Associations of Sleep Duration and Adherence to Age-Specific Sleep Recommendations with Body Fat and Related Anthropometric Characteristics in Children and Adolescents

BACKGROUND: Insufficient sleep has been proposed as a correlate of excess adiposity in pediatric populations, yet its associations with detailed anthropometric indicators remain unclear. OBJECTIVES: To examine relationships between sleep duration, adherence to age-specific sleep recommendations, adiposity, and anthropometric parameters in children and adolescents from Kraków, Poland. METHODS: This cross-sectional study included 1402 children and adolescents aged 3-16 years examined in 2020. Measurements comprised body height and mass, circumferences, skinfold thicknesses, and adiposity assessed by bioelectrical impedance. Sleep duration was reported by parents/legal guardians and categorized according to National Sleep Foundation recommendations. Associations were analyzed using ANCOVA models adjusted for age and sex. RESULTS: Sleep duration declined markedly with age but did not differ by sex. Longer sleep duration was consistently associated with lower body mass, body mass index, adiposity, waist, hip, neck and thigh circumferences, and waist-to-height ratio, although effect sizes were relatively small. Adherence to sleep recommendations was not independently associated with adiposity measures after adjustment for age. CONCLUSIONS: Longer sleep duration is modestly but consistently associated with more favorable adiposity-related parameters in children and adolescents. Sleep duration, rather than categorical compliance with recommendations, may be relevant for pediatric obesity prevention.