Objectives: To examine exposure to bicycling and its association with severe bicycle injuries in school-age children in a defined population.
Design: Random-digit dialing telephone survey and analysis of hospital discharge records.
Setting: Metropolitan Toronto, Ontario.
Subjects: Sample of parents of children aged 5 to 17 years who owned a bicycle; all children who were admitted to hospitals with bicycle-related injuries from April 1989 to March 1991.
Main outcomes: Median annual bicycling hours and distance by age and sex; age- and sex-specific incidence rates by population at risk, cumulative exposure hours, and riding distances.
Results: More than half of the children of all age groups were exposed to bicycling more than 100 hours per year. Boys spent more hours and rode longer distances than girls in every age group. The overall annual injury rates were 8.1 and 3.4 per 10,000 population at risk for boys and girls, respectively. About half of the injuries suffered were head injuries. When rates were estimated on the basis of exposure, boys still experienced a higher injury rate than girls. Boys displayed a slight increase with age in rates per unit of exposure hours. Conversely, age appeared to be negatively associated with overall and head injury rates when exposure was expressed by distance ridden.
Conclusions: Boys had a higher injury rate than girls, and bicycle-related injuries are more likely to be associated with exposure time than distance ridden.