A longitudinal study of sleep, weight status, and weight-related behaviors: Childhood Obesity Study in China Mega-cities.

BACKGROUND

The aim of the study was to examine correlates of sleep and assess its associations with weight status and related behaviors.

METHODS

Data were collected in 2015-2017 for 3298 children aged 6-17 years and their parents in 5 Chinese mega-cities. One thousand six hundred and ninety-one children with measured weight, height, and waist circumference in ≥2 surveys were included for longitudinal data analyses. Sleep and behaviors were self-reported.

RESULTS

Cross-sectional data analyses found that older (β = -0.29, 95% CI: -0.32, -0.27) and secondary school children (β = -1.22, 95% CI: -1.31, -1.13) reported shorter sleep than their counterparts. Children with ≥college-educated (vs <college) fathers (β = 0.17, 95% CI: 0.04, 0.31) or mothers (β = 0.16, 95% CI: 0.04, 0.29) reported longer sleep. Longer sleep was longitudinally associated with less sugar-sweetened beverage intake (β = -0.12 days/h sleep, 95% CI: -0.20, -0.03), more healthy snacks intake (β = 0.13 days/h sleep, 95% CI: 0.02, 0.25) and having breakfast (β = 0.07 days/h sleep, 95% CI: 0.04, 0.11), and shorter total screen time (β = -0.22 h/h sleep, 95% CI: -0.65, -0.21) and surfing the internet/computer time (β = -0.06 h/h sleep, 95% CI: -0.09, -0.04) among all children. Longer sleep reduced the risk of central obesity (OR = 0.46, 95% CI: 0.25, 0.85) for girls.

CONCLUSIONS

Sleep among urban Chinese children varies by demographic factors. Longer sleep is associated with healthier weight-related behaviors and lower central obesity risk.

IMPACT: Longer sleep was observed in younger, primary school children and children with college-educated parents. Longer sleep increased healthier weight-related behaviors and reduced general and central obesity risk. Provides data on the correlates of sleep duration of children. Gives insights on longitudinal relationships of sleep duration with weight-related behaviors and obesity risk. Findings help inform sleep interventions to increase sleep duration to prevent childhood obesity and unhealthy weight-related behaviors in urban settings of developing countries.