Trajectory of Postconcussive Symptoms 12 Months after Deployment in Soldiers with and Without Mild Traumatic Brain Injury

We analyzed data from a cohort of recently deployed soldiers from 2 US Army bases, Fort Carson and Fort Bragg (2009 to 2015). Soldiers with and without a recent history of mild traumatic brain injury (mTBI) on deployment were evaluated within days of return and at 3, 6, and 12 months. Those with mTBI were more likely than those without to endorse ≥1 postconcussive symptom as "severe" and/or "very severe" (47% vs. 21%, baseline; adjusted relative risk (RR) = 1.71, 95% confidence interval: 1.51, 1.93, all time points), which remained significant after adjusting for posttraumatic stress disorder (adjusted RR = 1.34, 95% confidence interval: 1.20, 1.50). Prevalence and relative risks for 3 of the most common baseline symptoms remained constant over time: sleep problems (RR = 2.19), forgetfulness (RR = 2.56), and irritability (RR = 2.73). The pattern was slightly different for headache (baseline, RR = 3.44; 12 months, RR = 3.26), due to increased prevalence of headache in those without mTBI. The prevalence of clinically relevant postconcussive symptoms remained relatively constant over 1 year of follow-up, whether or not symptoms were associated with concussion. Service members with recent mTBI reported more symptoms than those without at all time points.