Pre-Existing Audiometric Hearing Loss is a Predictor of Significant Threshold Shift Following Injury During Combat Deployment.

OBJECTIVES: Military personnel are exposed to multiple risk factors for hearing loss, particularly on the battlefield. The objective of this study was to determine whether pre-existing hearing loss predicted hearing threshold shift in male U.S. military personnel following injury during combat deployment. DESIGN: This was a retrospective cohort study with 1573 male military personnel physically injured in Operations Enduring and Iraqi Freedom between 2004 and 2012. Audiograms before and after injury were analyzed and used to calculate significant threshold shift (STS), defined as a 30 dB or greater change in the sum of hearing thresholds at 2000, 3000, and 4000 Hz in either ear on the postinjury audiogram, relative to the same frequencies on the preinjury audiogram. RESULTS: Twenty-five percent (n = 388) of the sample had preinjury hearing loss, which mostly occurred in the higher frequencies (i.e., 4000 and 6000 Hz). The prevalence of postinjury STS ranged from 11.7% to 33.3% as preinjury hearing level moved from better to worse. In multivariable logistic regression, preinjury hearing loss was a predictor of STS, and there was a dose-response relationship between severity of preinjury hearing threshold and postinjury STS, specifically for preinjury hearing levels of 40 to 45 dBHL (odds ratio [OR] = 1.99; 95% confidence interval [CI] = 1.03 to 3.88), 50 to 55 dBHL (OR = 2.33; 95% CI = 1.17 to 4.64), and >55 dBHL (OR = 3.77; 95% CI = 2.25 to 6.34). CONCLUSIONS: These findings suggest that better preinjury hearing provides increased resistance to threshold shift than impaired preinjury hearing. Although STS is calculated using 2000 to 4000 Hz, clinicians must closely attend to the pure-tone response at 6000 Hz and use this test frequency to identify service members at-risk for STS prior to combat deployment.

Relationship Between Tinnitus and Hearing Outcomes Among US Military Personnel After Blast Injury.

OBJECTIVES: To examine the association between tinnitus and hearing outcomes among US military personnel after blast injury, including any hearing loss, low-frequency hearing loss, high-frequency hearing loss, early warning shift, and significant threshold shift. DESIGN: In this retrospective study, the Blast-Related Auditory Injury Database was queried for male military service members who had audiometric data 2 years before and after blast injury between 2004 and 2012 with no history of hearing loss or tinnitus before injury (n = 1693). Tinnitus was defined by diagnostic codes in electronic health records. Multivariable logistic regression examined the association between tinnitus and hearing outcomes, while adjusting for covariates. RESULTS: Overall, 14.2% (n = 241) of the study sample was diagnosed with tinnitus within 2 years after blast injury. The proportions of all examined hearing outcomes were higher among service members with tinnitus than those without ( p < 0.001). In multivariable analysis, service members with tinnitus had higher adjusted odds of any hearing loss (odds ratio [OR] = 1.72, 95% confidence interval [CI] = 1.20-2.47), low-frequency hearing loss (OR = 2.77, 95% CI = 1.80-4.26), high-frequency hearing loss (OR = 2.15, 95% CI = 1.47-3.16), early warning shift (OR = 1.83, 95% CI = 1.36-2.45), and significant threshold shift (OR = 2.15, 95% CI = 1.60-2.89) compared with service members without tinnitus. CONCLUSIONS: The findings of this study demonstrate that tinnitus diagnosed within 2 years after blast injury is associated with the examined hearing outcomes in US military personnel. Service members with blast injury who subsequently experience tinnitus should receive routine audiometric hearing conservation testing and be carefully examined for poor hearing outcomes by an audiologist.

Differences in quality-of-life scores across injury categories by mental health status among injured U.S. military service members and veterans.

PURPOSE: Posttraumatic stress disorder (PTSD) and depression are strong predictors of poor health-related quality of life (HRQOL) among injured U.S. military service members (SMs). Patterns of HRQOL between injury categories and injury categories stratified by mental health (MH) symptoms have not been examined. Among deployment-injured SMs and veterans (n = 4353), we examined HRQOL and screening data for PTSD and/or depression within specific injury categories. METHODS: Participants included those enrolled in the Wounded Warrior Recovery Project with complete data for HRQOL (SF-36) from June 2017 to May 2020. Injuries were categorized using the Barell Injury Diagnosis Matrix (Barell Matrix). Mean physical component summary (PCS) and mental component summary (MCS) scores were calculated for each injury category and stratified by the presence or absence of probable PTSD and/or depression. RESULTS: The average follow-up time that participants were surveyed after injury was 10.7 years. Most participants were male, non-Hispanic White, served in the Army, and enlisted rank. Mechanism of injury for 77% was blast-related. Mean PCS and MCS scores across the entire sample were 43.6 (SD = 10.3) and 39.5 (SD = 13.3), respectively; 50% screened positive for depression and/or PTSD. PCS and MCS scores were significantly lower within each injury category among individuals with probable PTSD and/or depression than those without. CONCLUSION: Among deployment-injured SMs, those with probable PTSD and/or depression reported significantly lower HRQOL within injury categories and HRQOL component (i.e., physical or mental) than those without. Findings are consistent with prior reports showing mental health symptoms to be strongly associated with lower HRQOL and suggest integration of mental health treatment into standard care practices to improve long-term HRQOL.

Deployment-related concussion and long-term health-related quality of life among US military personnel.

PURPOSE: To examine the relationship between deployment-related concussion and long-term health-related quality of life (HRQoL) among injured US military personnel. METHODS: The study sample included 810 service members with deployment-related injuries between 2008 and 2012 who responded to a web-based longitudinal health survey. Participants were categorized into three injury groups: concussion with loss of consciousness (LOC; n = 247), concussion without LOC (n = 317), or no concussion (n = 246). HRQoL was measured using the 36-Item Short Form Health Survey physical and mental component summary (PCS and MCS) scores. Current post-traumatic stress disorder (PTSD) and depression symptoms were examined. Multivariable linear regression models assessed the effects of concussion on PCS and MCS scores, while controlling for covariates. RESULTS: A lower PCS score was observed in participants with concussion with LOC (B = - 2.65, p = 0.003) compared with those with no history of concussion. Symptoms of PTSD (PCS: B = - 4.84, p < 0.001; MCS: B = - 10.53, p < 0.001) and depression (PCS: B = - 2.85, p < 0.001; MCS: B = - 10.24, p < 0.001) were the strongest statistically significant predictors of lower HRQoL. CONCLUSION: Concussion with LOC was significantly associated with lower HRQoL in the physical domain. These findings affirm that concussion management should integrate physical and psychological care to improve long-term HRQoL and warrant a more detailed examination of causal and mediating mechanisms. Future research should continue to incorporate patient-reported outcomes and long-term follow-up of military service members to further define the lifelong impact of deployment-related concussion.

Research Letter: Prevalence of Spine Injuries Among US Military Personnel With Combat-Related Concussion.

OBJECTIVE: To describe the prevalence of spine injuries among US service members with combat-related concussion. DESIGN AND PARTICIPANTS: A retrospective review of medical records for US service members injured during combat operations in Iraq and Afghanistan between 2002 and 2020. The study sample included 27 897 service members categorized into 3 groups: concussion with loss of consciousness (LOC, n = 4631), concussion non-LOC ( n = 5533), and non-concussion ( n = 17 333). MAIN MEASURES: Spine injuries were identified by International Classification of Diseases, Ninth Revision, Clinical Modification ( ICD-9-CM ) codes and classified by body region and nature of injury using the Barell injury diagnosis matrix. Differences in prevalence of spine injuries by concussion group were evaluated using χ 2 tests. RESULTS: Spine injuries were most prevalent among service members with concussion LOC (31.1%), followed by concussion non-LOC (18.3%), and non-concussion (10.0%, P < .001). Sprains and strains were the most prevalent spine injury category, with injuries to the cervical, thoracic, and lumbar regions significantly more prevalent in the concussion groups ( P values < .001), particularly individuals with LOC compared with non-concussion. CONCLUSION: The US military personnel with combat-related concussion, especially individuals with LOC, may also have spine injuries. Routine assessment for spine injury is recommended during concussion screening because this may impact clinical management and rehabilitation.

Symptom profiles following combat injury and long-term quality of life: a latent class analysis.

PURPOSE: The purpose of this study was to identify symptom profiles among U.S. military personnel within 1 year after combat injury and assess the relationship between the symptom profiles and long-term quality of life (QoL). METHODS: The study sample consisted of 885 military personnel from the Expeditionary Medical Encounter Database who completed (1) a Post-Deployment Health Assessment (PDHA) within 1 year following combat injury in Iraq or Afghanistan, and (2) a survey for the Wounded Warrior Recovery Project (WWRP), a longitudinal study tracking patient-reported outcomes (e.g., QoL) in injured military personnel. Fifteen self-reported symptoms from the PDHA were assessed using latent class analysis to develop symptom profiles. Multivariable linear regression assessed the predictive effect of symptom profiles on QoL using the physical (PCS) and mental (MCS) component summary scores from the 36-Item Short Form Survey included in the WWRP. Time between PDHA and WWRP survey ranged from 4.3 to 10.5 years (M = 6.6, SD = 1.3). RESULTS: Five distinct symptom profiles were identified: low morbidity (50.4%), multimorbidity (15.6%), musculoskeletal (14.0%), psycho-cognitive (11.1%), and auditory (8.9%). Relative to low morbidity, the multimorbidity (ß = - 5.45, p < 0.001) and musculoskeletal (ß = - 4.23, p < 0.001) profiles were associated with lower PCS, while the multimorbidity (ß = - 4.25, p = 0.002) and psycho-cognitive (ß = - 3.02, p = 0.042) profiles were associated with lower MCS. CONCLUSION: Multimorbidity, musculoskeletal, and psycho-cognitive symptom profiles were the strongest predictors of lower QoL. These profiles can be employed during screening to identify at-risk service members and assist with long-term clinical planning, while factoring in patient-specific impairments and preferences.

Co-occurrence of hearing loss and posttraumatic stress disorder among injured military personnel: a retrospective study.

BACKGROUND: Posttraumatic stress disorder (PTSD) and hearing loss are hallmark public health issues related to military service in Iraq and Afghanistan. Although both are significant individual contributors to disability among veterans, their co-occurrence has not been specifically explored. METHODS: A total of 1179 male U.S. military personnel who sustained an injury between 2004 and 2012 during operations in Iraq or Afghanistan were identified from clinical records. Pre- and postinjury audiometric data were used to define new-onset hearing loss, which was categorized as unilateral or bilateral. Diagnosed PTSD was abstracted from electronic medical records. Logistic regression analysis examined the relationship between hearing loss and PTSD, while adjusting for age, year of injury, occupation, injury severity, injury mechanism, and presence of concussion. RESULTS: The majority of the study sample were aged 18-25 years (79.9%) and sustained mild-moderate injuries (94.6%). New-onset hearing loss was present in 14.4% of casualties (10.3% unilateral, 4.1% bilateral). Rates of diagnosed PTSD were 9.1, 13.9, and 29.2% for those with no hearing loss, unilateral hearing loss, and bilateral hearing loss, respectively. After adjusting for covariates, those with bilateral hearing loss had nearly three-times higher odds of PTSD (odds ratio = 2.92; 95% CI, 1.47-5.81) compared to those with no hearing loss. Unilateral hearing loss was not associated with PTSD. CONCLUSIONS: Both PTSD and hearing loss are frequent consequences of modern warfare that adversely affect the overall health of the military. Bilateral, but not unilateral, hearing loss was associated with a greater burden of PTSD. This has implications for warfighter rehabilitation and should encourage collaboration between audiology and mental health professionals.

Multimorbidity and quality of life after blast-related injury among US military personnel: a cluster analysis of retrospective data.

BACKGROUND: Blast injury emerged as a primary source of morbidity among US military personnel during the recent conflicts in Iraq and Afghanistan, and led to an array of adverse health outcomes. Multimorbidity, or the presence of two or more medical conditions in an individual, can complicate treatment strategies. To date, there is minimal research on the impact of multimorbidity on long-term patient-reported outcomes. We aimed to define multimorbidity patterns in a population of blast-injured military personnel, and to examine these patterns in relation to long-term quality of life (QOL). METHODS: A total of 1972 US military personnel who sustained a blast-related injury during military operations in Iraq and Afghanistan were identified from clinical records. Electronic health databases were used to identify medical diagnoses within the first year postinjury, and QOL was measured with a web-based assessment. Hierarchical cluster analysis methods using Ward's minimum variance were employed to identify clusters with related medical diagnosis categories. Duncan's multiple range test was used to group clusters into domains by QOL. RESULTS: Five distinct clusters were identified and grouped into three QOL domains. The lowest QOL domain contained one cluster with a clinical triad reflecting musculoskeletal pain, concussion, and mental health morbidity. The middle QOL domain had two clusters, one with concussion/anxiety predominating and the other with polytrauma. The highest QOL domain had two clusters with little multimorbidity aside from musculoskeletal pain. CONCLUSIONS: The present study described blast-related injury profiles with varying QOL levels that may indicate the need for integrated health services. Implications exist for current multidisciplinary care of wounded active duty and veteran service members, and future research should determine whether multimorbidity denotes distinct post-blast injury syndromes.

Clinical audiometric patterns of hearing loss following blast-related injury in U.S. military personnel.

Objective: To identify clinical audiometric patterns of hearing loss following blast-related injury (BRI) in US military personnel.Design: Retrospective cohort study.Study sample: A total of 1186 male Navy and Marine Corps service members with normal hearing thresholds on pre-injury audiograms who had post-injury audiograms in the Blast-Related Auditory Injury Database.Results: Low- and high-frequency pure-tone averages (PTAs) were significantly higher in those with BRI than non-blast-related injury (NBRI) for both ears (p < 0.001 for all comparisons). Overall, 172 (15%) service members met criteria for post-injury hearing loss and were categorised into PTA or single-frequency hearing loss subgroups. PTA hearing loss was more common in the BRI group (50% vs. 33%, p < 0.036), whereas single-frequency hearing loss was more common in the NBRI group. Most hearing loss was mild to moderate in degree, and three distinct audiometric patterns emerged (i.e. flat, sloping and rising). A flat pattern was the most prevalent configuration among those with PTA hearing loss, especially bilateral loss. Single-frequency hearing loss was mostly unilateral and high frequency.Conclusions: In this study, BRI produced hearing loss across test frequencies, generating more clinically actionable post-injury audiograms than NBRI. We found that post-injury audiometric patterns of hearing loss among military personnel may vary.

Impact of Blast Injury on Hearing in a Screened Male Military Population.

Exposure to hazardous intensity levels of combat noise, such as blast, may compromise a person's ability to detect and recognize sounds and communicate effectively. There is little previous examination of the onset of hearing health outcomes following exposure to blast in representative samples of deployed US military personnel. Data from the prospective Blast-Related Auditory Injury Database were analyzed. We included only those participants with qualified hearing tests within a period of 12 months prior to, and following, injury (n = 1,574). After adjustment for relevant covariates and potential confounders, those who sustained a blast injury had significantly higher odds of postinjury hearing loss (odds ratio = 2.21; 95% confidence interval: 1.42, 3.44), low-frequency hearing loss (odds ratio = 1.95; 95% confidence interval: 1.01, 3.78), high-frequency hearing loss (odds ratio = 2.45; 95% confidence interval: 1.43, 4.20), and significant threshold shift compared with a group with non-blast-related injury. An estimated 49% of risk for hearing loss in these blast-injured, deployed military members could be attributed to the blast-related injury event. This study reinforced that it is imperative to identify at-risk populations for early intervention and prevention, as well as to consistently monitor the effects of blast injury on hearing outcomes.

Preliminary study of hearing protection and non-impact, blast-induced concussion in US military personnel.

PRIMARY OBJECTIVE: To examine the relationship between hearing protection and non-impact, blast-induced concussion in US military personnel. RESEARCH DESIGN: Retrospective cohort study. METHODS AND PROCEDURES: A total of 501 US service members from the Expeditionary Medical Encounter Database with hearing protection status reported either 'worn' or 'not worn' were eligible for analysis. Clinical records were reviewed for concussion diagnoses. Univariate and multiple logistic regressions were performed. MAIN OUTCOMES AND RESULTS: Overall, 270 (53.9%) service members sustained non-impact, blast-induced concussion and 231 (46.1%) sustained other blast injuries. Only 39.6% (107 of 270) of service members with concussion wore hearing protection at the point of injury compared with 61.0% (141 of 231) of those with other injuries (p < 0.001). After adjusting for covariates, service members wearing hearing protection had significantly lower odds of concussion compared with those not wearing hearing protection (odds ratio = 0.42, 95% confidence interval = 0.29-0.62). CONCLUSIONS: To our knowledge, this preliminary study is the first to demonstrate that hearing protection is associated with lower odds of non-impact, blast-induced concussion. The benefits of using hearing protection in terms of force readiness could be significant since many service members wounded in recent conflicts were diagnosed with concussion.

Sex Differences in Screening Positive for Post-Traumatic Stress Disorder After Combat Injury.

INTRODUCTION: U.S. military women were at risk of combat exposure and injury from asymmetric warfare during the conflicts in Iraq and Afghanistan. Previous research has yielded mixed results when examining sex differences in PTSD following operational deployment. To date, no study has explored sex differences in PTSD after combat injury. MATERIALS AND METHODS: This retrospective study included U.S. military service men and women who experienced a combat injury in Iraq or Afghanistan (March 2003 to March 2013) and completed a Post-Deployment Health Assessment (PDHA) within 1 year of injury. The PDHA is administered at the end of deployment and includes the 4-item Primary Care PTSD Screen. The prevalence of screening positive for PTSD was evaluated by sex using a chi-square test. Multivariable logistic regression was used to assess the association between sex and PTSD while adjusting for covariates. RESULTS: The study sample included 16,215 injured military personnel (666 women and 15,549 men). The average time between injury and PDHA was 132 days (SD = 91.0). Overall, women had a higher prevalence of screening positive for PTSD than men (48.3% vs. 40.9%, P < .001). In multivariable regression, women had higher odds than men of screening positive for PTSD (odds ratio, 1.34; 95% confidence interval, 1.14-1.57). Psychiatric history was the strongest predictor of screening positive for PTSD regardless of sex (odds ratio, 1.59; 95% confidence interval, 1.45-1.74). CONCLUSIONS: In this novel study of military service members, women were more likely to screen positive for PTSD than men after combat injury. Strategies to mitigate PTSD, enhance resiliency, and incorporate psychological care into injury rehabilitation programs for women may be needed for future U.S. military conflicts where they will play a larger role in combat operations.

Investigating insomnia in United States deployed military forces: A topic modeling approach.

STUDY OBJECTIVES: This retrospective study analyzed free-text clinical notes from medical encounters for insomnia among a sample of deployed US military personnel. Topic modeling, a natural language processing technique, was used to identify thematic patterns in the clinical notes that were potentially related to insomnia diagnosis. METHODS: Clinical notes of patient clinical encounters coded for insomnia from the US Department of Defense Military Health System Theater Medical Data Store were analyzed. Following preprocessing of the free text in the clinical notes, topic modeling was employed to identify relevant underlying topics or themes in 32,864 unique patients. The machine-learned topics were validated using human-coded potential insomnia etiological issues. RESULTS: A 12-topic model was selected based on quantitative metrics, interpretability, and coherence of terms comprising topics. The topics were assigned the following labels: personal/family history, stimulants, stress, family/relationships, other sleep disorders, depression, schedule/environment, anxiety, other medication, headache/concussion, pain, and medication refill. Validation of these topics (excluding the two medication topics) against their corresponding human-coded potential etiological issues showed strong agreement for the assessed topics. CONCLUSIONS: Analysis of free-text clinical notes using topic modeling resulted in the identification of thematic patterns that largely mirrored known correlates of insomnia. These findings reveal multiple potential etiologies for deployment-related insomnia. The identified topics may augment electronic health record diagnostic codes and provide valuable information for sleep researchers and providers. As both civilian and military healthcare systems implement electronic health records, topic modeling may be a valuable tool for analyzing free-text data to investigate health outcomes.

Sex Differences in Postinjury Health Profiles Among U.S. Military Personnel Following Deployment-Related Concussion.

Background: Women in the U.S. military are now authorized to serve in direct combat occupations. This may increase their risk of combat injuries, such as concussion, in future conflicts. Knowledge of sex differences in health profiles after concussion is paramount for military medical planning efforts. The purpose of this study was to assess sex-related differences in health profiles among U.S. military personnel following deployment-related concussion. Materials and Methods: We conducted a retrospective study of service members who sustained a concussion during combat deployment between 2004 and 2013. Postinjury diagnoses were abstracted from outpatient encounters in electronic health records for 24 months after concussion. We used hierarchical clustering to identify clusters, termed "health profiles," and logistic regression to determine whether sex predicted membership in the health profiles. Results: The study sample included 346 women and 4536 men with deployment-related concussion. Five postinjury health profiles were identified and classified as no morbidity, back pain, tinnitus/memory loss, posttraumatic stress disorder/postconcussion syndrome, and multimorbidity. Women relative to men had higher odds of membership in the back pain (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.05-1.67) and multimorbidity profiles (OR = 1.44; 95% CI = 1.03-2.00) and lower odds than men in the tinnitus/memory loss profile (OR = 0.62; 95% CI = 0.42-0.91). Conclusions: Postinjury health profiles among U.S. service members differ by sex following deployment-related concussion, particularly with a higher burden of multimorbidity among women than men, which may require interdisciplinary care. Women also had higher odds of membership in the back pain profile and lower odds in the tinnitus/memory loss profile than men. To prepare for future military operations where women may have greater exposure to combat, continued research elucidating health-related sex differences after deployment-related concussion is imperative.

Postconcussive symptom reporting among US combat veterans with mild traumatic brain injury from Operation Iraqi Freedom.

OBJECTIVE: To examine the association between postconcussive symptoms and mild traumatic brain injury (MTBI) among combat veterans while adjusting for posttraumatic stress disorder (PTSD) and depression. PATIENTS: Military personnel with provider-diagnosed MTBI (n = 334) or nonhead injury (n = 658) were identified from the Expeditionary Medical Encounter Database. MAIN OUTCOME MEASURES: Post-Deployment Health Assessments and Re-Assessments were used to examine postconcussive symptoms and self-rated health. RESULTS: Personnel with MTBI were more likely to report headache (odds ratio [OR] = 3.37; 95% confidence interval [CI] = 2.19-5.17), back pain (OR = 1.79; 95% CI = 1.23-2.60), memory problems (OR = 1.86; 95% CI = 1.20-2.88), tinnitus (OR = 1.63; 95% CI = 1.10-2.41), and dizziness (OR = 2.13; 95% CI = 1.06-4.29) compared with those with non-head injuries. Among those with MTBI, self-reported decline in health was associated with memory problems (OR = 5.07; 95% CI = 2.56-10.02) and dizziness (OR = 10.60; 95% CI = 3.48-32.27). CONCLUSIONS: Mild traumatic brain injury is associated with reports of negative health consequences among combat veterans even when accounting for co-occurring psychological morbidity. The identification of postconcussive symptoms related to declines in a service member's self-rated health may be important in targeting and prioritizing clinical interventions.

Macrotraumatic Fractures of the Multisegmented Ankle-Foot Complex in Military Tactical Athletes: A Cohort Study.

BACKGROUND: Ankle-foot injuries are common in military personnel and substantially degrade function and force readiness. The purpose of this retrospective cohort study was to assess the incidence and contributing factors of traumatic ankle-foot fractures in the US military. METHODS: A population-based study of all service members in the US military was performed assessing the factors of sex, occupation, service branch, rank, and year on segmental tibia-fibula, rearfoot, and forefoot fracture incidence between 2006 and 2015. The Defense Medical Epidemiology Database was queried for the number of individuals with fractures of the tibia-fibula, rearfoot, and forefoot using International Classification of Diseases, Ninth Revision, Clinical Modification on the initial medical encounter. Unadjusted relative risk (RR) calculations were performed assessing sex and occupation. A negative binomial regression assessed the adjusted factors of sex, branch, rank, and year. RESULTS: During this study, 95,540 enlisted service members (8.4 per 1,000 person-years) and 13,318 military officers (5.8 per 1,000 person-years) were diagnosed with ankle-foot fractures. In the adjusted analysis, sex was found to only be a significant factor in forefoot fractures (RR, 1.54), with female service members having a significantly higher risk. There were no significant sex-related differences observed in tibia-fibula or rearfoot fractures. US Navy and Air Force personnel had significantly lower risk of tibia-fibula fractures (RR range, 0.76-0.84) compared with the US Army. Forefoot fracture risk was significantly higher in the US Marine Corps (RR, 1.47) compared with the US Army. Officers had consistently lower risk for fractures in each segment (RR range, 0.68-0.77) compared with enlisted personnel. Enlisted engineers, aviation, and artillery/gunnery compared to infantry, and ground/naval gunfire officers had the greatest relative risk compared all other officer fields (RR range, 1.11-3.67). CONCLUSIONS: Sex, occupation, branch, and rank were salient factors for macrotraumatic ankle-foot fractures. These findings can be used to inform and increase precision in medical planning and in the targeted development of preventive interventions.

Associations between health-related behaviors and self-reported cognitive symptoms in U.S. military personnel injured on deployment.

Health behaviors may be core contributors to cognition and mental health following mild traumatic brain injury (TBI). The aims of the present study examined: (1) whether health behaviors including sleep duration, alcohol use, and physical activity differed in injured military personnel with and without deployment-related mild TBI history and (2) the relative contributions of health behaviors and deployment-related mild TBI history to self-reported cognitive, posttraumatic stress disorder (PTSD), and depressive symptoms. Participants included 3076 military personnel injured on deployment participating in the Wounded Warrior Recovery Project, an ongoing web-based study. Military personnel with deployment-related mild TBI history reported similar rates of physical activity and levels of alcohol problems as those without, but were less likely to report receiving the recommended duration of sleep. When adjusting for demographic and injury variables, all three health behaviors were associated with cognitive, PTSD, and depressive symptoms. Alcohol problems demonstrated significant but small effects across all outcomes measures (ηp2=.01) whereas physical activity was associated with slightly larger effects albeit still within the small range (ηp2=.02-0.04). Duration of sleep bordered a medium effect for cognitive symptoms (ηp2=.05) and was in the medium range for PTSD and depressive symptoms (ηp2=.06). Although deployment-related mild TBI history was significant in all models, effect sizes were small (ηp2=.01). Findings from the present study provide support that health behaviors have stronger effects with regard to cognitive, PTSD, and depressive symptoms compared to deployment-related mild TBI history in military personnel and, given their modifiable nature, may represent treatment targets in this population.

Effect of dwell time on the mental health of US military personnel with multiple combat tours.

OBJECTIVE: We investigated the association of the length of time spent at home between deployments, or dwell time, with posttraumatic stress disorder (PTSD) and other mental health disorders. METHODS: We included US Marine Corps personnel identified from military deployment records who deployed to Operation Iraqi Freedom once (n = 49,328) or twice (n = 16,376). New-onset mental health diagnoses from military medical databases were included. We calculated the ratio of dwell-to-deployment time (DDR) as the length of time between deployments divided by the length of the first deployment. RESULTS: Marines with 2 deployments had higher rates of PTSD than did those with 1 deployment (2.1% versus 1.2%; P < .001). A DDR representing longer dwell times at home relative to first deployment length was associated with reduced odds of PTSD (odds ratio [OR] = 0.47; 95% confidence interval [CI] = 0.32, 0.70), PTSD with other mental health disorder (OR = 0.56; 95% CI = 0.33, 0.94), and other mental health disorders (OR = 0.62; 95% CI = 0.51, 0.75). CONCLUSIONS: Longer dwell times may reduce postdeployment risk of PTSD and other mental health disorders. Future research should focus on the role of dwell time in adverse health outcomes.

Occupational correlates of low back pain among U.S. Marines following combat deployment.

Many U.S. Marines have experienced routine combat deployments during Operation Iraqi Freedom, which present numerous occupational hazards that may result in low back pain (LBP). The objective of this retrospective cohort study was to identify new-onset LBP among Marines following initial deployment to Operation Iraqi Freedom. Active duty Marines deployed to Iraq or Kuwait between 2005 and 2008 were identified from deployment records and linked to medical databases (n = 36,680). The outcome of interest was an International Classification of Diseases, 9th Revision, Clinical Modification code indicating LBP (724.2) within 1 year postdeployment. Multivariate logistic regression examined the effect of occupation on LBP. Overall, 4.1% (n = 1,517) of Marines were diagnosed with LBP. After adjusting for covariates, the service/supply (odds ratio 1.33, 95% confidence interval, 1.12-1.59) and electrical/mechanical/craftsworker occupations (odds ratio 1.31, 95% confidence interval, 1.12-1.53) had higher odds of LBP when compared to the administrative/other referent group. Within these groups, the highest LBP prevalence was in the construction (8.6%) and law enforcement (6.2%) subgroups. Although infantry occupations purposefully engage the enemy and often face sustained physical rigors of combat, LBP was most prevalent in noninfantry occupations. Future studies should include detailed exposure histories to elucidate occupation-specific etiologies of LBP in order to guide prevention efforts.

The Neuromusculoskeletal Epidemiological Outcome (NEO) matrix: An innovative injury classification based on anatomical location and primary tissue type.

INTRODUCTION: The purpose of this paper is to propose the Neuromusculoskeletal Epidemiological Outcome (NEO) Matrix, an injury classification based on anatomical location and primary tissue type to classify NMSKI of the trunk and extremities in orthopaedic and sports medicine epidemiological research. MATERIALS AND METHODS: In the proposed NEO matrix, NMSKI diagnosis (International Classification of Disease) codes are classified by the anatomical complex affected. These regional anatomical complexes are frequently employed in orthopaedic and sports medicine disciplines in biomechanical and clinical research. The complexes are arranged from distal to proximal in the lower extremity, inferior to superior in the trunk and head, and proximal to distal in the upper extremity. Injuries are characterized by the primary tissue type affected (Osseous; Articular; Musculotendinous; Neural; Non-specific) based on classified using International Classification of Disease codes. DISCUSSION: The expected patterns of impairment and healing rates of bone, cartilage, ligaments, muscles, tendons, and neural structures vary considerably by the tissue type based on the differences in function, perfusion, and metabolic physiology. Using knowledge of the function of the tissues, expected minimum healing times, and expected sequelae of residual body system impairments, an estimation of morbidity and expected recovery times can be made. While heterogeneity is certainly expected due to varying pathomechanics involved and intrinsic and environmental factors, the NEO matrix classifies the ICD diagnosis codes in framework that qualifies the expected patterns of impairment based on the body system type. CONCLUSION: The NEO matrix provides an alternative approach for characterizing NMSKI in epidemiological research.