Environmental Factors and Preschoolers’ Outdoor Play and Sleep Duration in Low-, Middle- and High-Income Countries

Background: Participation in outdoor play and obtaining good quality sleep are essential for preschoolers’ healthy growth and development. Environmental threats such as poor weather, pollution, and concerns of safety are disproportionately experienced by young children, especially those who live in low- and middle-income countries (LMICs). However, there is little evidence of the influence of environmental factors upon preschoolers’ outdoor play and sleep behaviours. The overall aim of this thesis was to examine the associations between diverse environmental factors and preschoolers’ outdoor play and sleep behaviours within family and early childhood education care (ECEC) settings.Methods: This thesis is comprised of four studies and is presented across four chapters. Study 1 was a systematic review which examined the associations between post-natal pollution exposures, 24-hour movement behaviours and motor development outcomes among children aged birth to 12 years. Studies 2, 3 and 4 used cross-sectional data from the third phase of the SUNRISE International Study of Movement Behaviours in the Early Years Pilot Study. Study 2 examined the parental perceptions of environmental factors on preschoolers’ outdoor play and outdoor play spaces. Study 3 examined the parental perceptions of environmental factors on preschoolers’ sleep durations and sleep arrangements. Study 4 explored the associations between environmental factors, outdoor play and sleep behaviours in ECEC settings.Results: The systematic review identified 18 eligible studies, most of which were conducted in high-income countries (n=13). Studies measured outdoor air (n=7), indoor air (n=4), land (n=3), and noise pollution (n=4). Overall, findings were mixed and inconsistent. Motor development outcomes were the most frequently examined in relation to a pollution measure (n=12), followed by sleep (n =5) and physical activity and sedentary behaviour (n =1).Study 2 analysed parent questionnaire data, which examined outdoor play patterns from 1855 preschoolers across 19 countries (16 LMICs). Preschoolers’ outdoor play was associated with five environmental factors. On weekdays, heat (−25.6; 95% CI, −44.6, −6.6), cold (−26.9; 95% CI, −45.9, −8.4), and rain (−24.8; 95% CI, −43.3, −6.6) were negatively associated with outdoor play. For weekends, cold (−41.2; 95% CI, −62.4, −20.0) and social instability (−40.7; 95% CI, −61.5, −20.3) were negatively associated with outdoor play. For the spaces in which preschoolers play, seven associations were reported. Playing at friends’ or relatives’ homes (29.5 [95% CI, 18.6 to 40.5]; 37.9 [25.6 to 50.4]), greenspaces (23.1 [95% CI, 9.6 to 36.6]; 30.4 [95% CI, 15.1 to 45.8]), and on the street (41.4 [95% CI, 26.9 to 55.7]; 34.9 [95% CI, 18.2 to 51.3]) were associated with weekday and weekend day outdoor play, respectively. Playing on the family’s property was also associated with weekend day outdoor play (25.5 [95% CI, 18.2 to 51.3]). Study 3 analysed parent questionnaire data, which examined sleep durations and sleep arrangements among 2219 children from 23 countries (19 LMICs). There were significant differences between nighttime sleep (F=14.27, p=