Age-related change in sedentary behaviour during childhood and adolescence: A systematic review and meta-analysis

Sedentary behaviours are highly prevalent in youth and and may be associated with markers of physical and mental health. This systematic review and meta-analysis aimed to quantify age-related change in sedentary behaviour during childhood and adolescence. Ten electronic databases were searched. Inclusion criteria specified longitudinal observational studies or control group from an intervention; participants aged ≥5 and ≤18 years; a quantitative estimate of duration of SB; English language, peer-reviewed publication. Meta-analyses summarised weighted mean differences (WMD) in device-assessed sedentary time and questionnaire-assessed screen-behaviours over 1, 2, 3 or 4+ years follow-up. Effect modification was explored using meta-regression. Eighty-five studies met inclusion criteria. Device-assessed sedentary time increased by (WMD 95% Confidence Interval (CI)) 27.9 (23.2, 32.7), 61.0 (50.7, 71.4), 63.7 (53.3, 74.0), 140.7 (105.1, 176.4) minutes per day over 1, 2, 3, 4+ years follow-up. We observed no effect modification by gender, baseline age, study location, attrition or quality. Questionnaire-assessed time spent playing video games, computer use, and a composite measure of sedentary behaviour increased over follow-up duration. Evidence is consistent in showing an age-related increase in various forms of sedentary behaviour; evidence pertaining to variability across socio-demographic subgroups and contemporary sedentary behaviours are avenues for future research.