Sleep duration and compliance with sleep recommendations among Brazilian children and adolescents: an updated systematic review and meta-analysis.

OBJECTIVE: To update the evidence on sleep duration among children and adolescents, provide pooled estimates of mean sleep duration and compliance with sleep recommendations, and examine whether differences in measurement methods, assessment instruments, and guideline criteria contribute to variability in reported estimates. SOURCES: Eight databases (PubMed, PsycINFO, CINAHL, SciELO, Embase, Web of Science, Scopus, and LILACS) were searched from January 2020 to June 2025, supplemented by studies identified in a previous review. Population- or school-based observational studies of participants aged 0-18 years that reported sleep duration were eligible. Random-effects meta-analyses were conducted, and subgroup analyses and meta-regression were used to explore heterogeneity. SUMMARY OF THE FINDINGS: Eighty-four studies involving 177,074 participants were included. The pooled prevalence of adequate sleep duration was 45% (95% CI, 29-62%) among preschoolers, 65% (95% CI, 55-74%) among school-age children, and 47% (95% CI, 40-55%) among adolescents. Mean sleep duration decreased with age, ranging from 10.50 h (95%CI, 9.85-11.20) in preschoolers to 7.77 h (95%CI, 7.42-8.12) in adolescents. Questionnaire-based measures yielded higher estimates than accelerometry, and prevalence varied by the sleep guideline adopted. Heterogeneity was substantial across analyses (I² > 98%). CONCLUSIONS: Many Brazilian children and adolescents do not achieve recommended sleep duration, which can compromise their health and development. Although the pooled estimates should be interpreted with caution due to substantial between-study heterogeneity, the findings highlight the need for standardized sleep assessment and reporting to improve comparability across studies and strengthen epidemiological surveillance and public health planning.