Associations of diarised sleep onset time, period and duration with total and central adiposity in a biethnic sample of young children: the Born in Bradford observational cohort study

Abstract

ObjectivesTo investigate associations of parent-reported sleep characteristics with adiposity levels in a biethnic sample of young children.DesignA cross-sectional observational study.SettingThe Born in Bradford 1000 study, UK.ParticipantsChildren aged approximately 18 months (n=209; 40.2% South Asian; 59.8% white) and 36 months (n=162; 40.7% South Asian; 59.3% white).Primary and secondary outcome measuresChildren’s body mass index (BMI) z-score, sum of two-skinfolds (triceps and subscapular) and waist circumference. Adjusted regression was used to quantify associations of sleep parameters with adiposity stratified by ethnicity and age group. The results are beta coefficients (95% CIs) and unless otherwise stated represent the difference in outcomes for every 1-hour difference in sleep parameters.ResultsThe average sleep onset time was markedly later in South Asian (21:26±68 min) than white children (19:41±48 min). Later sleep onset was associated with lower BMI z-score (−0.3 (−0.5 to −0.0)) and sum of two-skinfolds (−1.5 mm (−2.8 mm to −0.2 mm)) in white children aged 18 months and higher BMI z-score in South Asian children aged 36 months (0.3 (0.0–0.5)). Longer sleep duration on weekends than weekdays was associated with higher BMI z-score (0.4 (0.1–0.8)) and waist circumference (1.2 cm (0.3–2.2 cm)) in South Asian children aged 18 months, and later sleep onset on weekends than weekdays was associated with larger sum of two-skinfolds (1.7 mm (0.3–3.1 mm)) and waist circumference (1.8 cm (0.6–2.9 cm)). Going to sleep ≥20 min later on weekends than weekdays was associated with lower waist circumference in white children aged 18 months (−1.7 cm (−3.2 cm to −0.1 cm)).ConclusionsSleep timing is associated with total and central adiposity in young children but associations differ by age group and ethnicity. Sleep onset times and regular sleep schedules may be important for obesity prevention.

Independent associations of sleep timing, duration and quality with adiposity and weight status in a national sample of adolescents: The UK Millennium Cohort Study

“…Furthermore, it is a limitation that information was not available for potentially key mediating variables, such as unhealthy snacking and meal times. Sleep restriction studies report increased snacking under short sleep conditions, particularly when participants would normally be asleep (Beebe et al, 2013; Nedeltcheva et al, 2009), and an investigation of young children found that an association of later sleep onset with higher adiposity was attenuated when adjusted for timing of the evening meal (Collings et al, 2021). Animal models and clinical trials of adult populations indicate that early and time‐restricted feeding has numerous physiological benefits, including lower adiposity (de Cabo & Mattson, 2019; Sutton et al, 2018).…”

Cross‐sectional and prospective associations of sleep duration and bedtimes with adiposity and obesity risk in 15 810 youth from 11 international cohorts

“…It is a limitation that not all participating studies were nationally representative and the vast majority of participants were white. There is evidence for effect modification of sleep‐health associations by ethnicity, and hence caution is warranted before generalizing the results to non‐white youth 44,45 . All studies ascertained information for sleep by subjective reporting, and most studies asked about the time that participants usually went to bed and got out of bed.…”

“…There is evidence for effect modification of sleep-health associations by ethnicity, and hence caution is warranted before generalizing the results to non-white youth. 44,45 All studies ascertained information for sleep by subjective reporting, and most studies asked about the time that participants usually went to bed and got out of bed. The data for sleep duration may therefore be overestimated due to factors including screen-time engagement whilst in bed, sleep onset latency, overnight waking, and wakefulness on mornings prior to getting up (the latter three behaviours are, nevertheless, components of a normal sleep-wake cycle 46 ).…”

Asia–Pacific consensus statement on integrated 24-hour activity guidelines for the early years

“…Develop a bedtime routine and keep to a consistent bedtime where possible, 59 , 118 as these practices promote better quality and duration of sleep in toddlers, 59 , 118 and possibly help to prevent obesity. 119 Pre-bedtime activities like storytelling or cuddling also help toddlers sleep better and longer. 120 Provide a dark and quiet environment with comfortable ambient temperature that is conducive for sleep, and avoid screen time at least 30 min before bedtime.…”