Distribution and associated factors of outdoor time among children and adolescents: a systematic review and meta-analysis.

Abstract

This systematic review and meta-analysis summarised the distribution of outdoor time among children and adolescents and examined its temporal trends and associated factors. We systematically searched PubMed, Web of Science and Embase for studies published between 2005 and 2025 that reported the distribution and associated factors of outdoor time among children and adolescents aged 3-18 years. The risk of bias in the included studies was assessed using the Effective Public Health Practice Project tool. Meta-analysis was performed for major factors associated with outdoor time. A total of 35 studies involving 131 091 participants were included. The overall mean outdoor time was 123.1 min/day (95% CI 109.9 to 136.2). Regionally, the higher mean value was observed in Africa (200.9 min/day, 95% CI 44.4 to 467.7), followed by South America (190.5 min/day, 95% CI 57.6 to 323.4), Oceania (129.4 min/day, 95% CI 3.2 to 466.4), Europe (128.0 min/day, 95% CI 108.4 to 147.5) and North America (116.4 min/day, 95% CI 79.9 to 152.8), while Asia showed the lowest estimates (99.7 min/day, 95% CI 79.7 to 119.6). Outdoor time was generally lower among girls, myopic individuals, urban areas and on weekdays. In terms of time trends, outdoor time has shown a declining tendency during the 2010s. The associated factors of outdoor time span multiple levels, including individual, family, school, societal and environmental factors. In regions and populations with a higher prevalence of myopia, outdoor time is also relatively short. It is recommended to further promote initiatives to increase outdoor activity time in order to achieve better myopia control. CRD420251088008.