The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 62... ...
to provide information from health care and other administrative records for use in original analyses to be conducted by the committee. Because the results of any single data analysis may be limited by data quality and availability, the committee supplemented its original data analyses with a structured literature review to facilitate a more holistic assessment of potential relationships of military-related exposures and selected health outcomes.
|
From page 63... ...
were requested but not provided, and the effect that lack is described in the next section on outcomes data. TABLE 4-1 Summary of Data and Data Sources Requested and Included in the Limited Data set VA provided to the Committee Dataset Data Owner Data Description Sources of Exposure Data Exposure Pathway DHA ILER Reported environmental exposures (from monitoring by environmental science and engineering officers)
|
From page 64... ...
. The committee chose to add anxiety disorders, adjustment disorders, sleep disorders, and SUDs because of known or perceived interest in their etiology among post-9/11 veteran communities.
|
From page 65... ...
BOX 4-1 Health Outcomes Mental Health Outcomes • Adjustment disorders • Attention disorders • Anxiety disorders • Depression • Posttraumatic stress disorder • Serious mental illness: o Psychosis and schizophrenia o Bipolar disorder • Sleep disorders • Substance use disorders • Nonfatal suicide attempts and intentional self-harm Neurologic Outcomes • Amyotrophic lateral sclerosis • Dementia • Multiple sclerosis • Parkinson's disease Chronic Multisymptom Illness NOTE: Traumatic brain injury was included in the statement of task but not considered as an independent outcome because it is diagnosed from a physical trauma and does not have a known exposure pathway. Data on each of the outcomes came from ICD-10 diagnostic codes recorded in inpatient and outpatient records available in VHA's Corporate Data Warehouse (CDW)
|
From page 66... ...
The committee worked with DHA to develop a custom data extract comprising exposure information linked to personnel and deployment records. The committee requested all relevant deployment information from the geographic areas of interest 3 and two sources of exposure data from Defense Occupational and Environmental Health Readiness 3 The Southwest Asia Theater of Operations and Afghanistan.
|
From page 67... ...
After preliminary analyses, the committee determined that differences in the two datasets and sample sizes required a different approach. For example, in the exposure pathway data, exhaust exposures were identified using keywords such as "exhaust" and "combustion." In contrast, keywords in the industrial hygiene data identified specific chemicals typically associated with exhaust, such as "nitrogen dioxide," "sulfur dioxide," and "polycyclic aromatic compounds." Without clear source attribution, many of the industrial hygiene keywords were associated with multiple exposures of interest and so not directly comparable to those in the other dataset (e.g., specific chemicals versus broader sources in the exposure pathway dataset)
|
From page 68... ...
Solid bullets denote committee-determined groupings of exposure categories, and indented, empty bullets denote the specific types of exposures as named in the exposure pathway data that are included in the broader category designation. BOX 4-2 Exposures from ILER-Exposure Pathway Data • Burn Pits o Burn pit, burn barrel, landfill • Dust o Desert dust, road dust, PM10, PM2.5, combined PM10 and PM2.5 • Exhaust o Diesel, jet • Fuel o Diesel, jet • Incinerator Emissions • Metals o Aluminum smelting, hexavalent chromium, welding metals, lead, depleted uranium • Mold • Radiation o Ionizing radiation, nickel-63 • Solvents o Oil, cleaners, and solvents Covariate Data Covariate data came from both ILER and VA.
|
From page 69... ...
. Some information was available on factors such as TBI and combat-related or other traumas that may have been concurrent with deployment-related environmental and occupational exposures and could influence the associations of interest; however, the data do not specify the timing of these exposures.
|
From page 70... ...
Analytic Methods Before running preliminary descriptive statistics, the committee determined that several models would be run for each exposure–outcome pair, as each model would add complexity or account for different factors. For each pair, unadjusted and adjusted conditional logistic regression models were used to estimate the odds of exposure for matched case-control pairs.
|
From page 71... ...
The study population does not capture health effects of military exposures from those who are still in the military. Separation may be affected by any health effects of military exposures (e.g., those with serious health conditions caused or exacerbated by exposures may be more likely to separate sooner)
|
From page 72... ...
. However, approximately 40% of exposure pathways and 50% of industrial hygiene exposure end dates were missing or invalid dates.
|
From page 73... ...
. This type of selection bias will often cause service members with occupational exposures at lower levels to exhibit less risk for disease until they have a much higher dose, duration, or accumulation of exposures.
|
From page 74... ...
However, because many mental health and neurologic conditions are disqualifying for military service, it is likely that these were incident at some point within service or after separation. STRUCTURED LITERATURE REVIEW In recognition of the limitations of drawing conclusions from any singular analysis, particularly when the quality of the underlying data is limited, the committee conducted a review of the epidemiologic literature as a source of supporting evidence to contextualize the results of PREPUBLICATION COPY: UNCORRECTED PROOFS
|
From page 75... ...
The committee acknowledges that reliance on general epidemiologic literature rather than veteran-specific literature may in some cases have limited relevance to military exposures. For example, because the committee only had information on exposure sources and not specific toxicants, the chemical composition of military exposures may differ from civilian exposures (e.g., PM from burn pits may not be chemically similar to PM from ambient air)
|
From page 76... ...
Publication Types: Peer-reviewed primary research, systematic reviews, meta-analyses Publication Dates: January 1, 2013–August 1, 2024 Exposure of Interest Sample Search Terms Burn Pits • Burn pit • Pit registry • Waste burning • Air pollution • Open burning • Smoke • Soot Particulate Matter • Exhaust gas • Air pollutant • Atmospheric pollution • Air pollution • Ozone • PM10 • PM2.5 • Ambient particulate matter • Vehicular emissions PREPUBLICATION COPY: UNCORRECTED PROOFS
|
From page 77... ...
Depression • Depression • Mood disorders (excluding bipolar disorder) Posttraumatic Stress Disorder (PTSD)
|
From page 78... ...
• Alcohol-related disorders • Opioid-related disorders • Substance-related disorders • (Excluding tobacco use disorder, neonatal abstinence syndrome) Nonfatal Suicide Attempts and Intentional • Self-injurious behavior Self-Harm • Suicidal ideation • Suicide • Attempted suicide • Suicide, completed Amyotrophic Lateral Sclerosis (ALS)
|
From page 79... ...
Selection bias is challenging to overcome once data collection is complete, particularly in situations with limited information about the base population from which the sample was drawn (all veterans who served in Southwest Asia theater of operations or Afghanistan after 9/11)
|
From page 80... ...
Second, the committee's charge was to assess "… possible [emphasis added] relationships between toxic exposures experienced during military service and mental health conditions and other health outcomes." The committee interpreted "possible" to mean that VA was interested in holistic evidence regarding whether associations were possible and not formal determinations about evidence based on specific statistics, such as p-values.
|
From page 81... ...
evaluating the health effects of environmental and occupational exposures. Because the committee was not tasked with a weight-of-the-evidence review, each individual study captured in its search was not assessed; rather, their number, general quality, and consistency were used to support findings for each exposure–outcome pair in the original data analysis.
|
From page 82... ...
The committee considered four possible hypothetical scenarios of consistency of findings between its original analyses and the epidemiologic literature, in terms of strength and magnitude of the observed association. For each one, the committee classified a possible relationship into one of two conclusions: • The committee concluded that there was a possible risk-conferring relationship between a given exposure and a given outcome for the following three scenarios: o The evidence from both the data analyses and available epidemiologic literature showed consistent risk-conferring effects, o The evidence from the data analysis showed a possible risk-conferring relationship and there was mixed, limited, or no identified epidemiologic literature, or o The data analysis did not show a possible risk-conferring relationship, but the epidemiologic literature showed suggestive evidence of a risk conferring relationship.
|
From page 83... ...
Neurologic outcomes include ALS, dementia, MS, and Parkinson's disease. The committee identified burn pits, dust and PM, exhaust, fuels, incinerator emissions, metals, mold, radiation, and solvents as the military-related environmental and occupational exposures based on its expertise and the available data.
|
From page 84... ...
1998. Chronic multisymptom illness affecting Air Force veterans of the Gulf War.
|
From page 85... ...
2014. Chronic multisymptom illness in Gulf War veterans: Case definitions reexamined.
|
From page 86... ...
2000. Prevalence and patterns of Gulf War illness in Kansas veterans: Association of symptoms with characteristics of person, place, and time of military service.
|
From page 87... ...
Version 3.0 -- June 2021. Washington, DC: Department of Veterans Affairs and Department of Defense.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.