Impact of Sleep Quality on Pediatric Obesity: A Longitudinal Field Study

Thesis Abstract

Sleep quality is increasingly recognized as a potential determinant of pediatric adiposity, yet longitudinal evidence detailing how sleep parameters influence obesity trajectories during childhood remains limited. This study addresses the problem of insufficient understanding of the temporal relationship between sleep quality and obesity progression in children, accounting for behavioral, metabolic, and psychosocial mediators. The aim is to elucidate how baseline and changing sleep characteristics predict adiposity gain over a three-year period in a community-based cohort of school-aged children, and to examine whether physical activity, dietary intake, and bedtime routines mediate or moderate this relationship. Specific objectives are to (i) quantify associations between sleep duration, sleep efficiency, and sleep latency with body mass index z-scores (BMIz) and percentage body fat; (ii) assess the prospective influence of sleep on waist circumference and central adiposity; (iii) identify mediating roles of physical activity and dietary patterns; (iv) evaluate moderating effects of screen time and socioeconomic status; and (v) test the applicability of the biopsychosocial model and the Theory of Sleep and Metabolism in explaining observed relationships. A mixed-methods longitudinal design will be employed. The quantitative component will involve a cohort of 1,200 children aged 6–10 years at baseline recruited from ten primary schools across a metropolitan area, with annual follow-ups over three years. Sleep data will be collected using actigraphy (Monitors for seven consecutive days) and parental sleep diaries, while adiposity measures will include standardized height, weight, BMIz, waist circumference, and dual-energy X-ray absorptiometry (DXA) in a subsample (n=300) to obtain precise body composition metrics. Additional quantitative data will include accelerometer-based physical activity, 24-hour dietary recalls, screen time logs, and socioeconomic indicators. Validated instruments will assess bedtime routines, sleep quality via the Children’s Sleep Habits Questionnaire, and psychosocial stress. Regression-based longitudinal analyses (mixed-effects models) will examine the trajectory of BMIz and adiposity indices as outcomes, with sleep characteristics as primary predictors, adjusting for confounders. Structural equation modeling will test mediation paths through physical activity and diet, while interaction terms will explore moderation by screen time and socioeconomic status. Qualitative components will consist of semi-structured interviews with a purposive subsample of parents and children (n=40) to explore contextual factors affecting sleep practices and perceptions of weight, with thematic analysis guided by the biopsychosocial framework. Expected findings include a negative association between adequate sleep duration and sleep efficiency with subsequent increases in BMIz and central adiposity, independent of baseline adiposity and physical activity. It is anticipated that poor sleep will be associated with higher caloric intake, greater consumption of energy-dense snacks, and reduced physical activity, partially mediating the sleep–obesity relationship. The theoretical contribution will involve testing the applicability of the biopsychosocial model and sleep-metabolism theory in a diverse pediatric population, potentially refining theoretical assumptions about the temporal sequencing of sleep and obesity development. The study will offer precise estimates of effect sizes for sleep duration and quality on adiposity progression, informing thresholds for clinically meaningful sleep recommendations in children and identifying high-risk subgroups based on socioeconomic and behavioral contexts. The knowledge contribution includes (i) elucidating causal pathways linking sleep quality to pediatric obesity through mediation by lifestyle behaviors, (ii) establishing longitudinal benchmarks for sleep-related obesity risk in early schooling years, and (iii) integrating objective sleep measures with robust adiposity metrics to strengthen causal inference in pediatric populations. Practical implications involve informing school and family-based interventions promoting consistent bedtimes, sleep hygiene education, and integrated strategies targeting physical activity and dietary patterns to mitigate obesity risk. The study concludes with evidence-based recommendations for pediatric health guidelines emphasizing sleep optimization as a modifiable risk factor for obesity, guidance for clinicians on screening sleep problems in weight management, and policy suggestions for reducing screen exposure and promoting structured sleep routines in children.