Fatal motor vehicle crashes among veterans of the 1991 Gulf War and exposure to munitions demolitions at Khamisiyah: a nested case-control study

Convergence and divergence in mortality: A global study from 1990 to 2030

An empirical question that has motivated demographers is whether there is convergence or divergence in mortality/longevity around the world. The epidemiological transition is the starting point for studying a global process of mortality convergence. This manuscript aims to provide an update on the concept of mortality convergence/divergence. We perform a comprehensive examination of nine different mortality indicators from a global perspective using clustering methods in the period 1990-2030. In addition, we include analyses of projections to provide insights into prospective trajectories of convergence clubs, a dimension unexplored in previous work. The results indicate that mortality convergence clubs of 194 countries by sex resemble the configuration of continents. These five clubs show a common steady upward trend in longevity indicators, accompanied by a progressive reduction in disparities between sexes and between groups of countries. Furthermore, this paper shows insights into the historical evolution of the convergence clubs in the period 1990-2020 and expands their scope to include projections of their expected future evolution in 2030.

Trends in brain cancer mortality among U.S. Gulf War veterans: 21 year follow-up

OBJECTIVE

Previous mortality studies of U.S. Gulf War veterans through 2000 and 2004 have shown an increased risk of brain cancer mortality among some deployed individuals. When veterans possibly exposed to environmental contaminants associated with demolition of the Khamisiyah Ammunition Storage Facility at Khamisiyah, Iraq, have been compared to contemporaneously deployed unexposed veterans, the results have suggested increased risk for mortality from brain cancer among the exposed. Brain cancer mortality risk in this cohort has not been updated since 2004.

METHODS

This study analyzes the risk for brain cancer mortality between 1991-2011 through two series of comparisons: U.S. Gulf War deployed and non-deployed veterans from the same era; and veterans possibly exposed to environmental contaminants at Khamisiyah compared to contemporaneously deployed but unexposed U.S. Gulf War veterans. Risk of brain cancer mortality was determined using logistic regression. Life test hazard models were created to plot comparisons of annual hazard rates. Joinpoint regression models were applied to assess trends in hazard rates for brain cancer mortality.

RESULTS

U.S. Army veterans possibly exposed at Khamisiyah had similar rates of brain cancer mortality compared to those not possibly exposed; however, veterans possibly exposed had a higher risk of brain cancer in the time period immediately following the Gulf War.

CONCLUSION

Results from these analyses suggest that veterans possibly exposed at Khamisiyah experienced different patterns of brain cancer mortality risk compared to the other groups.

All-Cause Mortality Among US Veterans of the Persian Gulf War: 13-Year Follow-up

OBJECTIVE

We determined cause-specific mortality prevalence and risks of Gulf War deployed and nondeployed veterans to determine if deployed veterans were at greater risk than nondeployed veterans for death overall or because of certain diseases or conditions up to 13 years after conflict subsided.

METHODS

Follow-up began when the veteran left the Gulf War theater or May 1, 1991, and ended on the date of death or December 31, 2004. We studied 621   901 veterans who served in the 1990-1991 Persian Gulf War and 746   247 veterans who served but were not deployed during the Gulf War. We used Cox proportional hazard models to calculate rate ratios adjusted for age at entry to follow-up, length of follow-up, race, sex, branch of service, and military unit. We compared the mortality of (1) Gulf War veterans with non-Gulf War veterans and (2) Gulf War army veterans potentially exposed to nerve agents at Khamisiyah in March 1991 with those not exposed. We compared standardized mortality ratios of deployed and nondeployed Gulf War veterans with the US population.

RESULTS

Male Gulf War veterans had a lower risk of mortality than male non-Gulf War veterans (adjusted rate ratio [aRR] = 0.97; 95% confidence interval [CI], 0.95-0.99), and female Gulf War veterans had a higher risk of mortality than female non-Gulf War veterans (aRR = 1.15; 95% CI, 1.03-1.28). Khamisiyah-exposed Gulf War army veterans had >3 times the risk of mortality from cirrhosis of the liver than nonexposed army Gulf War veterans (aRR = 3.73; 95% CI, 1.64-8.48). Compared with the US population, female Gulf War veterans had a 60% higher risk of suicide and male Gulf War veterans had a lower risk of suicide (standardized mortality ratio = 0.84; 95% CI, 0.80-0.88).

CONCLUSION

The vital status and mortality risk of Gulf War and non-Gulf War veterans should continue to be investigated.

A systematic review of post-deployment injury-related mortality among military personnel deployed to conflict zones

BACKGROUND

This paper reports on a systematic review of the literature on the post-conflict injury-related mortality of service members who deployed to conflict zones.

METHODS

Literature databases, reference lists of articles, agencies, investigators, and other sources were examined to find studies comparing injury-related mortality of military veterans who had served in conflict zones with that of contemporary veterans who had not served in conflict zones. Injury-related mortality was defined as a cause of death indicated by International Classification of Diseases E-codes E800 to E999 (external causes) or subgroupings within this range of codes.

RESULTS

Twenty studies met the review criteria; all involved veterans serving during either the Vietnam or Persian Gulf conflict. Meta-analysis indicated that, compared with non-conflict-zone veterans, injury-related mortality was elevated for veterans serving in Vietnam (summary mortality rate ratio (SMRR) = 1.26, 95% confidence interval (95%CI) = 1.08-1.46) during 9 to 18 years of follow-up. Similarly, injury-related mortality was elevated for veterans serving in the Persian Gulf War (SMRR = 1.26, 95%CI = 1.16-1.37) during 3 to 8 years of follow-up. Much of the excess mortality among conflict-zone veterans was associated with motor vehicle events. The excess mortality decreased over time. Hypotheses to account for the excess mortality in conflict-zone veterans included post-traumatic stress, coping behaviors such as substance abuse, ill-defined diseases and symptoms, lower survivability in injury events due to conflict-zone comorbidities, altered perceptions of risk, and/or selection processes leading to the deployment of individuals who were risk-takers.

CONCLUSION

Further research on the etiology of the excess mortality in conflict-zone veterans is warranted to develop appropriate interventions.

The long-term hospitalization experience following military service in the 1991 Gulf War among veterans remaining on active duty, 1994-2004

BACKGROUND

Despite more than a decade of extensive, international efforts to characterize and understand the increased symptom and illness-reporting among veterans of the 1991 Gulf War, concern over possible long-term health effects related to this deployment continue. The purpose of this study was to describe the long-term hospitalization experience of the subset of U.S. Gulf War veterans still on active duty between 1994 and 2004.

METHODS

Gulf War veterans on active duty rosters as of October 1, 1994, were identified (n = 211 642) and compared with veterans who had separated from military service and then assessed for attrition at three-year intervals during a 10-year follow-up period, examining demographic and military service characteristics, Gulf War exposure variables, and hospitalization data. Cox proportional hazard modeling was used to evaluate independent predictors of all-cause hospitalization among those still on active duty and to estimate cumulative probability of hospitalization, 1994-2004, by service branch.

RESULTS

Members of our 1994 active duty cohort were more likely to be officers, somewhat older, and married compared with those who had separated from the military after serving in the 1991 Gulf War. Selected war-related exposures or experiences did not appear to influence separation with the exception of in-theater presence during the brief ground combat phase. Overall the top three diagnostic categories for hospitalizations were musculo-skeletal, injury and poisoning, and digestive disorders. Diseases of the circulatory system and symptoms, signs, and ill-defined conditions increased proportionately over time. In-theater hospitalization was the only significant independent predictor of long-term hospitalization risk among selected war-related exposures or experiences examined. The cumulative probability of hospitalization was highest for Army and lowest for Marines.

CONCLUSION

Our results were generally consistent with a previous hospitalization study of US Gulf War veterans for the period August 1991 to July 1999. Although lack of a comparison group for our study limits interpretation of overall findings, intra-cohort analyses showed no significant associations between long-term hospitalization and war-related exposures or experiences, with the exception of in-theater hospitalization, within our active duty subset of 1991 Gulf War veterans.

Quantitative magnetic resonance brain imaging in US army veterans of the 1991 Gulf War potentially exposed to sarin and cyclosarin

BACKGROUND

In March 1991, a munitions storage complex at Khamisiyah, Iraq was destroyed, potentially exposing more than 100,000 US troops to low levels of the organophosphate nerve agents sarin and cyclosarin. Little is known about the neurophysiological effects of low-dose exposure to sarin/cyclosarin in humans, although some research has indicated subtle but persistent neurobehavioral and neurochemical changes in individuals exposed to sarin/cyclosarin at levels insufficient to produce obvious clinical symptoms. However, the neuroanatomical correlates of these changes are unclear. The current study examined the association between modeled estimates of sarin/cyclosarin exposure levels and volumetric measurements of gross neuroanatomical structures in 1991 Gulf War veterans with varying degrees of possible low-level sarin/cyclosarin exposure.

METHODS

Twenty-six GW-deployed veterans recruited from the Devens Cohort Study participated. Magnetic resonance images of the brain were acquired and analyzed using morphometric techniques, producing volumetric measurements of white matter, gray matter, right and left lateral ventricles, and cerebrospinal fluid. Volumetric data were analyzed using exposure estimates obtained from refined models of the 1991 Khamisiyah presumed exposure hazard area.

RESULTS

Binary comparisons of sarin/cyclosarin 'exposed' (N=13) and 'unexposed' (N=13) veterans revealed no differences in volumetric measurements of discrete brain tissues. However, linear trend analyses showed a significant association between higher levels of estimated sarin/cyclosarin exposure and both reduced white matter (adjusted parameter estimate=-4.64, p<0.0001) and increased right lateral ventricle (adjusted parameter estimate=.11, p=0.0288) and left lateral ventricle (adjusted parameter estimate=.13, p<0.0001) volumes.

CONCLUSIONS

These findings suggest subtle but persistent central nervous system pathology in Gulf War veterans potentially exposed to low levels of sarin/cyclosarin and argue for further investigation of the long-term effects of low-dose sarin/cyclosarin exposures in humans.

Effects of sarin and cyclosarin exposure during the 1991 Gulf War on neurobehavioral functioning in US army veterans

BACKGROUND

During the Gulf War (GW), in early March 1991, a munitions dump at Khamisiyah, Iraq, was destroyed. Later, in 1996, the dump was found to have contained the organophosphate chemical warfare agents, sarin and cyclosarin.

METHODS

Data collected in a study conducted between 1994 and 1996, before the Khamisiyah incident was publicly disclosed, were used to examine neurobehavioral task performances of GW veterans (n=140) categorized as having received high, moderate, or low-to-no exposure dose levels to sarin and cyclosarin at Khamisiyah, Iraq. Exposure levels were based on modeled estimates of the exposure plume and on troop location information at the time of the Khamisiyah event. Based on recent findings observed in follow-up studies of persons exposed to sarin during the 1995 terrorist attacks in Japan, we hypothesized that exposure to sarin and cyclosarin would be associated with poorer performances on objective neurobehavioral tasks in specific functional domains (particularly in visuospatial abilities and psychomotor functioning) in a dose-dependent manner.

RESULTS

Sarin and cyclosarin exposure was significantly associated with less proficient neurobehavioral functioning on tasks involving fine psychomotor dexterity and visuospatial abilities 4-5 years after exposure.

CONCLUSIONS

Findings suggest a dose-response association between low-level exposure to sarin and cyclosarin and specific functional central nervous system effects 4-5 years after exposure.