Background Alberta remains the only province in Canada without booster seat legislation. This presents an opportunity to study the effectiveness of booster seats in real-world settings. To date, results of booster seat effectiveness compared with seat-belt-only use has demonstrated mixed findings.

Methods We used Alberta police collision report data from 2010-2016. The study population includes all motor vehicle collisions involving at least one 4-8-year-old. Using a case-control study design, children who were reported by police to be injured (cases) were compared with those uninjured (controls) for booster seat use. Logistic regression was used to estimate the association between booster seat use and injury.

Results There were 12,922 children involved in a collision, resulting in 673 child injuries. There were 793 children in the front seat excluded from analysis. Unadjusted analyses indicate that compared with booster seat users, there were greater odds of injury for seat-belt users (OR=1.21; 95% CI: 1.02–1.44) and those not using any restraints (OR= 8.16; 95% CI: 4.66–14.31). When stratifying by impact and collision types, front-end vehicle-on-vehicle collisions demonstrated greater odds of injury for seat-belt wearers relative to those in booster seats (OR= 1.51 95% CI: 1.10–2.08).

Conclusion Crude analyses indicate a protective effect of booster seats compared with seat-belts, depending on the type of collision and impact location.

Learning Outcomes These regionally-specific injury data may help inform policy on the use of booster seats. Stratification by collision impact location may be necessary to inform analyses on booster seat effectiveness.