Background Head injury is common, and the risk of subsequent disability and death is high. Increased risk of death years after injury might be explained by factors associated with, but not a consequence of, the head injury. This unique prospective study investigates mortality over 13 years after injury.

Methods A cohort of n=767 with head injury was compared with two case control groups, matched for age, gender and deprivation, and in one control group, matched for duration of hospital admission following (non-head) injury.

Results Two-fifths of the head injury cohort had died. The death rate (30.99 per 1000 per year) was much higher than in community controls (13.72 per 1000 per year). More than 1 year after injury, the death rate in younger (15–54 years) adults was much higher than in community controls (17.36 vs 2.36 per 1000 per year) whereas in older adults the difference was more marginal (61.47 vs 42.36). Death rate was elevated after mild and after more severe head injury, including in younger adults after mild head injury (14.82 per 1000 per year mild head injury vs 2.21 community). Female gender and greater deprivation were not associated with increased death rates after head injury. Late after injury, deaths occurred from the same main causes as for the general population.

Conclusion Head injury is associated with increased vulnerability to death from a variety of causes for at least 13 years after hospital admission. There is a need to understand how head injury influences mortality, particularly in younger adults and after mild head injury.