High-Risk Periods for Adult Traumatic Brain Injuries: A Nationwide Population-Based Study

There is minimal existing available information on nationwide seasonal peaks in traumatic brain injuries (TBIs). This lack of information is an impediment to the effective development of prevention programs, societal policies, and hinders the resourcing of medical emergency services. Our current aim is to study nationwide population-based high-risk periods TBI over a 15-year study period in Finland.

Nationwide databases were searched for all admissions with a TBI diagnosis and later for deaths of persons ≥16 years of age during 2004-2018. The search included all hospitals that provide acute TBI care in Finland.

The study period included 69,231 TBI-related hospital admissions (men = 62%). We found that for men, the highest rate of TBIs occurred on Saturdays, whereas women experience the highest rate of TBIs on Mondays. The highest rate of TBIs in men occurred in July, while women experienced the highest rate of TBIs in January. TBI-related hospital admissions (incidence risk ratio [IRR] 1.090, 95% CI 1.07-1.11, p < 0.0001) and mortality within 30 days after TBI (hazard ratio [HR] 1.057, 95% CI 1.001-1.116, p = 0.0455) were more common on public holidays and weekends than on weekdays. There was an increasing trend in the proportion of TBI-related hospital admissions occurring on public holidays and weekends from 2004 (31.5%) to 2018 (33.4%) (p = 0.0007). In summer months, TBI-related hospital admissions (IRR 1.10, 95% CI 1.08-1.12, p < 0.0001) and 30-day mortality (HR 1.069, 95% CI 1.010-1.131, p = 0.0211) were more common than in other months. TBIs occurred more often in younger and healthier individuals on these index days and times. In terms of specific public holidays, the TBI risk was overall higher on New Year's Eves and Days (IRR 1.40, 95% CI 1.25-1.58, p < 0.0001) and Midsummer's Eves and Days (IRR 1.36, 95% CI 1.20-1.54, p < 0.0001), compared to nonworking days. This finding was significant in both genders.

TBI-related hospital admissions and mortality were more common on public holidays, weekends, and in summer months in Finland. People who sustained TBIs on these days were on average younger and healthier. The occurrence of TBIs on public holidays and weekends is increasing at an alarming rate.