On September 11, 2020 the National Academies of Sciences, Engineering and Medicine, Committee on Respiratory Health Effects of Airborne Hazards Exposures in the Southwest Asia Theater of Military Operations, released the subject Report. In part, the Report said that:
“Southwest Asia theater veterans were exposed to a broad range of potentially hazardous airborne agents. These include such regional environmental exposures as air pollution from dusts; local point and area sources such as traffic, waste management, and local industries; and the aeroallergens and microbial agents present in the theater. Exposures related to military operations are also contributors, such as exhaust from heaters, military vehicles, and aircraft as well as smoke from structural fires, explosions, burning oil wells, or burn pits.” Continuing,
“CONCLUSIONS REGARDING THE ASSOCIATION BETWEEN IN-THEATER AIRBORNE HAZARDS AND RESPIRATORY HEALTH OUTCOMES
The health effects of these airborne hazards were likely influenced by factors common to military operations in Southwest Asia. These effect modifiers include temperature extremes, psychosocial stress, sleep deprivation, and noise.
The committee formulated a list of 27 health outcomes for their literature review, delineated in Box S-2 [below]. The list included the conditions explicitly listed in the Statement of Task and those that the committee believed to be “of great concern to veterans.”
Of these outcomes, none met the criteria for sufficient evidence of an association. The evidence for respiratory symptoms—which included chronic persistent cough, shortness of breath (dyspnea), and wheezing—met the criteria for limited or suggestive evidence of an association for both veterans who served in the 1990–1991 Gulf War and those who served in the post-9/11 conflicts. Studies considered in previous National Academies reports were relatively consistent in reporting associations between deployment and more prevalent self-reported respiratory symptoms in theater veterans, and outcomes from more recent studies are largely in line with those findings. Importantly, a recent study that compared symptom reporting before, during, and after deployment found that the self-reported frequency of symptoms was increased both during and after deployment relative to pre-deployment. Many of the studies considered, however, were weakened by bias induced by the self-selection of their participants (which may have led to people being more likely to participate if they had respiratory symptoms than if they did not) and by the lack of control for cigarette smoking, which is known to exacerbate symptoms. These concerns, while serious, were consistent with a classification in the limited or suggestive category. Lastly, the committee
BOX S-2
Respiratory Health Outcomes Addressed
Non-Cancer Respiratory Disorders
Upper Airway Disorders
Rhinitis Sinusitis
Non-Infectious Lower Airway
Asthma
Chronic bronchitis
Chronic obstructive pulmonary disease
Interstitial Lung Diseases
Acute eosinophilic pneumonia Hypersensitivity pneumonitis Idiopathic interstitial pneumonia
Infectious Lower Airway
Acute bronchitis Pneumonia
Respiratory Symptoms
Chronic persistent cough Shortness of breath (dyspnea)
Respiratory Cancers
Esophageal cancer Laryngeal cancer
Other Outcomes
Sleep apnea
Vocal cord dysfunction
Constrictive bronchiolitis Emphysema
Idiopathic pulmonary fibrosis Pulmonary alveolar proteinosis Sarcoidosis
Tuberculosis
Wheeze
Lung cancer
Oral, nasal, and pharyngeal cancers
Changes in pulmonary function
Mortality due to diseases of the respiratory system
concluded that there is limited or suggestive evidence of no association between deployment to the 1990–1991 Gulf War and changes in lung function.
The committee found that there was inadequate or insufficient information to evaluate the association between service in the Southwest Asia theater and all of the remaining respiratory health outcomes it examined. While there are a variety of reasons for this that vary by the outcome under consideration, one prominent cause was the lack of good exposure characterization. Many studies used deployment to the theater as their only metric of exposure, and this undoubtedly led to people with widely different exposure experiences being grouped together for analysis purposes. Such grouping would be expected to diminish the possibility of observing an effect if one existed if there were large numbers of those with relatively low exposure compared with those with relatively high exposure.
