Traumatic brain injury in Denmark 2008–2012

Aims: To examine the epidemiology of traumatic brain injury (TBI) in Denmark, including the relative frequency, distribution of injuries and the external causes across the days of the week, sex and age. Methods: I carried out a nationwide register-based study of the full population aged 16–65 years with a diagnosis of TBI between 2008 and 2012, a total of 27,030 hospital contacts. I calculated the average annual relative frequency and the sex risk ratio for four TBI diagnoses across age. I report the distribution of five external causes and the odds ratio of acquiring a TBI during the weekend. Results: The relative frequency of TBI peaked among 16- to 35-year-olds for all diagnosis except for haemorrhages, which increase with age. During weekends, the relative frequency of concussions increases for men, whereas the relative frequency of severe TBI increases for young men and decreases for older men. The relative frequency of TBI is stable throughout the week for women aged 16–35 years, but decreases for women aged 36–65 years. For 16- to 35-year-olds, the main external causes of TBI are falls and road traffic accidents. During the weekend, the risk of violence-, sport- and fall-related TBI increases for 16- to 35-year-olds, whereas the risk of TBI related to road traffic accidents decreases for women and older men. The risk of sports-related TBI increases during weekends for older men. Conclusions: Injury patterns and external causes across TBI diagnoses differ substantially across sex, age and the day of week, indicating differences in the behavioural patterns that result in a TBI.