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. Author manuscript; available in PMC: 2025 Mar 1.
Published in final edited form as: Ann Epidemiol. 2024 Jan 5;91:23–29. doi: 10.1016/j.annepidem.2024.01.002

Divergent Trends in Accidental Deaths Since Return from an Afghanistan/Iraq Deployment among Army Soldiers

Rachel Sayko Adams 1,2,3, Jeri E Forster 3,4, Jaimie L Gradus 6, Claire A Hoffmire 3,4, Trisha A Hostetter 3, Mary Jo Larson 2, Alexandra A Smith 3, Colin G Walsh 7, Lisa A Brenner 3,4,5
PMCID: PMC10973698  NIHMSID: NIHMS1960103  PMID: 38185289

Abstract

Purpose:

Accidental death is a leading cause of mortality among military members and Veterans; however, knowledge is limited regarding time-dependent risk following deployment and if there are differences by type of accidental death.

Methods:

Longitudinal cohort study (N=860,930) of soldiers returning from Afghanistan/Iraq deployments in fiscal years 2008–2014. Accidental deaths (i.e., motor vehicle accidents [MVA], accidental overdose, other accidental deaths), were identified through 2018. Crude and age-adjusted mortality rates, rate ratios, time-dependent hazard rates and trends postdeployment were compared across demographic and military characteristics.

Results:

During the postdeployment observation period, over one-third of deaths were accidental; most were MVA (46.0%) or overdoses (37.9%). Across accidental mortality categories (all, MVA, overdose), younger soldiers (18–24, 25–29) were at higher risk compared to older soldiers (40+), and females at lower risk than males. MVA death rates were highest immediately postdeployment, with a significant decreasing hazard rate over time (annual percent change [APC]: −6.5%). Conversely, accidental overdose death rates were lowest immediately following deployment, with a significant increasing hazard rate over time (APC: 9.9%).

Conclusions:

Observed divergent trends in risk for the most common types of accidental deaths provide essential information to inform prevention and intervention planning for the immediate postdeployment transition and long-term.

Keywords: accidental death, motor vehicle accidents, overdose, military, Veterans, deployment

INTRODUCTION

Studies have been conducted regarding suicide rates among military members/Veterans who deployed in the Afghanistan/Iraq conflicts,1,2 however, there has been less work on accidental death risk (e.g., motor vehicle accident [MVA] or accidental overdose deaths).3,4 Yet, studies have shown that accidental death is the most common type of mortality during- and post-service among those who served in Afghanistan/Iraq.4–6 We do not know if accidental death risk varies in the years following deployment; information that is critical to prevention and intervention planning following combat deployments.

Accidental death research among military members/Veterans from the Afghanistan/Iraq cohort has focused on accidental deaths overall, or on one type.7–11 The Department of Defense’s (DoD) Armed Forces Health Surveillance Division reported that transportation deaths (e.g., MVA) were the most common type (over 30% annually) of non-war related death during the first decade of the conflicts.5 Another study found that among Veterans discharged from military service in 2001–2007, MVA mortality risk was highest in the first 3 years following military discharge12. Moreover, Veterans are at disproportionately higher risk for accidental overdose deaths compared to the general population.13,14

We examined a cohort of 860,930 soldiers returning from an Afghanistan/Iraq deployment between fiscal years (FYs) 2008–2014. Study objectives were to: 1) estimate average annual accidental death mortality rates (all, MVA, overdose) by demographic and military characteristics and compare rates across groups; and 2) estimate postdeployment time-dependent hazard rates and trends for accidental death, and compare trends across groups.

METHODS

Data Sources

Data were from the Substance Use and Psychological Injury Combat Study (SUPIC), an observational, population-based, longitudinal cohort study of all Army soldiers returning from an Afghanistan/Iraq deployment ending in FYs 2008–2014.15 Deployment data was from the Contingency Tracking System maintained by the Defense Manpower Data Center to identify the index Afghanistan/Iraq deployment (i.e., first deployment ending during the study window). Demographic characteristics were from the Defense Enrollment Eligibility Records System. All-cause mortality data was from the VA/DoD Mortality Data Repository (MDR), containing National Death Index (NDI) data of death records from state vital statistics offices.

Study Population

The analytic cohort was derived from the SUPIC cohort (n=865,640).1 We excluded 141 without a usable Social Security number, and 1123 deaths that occurred before the index deployment end. Inclusion criteria included having data for military component, an index deployment length of 30-days to 5-years; and for records matching to VHA medical records, Social Security Number, date of birth, and sex assigned in the medical record consistency, resulting in removal of 3446 records for an analytic cohort of 860,930 soldiers.

Measures

Accidental death was determined by identifying accidental underlying cause of death ICD-10 codes within the NDI (Supplemental Table 1).16 Independent variables included: 1) age group at end of index deployment; 2) sex assigned in the medical record; 3) race and ethnicity; 4) rank at end of index deployment (Junior Enlisted [E1-E4], Senior Enlisted [E5-E-9]/Warrant Officer, and Officer); 5) component (National Guard, NG; and Reserve Component, RC; and Active Duty, AD); and 6) FY return from index deployment (2008–2009, 2010–2011, 2012–2014).

Statistical Analysis

Demographic and military characteristics were summarized by cohort and cause of death: 1) all accidental; 2) MVA; and 3) accidental overdose, using frequencies. The follow-up period was October 1, 2007 – December 31, 2018, including up to 11-years of postdeployment data depending on when the soldier returned from the index deployment. Crude and age-adjusted (using the direct standardization method) average annual mortality rates were calculated for accidental, MVA, and accidental overdose deaths per 100,000 person-years over the follow-up period. This analysis was performed by demographics, rank group, component, and FY of return from index deployment. Age-adjusted rates were standardized based on the 2000 US population,17 using age categories 18–24, 25–29, 30–34, 35–39, and 40+, unless otherwise noted. Rates based on <16 events were considered unreliable, and results for cell sizes <10 were suppressed.18 Rate ratios (RRs) were computed to compare age-adjusted rates and rate and RR estimates reported include 95% confidence intervals (CIs).

Hazard rates, per 100,000 alive at the beginning of each time window, were calculated for each death category in 1- or 2-year intervals by demographics, rank, and component. Annual percent change (APC) in hazard rates were estimated using trend analysis (joinpoint regression),19 and tests for parallelism compared trends across groups.20 Analyses were performed in SAS software v9.4 and Joinpoint.21 Permission to not obtain written consent was received from all pertinent institutions.

RESULTS

Demographic and military characteristics for this cohort are in Table 1 and have been previously described.1 Among the 10,036 all-cause deaths during the study period, 3442 (34.3%) were accidental deaths, 2695 were suicides (26.9%)1, and 3899 were other deaths (38.8%). Among accidental deaths, 1585 (46.0%) were MVAs and 1226 (35.6%) accidental overdoses.

Table 1.

Cohort Sample Characteristics of Soldiers Returning from an Afghanistan/Iraq deployment ending in fiscal years 2008–2014, and by Accidental Underlying Cause of Death Category

 Full Cohort (N=860,930) All Accidental Deaths (N=3442) MVA Deaths (N=1585) Accidental Overdose Deaths (N=1226)
Age Category at End of Index Deployment
 18–24 320,548 (37.2%) 1761 (51.2%) 855 (53.9%) 640 (52.2%)
 25–29 217,275 (25.2%) 885 (25.7%) 357 (22.5%) 363 (29.6%)
 30–34 117,585 (13.7%) 330 (9.6%) 141 (8.9%) 115 (9.4%)
 35–39 92,002 (10.7%) 214 (6.2%) 108 (6.8%) 53 (4.3%)
 40+ 113,520 (13.2%) 252 (7.3%) 124 (7.8%) 55 (4.5%)
Sex
 Female 94,441 (11.0%) 136 (3.9%) 69 (4.3%) 49 (4.0%)
 Male 766,489 (89.0%) 3306 (96.1%) 1516 (95.7%) 1177 (96.0%)
Race/Ethnicity
 Asian or Pacific Islander 68,699 (8.0%) 276 (8.0%) 112 (7.1%) 116 (9.5%)
 American Indian/Alaskan Native 7918 (0.9%) 41 (1.2%) 24 (1.5%) Suppressed
 Black non-Hispanic 143,350 (16.6%) 395 (11.5%) 243 (15.3%) 70 (5.7%)
 Hispanic 91,365 (10.6%) 279 (8.1%) 162 (10.2%) 55 (4.5%)
 White non-Hispanic 539,434 (62.7%) 2426 (70.5%) 1033 (65.2%) 971 (79.2%)
 Other/Unknown/Missing 10,164 (1.2%) 25 (0.7%) 11 (0.7%) Suppressed
Rank Group at End of Index Deployment
 Junior Enlisted (E1-E4) 413,463 (48.0%) 2249 (65.3%) 1004 (63.3%) 927 (75.6%)
 Senior Enlisted (E5-E9) / Warrant Officer 339,205 (39.4%) 1056 (30.7%) 520 (32.8%) 279 (22.8%)
 Officer 108,257 (12.6%) 137 (4.0%) 61 (2.9%) 20 (1.6%)
 Missing 5 (0%) 0 (0%) 0 (0%) 0 (0%)
Component
 National Guard 206,332 (24.0%) 837 (24.3%) 430 (27.1%) 262 (21.4%)
 Reserve Component 81,067 (9.4%) 229 (6.7%) 112 (7.1%) 74 (6.0%)
 Active Duty 573,531 (66.6%) 2376 (69.0%) 1043 (65.8%) 890 (72.6%)
Fiscal Year of Return from Index Deployment
 2008–09 316,420 (36.8%) 1631 (47.4%) 725 (45.7%) 597 (48.7%)
 2010–11 326,101 (37.9%) 1294 (37.6%) 597 (37.7%) 487 (39.7%)
 2012–14 218,409 (25.4%) 517 (15.0%) 263 (16.6%) 142 (11.6%)
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All Accidental Deaths

Age-adjusted accidental mortality rates were higher among younger age groups; for example, the rate for soldiers aged 18–24 was 2.58 times (95% CI: 2.26, 2.94) the rate for those 40+ (Table 2). Females had a significantly lower age-adjusted mortality rate than males (RR=0.41, 95% CI: 0.30, 0.56). Age-adjusted accidental mortality rates were lower for Black non-Hispanic, Hispanic, and Asian American or Pacific Islander soldiers than for White non-Hispanic soldiers (0.68, 0.76 and 0.69 times, respectively). Junior Enlisted soldiers had an age-adjusted mortality rate 1.74 times (95% CI: 1.42, 2.12) that of Senior Enlisted/Warrant Officers and 3.18 times (95% CI: 2.43, 4.17) that of Officers. NG soldiers had an age-adjusted mortality rate that was 1.25 times (95% CI: 1.10, 1.42) that of AD members and 1.36 times (95% CI: 1.13, 1.64) that of RC members. Compared to those returning from their index deployment in FY 2012–2014, those returning earlier had higher age-adjusted mortality rates. The overall hazard rate for all accidental deaths was generally stable over time (APC= −0.2%, 95% CI: −1.8%, 1.5%; Figure 1/Supplemental Table 2).

Table 2.

All Accidental, Motor Vehicle Accident, and Accidental Overdose Mortality Rates among Soldiers Returning from an Afghanistan/Iraq deployment ending in fiscal years 2008–2014

Characteristic All Accidental Deaths MVA Deaths Accidental Overdose Deaths
Crude Rate (95% CI)  Age-Adjusted Rate a (95% CI) Rate Ratio (95% CI) Crude Rate (95% CI)  Age-Adjusted Rate a (95% CI) Rate Ratio (95% CI) Crude Rate (95% CI)  Age-Adjusted Rate b (95% CI) Rate Ratio (95% CI)
Age Group
 18–24 67.35 (64.24, 70.57) n/a 2.58 (2.26, 2.94) 32.70 (30.55, 34.97) n/a 2.54 (2.11, 3.07) 24.48 (22.62, 26.45) n/a 4.29 (3.26, 5.65)
 25–29 48.21 (45.08, 51.49) n/a 1.85 (1.60, 2.12) 19.45 (17.48, 21.57) n/a 1.51 (1.23, 1.86) 19.77 (17.79, 21.92) n/a 3.47 (2.61, 4.61)
 30–34 33.01 (29.55, 36.78) n/a 1.26 (1.07, 1.49) 14.11 (11.87, 16.64) n/a 1.10 (0.86, 1.40) 11.51 (9.5, 13.81) n/a 2.02 (1.46, 2.78)
 35–39 26.79 (23.32, 30.63) n/a 1.03 (0.85, 1.23) 13.52 (11.09, 16.33) n/a 1.05 (0.81, 1.36) 6.64 (4.97, 8.68) n/a 1.16 (0.80, 1.70)
 40+ 26.12 (23.00, 29.55) n/a Reference 12.85 (10.69, 15.33) n/a Reference 5.70 (4.29, 7.42) n/a Reference
Sex
 Female 17.41 (14.61, 20.60) 14.86 (10.68, 20.48) 0.41 (0.30, 0.56) 8.83 (6.87, 11.18) 6.72 (4.08, 10.83) 0.39 (0.25, 0.61) 6.27 (4.64, 8.29) 4.53 (2.60, 7.89) 0.42 (0.26, 0.70)
 Male 51.40 (49.66, 53.18) 36.37 (34.23, 38.64) Reference 23.57 (22.40, 24.79) 17.29 (15.80, 18.92) Reference 18.30 (17.27, 19.37) 10.66 (9.64, 11.81) Reference
Race/Ethnicity
 AAPI 45.78 (40.54, 51.51) 26.38 (21.12, 32.98) 0.69 (0.55, 0.86) 18.58 (15.30, 22.35) 11.76 (8.20, 16.78) 0.70 (0.50, 0.99) 19.24 (15.90, 23.08) 10.72 (7.88, 14.52) 0.75 (0.56, 1.02)
 AIAN 60.95 (43.74, 82.69) 44.07 (25.58, 73.91) 1.15 (0.71, 1.86) 35.68 (22.86, 53.09) Suppressedc Suppressedc Suppressedc Suppressedc Suppressedc
 BNH 33.05 (29.87, 36.48) 26.09 (22.73, 29.90) 0.68 (0.59, 0.79) 20.33 (17.86, 23.06) 17.12 (14.34, 20.35) 1.02 (0.84, 1.24) 5.86 (4.57, 7.40) 4.43 (3.23, 6.00) 0.31 (0.23, 0.42)
 Hispanic 36.61 (32.44, 41.17) 28.98 (23.70, 35.28) 0.76 (0.62, 0.93) 21.26 (18.11, 24.80) 14.30 (10.87, 18.73) 0.85 (0.65, 1.12) 7.22 (5.44, 9.39) 5.34 (3.51, 7.93) 0.37 (0.25, 0.55)
 WNH 53.93 (51.81, 56.12) 38.29 (35.95, 40.77) Reference 22.96 (21.58, 24.41) 16.82 (15.27, 18.53) Reference 21.59 (20.25, 22.99) 14.26 (13.00, 15.63) Reference
Rank Group
 JE 67.04 (64.30, 69.87) 55.08 (45.50, 66.51) vs. SE/WO: 1.74 (1.42, 2.12)
vs. Officer: 3.18 (2.43, 4.17) 		29.93 (28.10, 31.84) 18.22 (13.40, 24.84) vs. SE/WO: 1.10 (0.81, 1.50)
vs. Officer: 2.16 (1.44, 3.24) 		27.63 (25.88, 29.47) 25.50 (21.84, 29.64) vs. SE/WO: 3.23 (2.65, 3.93)
vs. Officer: 11.57 (7.18, 18.63)
 SE/WO 35.71 (33.59, 37.93) 31.69 (29.12, 34.46) vs. Officer: 1.83 (1.48, 2.27) 17.58 (16.10, 19.16) 16.52 (14.65, 18.60) vs. Officer: 1.96 (1.43, 2.68) 9.43 (8.36, 10.61) 7.89 (6.91, 8.99) vs. Officer: 3.58 (2.24, 5.74)
 Officer 15.20 (12.76, 17.97) 17.31 (14.04, 21.15) Reference 6.77 (5.18, 8.70) 8.43 (6.17, 11.28) Reference 2.22 (1.36, 3.43) 2.20 (1.32, 3.47) Reference
Component
 NG 49.04 (45.77, 52.47) 39.36 (35.72, 43.34) vs. AD: 1.25 (1.10, 1.42)
vs. RC: 1.36 (1.13, 1.64) 		25.19 (22.87, 27.69) 19.46 (16.97, 22.29) vs. AD: 1.32 (1.10, 1.60)
vs. RC: 1.33 (1.02, 1.73) 		15.35 (13.55, 17.32) 11.17 (9.48, 13.14) vs. AD: 1.11 (0.91, 1.35)
vs. RC: 1.49
(1.09, 2.05)
 RC 34.59 (30.25, 39.37) 28.94 (24.47, 34.13) vs. AD: 0.92 (0.77, 1.11) 16.92 (13.93, 20.36) 14.61 (11.46, 18.50) vs. AD: 0.99 (0.76, 1.29) 11.18 (8.78, 14.03) 7.48 (5.59, 9.97) vs. AD: 0.74 (0.55, 1.00)
 AD 49.05 (47.09, 51.06) 31.43 (28.73, 34.39) Reference 21.53 (20.24, 22.88) 14.70 (12.81, 16.88) Reference 18.37 (17.18, 19.62) 10.07 (8.95, 11.33) Reference
FY of Return from Deployment
 2008–2009 51.17 (48.72, 53.72) 35.90 (32.95, 39.13) vs. FY 10–11: 1.03 (0.90, 1.16)
vs. FY 12–14: 1.30 (1.08, 1.57) 		22.75 (21.12, 24.46) 17.47 (15.34, 19.88) vs. FY 10–11: 1.10 (0.92, 1.33)
vs. FY 12–14: 1.28 (0.98, 1.68)		 18.73 (17.26, 20.30) 10.24 (8.94, 11.80) vs. FY 10–11: 0.89 (0.73, 1.09)
vs. FY 12–14: 1.59 (1.13, 2.23)
 2010–2011 47.75 (45.18, 50.42) 35.01 (31.83, 38.51) vs. FY 12–14: 1.27 (1.04, 1.54) 22.03 (20.30, 23.87) 15.83 (13.74, 18.23) vs. FY 12–14: 1.16 (0.88, 1.53) 17.97 (16.41, 19.64) 11.46 (9.80, 13.44) vs. FY 12–14: 1.78 (1.26, 2.52)
 2012–2014 39.28 (35.97, 42.82) 27.64 (23.18, 32.94) Reference 19.98 (17.64, 22.55) 13.65 (10.57, 17.60) Reference 10.79 (9.09, 12.72) 6.44 (4.58, 9.15) Reference
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Note. AAPI=Asian American or Pacific Islander; AD= Active Duty; AIAN=American Indian/Alaskan Native; BNH=Black non-Hispanic; FY=Fiscal Year; JE=Junior Enlisted [E1-E4]; NG=National Guard; RC=Reserve Component; SE/WO=Senior Enlisted [E5-E9]/Warrant Officer; WNH=White, non-Hispanic; Boldface indicates statistical significance (P<0.05)

a

Rates for Race/Ethnicity adjusted using age groups 18–24, 25–29, 30–34, 35+

b

Rates for Race/Ethnicity adjusted using age groups 18–24, 25–29, 30+, rates for Sex and Component adjusted using age groups 18–24, 25–29, 30–34, 35+, and rates for Rank adjusted using age groups 18–29, 30+

c

Suppressed, cell(s) <10.

Figure 1.

Figure 1.

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Overall All Accidental, MVA and Overdose Hazard Rates with Trend Lines

MVA Deaths

Soldiers in the 18–24 and 25–29 age groups had higher mortality rates than the oldest age group (RR=2.54, 95% CI: 2.11, 3.07; and RR=1.51, 95% CI: 1.23, 1.86, respectively – Table 2), and female soldiers had lower age-adjusted mortality rates (RR=0.39, 95% CI: 0.25, 0.61) compared to males. Compared to White non-Hispanic soldiers, only Asian American or Pacific Islander soldiers had different mortality rates, (RR=0.70, 95% CI: 0.50, 0.99). Junior Enlisted and Senior Enlisted/Warrant Officers had higher age-adjusted mortality rates than Officers. NG had an age-adjusted MVA mortality rate 1.32 times (95% CI: 1.10, 1.60) AD members, and 1.33 times (95% CI: 1.02, 1.73) RC members. There was a decreasing hazard for MVA death postdeployment (APC= −6.5%, 95% CI: −8.8%, −4.2%; Figure 1; see Supplemental Table 3 for hazard rates across groups).

Accidental Overdose Deaths

RRs for age groups 18–24, 25–29 and 30–34, as compared to 40+, were greater in magnitude than for MVA and all accidental deaths – Table 2. Those aged 18–24 had a mortality rate 4.29 times (95% CI: 3.26, 5.65) that of the 40+ group; the mortality rate for those aged 25–29 was 3.47 times (95% CI: 2.61, 4.61) that of the 40+ group; and those aged 30–34 had an accidental overdose mortality rate 2.02 times (95% CI: 1.46, 2.78) those aged 40+. Females had an age-adjusted accidental overdose mortality rate that was 0.42 times that of males (95% CI: 0.26, 0.70). Age-adjusted overdose mortality rates were lower for Black non-Hispanic and Hispanic soldiers compared to White non-Hispanic soldiers (RR=0.31, 95% CI: 0.23, 0.42, and RR=0.37, 95% CI: 0.25, 0.55, respectively). Compared to Senior Enlisted/Warrant Officers, Junior Enlisted had age-adjusted mortality rates 3.23 times that of Senior Enlisted/Warrant Officers (95% CI: 2.65, 3.93) and 11.57 times that of Officers (95% CI: 7.18, 18.63). Senior Enlisted/Warrant Officers also had an age-adjusted mortality rate 3.58 times that of Officers (95% CI: 2.24, 5.74). NG had a higher age-adjusted rate than RC (RR=1.49, 95% CI: 1.09, 2.05) and the age-adjusted overdose mortality rate for NG was 1.11 times that of AD (95% CI: 0.91, 1.35). Compared to those returning in FY 2012–2014, those returning earlier had higher age-adjusted mortality rates. There was a substantial increase in the hazard for accidental overdose deaths with an APC of 9.9% (95% CI: 7.2%, 12.6%), Figure 1/Supplemental Table 4

DISCUSSION

Among over 860,000 soldiers returning from an Afghanistan/Iraq deployment in FYs 2008–2014, we found that accidental deaths accounted for 34% of all deaths through 2018, predominantly comprised of MVA (46%) and accidental overdose (36%). An innovation was our examination of trends in accidental death rates postdeployment, which revealed divergent time-trends in risk for MVA compared to accidental overdose deaths. MVA deaths were highest in the immediate years postdeployment, with decreasing hazard rates following deployment (average decrease of 6.5%). Conversely, accidental overdose deaths were lowest in the years immediately following deployment, with increasing hazard rates (average increase of 9.9%). These divergent trends for the two most common types of accidental deaths provide critical information to inform prevention and intervention planning for military members returning from future combat deployments.

While previous studies have found that the years following military separation are high risk for MVA among Afghanistan/Iraq Veterans,12,22 our study indicates that the risk is highest in the immediate years following deployment; thus risk escalates while still in military service. Contributors of risk for MVA death among military members/Veterans may include high prevalence of binge drinking and driving while under the influence,23–25 aggressive driving, engaging in thrill-seeking behavior, evasive driving skills learned during deployment,7 and altered perceptions of risk following deployment.7,8,12 Our study findings suggest deployment return is a critical transition period for MVA death risk and implementation of interventions to decrease risky driving upon deployment return are warranted.7

The Afghanistan/Iraq conflicts overlapped with the opioid epidemic in the US and overdose crisis.26 Illicit drug use has been lower during military service due to DoD’s “zero tolerance” policy,24,27,28 yet, similar to VHA and civilian healthcare settings,29 opioid prescribing in the Military Health System escalated during the opioid epidemic, and prescription opioid misuse increased.24 Increasing accidental overdose deaths over the 11-years following deployment, particularly among the majority younger and male population of military members, suggest that evidence-based prevention and intervention efforts should be implemented and sustained indefinitely for those who deployed to Afghanistan/Iraq (e.g., widespread naloxone distribution, access to medications and treatment for opioid use disorders).30

Military members who deployed to Afghanistan/Iraq were particularly young. The two youngest age groups in our study (18–24 and 25–29) had the highest accidental death hazard rates over time, which remained stable over the 11-year postdeployment period. Consistent with other research,4 males had higher accidental age-adjusted death rates, as did Junior Enlisted. More research is warranted to investigate differences in risk for accidental deaths by component. Compared to AD members who typically return to living on military bases following deployments, NG members typically return home, which may limit peer connection and monitoring from commanders and result in more diverse home and driving environments.1 White non-Hispanic soldiers generally exhibited the highest risk for MVA and accidental overdose death with Asian American or Pacific Islander soldiers having consistently lower risk across all three categories. Continued efforts to elucidate accidental death risk across racial and ethnic groups are needed. It is possible that rates differ by mental health and substance use diagnostic status11 or by number of deployments.1,31,32 Future research is warranted.

Limitations

Determining whether an injury death is intentional (suicide) or unintentional (accident) can be challenging, and some deaths may have been misclassified.33,34 Some of our measurements are imprecise due to small samples sizes. Thus, we considered effect size as well as statistical significance when interpreting and highlighting findings. Results may not generalize to other services or other conflict years.

CONCLUSIONS

Accidental deaths accounted for over 34% of deaths following return from an Afghanistan/Iraq deployment. Understanding accidental death risk among those who deployed is an important, first step in the process of identifying evidence-based strategies to facilitate prevention. Observed divergent trends in risk for the most common types of accidental deaths provide essential information to inform prevention and intervention planning.

Supplementary Material

Supp File 1
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Supp File 2
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Supp File 5

Highlights.

  1. Accidental deaths were the most common type of postdeployment mortality.

  2. Accidental deaths were mostly motor vehicle accidents or overdose deaths.

  3. Motor vehicle accident death rates were highest immediately postdeployment.

  4. Accidental overdose death rates were lowest immediately postdeployment.

  5. Hazard rates for types of accidental deaths had divergent trends over time.

Grants and/or Financial Support:

This study was funded by the National Institute of Mental Health and Office of the Director at NIH (R01MH120122). Funding to support cohort development was from the National Center for Complementary and Integrative Health (NCCIH; R01AT008404) and the National Institute on Drug Abuse (NIDA; R01DA030150). The opinions and assertions herein are those of the authors and do not necessarily reflect the official views of the Department of Defense, Uniformed Services University, the Veterans Health Administration, the US Army, US Navy, US Air Force, the US Government, National Institutes of Health, or the Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., and do not imply endorsement by the Federal Government.

Abbreviations

AD

active duty

APC

annual percent change

CI

confidence interval

DoD

Department of Defense

FY

fiscal year

MDR

Mortality Data Repository

MHS

Military Health System

MVA

motor vehicle accidents

NDI

National Death Index

NG

National Guard

RC

Reserve Component

RR

rate ratio

SUPIC

Substance Use and Psychological Injury Combat Study

VA

Veterans Health Administration

Footnotes

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Disclaimer: Approval for this study was granted by the Brandeis University Committee for Protection of Human Subjects, the Colorado Multiple Institutional Review Board, the Department of Veterans Affairs Eastern Colorado Health Care System Institutional Review Board, the Vanderbilt University Institutional Review Board, and the Human Research Protection Program at the Office of the Assistant Secretary of Defense for Health Affairs/ Defense Health Agency. All analyses were performed in accordance with the ethical standards as laid down in the Declaration of Helsinki and its later amendments or comparable ethical standards. This study used secondary existing data only and did not require written informed consent. Clearance for publication was provided by the Office of Regulatory Affairs and Research Compliance at Henry M. Jackson Foundation for the Advancement of Military Medicine.

Declaration of interests

The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:

Rachel Sayko Adams, PhD, MPH reports financial support was provided by Grants from NIH and Henry Jackson Foundation, VA IPA. Jeri Forster, PHD reports financial support was provided by Grants from the VA, DoD and NIH. Claire Hoffmire, PhD reports financial support was provided by Dr. Hoffmire reports grants from the VA and NIH. Colin Walsh, MD reports financial support was provided by Grants from NIH, US Food and Drug Admin. Mary Jo Larson, PhD reports financial support was provided by Grants from the NIH and USU and DoD. Jaimie Gradus, PhD reports financial support was provided by Dr. Gradus reports grants from the VA, DoD, and NIH. Lisa A. Brenner, PhD reports financial support was provided by VA, DoD, NIH, State of Colorado. Colin Walsh MD reports financial support was provided by Military Suicide Research Consortium, Wellcome Leap. Colin Walsh, MD reports financial support was provided by Selby Stead Fund, Vanderbilt Univ. Medical Center. Colin Walsh, MD reports financial support was provided by TN Department of Health. Colin Walsh, MD reports financial support was provided by Southeastern Home Office Underwriters Ass. and Hannover Re. Colin Walsh, MD reports financial support was provided by Holding equity in Sage AI outside the submitted work. Lisa Brenner, PhD reports financial support was provided by Editorial renumeration from Wolters Kluwer. Lisa Brenner, PhD reports financial support was provided by Royalties American Psychological Association and Oxford Unv. Press. Lisa Brenner, PhD reports financial support was provided by Consults with sports leagues via her university affiliation.

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Supplementary Materials

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