Systematic review of sedentary behavior and cognitive development in early childhood

Objective To comprehensively review observational and experimental studies examining the relationship between sedentary behavior and cognitive development during early childhood (birth to 5years). Method Electronic databases were searched in July, 2014 and no limits were imposed on the search. Included studies had to be peer-reviewed, published, and meet the a priori determined population (apparently healthy children aged birth to 5years), intervention (duration, types, and patterns of sedentary behavior), comparator (various durations, types, or patterns of sedentary behavior), and outcome (cognitive development) study criteria. Data extraction occurred in October and November 2014 and study quality and risk of bias were assessed in December 2014. Results A total of 37 studies, representing 14,487 participants from nine different countries were included. Thirty-one studies used observational study designs and six studies used experimental study designs. Across study designs, increased or higher screen time (most commonly assessed as television viewing (TV)), reading, child-specific TV content, and adult-specific TV content had detrimental (negative) associations with cognitive development outcomes for 38%, 0%, 8%, and 25% of associations reported, respectively, and beneficial (positive) associations with cognitive development outcomes for 6%, 60%, 13%, and 3% of associations reported, respectively. Ten studies were moderate quality and 27 studies were weak quality. Conclusions The type of sedentary behavior, such as TV versus reading, may have different impacts on cognitive development in early childhood. Future research with reliable and valid tools and adequate sample sizes that examine multiple cognitive domains (e.g., language, spatial cognition, executive function, memory) are needed. Registration no. CRD42014010004.