Temporal and geographic patterns of stab injuries in young people: a retrospective cohort study from a UK major trauma centre.

Abstract

OBJECTIVES: To describe the epidemiology of assaults resulting in stab injuries among young people. We hypothesised that there are specific patterns and risk factors for injury in different age groups. DESIGN: Eleven-year retrospective cohort study. SETTING: Urban major trauma centre in the UK. PARTICIPANTS: 1824 patients under the age of 25 years presenting to hospital after a stab injury resulting from assault. OUTCOMES: Incident timings and locations were obtained from ambulance service records and triangulated with prospectively collected demographic and injury characteristics recorded in our hospital trauma registry. We used geospatial mapping of individual incidents to investigate the relationships between demographic characteristics and incident timing and location. RESULTS: The majority of stabbings occurred in males from deprived communities, with a sharp increase in incidence between the ages of 14 and 18 years. With increasing age, injuries occurred progressively later in the day (r2=0.66, p<0.01) and were less frequent within 5 km of home (r2=0.59, p<0.01). Among children (age <16), a significant peak in injuries occurred between 16:00 and 18:00 hours, accounting for 22% (38/172) of injuries in this group compared with 11% (182/1652) of injuries in young adults. In children, stabbings occurred earlier on school days (hours from 08:00: 11.1 vs non-school day 13.7, p<0.01) and a greater proportion were within 5 km of home (90% vs non-school day 74%, p=0.02). Mapping individual incidents demonstrated that the spike in frequency in the late afternoon and early evening was attributable to incidents occurring on school days and close to home. CONCLUSIONS: Age, gender and deprivation status are potent influences on the risk of violent injury in young people. Stab injuries occur in characteristic temporal and geographical patterns according to age group, with the immediate after-school period associated with a spike in incident frequency in children. This represents an opportunity for targeted prevention strategies in this population.