Purpose: This study investigated the relationship between outdoor time and physical activity (PA), sedentary time (SED), and body mass index z scores among children from 12 lower-middle-income, upper-middle-income, and high-income countries. Methods: In total, 6478 children (54.4% girls) aged 9–11 years participated. Outdoor time was self-reported, PA and SED were assessed with ActiGraph GT3X+ accelerometers, and height and weight were measured. Data on parental education, neighborhood collective efficacy, and accessibility to neighborhood recreation facilities were collected from parent questionnaires. Country latitude and climate statistics were collected through national weather data sources. Gender-stratified multilevel models with parental education, climate, and neighborhood variables as covariates were used to examine the relationship between outdoor time, accelerometry measures, and body mass index z scores. Results: Each additional hour per day spent outdoors was associated with higher moderate- to vigorous-intensity PA (boys: +2.8 min/d; girls: +1.4 min/d), higher light-intensity PA (boys: +2.0 min/d; girls: +2.3 min/d), and lower SED (boys: −6.3 min/d; girls: −5.1 min/d). Effect sizes were generally weaker in lower-middle-income countries. Outdoor time was not associated with body mass index z scores. Conclusions: Outdoor time was associated with higher PA and lower SED independent of climate, parental education, and neighborhood variables, but effect sizes were small. However, more research is needed in low- and middle-income countries.
Larouche, Belanger, Chaput, and Tremblay are with the Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada. Larouche is also with the Faculty of Health Sciences, University of Lethbridge, Lethbridge, Alberta, Canada. Mire, Barreira, Hu, Tudor-Locke, and Katzmarzyk are with Pennington Biomedical Research Center, Baton Rouge, LA, USA. Chaput and Tremblay are also with the Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada. Fogelholm is with the Department of Food and Environmental Sciences, University of Helsinki, Helsinki, Finland. Lambert is with the UCT/MRC Research Unit for Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. Maher and Olds are with the University of South Australia, Adelaide, South Australia, Australia. Maia is with the Faculdade de Desporto, Universidade do Porto, Porto, Portugal. Onywera is with the Department of Recreation Management & Exercise Science, Kenyatta University, Nairobi, Kenya. Sarmiento is with the Facultad de Medicina, Universidad de los Andes, Bogotá, Colombia. Standage is with the Department for Health, University of Bath, Claverton Down, Bath, United Kingdom. Tudor-Locke is also with the School of Public Health and Health Sciences, University of Massachusetts, Amherst, MA, USA.