Early predictors of injury mortality among Swedish conscripts: a 35-year cohort study.

Injuries represent an important cause of mortality among young adults. We studied the associations between adolescents' family, psychological, behavioural and drug-related risk factors in relation to unintentional injury death. A population-based cohort of 49,411 Swedish conscripts aged 18-20 years was followed for 35 years. The end-point of study was injury death up to 2004. The relationship between two family, four psychological and eight behavioural risk factors and injury death were analysed with Cox proportional hazards analyses and χ(2) tests. Among 485 unintentional injury deaths, 40% occurred in subjects aged 25 years or under. The incidence per 1000 person years was 0.29 (95% CI, 0.26-0.31) and the mean age of death was 33 years. Problem drinking at both adolescent and adulthood was more strongly associated with injury death (HR=5.40) than illicit drug use (HR=2.70) even after adjusted for behavioural risk factors: (HR=3.43) and (HR=1.75), respectively. Adolescent risk factors such as contact with police and juvenile authorities, low emotional control, conduct problems at school and low social maturity were significant predictors of injury death in multivariate analyses. Young adults with social, behavioural and psychological problems and especially alcohol and drug use at both adolescent and adulthood have a high mortality rate due to road traffic injuries and all kind of injuries. Early identification of vulnerable groups of adolescents with psychological and behavioural problems including alcohol and drug use at local levels could make a difference.