Mortality Surveillance for Infectious Diseases in the U.S. Department of Defense (1998-2013).

INTRODUCTION: The Mortality Surveillance Division (MSD) of the U.S. Armed Forces Medical Examiner System was established in 1998 to improve surveillance for all military deaths although emphasizing deaths from infectious diseases. Establishment of the MSD was part of the 1997 Department of Defense initiative to improve surveillance and response for emerging infectious diseases. Before 1998, mortality surveillance was limited to compiling information from death certificates, a system that provided limited useful information and lacked the timeliness needed to take meaningful action to address emerging infectious disease threats. MATERIALS AND METHODS: The MSD was tasked to quickly identify all infectious disease deaths and the infecting agents. The system developed by the MSD staff identified deaths in near real-time and immediately notified military Public Health authorities of situations that warranted an investigation. Autopsy, medical, and investigative reports were collected. Testing specimens for agent identification was encouraged. The data and information collected were archived in the MSD-developed Medical Mortality Registry (MMR), a database that included all active duty Service Member deaths and contained manner and cause of death with medical, demographic, circumstantial, and diagnostic information. The MMR was the only comprehensive, autopsy-based source for mortality information on active duty military deaths. RESULTS: During 1998-2013, 217 (1.3%) infectious disease deaths were identified among 16,192 noncombat deaths. Of the 217 deaths, 29.5% were classified as respiratory, 18.0% cardiac, 15.2% blood borne, 12.9% nervous system, and 12.4% sepsis. A pathogen was identified for 64.5%. Agents of military interest identified included Neisseria meningitidis, influenza viruses, adenoviruses, and malaria. Neisseria meningitidis was identified in 10 fatal cases; grouping of the agent was done for eight cases. Four were group B, two were C, and two were Y. All eight had been immunized with a quadrivalent meningococcal vaccine. The most commonly detected respiratory agent was influenza virus (nine deaths), three of which were the 2009 pandemic H1N1 influenza virus. Adenoviruses were identified as the infectious agents in a total of nine deaths. Two deaths resulted from Plasmodium falciparum malaria infections acquired in Africa during military deployments. An important but unexplained finding was that Black Service Members made up only16.3% of all military personnel but accounted for 28.6% of all infectious disease deaths. CONCLUSION: The time lag between death and notification of the MSD at the start of this surveillance program was 24 to 48 hours. The lag at the end of the reported surveillance period was 8 to 24 hours. The MSD surveillance system identified an agent in 140 of 217 (64.5%) uniformed deaths. In a similar program by the Centers for Disease Control and Prevention, in 122 cases with specimens, an agent could be identified in 34 (28%). MMR data and information provided strong support for re-establishing the military recruit adenovirus vaccination program, which ceased in 1999 and was finally re-established in 2011. MMR data and information also assisted in monitoring the military meningococcal vaccine program, helped to describe the virulence of circulating influenza viruses, and identified areas where deadly malaria infections were not being prevented.

Adenovirus-associated deaths in US military during postvaccination period, 1999-2010.

Adenoviruses are frequent causes of respiratory disease in the US military population. A successful immunization program against adenovirus types 4 and 7 was terminated in 1999. Review of records in the Mortality Surveillance Division, Armed Forces Medical Examiner System, identified 8 deaths attributed to adenovirus infections in service members during 1999-2010.

Sudden death in young adults: an autopsy-based series of a population undergoing active surveillance.

OBJECTIVES: The purpose of this study was to define the incidence and characterization of cardiovascular cause of sudden death in the young. BACKGROUND: The epidemiology of sudden cardiac death (SCD) in young adults is based on small studies and uncontrolled observations. Identifying causes of sudden death in this population is important for guiding approaches to prevention. METHODS: We performed a retrospective cohort study using demographic and autopsy data from the Department of Defense Cardiovascular Death Registry over a 10-year period comprising 15.2 million person-years of active surveillance. RESULTS: We reviewed all nontraumatic sudden deaths in persons 18 years of age and over. We identified 902 subjects in whom the adjudicated cause of death was of potential cardiac etiology, with a mean age of 38 ± 11 years. The mortality rate for SCD per 100,000 person-years for the study period was 6.7 for males and 1.4 for females (p < 0.0001). Sudden death was attributed to a cardiac condition in 715 (79.3%) and was unexplained in 187 (20.7%). The incidence of sudden unexplained death (SUD) was 1.2 per 100,000 person-years for persons <35 years of age, and 2.0 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). The incidence of fatal atherosclerotic coronary artery disease was 0.7 per 100,000 person-years for those <35 years of age, and 13.7 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). CONCLUSIONS: Prevention of sudden death in the young adult should focus on evaluation for causes known to be associated with SUD (e.g., primary arrhythmia) among persons <35 years of age, with an emphasis on atherosclerotic coronary disease in those ≥ 35 years of age.

Deaths attributed to suicide among enlisted U.S. Armed Forces recruits, 1980-2004.

OBJECTIVE: The purpose of this study was to describe the epidemiology of suicides among U.S. Air Force, Army, Marine Corps, and Navy recruits from 1980 through 2004. METHODS: Recruit suicides were identified through the Department of Defense Recruit Mortality Registry. We calculated crude, category-specific, and age-adjusted mortality rates as deaths per 100,000 recruit-years. RESULTS: There were 46 onsite suicides by gunshot (39%), hanging (35%), fall/jump (22%), and drug overdose (4%). An additional 20 recruits committed suicide from 1980 through 2004 after leaving the military training site. Methods included gunshot (70%), hanging (20%), fall/jump (5%), and poisoning (5%). Therefore, the overall recruit suicide rate was 6.9 (95% confidence interval = 5.4-8.8) deaths per 100,000 recruit-years. Only three (5%) suicides occurred among females resulting in a 3.5 times higher risk for males compared to females (95% confidence interval = 1.1-11.2). CONCLUSIONS: Suicide rates among military recruits were lower than those of comparably aged U.S. civilians. However, the occurrence of any suicide during basic military training emphasizes the importance of routine evaluation of the effectiveness of each military service's suicide prevention program as it applies to this population.

Causes of sudden death in young female military recruits.

This study sought to examine the incidence of sudden death in a large, multiethnic cohort of young women. Approximately 852,300 women entered basic military training from 1977 to 2001. During this period, there were 15 sudden deaths in female recruits (median age 19 years, 73% African-American), occurring at a median of 25 days after arrival for training. Of the sudden deaths, 13 (81%) were due to reasons that may have been cardiac in origin. Presumed arrhythmic sudden death in the setting of a structurally normal heart was seen in 8 recruits (53%), and anomalous coronary origins were found in 2 recruits (13%). The mortality rate was 11.4 deaths per 100,000 recruit-years (95% confidence interval 6.9 to 18.9). The rate was significantly higher for African-American female recruits (risk ratio 10.2, p <0.001). Sudden death with a structurally normal heart was the leading cause of death in female recruits during military training.

Sudden death in young adults: a 25-year review of autopsies in military recruits.

BACKGROUND: Sudden death among military recruits is a rare but devastating occurrence. Because extensive medical data are available on this cross-sectional and diverse population, identification of the underlying causes of sudden death may promote health care policy to reduce the incidence of sudden death. OBJECTIVE: To determine the causes of nontraumatic sudden death among a cohort of military recruits. DESIGN: Retrospective cohort study using demographic and autopsy data from the Department of Defense Recruit Mortality Registry. SETTING: Basic military training. PATIENTS: All nontraumatic sudden deaths from a monitored 6.3 million men and women age 18 to 35 years. MEASUREMENTS: Descriptive analysis, crude mortality rates of causes of sudden death, and frequency of events as a function of cause of death. RESULTS: Of 126 nontraumatic sudden deaths (rate, 13.0/100,000 recruit-years), 108 (86%) were related to exercise. The most common cause of sudden death was an identifiable cardiac abnormality (64 of 126 recruits [51%]); however, a substantial number of deaths remained unexplained (44 of 126 recruits [35%]). The predominant structural cardiac abnormalities were coronary artery abnormalities (39 of 64 recruits [61%]), myocarditis (13 of 64 recruits [20%]), and hypertrophic cardiomyopathy (8 of 64 recruits [13%]). An anomalous coronary artery accounted for one third (21 of 64 recruits) of the cases in this cohort, and, in each, the left coronary artery arose from the right (anterior) sinus of Valsalva, coursing between the pulmonary artery and aorta. LIMITATIONS: This cohort underwent a preenlistment screening program that included history and physical examination; this may have altered outcomes. CONCLUSIONS: Cardiac abnormalities are the leading identifiable cause of sudden death among military recruits; however, more than one third of sudden deaths remain unexplained after detailed medical investigation.

Traumatic deaths during U.S. Armed Forces basic training, 1977-2001.

BACKGROUND: A Recruit Mortality Registry, linked to the Department of Defense Medical Mortality Registry, was created to provide comprehensive medical surveillance data for deaths occurring during enlisted basic military training. METHODS: Recruit deaths from 1977 through 2001 were identified and confirmed through redundant sources. Complete demographic, circumstantial, and medical information was sought for each case and recorded on an abstraction form. Mortality rates per 100,000 recruit-years were calculated by using recruit accession data from the Defense Manpower Data Center. RESULTS: There were 276 recruit deaths from 1977 through 2001 and age-specific recruit mortality rates were less than half of same-age U.S. civilian mortality rates. Only 28% (77 of 276) of recruit deaths were classified as traumatic (suicide, unintentional injury, and homicide), in comparison to three quarters in both the overall active duty military population and the U.S. civilian population (ages 15-34 years). The age-adjusted traumatic death rates were highest in the Army (four times higher than the Navy and Air Force, and 80% higher than the Marine Corps). The majority (60%) of traumatic deaths was due to suicide, followed by unintentional injuries (35%), and homicide (5%). The overall age-adjusted traumatic mortality rate was more than triple for men compared with women in all military services (rate ratio=3.9; p=0.01). CONCLUSIONS: There was a lower proportion of traumatic deaths in recruits compared to the overall active duty military population and same-age U.S. civilian population. This finding could be attributed to close supervision, emphasis on safety, and lack of access to alcohol and motor vehicles during recruit training.

Nontraumatic deaths during U.S. Armed Forces basic training, 1977-2001.

BACKGROUND: A Recruit Mortality Registry, linked to the Department of Defense Medical Mortality Registry, was created to provide comprehensive medical surveillance data for deaths occurring during enlisted basic military training. METHODS: Recruit deaths from 1977 through 2001 were identified and confirmed through redundant sources. Complete demographic, circumstantial, and medical information was sought for each case and recorded on an abstraction form. Mortality rates per 100,000 recruit-years were calculated by using recruit accession data from the Defense Manpower Data Center. RESULTS: There were 276 recruit deaths from 1977 through 2001 and age-specific recruit mortality rates were less than half of same-age U.S. civilian mortality rates. The majority (72%) of recruit deaths were classified as nontraumatic and 70% of these deaths (139 of 199) were related to exercise. Of the exercise-related deaths, 59 (42%) were cardiac deaths, and heat stress was a primary or contributory cause in at least 46 (33%). Infectious agents accounted for only 49 (25%) of the nontraumatic deaths. Nontraumatic death rates increased with age (rate ratio is 2.5 for 25+ v <25 years; p<0.001). The age- and gender-adjusted nontraumatic death rates were 2.6 times higher for African American than non-African American recruits (p<0.001). CONCLUSIONS: Although recruit mortality rates are lower than the same-age U.S. civilian population, preventive measures focused on reducing heat stress during exercise might be effective in decreasing the high proportion of exercise-related death. The availability of 25 years of comprehensive recruit mortality data will permit the ongoing evaluation of cause-of-death trends, effectiveness of preventive measures, and identification of emerging threats during basic military training.

Nontraumatic exercise-related deaths in the U.S. military, 1996-1999.

We identified 215 exercise-related deaths in U.S. military personnel on active duty during 1996-1999. The most complete case information was for active duty Army personnel during 1998-1999, providing an exercise-related death rate of 4.3 per 100,000 person-years (41/963,000) and accounting for 6% of Army deaths (14 during physical fitness testing). The cause of death was confirmed by autopsy or clinical data for 85% of the cases. Arteriosclerotic coronary artery disease was the predominant cause of death for those 30 to 58 years of age. For age 17 to 34 years, 50% of deaths were attributable to preexisting heart disease (16% from coronary anomalies), 20% attributable to nontraumatic drowning, and 12% attributable to exertional heat illness, also a potential contributory factor in cardiac deaths. Most exercise-related deaths were related to running (60%), sports (14%), and swimming (13%). Improvements in health promotion, medical management, and stricter exclusion from inappropriate exercise (especially fitness test runs) could reduce these deaths.

Musculoskeletal injuries in an Army airborne population.

To maintain operational readiness, military personnel engage in vigorous physical and training activities that carry risk for injury. A 1-year prospective cohort study, starting April 1996, was conducted at Fort Bragg, North Carolina among 1,965 members of the 82nd Airborne Division to quantify musculoskeletal injuries. Information collected included type of injury, site, circumstances, and resultant limited duty days. These soldiers suffered 508 overuse injuries (including 38 stress fractures), 1,415 traumatic injuries (including 100 fractures), and 101 unclassified injuries. Injury rates were 6.8% per soldier per month for traumatic injury and 2.4% for overuse injury (totaling 1.2 injuries per soldier per year). Injuries resulted in 22,041 limited duty days, averaging 11 days per injury and 13 days per soldier (4.5% of total workdays). Fractures and stress fractures/reactions produced the most days lost per case. Most of these injuries resulted from military-specific activities.