outcomes were similar among personnel deployed to bases with burn pits, those deployed to bases without burn pits, and those deployed to Korea (AFHSC et al., 2010). Both Abraham et al. (2014) and Sharkey et al. (2015) reported on analyses with an additional 12 months of follow-up (48 months total, starting April 2006) for respiratory outcomes. While both studies used the same cohort and data sources, there were slight methodologic differences, including the size of the nondeployed referent group (112,091 in Abraham et al. and 237,714 in Sharkey et al.) and the covariates used. None of the analyses were able to control for smoking or other important exposures related to respiratory disease, and both were limited by their exclusive use of military medical records (medical encounters outside of the military system were not included).

Sharkey et al. (2015) conducted the same analysis using the same cohort as that reported by AFHSC et al. in 2010 with 48 months of follow-up instead of 36 months. The analyses adjusted for age, grade, sex, race, and service branch. As was found in the earlier analysis, the risks of respiratory illnesses at the four Southwest Asia bases and Korea were all similar to, or statistically significantly lower than, the risks for personnel who remained in the United States. Incidence rate ratios (IRRs) were reported for the bases, but no comparisons between bases with and bases without burn pits were made. For respiratory diseases as a whole (ICD-9 codes 460–519), IRRs for medical encounters ranged from 0.70 to 1.01. IRRs for acute respiratory infection medical encounters (ICD-9 codes 460–466) ranged from 0.64 to 0.95; chronic obstructive pulmonary disease (COPD) medical encounters (ICD codes 490–492 and 494–496) ranged from 0.66 to 1.00; asthma (ICD-9 code 493) ranged from 0.76 to 0.95; and medical encounters for respiratory symptoms and other chest symptoms (ICD-9 code 786) ranged from 0.80 to 1.04. In all but one instance, the lowest IRR was for Camp Buehring, and the highest was for Camp Arifjan (for asthma, the highest IRR was for Camp Taji)—the two camps without burn pits.

Abraham et al. (2014) conducted another analysis of the same population and data with a few differences. First, the U.S.-based reference group was much smaller than that used previously and by Sharkey et al. The reference group for Abraham et al. was defined as service members stationed in the United States as of April 2006 and for whom deployment occurred after June 2007, resulting in a reference group of 112,091 U.S.-based personnel (the number of personnel at the four bases and Korea remained the same between studies). Second, the authors made additional comparisons between the four bases and Korea and between bases with and without burn pits.

Compared with the rates for all U.S. personnel, the rates of medical encounters for respiratory diseases among personnel deployed to the four bases were elevated (respiratory symptoms: IRR = 1.25, 95% CI 1.20–1.30; asthma: IRR = 1.54, 95% CI 1.33–1.78; COPD and allied conditions: IRR = 1.12, 95% CI 0.96–1.31). Rates for bases with burn pits and without burn pits were also significantly elevated for both asthma and respiratory symptoms (as well as for Joint Base Balad, Camp Taji, and Camp Arifjan, individually). Compared with the rates for personnel stationed in Korea, the rates of medical encounters for respiratory symptoms and asthma were only slightly elevated and not statistically significant. However, rates of medical encounters for COPD and allied symptoms were elevated compared with personnel stationed in Korea, although the difference was statistically significant only for Camp Arifjan (IRR = 1.43, 95% CI 1.05–1.94) and the pooled estimates that included it. Comparing the bases with burn pits with the bases without burn pits (Balad and Taji to Arifjan and Buehring) showed no statistically significant associations (respiratory symptoms: IRR = 0.95, 95% CI 0.88–1.03; asthma: IRR = 0.93, 95% CI 0.69–1.25; COPD and allied conditions: IRR = 0.90, 95% CI 0.65–1.23). The results of these studies indicate that post-deployment health risk is elevated but that the risk is not associated with burn pits (Abraham et al., 2014).

Three publications (Jones et al., 2012; Powell et al., 2010; Smith et al., 2012) reported on the health of participants of the Millennium Cohort Study who had deployed within 3 miles of a burn pit between 2003 and 2008, and were additional analyses of investigations performed by the Naval Health Research Center (AFHSC et al., 2010). The earlier results by the Naval Health Research Center were based on a 5-mile radius and were reviewed in the 2011 IOM report (AFHSC et al., 2010). The Millennium Cohort consisted of more than 27,000 personnel deployed in support of OEF/OIF and included more than 3,000 participants considered exposed, with at least one deployment within a 3-mile radius of a documented burn pit (at Joint Base Balad, Camp Taji, or Camp Speicher). Burn pit exposure proxies were defined as the cumulative number of days within the specified radius and the cumulative number of days within the radius at specific bases. Exposed participants were compared with participants

who were deployed to other locations in Iraq and Afghanistan. The Millennium Cohort is considered representative of U.S. military personnel, with reliable self-reported information obtained prior to enrollment which serves as a baseline for subsequent health status. The self-reported health of respondents who participated in the 2004–2006 and 2007–2008 survey cycles was examined (AFHSC et al., 2010).

New cases of self-reported asthma, chronic bronchitis or emphysema, and persistent cough or shortness of breath were reported at follow-up (2007–2008) but not at the baseline assessment (2004–2006). There were no significant differences in newly diagnosed asthma, bronchitis, emphysema, or self-reported respiratory symptoms between those deployed to areas within 5 miles of burn pits and those not exposed, nor were there differences by base site. Analyses were adjusted for smoking status, physical activity, and other covariates measured at baseline (AFHSC et al., 2010). The findings using a 3-mile radius were similar to those using a 5-mile radius (Smith et al., 2012). After adjusting for all covariates in the multivariable logistic regression, the authors found that deployment within 3 miles of the burn pits did not significantly increase the risk for newly reported chronic bronchitis or emphysema (adjusted odds ratio [AOR] = 0.91; 95% CI 0.67–1.24), newly reported asthma (AOR = 0.94; 95% CI 0.70–1.27), or self-reported respiratory symptoms (AOR = 1.03; 95% CI 0.94–1.13) when compared with deployments to other regions of Iraq or Afghanistan with no documented burn pits. Risk did not increase with cumulative days of exposure or by base. Deployment location within 3 miles of the burn pits was not statistically associated with an increase in odds of newly reported symptoms when compared with those who were deployed to other locations (p = 0.71). The study found no significant associations with cumulative days exposed (p = 0.63) nor with deployment to a specific burn pit site (p = 0.97). Within the 2-mile radius, results were similar with the exception of U.S. Air Force personnel deployed to Joint Base Balad, who were found to be at an increased risk for respiratory symptoms (AOR = 1.24; 95% CI 1.01–1.52) when compared with those deployed to other locations.

Autoimmune Diseases

Similar to Smith et al. (2012), Jones et al. (2012) reported on the risks of disease among service personnel deployed within a 3-mile radius of a burn pit. Newly reported lupus and rheumatoid arthritis were identified at baseline using the question, “Has your doctor or other health professional ever told you that you have any of the following conditions?” At follow-up, participants were asked the same question but in the context of “in the last 3 years.” Case confirmation of newly reported lupus and rheumatoid arthritis was performed through a review of electronic medical records. Analyses were restricted to U.S. Army and Air Force personnel.

For lupus, the study population consisted of 19,157 Millennium Cohort members, with 3,201 having served within 3 miles of a burn pit; 21 new cases of lupus were identified (Jones et al., 2012). At the 5-mile radius of a burn pit, there was no association with a new diagnosis of lupus, cumulative exposure, or being deployed to Camp Taji or Camp Speicher. However, a significant increase was observed in the likelihood of a lupus diagnosis for those deployed to Joint Base Balad (OR = 3.52, 95% CI 1.59–7.79) compared with those deployed to locations without burn pits (AFHSC et al., 2010; IOM, 2011). At the 3-mile radius, there was no association between cumulative days of burn pit exposure and lupus. However, all six of the lupus cases within 3 miles were stationed at Joint Base Balad, which resulted in a statistically significant risk (OR = 3.65, 95% CI 1.56–8.51).

For rheumatoid arthritis, the study population consisted of 18,848 Millennium Cohort Study members, with 3,145 having served within 3 miles of a burn pit, and 234 new cases of rheumatoid arthritis (Jones et al., 2012). Within 5 miles, there was no association with deployment to a burn pit location, cumulative days exposed, or specific site, with the exception of an increase in rheumatoid arthritis diagnoses for those exposed to burn pits for 132–211 days (OR = 2.03, 95% CI 1.18–3.49), although exposure for more than 211 days was not statistically significant (AFHSC et al., 2010; IOM, 2011). Within 3 miles of a burn pit, there was no association of rheumatoid arthritis with either cumulative days of exposure or site (Jones et al., 2012).

Electronic medical records were used to confirm 2 lupus cases and 10 rheumatoid arthritis cases among active-duty personnel diagnosed while in the military. Among the verified cases, no association between lupus or rheumatoid arthritis and exposure to burn pits was found (AFHSC et al., 2010; IOM, 2011; Jones et al., 2012). The investigators found that deployed personnel exposed to documented burn pits in the combined Joint Base Balad, Camp Taji, and Camp Speicher sites were not at an elevated risk of lupus or rheumatoid arthritis (Jones et al., 2012).

Chronic Multisymptom Illness

Following Smith et al. (2012) and Jones et al. (2012), Powell et al. (2012) also investigated the health effects of exposure to burn pits among Millennium Cohort Study members deployed within 3 miles of a burn pit. In this study, chronic multisymptom illness (CMI) was defined as having reported at least one symptom in at least two of the following symptom constructs: general fatigue, mood and cognitive problems, and musculoskeletal discomfort.

Among the 21,400 study participants, 3,578 had served within 3 miles of a burn pit. There were 956 personnel deployed within 3 miles of a burn pit and 4,608 unexposed personnel with CMI (Powell et al., 2012). CMI was not statistically significantly associated (p = 0.16) with being deployed within a 5-mile radius of a burn pit, cumulative exposure to a burn pit overall, or being deployed to Joint Base Balad, Camp Taji, or Camp Speicher when adjusted for baseline covariates (sex, birth year, education, service component, service branch, pay grade, smoking status, alcohol-related problems, mental health symptoms, and baseline CMI status). However, cumulative exposure to a burn pit for more than 210 days was associated with a slight increase in risk for CMI (OR = 1.22, 95% CI 1.04–1.44) (AFHSC et al., 2010; IOM, 2011).

After adjusting for baseline covariates in the models, deployment within a 3-mile radius of a documented burn pit was not found to be significantly associated with CMI (p = 0.23), nor were cumulative days of burn pit exposure or individual sites. There was a small significant increase in risk among persons exposed for greater than 209 days (OR = 1.19, 95% CI 1.02–1.40) as there was for those deployed within the 5-mile radius. The authors found no increased risk of reporting CMI symptoms when they compared personnel deployed within 2, 3, and 5 miles of a documented burn pit and when comparing lengths of time at the various bases (Powell et al., 2012).

Discussion

The committee reviewed five publications reporting new epidemiologic studies of long-term health effects in military personnel associated with burn pits. Three examined respiratory outcomes, one investigated rates of lupus and rheumatoid arthritis, and one examined CMI. All suffer from various limitations, such as a reliance on self-reported data (Jones et al., 2012; Powell et al., 2012; Smith et al., 2012) and two publications described nearly the same study but with slight methodological differences, so they cannot be interpreted independently (Abraham et al., 2014; Sharkey et al., 2015).

None of these studies provide a thorough evaluation of the health effects associated with burn pit exposures, even though they all contribute pieces to the overall picture of the evidence base. There are still many gaps in that picture, and there is still work to be done. Furthermore, no single epidemiologic study is ever definitive.

Overall, little new evidence linking respiratory symptoms or diseases with exposure to burn pits has been published, although some studies suggest that deployment to the Southwest Asia theater of operations may play a role (Abraham et al., 2014). Recently published reviews further support this observation and indicate a predominance of airway obstruction and hyperreactivity among deployed personnel (Abraham et al., 2015; Falco et al., 2015; Morris et al., 2011). Furthermore, these studies do not provide new evidence linking burn pit exposure to autoimmune disease or CMI.

The 2011 IOM report indicated that there was “limited/suggestive evidence of an association between exposure to combustion products and reduced pulmonary function,” but evidence was inadequate/insufficient for other health outcomes mostly based on studies in firefighters and incinerator workers or communities around incinerators. While the new evidence is less than sufficient, it does not show that service members are at an increased risk of health effects associated with burn pits in particular, although other hazards may be important contributors to respiratory symptoms and disease.

ORGANIZATION OF THE REPORT

The remainder of this report is divided into six chapters plus supporting appendixes. Chapter 2 presents a broad overview of the use of registries for health research and a discussion of some of the inherent limitations of using registry data for assessing associations and drawing conclusions concerning the relationship between exposures and health outcomes.

Chapter 3 centers on the origin, development, and implementation of the AH&OBP Registry and its key element, the self-assessment questionnaire. It includes assessments of the design of the questionnaire and the recruitment and enrollment of registry participants.

Chapter 4 is the first of three chapters that describe the methods and results of the committee’s analysis of the initial months of AH&OBP Registry data. An overview of the data requested and received is presented along with descriptive statistics regarding the demographic and military service characteristics of registry respondents.

Chapter 5 summarizes the information provided to the committee on respondents’ exposure to burn pit emissions and other important airborne exposures. The limitations of these data are discussed, and suggestions are offered for how the data may best be put to use in evaluating the magnitude, duration, and frequency of respondents’ exposure.

Chapter 6 turns to the AH&OBP Registry’s health outcomes data, focusing on those conditions and diseases that the committee believes are most relevant to assessing the potential health effects of exposures to burn pits and other airborne hazards. It presents descriptive statistics for these outcomes, describes the approaches used to analyze the data, and concludes with a discussion of how this information may be used to assess associations between health outcome and exposures.

The final chapter of this report, Chapter 7, draws together the committee’s primary findings, conclusions, and recommendations and offers perspectives on them.

Appendix A contains an excerpt from Public Law 112-260, § 201 regarding the origination of the AH&OBP Registry and this study. The agenda for a public workshop held by the committee in May 2015 is presented in Appendix B. The most recent version of the AH&OBP Registry questionnaire that is publicly available (dated December 15, 2014) is reproduced in Appendix C. Appendix D contains a list of each data variable requested by the committee, the source of each data variable, and whether the variable was made available. Appendix E presents tables of the multivariate model results and estimates that were used to generate the figures in Chapter 6. Appendix F provides biographical sketches of the committee members and the National Academies staff who worked on this report.

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