Occupational outcomes following mild traumatic brain injury in Canadian military personnel deployed in support of the mission in Afghanistan: a retrospective cohort study

Abstract

ObjectiveDeployment-related mild traumatic brain injury (MTBI) occurs in a significant number of military personnel but its long-term impacts are unclear. This study explores the impact of deployment-related MTBI on continued fitness-for-duty, with the ultimate intent of identifying potential targets for intervention to attenuate its effects.ParticipantsConsisted of 16 193 Canadian Armed Forces (CAF) personnel who deployed in support of the mission in Afghanistan and completed an enhanced postdeployment screening (EPDS) questionnaire over the period January 2009–July 2012.Primary outcomeThe primary outcome was development of permanent medical unfitness defined as a ‘career-limiting medical condition’ (CL-MC). The secondary outcome was the diagnostic categories recorded for each individual at the time a CL-MC was established.DesignThis study used a retrospective cohort design. Linked administrative and health data provided the primary outcome and the diagnoses responsible for it. Survival analysis was used to estimate the risk of a CL-MC and Cox regression provided adjusted HRs (aHRs) for the association between a CL-MC and MTBI, accounting for key covariates and confounders. Diagnostic categories associated with CL-MCs were identified.ResultsOver a median follow-up period of 3.42 years, 6.57% of the study population developed a CL-MC. MTBI was independently associated with CL-MCs (aHR=1.65, 95% CI 1.35 to 2.03). Mental disorders and musculoskeletal conditions were the primary diagnoses associated with CL-MCs (identified as the primary diagnosis in 55.4% and 25.9%, respectively), and a neurological condition was only documented in 5.8% of those with MTBI who developed a CL-MCConclusionsDeployment-related MTBI was associated with adverse occupational outcome but mental disorders and musculoskeletal conditions primarily drove subsequent medical unfitness. These findings support a diagnostic and treatment approach focusing on these comorbidities as the most promising strategy to minimise the burden of disability in MTBI-exposed military personnel.

High-Intensity Interval Training Is Associated With Alterations in Blood Biomarkers Related to Brain Injury

“…However, as opposed to severe traumatic brain injury (TBI) where peripheral blood biomarker concentrations can acutely fluctuate by several orders of magnitude ( Di Battista et al, 2016a ), the relatively modest changes observed in concussion are often more difficult to characterize. Moreover, concussions occur frequently in the athletic and military settings where injury commonly accompanies physical exertion ( Garber et al, 2014 , 2016 ). This presents both methodological and analytical challenges, as exercise itself elicits profound physiological and biochemical alterations, and many of these perturbations are similar to those seen in concussion and/or mild head trauma ( Reihmane et al, 2012 ; Cook et al, 2013 ; Koh and Lee, 2014 ; Stocchero et al, 2014 ; Bessa et al, 2016 ; Kaspar et al, 2016 ; He et al, 2017 ).…”

An investigation of neuroinjury biomarkers after sport-related concussion: from the subacute phase to clinical recovery

“…Concussion spans all age groups and includes specialised subpopulations such as athletes and military personnel (1,2). Despite the high prevalence and societal burden, concussion pathophysiology is unclear (3).…”

Contribution of mental and physical disorders to disability in military personnel

“…PTSD contributes heavily to medical discharge, though other mental disorders clearly also contribute [ 6 ]. Research on the contribution of TBI is limited; however, one study suggests a substantial contribution [ 7 ] while another similar study suggests minimal contribution [ 8 ] to disability. Amputations, though frequently disabling, represent only a small subset of all musculoskeletal problems, even in a war zone [ 9 ].…”

“…Past research has been constrained by its focus on only a particular subset of the military population (e.g. deployed personnel [ 6 , 8 ]), a single condition (such as TBI [ 8 ]) or a single disability-related outcome (e.g. medical discharge [ 6 , 8 ]).…”

“…deployed personnel [ 6 , 8 ]), a single condition (such as TBI [ 8 ]) or a single disability-related outcome (e.g. medical discharge [ 6 , 8 ]). Other constraints include consideration of only service limitation as the extent of disability, the failure to adjust for confounding factors (including the presence of multiple conditions driving disability), and the inability to assess interactions between health problems, including those due to sports and physical training.…”