Advances in Comprehensive Exposure Assessment: Opportunities for the US Military

The need for a cancer exposome atlas: a scoping review

BACKGROUND

Despite advances in understanding genetic susceptibility to cancer, much of cancer heritability remains unidentified. At the same time, the makeup of industrial chemicals in our environment only grows more complex. This gap in knowledge on cancer risk has prompted calls to expand cancer research to the comprehensive, discovery-based study of nongenetic environmental influences, conceptualized as the "exposome."

METHODS

Our scoping review aimed to describe the exposome and its application to cancer epidemiology and to study design limitations, challenges in analytical methods, and major unmet opportunities in advanced exposome profiling methods that allow the quantification of complex chemical exposure profiles in biological matrices. To evaluate progress on incorporating measurements of the exposome into cancer research, we performed a review of such "cancer exposome" studies published through August 2023.

RESULTS

We found that only 1 study leveraged untargeted chemical profiling of the exposome as a method to measure tens of thousands of environmental chemicals and identify prospective associations with future cancer risk. The other 13 studies used hypothesis-driven exposome approaches that targeted a set of preselected lifestyle, occupational, air quality, social determinant, or other external risk factors. Many of the included studies could only leverage sample sizes with less than 400 cancer cases (67% of nonecologic studies) and exposures experienced after diagnosis (29% of studies). Six cancer types were covered, most commonly blood (43%), lung (21%), or breast (14%) cancer.

CONCLUSION

The exposome is underutilized in cancer research, despite its potential to unravel complex relationships between environmental exposures and cancer and to inform primary prevention.

Military and occupational exposures among Veterans in the Million Veteran Program by survey self-report: a descriptive study

OBJECTIVE

We aimed to characterise self-reported military and occupational exposures including Agent Orange, chemical/biological warfare agents, solvents, fuels, pesticides, metals and burn pits among Veterans in the Department of Veterans Affairs Million Veteran Program (MVP).

METHODS

MVP is an ongoing longitudinal cohort and mega-biobank of over one million US Veterans. Over 500 000 MVP participants reported military exposures on the baseline survey, and over 300 000 reported occupational exposures on the lifestyle survey. We determined frequencies of selected self-reported occupational exposures by service era, specific deployment operation (1990-1991 Gulf War, Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF)), service in a combat zone and occupational categories. We also explored differences in self-reported exposures by sex and race.

RESULTS

Agent Orange exposure was mainly reported by Vietnam-era Veterans. Gulf War and OEF/OIF Veterans deployed to a combat zone were more likely to report exposures to burn pits, chemical/biological weapons, anthrax vaccination and pyridostigmine bromide pill intake as compared with non-combat deployers and those not deployed. Occupational categories related to combat (infantry, combat engineer and helicopter pilot) often had the highest percentages of self-reported exposures, whereas those in healthcare-related occupations (dentists, physicians and occupational therapists) tended to report exposures much less often. Self-reported exposures also varied by race and sex.

CONCLUSIONS

Our results demonstrate that the distribution of self-reported exposures varied by service era, demographics, deployment, combat experience and military occupation in MVP. Overall, the pattern of findings was consistent with previous population-based studies of US military Veterans.

International perspective on military exposure data sources, applications, and opportunities for collaboration

Military personnel may be exposed to a range of hazards. The assessment, documentation and reporting of military exposure information are important steps to guide health protection, services, and research to support actively serving members and veterans. In 2021, a Working Group of researchers from veteran and defense administrations across the Five Eyes countries (Australia, Canada, New Zealand, the United Kingdom, and the United States) was established to examine large military exposure data sources available in each country, their applications, and opportunities to leverage information across administrations and internationally. We provide a brief summary of this work here to highlight some successful examples of data applications and to elicit interest in this evolving area of exposure science.

A Clinician's Guide to Occupational Exposures in the Military

PURPOSE OF REVIEW

Adverse occupational and environmental exposures are common causes of respiratory disease and health consequences requiring medical care. Understanding how these various exposures affect patients and how to elicit an adequate history is critical for any clinician. Military personnel are often overlooked when discussing groups at risk for environmental exposure-associated airway disease. There are close to 20 million active duty and veterans in the USA, and nearly all clinicians will at some point care for a patient that has served in the military.

RECENT FINDINGS

Exposures related to military work include burn pits, chemicals/toxins, sandstorms, and living conditions. Burn pits and military waste are increasingly recognized as potential hazards attributed to the ongoing conflicts in the Middle East. The link between these various military exposures and acute or chronic airway diseases remains difficult. Epidemiological studies are emerging to demonstrate correlations with chronic lung disease and prolonged burn pit exposure. This review provides an overview of potential occupational and environmental exposures that may affect current and/or former military service men and women.

Lessons Learned From Presumptive Condition Lists in Veteran Compensation Systems

Presumptive condition lists formally accept connections between military factors and veteran health conditions. An environmental scan of such lists and their evidentiary basis was conducted across four veterans' administrations to inform other administrations considering the development of such lists. Information on included conditions, qualifying military factors, and scientific processes was obtained through targeted internet searches and correspondence with veterans' administrations. The content of presumptive condition lists across jurisdictions varied by conditions included, as well as military eligibility requirements (e.g., service in particular conflict, context, or time period). Scientific review processes to develop lists also varied across jurisdictions. Findings indicate that evidence and experience may be leveraged across compensation systems (veteran and civilian). Ongoing research to understand links between military exposures and veteran health is recommended.

Hazardous Non-Combat Exposures in the U.S. Department of Defense

Hazardous non-combat exposures are inherent to military service and occur in three settings: installation workplaces, installation environments, and deployment environments. Few military clinicians receive training in how to recognize, assess, and manage patients with these exposures, and systems improvements are needed to support clinicians with respect to exposure recognition and management. This commentary highlights key concepts surrounding military non-combat exposures by discussing three case examples of exposures occurring in each of these settings. In the workplace, well-coordinated, interdisciplinary occupational health teams improve identification of exposure-related illnesses, and these teams may be further supported by the development of automated clinical decision-support systems. Installation environmental exposures are characterized by high perceived risk, uncertainty in estimating actual risk, and a wide range of stakeholders including military family members and individuals in the surrounding community. Recognizing environmental exposure concerns, gathering a thorough environmental exposure history, and practicing exposure risk communication are vital skills to address these situations. During deployments, exposures may initially be perceived as low risk but then become a concern years later. A functional understanding of the capabilities and limitations of exposure monitoring and potential health effects of exposures helps the military clinician effectively communicate potential health risks to line leaders. For any of these exposure settings, service public health centers and OEM specialty leaders and consultants are available for consultation.

New and Emerging Risk Factors in Occupational Health

Workplace health and safety is constantly evolving both in developed and developing countries. Under the tumultuous development of technology, working environments are changing, leading to the onset of new occupational hazards and unprecedented risk conditions deriving from the new ways of organizing work. At the same time, progress in medical science, with the knowledge in the fields of genetics, metabolomics, big data, and smart technologies, makes it possible to promptly identify and treat risk conditions that would have escaped notice in the past. Personalized occupational medicine represents the frontier of prevention in the workplace, from the perspective of total worker health and the sustainability of resources. The contributions to this Special Issue range from chemical, physical, and biological to psychosocial risks, and from the search for new ways to control long-known risks, such as mercury toxicity, to observations of the most frequent pathologies in the workplace in the last twenty years, such as repetitive trauma diseases, immunodeficiency transmitted as a result of biological injuries, and violence and psychological trauma in the workplace. New insights are needed in occupational health and safety practice to address the new challenges in this field.

Considering Exposure Assessment in Epidemiological Studies of Chronic Health in Military Populations

Exposure assessment is an important factor in all epidemiological research seeking to identify, evaluate, and control health risks. In the military and veteran context, population health research to explore exposure-response links is complicated by the wide variety of environments and hazards encountered during active service, long latency periods, and a lack of information on exposures in potentially vulnerable subgroups. This paper summarizes some key considerations for exposure assessment in long-term health studies of military populations, including the identification of hazards related to military service, characterization of potentially exposed groups, exposure data collection, and assignment of exposures to estimate health risks. Opportunities and future directions for exposure assessment in this field are also discussed.

Use of Biomarkers to Assess Environmental Exposures and Health Outcomes in Deployed Troops

OBJECTIVE

This paper provides an overview of our Military Biomarkers Research Study (MBRS) designed to assess whether biomarkers can be used to retrospectively assess deployment exposures and health impacts related to deployment environmental exposures.

METHODS

The MBRS consists of four phases. Phase I was a feasibility study of stored sera. Phase II looks at associations between exposures and biomarkers. Phase III examines relationships of biomarkers and health outcomes, and Phase IV investigates in vitro biomarker changes associated with exposures to chemicals of interest. This paper briefly summarizes work already published and introduces the new reports contained in this supplement.

RESULTS

Novel biomarkers were identified. These were associated with deployment exposures.

CONCLUSIONS

Significant associations were noted between deployment exposures, microRNA biomarkers and metabolomic biomarkers, and deployment health outcomes.