Associations between circadian rhythm characteristics and adiposity in Czech children and adolescents

Background: While the influence of circadian rhythms on health outcomes has been increasingly studied, the role of rest-activity circadian rhythms in the development of pediatric obesity remains underexplored.
Purpose: This study examined the associations between accelerometer-measured rest-activity rhythm characteristics and obesity among Czech children and adolescents.
Methods: This study included a sample of 400 children (11.8±1.6 years; 56% girls) and 351 adolescents (16.2±1.4 years; 56% girls), who provided valid wrist-worn accelerometer data. The accelerometers ActiGraph wGT3X+ and GT9X Link were set to collect raw data continuously, 24 hours a day, for 7 consecutive days. For each of the circadian rhythm characteristics, participants were categorized into quartiles. The fat mass percentage (FM%) was assessed using bioelectrical impedance analysis method. Obesity was defined as exceeding the 85th percentile of FM%. The logistic regression analyses (adjusted for sex and age) were used to investigate the associations between the circadian rhythm characteristics and adiposity.
Results: The analysis identified an association between the timing of the least active continuous 5-hour period (L5hr) and adiposity in children (OR = 1.40; 95% CI: 1.04–1.88) indicating a higher likelihood of obesity with later timings of these inactive periods. Conversely, no significant associations were found for other circadian rhythm metrics, including Relative Amplitude, Interdaily stability, Intradaily variability, Mesor, Amplitude, Acrophase, and Acrotime, M5hr, L10hr, and M10hr.
Conclusions: The findings highlight the importance of the timing within the circadian cycle of physical inactivity in relation to excess adiposity among children. This study contributes to the growing evidence supporting the integration of circadian health into obesity prevention strategies for youth.
Practical Implications: The observed association between the timing of circadian rhythm inactivity and obesity underscores the need for detailed future investigations.
Funding: This study was supported by the research grant from the Czech Science Foundation (22-02392S).