Adolescent psychological wellbeing is a critical determinant of lifelong health. Global data suggest a concerning decline in adolescent wellbeing. While the 24-hour movement behaviours, moderate to vi Show more
Adolescent psychological wellbeing is a critical determinant of lifelong health. Global data suggest a concerning decline in adolescent wellbeing. While the 24-hour movement behaviours, moderate to vigorous physical activity (MVPA), light physical activity (LPA), sedentary time, and sleep, have been linked to mental health outcomes; their associations with specific domains of adolescent psychological wellbeing remain underexplored. This study used compositional data analysis (CoDA) to examine how time-use relate to domain-specific wellbeing in Australian secondary school adolescents. Data were drawn from 124 adolescents (aged 13–17 years) participating in the TransformUs Secondary effectiveness trial. Wrist worn Actigraph GT9X accelerometer captured 24-hour movement behaviour over at least three valid days (≥ 16 h/day). Wellbeing was assessed using the EPOCH Measure of Adolescent Wellbeing, which includes five domains: engagement, perseverance, optimism, connectedness, and happiness. CoDA was used to examine associations between the composition of daily movement behaviours and EPOCH domains using isometric log-ratio (ILR) transformations. A compositional time reallocation analysis (30-minutes) was also performed to explore hypothetical associations with wellbeing outcomes. The average daily time-use composition was 680.9 min (47.3%) sedentary time, 473.0 min (32.8%) sleep, 250.7 min (17.4%) LPA, and 35.3 min (2.5%) MVPA. Greater time spent in LPA relative to other behaviours was significantly associated with higher happiness scores ( Adolescent daily movement behaviour composition was associated with domain-specific psychological wellbeing, particularly happiness. LPA was a potential contributor to positive psychological wellbeing. These findings suggest that even modest changes in daily routines, such as replacing sedentary time and LPA, may support adolescent flourishing. Future research should confirm these findings longitudinally and employ in intervention studies. The online version contains supplementary material available at 10.1186/s44167-025-00094-8. Show less
Type I interferons (IFNs) exert a broad range of biological effects important in coordinating immune responses, which have classically been studied in the context of pathogen clearance. Yet, whether i Show more
Type I interferons (IFNs) exert a broad range of biological effects important in coordinating immune responses, which have classically been studied in the context of pathogen clearance. Yet, whether immunomodulatory bacteria operate through IFN pathways to support intestinal immune tolerance remains elusive. Here, we reveal that the commensal bacterium, Bacteroides fragilis, utilizes canonical antiviral pathways to modulate intestinal dendritic cells (DCs) and regulatory T cell (Treg) responses. Specifically, IFN signaling is required for commensal-induced tolerance as IFNAR1-deficient DCs display blunted IL-10 and IL-27 production in response to B. fragilis. We further establish that IFN-driven IL-27 in DCs is critical in shaping the ensuing Foxp3+ Treg via IL-27Rα signaling. Consistent with these findings, single-cell RNA sequencing of gut Tregs demonstrated that colonization with B. fragilis promotes a distinct IFN gene signature in Foxp3+ Tregs during intestinal inflammation. Altogether, our findings demonstrate a critical role of commensal-mediated immune tolerance via tonic type I IFN signaling. Show less