Head trauma sustained under the influence of alcohol is a predictor for future traumatic brain injury: a long‐term follow‐up study

Background and purpose Hazardous drinking may result in recurrent head trauma. It was investigated whether head trauma sustained under the influence of alcohol is a predictor of future traumatic brain injury ( TBI ). Methods All subjects with head trauma ( n  =   827) brought to the emergency room at Oulu University Hospital during 1999 were identified and followed up until death or the end of 2009. The N ational H ospital D ischarge R egister and hospital charts were used to identify TBI s during the follow‐up and K aplan– M eier curves and the C ox proportional hazards model were used to characterize predictors of TBI . Results During the total follow‐up of 7386 person‐years, 52/827 subjects sustained a new head trauma with TBI and the risk of TBI was significantly ( P  =   0.005) higher amongst subjects who had been under the influence of alcohol at the time of the index trauma in 1999. New TBI occurred under the influence of alcohol in 30/52 cases (57.7%). An alcohol‐related index trauma [adjusted hazard ratio ( HR ) 2.51, 95% confidence interval ( CI ) 1.38–4.56, P  < 0.01] and history of TBI (HR 3.39, 95% CI 1.32–8.72, P  <   0.05) were independent risk factors for subsequent TBI after adjustment for sex and age. A history of harmful drinking was also a significant risk factor (adjusted HR 10.37, 95% CI 5.53–19.43, P  <   0.001). In the subset of 396 patients having an index head trauma without TBI , this being alcohol related was also a significant risk factor for subsequent TBI after adjustment for sex, age and history of TBI (HR 3.54, 95% CI 1.36–9.18, P  =   0.009). Conclusions Even head trauma without TBI under the influence of alcohol implies an elevated risk of subsequent TBI . A brief intervention to reduce hazardous drinking is needed to prevent TBI .