Drinking, substance use and the operation of motor vehicles by young adolescents in Canada

Background: Impaired driving is a recognized cause of major injury. Contemporary data are lacking on exposures to impaired driving behaviours and related injury among young adolescents, as well as inequities in these youth risk behaviours. Methods and Findings: Cycle 6 (2009/10) of the Health Behaviour in School-Aged Children survey involved 26,078 students enrolled in 436 Canadian schools. We profiled cross-sectionally the reported use of alcohol, marijuana, or other illicit drugs by on-road and off-road vehicle operators when young adolescents (mean age 13.3 (61.6) years) were either driving or riding as a passenger. Comparisons were made across vulnerable subgroups. Multi-level logistic regression analyses were used to quantify the effects of the driving behaviours on risks for motor vehicle-related injury. Attributable risk fractions were also estimated. A total of 10 % (63%) of participants reported recent operation of an on-road or off-road motor vehicle after consuming alcohol, marijuana, or other illicit drugs, while 21 % (63%) reported riding as a passenger with a driver under the same conditions. Larger proportions of youth reporting these risk behaviours were males, and from older age groups, rural communities, and socio-economically disadvantaged populations. The behaviours were consistently associated with increased risks for motor vehicle-related injury at the individual level (RR 2.35; 95 % CI: 1.54 to 3.58 for frequent vs. no exposure as a driver; RR 1.68; 95 % CI: 1.20 to 2.36 for frequent vs. no exposure as a passenger) and at th