Case series with exposure estimation to determine injury rates and injury profile, prospective case-control and case cross-over study to determine risk factors. The research will be conducted in a Calgary ski area terrain park nearby the Alberta Children’s Hospital. Case and Control Definition: Cases are defined as child and youth snowboarders using terrain park apparatuses and sustaining an injury, who completed an accident report form, visited the emergency department, and/or accessed ambulance transportation from the hill. Controls will include (1) a sample of non-injured child and youth snowboarders in the terrain park; (2) child and youth snowboarders with minor injuries; and (3) injured child and youth snowboarders acting as their own controls.
Cases: Accident report forms will be obtained for all young injured snowboarders and parents will be contacted to inform them of the study. Upon consent, phone interviews will be conducted asking about apparatus use at the time of injury, snowboard experience, injury circumstances and diagnosis. All snowboard injuries presenting to the Alberta Children’s Hospital will be captured. Accident report form data will be linked to emergency department data using date of injury, name, age and sex. Severely injured child and youth snowboarders (or their parents) presenting to the emergency department will be interviewed in the emergency department or by phone. A random sample of injured snowboarders will be re-interviewed to determine the quality of information captured on the accident report form. Controls: A sequential sample of uninjured snowboarders will be obtained as they descend the terrain park. A map of their particular run in the terrain park will be completed to indicate apparatus use. Basic demographic data (age, sex, experience) will be collected anonymously, and weather and snow conditions noted. A random sample of uninjured snowboarders will be re-interviewed to determine the quality of accident report form information.
209 snowboarders were injured in the terrain park in 2006-07 (10 in the half-pipe; 199 on “other” apparatuses). Assuming equal exposure opportunity for each apparatus, this study has a calculated power of 94% to detect a rate ratio of 2.5. Denominator (uninjured controls) data will be extrapolated and injury rates expressed as the number of injuries per 1,000 runs. For the case-control analysis, injured and uninjured groups will be compared for risk factor prevalence. The severe injury group will be compared to both the minor injury and uninjured groups. Logistic regression analysis will be used to relate the risk of injury associated with specific apparatuses adjusting for confounding factors. Injured cases will also serve as their own controls in the case-crossover analysis by comparing the discordance between the apparatus they were using when they sustained the injury and the apparatus they used immediately prior to the injury. Information captured in the accident report form and followup interview will be compared to assess data quality using the Kappa statistic measuring chance corrected proportional agreement.