The impact of booster seat use on child injury and mortality: Systematic review and meta-analysis of observational studies of booster seat effectiveness

Objective: To determine through systematic review and meta-analysis of observational studies if booster seats, compared to seatbelts alone, reduce injury and mortality from motor vehicle collisions among child passengers four to eight years of age. Methods: A comprehensive search of several data sources (including Medline, Embase, and PsycINFO) was conducted from inception to December 2016, to retrieve relevant publications in any language and from any geographic region. Data extraction was completed by two independent reviewers, capturing: study details, population characteristics, exposure (booster seat compared to seat belt use), outcomes (injury and fatality), and all associations reported between the exposure and outcomes. Risk of bias assessment was completed by two reviewers using the QUIPS tool. Meta-analysis of sufficiently similar studies was conducted using random effects models. Results: Eleven observational studies were included in qualitative syntheses. The systematic review and meta-analysis found no association between booster seat use, compared to seatbelts, and reduced injury (4 studies, OR 1.03; 95% CI 0.53–1.99) or fatality (2 studies, OR 0.91; 95% CI 0.73–1.13). Conclusions: Evidence on booster seat effectiveness to protect against injury and mortality in real-world conditions is limited. This review identified the need for high quality studies assessing the effects of different models of booster seats on children of varying ages and weights.