Chronic respiratory symptoms following deployment-related occupational and environmental exposures among US veterans

OBJECTIVES

Characterise inhalational exposures during deployment to Afghanistan and Southwest Asia and associations with postdeployment respiratory symptoms.

METHODS

Participants (n=1960) in this cross-sectional study of US Veterans (Veterans Affairs Cooperative Study 'Service and Health Among Deployed Veterans') completed an interviewer-administered questionnaire regarding 32 deployment exposures, grouped a priori into six categories: burn pit smoke; other combustion sources; engine exhaust; mechanical and desert dusts; toxicants; and military job-related vapours gas, dusts or fumes (VGDF). Responses were scored ordinally (0, 1, 2) according to exposure frequency. Factor analysis supported item reduction and category consolidation yielding 28 exposure items in 5 categories. Generalised linear models with a logit link tested associations with symptoms (by respiratory health questionnaire) adjusting for other covariates. OR were scaled per 20-point score increment (normalised maximum=100).

RESULTS

The cohort mean age was 40.7 years with a median deployment duration of 11.7 months. Heavy exposures to multiple inhalational exposures were commonly reported, including burn pit smoke (72.7%) and VGDF (72.0%). The prevalence of dyspnoea, chronic bronchitis and wheeze in the past 12 months was 7.3%, 8.2% and 15.6%, respectively. Burn pit smoke exposure was associated with dyspnoea (OR 1.22; 95% CI 1.06 to 1.47) and chronic bronchitis (OR 1.22; 95% CI 1.13 to 1.44). Exposure to VGDF was associated with dyspnoea (OR 1.29; 95% CI 1.14 to 1.58) and wheeze (OR 1.18; 95% CI 1.02 to 1.35).

CONCLUSION

Exposures to burn pit smoke and military occupational VGDF during deployment were associated with an increased odds of chronic respiratory symptoms among US Veterans.

Postdeployment Respiratory Health Care Encounters Following Deployment to Kabul, Afghanistan: A Retrospective Cohort Study

Inhalational hazards are numerous in operational environments. A retrospective cohort study was conducted to investigate associations between deployment to Kabul, Afghanistan and subsequent respiratory health among U.S. military personnel. The study population consisted of personnel who deployed to Kabul, select Operation Enduring Freedom locations, personnel stationed in the Republic of Korea, and U.S.-stationed personnel. Incidence rate ratios (IRRs) were estimated for respiratory symptoms, signs, and ill-defined conditions, asthma, and chronic obstructive pulmonary disease. A significantly elevated rate of symptoms, signs, and ill-defined conditions was observed among Kabul-deployed personnel compared to personnel deployed or stationed in Bagram (IRR 1.12; 95% confidence interval [CI], 1.05-1.19), Republic of Korea (IRR 1.20; 95% CI, 1.10-1.31), and the United States (IRR 1.52; 95% CI, 1.43-1.62). A statistically elevated rate of asthma was observed among personnel deployed to Kabul, relative to U.S.-stationed personnel (IRR 1.61; 95% CI, 1.22-2.12). Statistically significant rates were not observed for chronic obstructive pulmonary disease among Kabul-deployed personnel compared to other study groups. These findings suggest that deployment to Kabul is associated with an elevated risk of postdeployment respiratory symptoms and new-onset asthma.

Maximizing the Utility of the Serum Repository With Current Technologies and Recommendations to Meet Future Needs: Report of the Technical Panel

The Department of Defense Serum Repository (DoDSR) of the Armed Forces Health Surveillance Center (AFHSC), Silver Spring, Maryland, has over 55 million specimens. Over 80% of these specimens are linked to individual health data. In response to Congressional and Department of Defense (DoD) concern about toxic exposures of deployed Service members and rapidly developing laboratory capabilities that may identify those exposed, the AFHSC hosted two panels in 2013. The first, the Needs Panel, focused on assessing the needs of the DoD that may be met using the current DoDSR and an enhanced repository. The second panel, the Technical Panel, focused on identifying the emerging laboratory technologies that are or will be available to DoD public health workers and researchers. This report summarizes the recommendations of the Technical Panel, to include identified gaps in the ability of the current DoDSR to address questions of interest to the DoD, the availability of laboratory technology to address these needs, and the types and quality of specimens required from Service members possibly exposed.

A retrospective cohort study of military deployment and postdeployment medical encounters for respiratory conditions

Deployed military personnel are exposed to inhalational hazards that may increase their risk of chronic lung conditions. This evaluation assessed associations between Operation Iraqi Freedom (OIF) deployment and postdeployment medical encounters for respiratory symptoms and medical conditions. This retrospective cohort study was conducted among military personnel who, between January 2005 and June 2007, were deployed to either of two locations with burn pits in Iraq, or to either of two locations without burn pits in Kuwait. Incidence rate ratios (IRRs) were estimated using two nondeployed reference groups. Rates among personnel deployed to burn pit locations were also compared directly to those among personnel deployed to locations without burn pits. Significantly elevated rates of encounters for respiratory symptoms (IRR = 1.25; 95% confidence interval [CI]: 1.20-1.30) and asthma (IRR = 1.54; 95% CI: 1.33-1.78) were observed among the formerly deployed personnel relative to U.S.-stationed personnel. Personnel deployed to burn pit locations did not have significantly elevated rates for any of the outcomes relative to personnel deployed to locations without burn pits. These results are consistent with the hypothesis that OIF deployment is associated with subsequent risk of respiratory conditions. Elevated medical encounter rates were not uniquely associated with burn pits.

Trends in rates of chronic obstructive respiratory conditions among US military personnel, 2001-2013

BACKGROUND

The US military has been continuously engaged in combat operations since 2001. Assessing trends in respiratory health diagnoses during this time of prolonged military conflict can provide insight into associated changes in the burden of pulmonary conditions in the US military population.

PURPOSE

To estimate and evaluate trends in rates of chronic obstructive pulmonary diseases in the active duty US military population from 2001 through 2013.

METHODS

A retrospective analysis of ambulatory medical encounter diagnosis data corresponding to a study base of over 18 million personnel-years was performed to estimate average rates and evaluate temporal trends in rates of chronic obstructive lung conditions. Differences in rates and the time trends of those rates were evaluated by branch of military service, military occupation, and military rank.

RESULTS

During the 13-year period, we observed 482,670 encounters for chronic obstructive pulmonary disease and allied conditions (ICD-9 490-496) among active duty military personnel. Over half (57%) of the medical encounters in this category were for a diagnosis of bronchitis, not specified as acute or chronic. There was a statistically significant 17.2% average increase in the annual rates of this nonspecific bronchitis diagnosis from 2001-2009 (95% CI: 13.5% to 21.1%), followed by a 23.6% annual decline in the rates from 2009 through 2013 (95% CI: 8.6% to 36.2%). Statistically significant declines were observed in the rates of chronic bronchitis over time (annual percentage decline: 3.1%; 95% CI: 0.5% to 6.6%) and asthma (annual percentage decline: 5.9%; 95% CI: 2.5% to 9.2%). A 1.6% annual increase in the rate of emphysema and a 0.1% increase in the rate of chronic airways obstruction (not elsewhere classified) over the study period were not statistically significant (P>.05). The magnitude of the estimated rates of these chronic obstructive lung conditions, and, to a lesser extent, the temporal trends in these rates, were sensitive to the requirement that there be persistence of the diagnosis evidenced in the medical record in order qualify as an incident case.

CONCLUSIONS

We observed decreases in the rates of asthma and chronic bronchitis over the 13-year study period. The increase, and then decrease, over time in rates of bronchitis that has not been specified as acute or chronic drives the overall trends in chronic respiratory disease trends.