COVID-19–Related Life Experiences, Outdoor Play, and Long-term Adiposity Changes Among Preschool- and School-Aged Children in Singapore 1 Year After Lockdown

IMPORTANCE: Despite the potential for COVID-19 infection control–related events to have an effect on child well-being, comprehensive assessments of postlockdown changes and persistent outcomes are lacking. OBJECTIVE: To survey the extent of COVID-19 lockdown–related lifestyle changes, their differences by child age and family socioeconomic status, and the potential association with child adiposity 1 year after lockdown. DESIGN, SETTING, AND PARTICIPANTS: A self-administered, electronic survey was introduced to 2 ongoing child cohorts (the Singapore Preconception Study of Long-term Maternal and Child Outcomes [S-PRESTO] cohort of preschool children aged 1-4.5 years and the Growing Up in Singapore Towards Healthy Outcomes [GUSTO] cohort of primary school children aged 9-10.7 years) from July 8, 2020, to September 5, 2020, which was 1 to 3 months after the end of strict universal movement restrictions (duration of 73 days ending on June 19, 2020). All active participants from S-PRESTO and GUSTO, 2 population-based, longitudinal, parent-offspring cohorts in Singapore, were invited to participate and monitored through June 15, 2021. EXPOSURES: Exposures included family income before and after the COVID-19 lockdown, changes in child outdoor play or exercise, and COVID-19–related life events; all data were self-reported by parents and school-aged children 1 to 3 months after the lockdown. MAIN OUTCOMES AND MEASURES: Primary outcomes were self-reported COVID-19–related life events and changes in child online socialization, outdoor play or exercise, and intrafamily relationships. Study staff measured children’s weight, height, and skinfold thickness before and up to 1 year after lockdown. Body mass indices (calculated as weight in kilograms divided by height in meters squared) and World Health Organization–standardized scores were computed. Differences before and after lockdown were compared using baseline-adjusted linear regression. RESULTS: A total of 604 parents (53% of active cohort participants) and 356 school-aged children completed the survey and were similar to source cohorts. This represents 373 of 761 eligible children in the GUSTO cohort (mean [SD] age, 9.9 [0.4] years; 197 girls [52.8%]) and 231 of 370 eligible children in the S-PRESTO cohort (mean [SD] age, 2.6 [0.8] years; 121 boys [52.6%]). The COVID-19–related life changes were prevalent and varied (eg, 414 of 600 children [69.0%] reported changes in social activities). More than one-third of primary school–aged children (122 of 356 [34.3%]) and one-quarter of preschool-aged children (56 of 229 [24.5%]) eliminated any outdoor play after the lockdown. Lower family income before the lockdown was associated with increased odds of elimination of outdoor play (adjusted odds ratio per 1000 Singapore dollars [$730 US dollars] decrease, 1.09; 95% CI, 1.01-1.19). Complete elimination of outdoor activity (vs continued outdoor activity) was associated with an increase in body mass index of 0.48 (95% CI, 0.03-0.94) and a body mass index z score of 0.18 units (95% CI, 0-0.37) in school-aged children approximately 1 year after lockdown. CONCLUSIONS AND RELEVANCE: Results of this cohort study suggest that 1 to 3 months after a brief, strict lockdown, a large proportion of parents and school-aged children reported elimination of outdoor play, which was more prevalent in lower-income families. Future research to better understand clinical implications and ways to mitigate lockdown outcomes is essential.