Mild traumatic brain injury in UK military personnel returning from Afghanistan and Iraq: cohort and cross-sectional analyses.

OBJECTIVES: : To assess (a) the prevalence of mild traumatic brain injury (mTBI) in UK military personnel deployed to Iraq and/or Afghanistan, (b) the risk factors associated with mTBI, and (c) the association between mTBI and subsequent postconcussion symptoms (PCS).

PARTICIPANTS: : A total of 4620 personnel deployed to Iraq and/or Afghanistan who completed a questionnaire between 2007 and 2009, of whom 2333 were also studied in 2005, participated in the study.

MAIN OUTCOME MEASURES: : Mild traumatic brain injury during deployment, as identified using a modified version of the Brief Traumatic Brain Injury Screen questionnaire; symptoms associated with PCS in the month before questionnaire completion.

RESULTS: : The prevalence of mTBI was 4.4%, and the prevalence in those with a combat role was 9.5%. Having an mTBI was associated with current symptoms of posttraumatic stress disorder (adjusted odds ratio (AOR), 5.2; 95% confidence interval [CI], 2.3-11.4), alcohol misuse (AOR, 2.3; 95% CI, 1.4-3.7), and multiple physical symptoms (AOR, 2.6; 95% CI, 1.3-5.2). Only 3 of 9 symptoms remained associated with mTBI after adjustment. Psychological distress and alcohol misuse recorded before deployment were associated with subsequent mTBI.

CONCLUSIONS: : The prevalence of mTBI in UK military is lower than that in the US military. Symptoms of current posttraumatic stress disorder and alcohol misuse are associated with mTBI. Symptoms of mental disorder predated occurrence of mTBI. The majority PCS were not associated with mTBI.