Statement of purpose Among Canadian youth, injury is the most common reason for Emergency Department presentations. Youth who participate in activities that increase their injury risk commonly engage in multiple risk-taking behaviours. This study aimed to determine if clusters of risk-taking behaviours were associated with injury in youth and how these patterns varied across contexts.

Methods/approach Risk-taking behaviours and injury outcome data were collected from grade 9–10 students using the 2009–2010 Health Behaviours in School-Aged Children Survey (n = 10,429). Principal components analysis identified clusters of risk-taking behaviours. Within each identified cluster, the degree of risk-taking was stratified into quartiles from none to highest. Adjusted risk ratios with 95% confidence intervals described the association between injury risk and the degree of risk-taking behaviour within each cluster. For each cluster, the injury risk was stratified by home, school, neighbourhood, and sport contexts.

Results Four clusters of risk-taking behaviour were identified – substance use, high-risk substance use, externalising behaviours (eg, stealing, impaired driver/passenger), and physical activity. For each cluster, there was a significantly increased injury risk and the highest injury risk occurred among youth who performed the most risk-taking behaviours. Youth who engaged in the highest level of physical activity had the highest injury risk (aRR: 1.98; 95% CI: 1.75–2.23) compared with non-participants. Compared with youth who engage in no externalising behaviours, those who engaged in the highest level had the highest injury risk (aRR: 1.63; 95% CI: 1.48–1.79). The gradient between increased risk-taking behaviours and increased injury risk was most pronounced for injuries sustained in the neighbourhood.

Conclusions This study delineates clusters of risk-taking behaviours that put youth at progressively increasing injury risk.

Significance and contributions Understanding the clustered and cumulative nature of increasing risk-taking behaviours, and how these relate to context, highlight potential modifiable factors that may be important avenues for intervention.