Prevalence of sedentary behavior in children under 2 years: a systematic review

Sedentary behavior has negative health outcomes, evident even in young children. Identifying the prevalence of sedentary behavior in children <2years is important for determining the necessity for intervention strategies. The aim of this systematic review was to determine the prevalence of sedentary behavior in children <2years. Medline, PsycINFO, SPORTDiscus, and Education Research Complete electronic databases were searched, as were reference lists of included articles and the authors' own collections. Inclusion criteria were: published in a peer-reviewed English language journal; mean age of children <2years; and a reported measure of the prevalence of sedentary behavior. Twenty-four studies met the inclusion criteria. Most studies used parent-reported screen time as the sedentary behavior measure; only one study reported time spent restrained (i.e., kept inactive) and no studies reported objectively assessed sedentary time. Estimates of young children's screen time ranged from 36.6 to 330.9min/day. The proportion of children meeting the zero screen time recommendation ranged from 2.3% to 83.0%. In conclusion, very little is known about sedentary behaviors other than screen time in this age group. Although highly variable, findings suggest that children are already engaging in high levels of screen time by age 2 and the majority exceed current recommendations.