Time of Injury and Relation to Alcohol Intoxication in Moderate-to-Severe Traumatic Brain Injury: A Decade-Long Prospective Study.

Background: Knowledge about the causes and time of injury for traumatic brain injury (TBI) is important for the development of efficient prevention policies. We aimed to study time of injury and relation to alcohol intoxication for moderate-to-severe TBI in a level 1 trauma center in Norway.

Methods: From October 2004 to September 2014, 493 consecutive patients (≥16 years) with moderate (Glasgow Coma Scale [GCS] score 9-13) and severe TBI (GCS score 3-8) were prospectively included in the Trondheim TBI Study (222 patients with moderate and 270 patients with severe TBI).

Results: Mean age was 47 years (standard deviation 21 years). Positive blood alcohol concentration (BAC) was found in 29%, and median BAC was 41.5 mmol/L (interquartile range 28.7-54.3), equal to 1.91‰. Admissions were more frequent on Saturdays (relative risk [RR] 2.67, 95% confidence interval [CI] 1.87-3.80) and Sundays (RR 2.10, 95% CI 1.45-3.03) compared with Mondays, and positive BAC was more common on weekends than weekdays (43% vs. 16%). Furthermore, admissions were more frequent in June (RR 2.26, 95% CI 1.44-3.55), July (RR 2.07, 95% CI 1.31-3.28), and December (RR 2.07, 95% CI 1.31-3.28) compared with January. The number of patients with positive BAC was greatest in December (RR 5.75, 95% CI 1.99-16.63), and 70% of these were caused by falls.

Conclusions: Our findings demonstrate that moderate-to-severe TBI admissions display a clear weekly and seasonal variation and that alcohol is an important modifiable risk factor for moderate-to-severe TBI.