Short-term PM exposure and social stress cause pulmonary and cardiac dysfunction

Current understanding of the impact of United States military airborne hazards and burn pit exposures on respiratory health

Millions of United States (U.S.) troops deployed to the Middle East and Southwest Asia were exposed to toxic airborne hazards and/or open-air burn pits. Burn pit emissions contain particulate matter combined with toxic gasses and heavy metals. Ongoing research has demonstrated that exposures to the airborne hazards from military burn pits have profound and lasting health and wellness consequences. Research on the long-term health consequences of exposure to open burn pits has been limited. Work continues to understand the scope of the health impacts and the underlying pathobiology following exposures and to establish care standards. The U.S. Sergeant First Class Heath Robinson Honoring our Promise to Address Comprehensive Toxics (PACT) Act was signed into law August 2022. This act expands the benefits and services to U.S. Veterans exposed to toxicants, requires the Veterans Health Administration to provide toxic exposure screening, and supports increased research, education, and treatment due to toxic occupational exposures. This review highlights the state of the science related to military burn pit exposures research with an emphasis on pulmonary health. Clinical data demonstrate areas of reduced or delayed pulmonary ventilation and lung pathologies such as small airways scarring, diffuse collagen deposition and focal areas of ossification. Identification and characterization of foreign matter deposition in lung tissues are reported, including particulate matter, silica, titanium oxides, and polycyclic aromatic hydrocarbons. These data are consistent with toxic exposures and with the symptoms reported by post-deployment Veterans despite near-normal non-invasive pulmonary evaluations. On-going work toward new methods for non-invasive pulmonary diagnoses and disease monitoring are described. We propose various studies and databases as resources for clinical and health outcomes research. Pre-clinical research using different burn pit modeling approaches are summarized, including oropharyngeal aspiration, intranasal inhalation, and whole-body exposure chamber inhalation. These studies focus on the impacts of specific toxic substances as well as the effects of short-term and sustained insults over time on the pulmonary systems.

Associations Between Self-Reported Burn Pit Exposure and Functional Status, 1990-2021

INTRODUCTION

The Airborne Hazards and Open Burn Pit Registry (AHOBPR) allows service members to self-report exposure to burn pits during military deployments and functional status (a composite metric of physical fitness status). This study investigated whether general exposure to burn pits, specific performance of burn pit duties, or the cumulative number of days deployed in Southwest Asia was associated with a change in functional status.

MATERIALS AND METHODS

A retrospective cross-sectional analysis of 234,061 participants in the AHOBPR who completed questionnaires before August 2021 was conducted. Exposure was presumed if an individual reported any burn pits exposure during deployment or if an individual reported having to work at a burn pit as part of their duties and was quantified by the cumulative-reported exposure days. The outcome was the reported composite functional score. Statistical analysis used linear regression, which was adjusted for significant variables. A possible dose-response effect from cumulative deployment and burn pits exposure days was evaluated. Statistical significance was determined at P < 0.05.

RESULTS

The burn pit exposure groups were notably different in size (exposed: 230,079, non-exposed: 3982) and were significantly different for all compared variables. There was a negative association between cumulative exposure days and functional score with a significant test for trend. There was a marginal positive significant association between cumulative deployment days and functional score with a significant test for trend. Reporting exposure to burn pit duties was also significantly associated with a lower functional score.

CONCLUSION

This study suggests a dose-response relationship between cumulative burn pit exposure and decreased functional status. It also suggests a modest positive relationship between cumulative deployment days and reported function, which may represent a "healthy deployer" effect.

Military burn pit exposure and airway disease: Implications for our Veteran population

Millions of veterans have been exposed to burn pit smoke during combat deployments throughout the last three decades. Toxic compounds present in burn pit fumes that may cause or exacerbate upper and lower airway diseases include dioxins, polyaromatic hydrocarbons, and particulate matter, among others. There have been several observational studies evaluating the potential role of burn pit exposure in the development of a multitude chronic health conditions, and the veterans Administration has established the Airborne Hazards and Open Burn Pit Registry in 2014. However, specific causality of airway disease from burn pits has been difficult to prove, and there are multiple barriers toward etiologic research. Preclinical models have demonstrated airway dysfunction and inflammation but modeling human exposures remains challenging. Here, we review the current literature on the potential impact of burn pit exposure on chronic airway disease.