BACKGROUND:Excessive screen use in children and adolescents is an increasingly prevalent, pervasive and pressing public health issue in Canada. This project investigated the 'state of the effort' in relation to screen use and healthy development in children and adolescents in Canada. METHODS:Five investigations were employed to identify, describe, interpret and triangulate the current evidence, including a national opinion survey, environmental scan, school board policy scan, network analysis and text mining analysis of Canadian news headlines. RESULTS:Screen use and healthy child development is an important issue for Canadian parents (n = 385), and they believe schools (79%), governments (73%) and technology companies (71%) have a responsibility to promote safe use. Most policy documents found were relatively recent (2023+) with both provincial (e.g., educational settings with a focus on personal digital devices) and national scope (e.g., protecting children regarding online programming, content and privacy). Of the 38 largest school boards in Canada, 84% ban or restrict students' unnecessary use of mobile devices during classroom/instructional time and 42% block or restrict access to social media platforms. Linked network analysis clusters included health, research, advocacy, law, policy, education, environment and physical activity, with most partnerships being weak, indicating a suboptimal connection among these sectors. Dramatic increases in related media headlines were found in 2024 (n = 1061) compared with 2023 (n = 400), and most lexicon sentiments were negative. CONCLUSION:Concerns over excessive and inappropriate digital screen use among Canadian children and adolescents have escalated recently. This work highlights that while there is much recent activity across sectors occurring in Canada, policy is lacking, and efforts lack coordination, cross-sectoral collaboration, and synergy, likely resulting in suboptimal impact.

Background:Accurate and ongoing assessments of physical activity (PA) and sedentary time (SED) are needed to support public health surveillance, evaluate interventions, and advance the understanding of how movement behaviours relate to health. After six cycles of data collection (2007 to 2019) using the Actical (AC) accelerometer, the Canadian Health Measures Survey (CHMS) transitioned to the ActiGraph wGT3X-BT (AG). To understand how estimates from the AC accelerometer may compare with those from the AG in the context of the CHMS, this study compares AC and AG accelerometer estimates of PA, step counts, and SED using CHMS protocols. Methods:A convenience sample of 47 adults (aged 18 to 79 years) and 36 children and youth (aged 3 to 17 years) wore both AC and AG accelerometers on their waist for seven consecutive days. Estimates of PA and SED, step counts, and the percentage of those meeting PA recommendations were compared between the devices using descriptive, correlation, and agreement statistics. Results:Agreement ranged from poor to excellent, with variability across PA intensities and age groups. Significant absolute differences in SED and light PA (LPA) were observed across all age groups, and in step counts among children and youth. Agreement was good to excellent across most age groups for moderate-to-vigorous PA (MVPA), and among adults for step counts. While the percentage of those meeting PA recommendations was higher with the AG, results were not statistically different. Similar comparisons could be made with the AG device when using the normal and low frequency extension filters. Interpretation:The results of the present study provide data users and researchers with an indication of the expected differences between the devices across various movement behaviour outcomes in the context of the CHMS. Results suggest that comparisons between cycles 1 to 6 and Cycle 7 onward of the CHMS for MVPA are acceptable, but they should be carried out with caution. Comparisons of SED, LPA, vigorous PA, and step counts are not recommended.

OBJECTIVE:Optimal balances of sedentary behaviour, physical activity and sleep (collectively termed movement behaviours) for concussion management remain unknown. We sought to determine the optimal daily distribution of movement behaviours for reducing postconcussion symptom burden in children and adolescents. METHODS:This secondary analysis of the Paediatric Concussion Assessment of Rest and Exertion (PedCARE) study included participants aged 10 to <18 years with an acute concussion (>48 hours of presenting to emergency department). Health and Behaviour Inventory (HBI) concussion symptoms were measured at a 2-week post-emergency department follow-up. Persisting symptoms after concussion (PSAC) were classified through reliable change in total HBI scores. Movement behaviours were measured with accelerometers over 13 days. For each day of movement behaviours, compositional regression models were built to determine the optimal daily movement behaviours for predicting HBI scores and PSAC probability. RESULTS:Analyses included 259 participants (45% female, mean age 13.3 years). Compared with the average, movement behaviours associated with optimal postconcussion outcomes followed a trend of initially more rest (eg, day 2: 11.5 (95% CI 8.8 to 12.7) hours/day of sleep and 8.5 (95% CI 6.5 to 11.3) hours/day sedentary). Optimal patterns also included above-average moderate-to-vigorous physical activity across the 13 days (eg, days 2, 7, 13:0.6 (95% CI 0.2 to 1.2), 1.5 (95% CI 1.2 to 1.7), 1.1 (95% CI 0.2 to 1.7) hours/day, respectively), with increased light physical activity emerging as optimal later in recovery (eg, day 10:5.5 (95% CI 5.0 to 5.8) hours/day). CONCLUSIONS:This is the first study to use compositional data analyses to identify an optimal distribution of movement behaviours for concussion symptom recovery in children and adolescents. Our results can inform concussion management protocols that balance rest and activity throughout recovery.

Objective:To examine agreement between telephone and in-person administration of the Early Childhood Development Index 2030 (ECDI2030) survey. Methods:In this crossover study, we compared in-person ECDI2030 interviews with other modalities (primarily telephone-based interviews) selected at a country level in Brazil, Canada, India and Malawi. Eligible participants were primary caregivers of preschool-aged children (36-60 months old), with equal recruitment across child sex and urban and rural residence. The primary outcome was agreement in overall scores between in-person interviews and other tested modalities, assessed using paired t-tests and intraclass correlation coefficients. Findings:The analytical sample included 258 individuals, with 212 paired observations for in-person and telephone-based interviews. Pooled t-tests showed no significant differences in overall scores between the interview modalities. However, in-person interviews yielded slightly higher scores than telephone interviews for female children (mean difference: 0.23; Cohen's d diff: 0.22) and participants from India (mean difference: 0.47; Cohen's d diff: 0.44). Canadian participants had lower scores on the second assessment completed (mean difference: -0.27; Cohen's d diff: -0.36), regardless of modality. However, pooled and stratified intraclass correlation coefficients analyses indicated that these modalities were statistically similar, with values ranging from 0.89 to 0.93, which are values commonly categorized as good to excellent. Conclusion:This multinational, multicentre, crossover study shows high agreement between telephone and in-person administration of the ECDI2030 across economically, culturally and geographically diverse settings. Expanding administration modalities may improve feasibility, particularly in geographically dispersed populations and rural settings.

Background/Objectives The Government indicator evaluates national policies and strategies for child and adolescent physical activity, supporting country reporting and international comparisons within the Global Matrix initiative. To grade this indicator, countries/jurisdictions apply either the original method or, in recent editions, an alternative approach. The alternative approach was proposed by the Welsh team, who derived six criteria from the World Health Organization’s Health-enhancing Physical Activity Policy Audit Tool v2 and developed an accompanying scoring rubric. This study aimed to evaluate the Welsh approach in comparison with the original method to guide recommendations for future applications. Methods The study employed a mixed-methods design, including: 1) inductive content analysis of feedback collected via survey from 17 researchers and policy professionals from various countries, and 2) descriptive and Wilcoxon signed-rank analysis of Government indicator grades from Global Matrices 3.0 and 4.0 in 6 countries that transitioned to the Welsh approach and 28 countries/jurisdictions that retained the original method. Results User feedback on the Welsh approach was predominantly positive, noting its structure, transparency, and comprehensiveness as strengths, and indicating greater utility and suitability than the original method. Concerns included limited consideration of policy implementation and feasibility aspects. No statistically significant group-level temporal grade differences were found for both methods. Conclusion The Welsh approach adds structure and transparency to the Government indicator assessment. Further refinements to the Welsh approach may improve comparability and policy relevance, while both the Welsh and original methods remain acceptable for interim use within the Global Matrix, with potential applicability beyond it.

Surveillance of children’s sleep, physical activity (PA), and sedentary behaviour is a cornerstone of movement behaviour and health research, providing key information for guiding future health promotion policies, programs, and services. Systematic monitoring of these behaviours in preschool-aged children is lacking, particularly for certain sub-groups (males/females, urban/rural areas). This cross-sectional study aimed to assess the prevalence of 3- to 4-year-old children across five Canadian provinces meeting the 24-Hour Movement Guidelines for the Early Years, while examining associations with sex, age, and urban/rural location. Sleep and PA data were collected for 7 continuous days using waist-worn ActiGraph wGT3X+ accelerometers. Sleep duration was also gathered from parent reports, as were sedentary behaviour measures (screen and restrained time). Children were classified as meeting guidelines if they accumulated 10–13 h/day of sleep, ≥ 180 min/day of total PA (TPA), including ≥ 60 min/day of moderate-to-vigorous-intensity PA (MVPA), ≤ 1 h/day of screen time, and ≤ 1 h of restrained sedentary bouts. Within the final sample (n = 631), 29.0

Movement behaviours (e.g., sleep, sedentary behaviour, light physical activity [LPA], moderate to vigorous physical activity [MVPA]) are associated with numerous health and well-being outcomes. Compositional data analyses (CoDA) accounts for the interdependent nature of movement behaviours. This systematic review and meta-analysis provides a timely synthesis of the first decade of CoDA research examining the association between movement behaviours, health, and well-being in school-aged children. Databases were systematically searched for peer-reviewed studies examining CoDA associations between movement behaviours and health or well-being in school-aged children (5.0-17.9 years). All health and well-being outcomes were eligible for inclusion, as were all methods of reporting CoDA results. Where possible meta-analyses were conducted. Twenty-six studies were included in the review. Sample sizes ranged from 88 − 5,828 (median = 387) participants and the mean ages ranged from 8 to 16 years. Regression parameters (kstudies=16) were the most common method of reporting results, followed by substitution effects (kstudies=12), optimal compositions (kstudies=3), and movement behaviour clusters (kstudies =1). Weighted compositional means of movement behaviours were calculated (e.g., 49.8 min/day of MVPA). For regression analyses, results were generally null, though some favourable trends were observed for MVPA and unfavourable trends for LPA and sedentary behaviour within individual health and well-being outcomes categories. Meta-analyses of substitutions supported the benefits of MVPA, with the risks of reducing MVPA for other movement behaviours being double the magnitude compared to the benefits of adding MVPA. The most consistent conclusions within this review align with previous reviews that support the benefits of MVPA. Further, some evidence supported 24-hour movement behaviour guideline recommendations of increasing sleep and decreasing sedentary behaviour. This review also quantified not only the need to promote MVPA, but perhaps more importantly the urgency needed to preserve the limited MVPA children currently accumulate. Findings reinforce the “more/less is better” messages for movement behaviours, but do not allow us to recommend more specific balances of movement behaviours. As CoDA of movement behaviours progresses and accumulates further research, the methods and discussion points within the current review can aide future meta-analyses aimed at advancing the precision health guidance needed for optimizing children’s health and well-being.

INTRODUCTION:The global rise of the Internet and its near constant use by children and adolescents has given rise to concerns on the potential for Internet addiction (IA) and subsequent detrimental impacts on sleep habits. This study analyzed associations between IA and sleep outcomes in school-aged children and adolescents in the United States. METHODS:Broadly representative survey data was collected from Utah, surrounding states, and all other states (n = 775 parent-child dyads). Logistic regression models relating the association between Internet Addiction scores and self-reported sleep duration, sleep timing, sleep quality and screen use before sleep were completed. RESULTS:Severe IA was associated with 3.10 times higher odds of not meeting sleep guidelines compared to normal users (aOR = 3.10, 95 % CI: 1.97-4.90). Moderate and severe IA were associated with later bedtimes (aOR = 1.53, 95 % CI: 1.05-2.22 and aOR = 2.21, 95 % CI: 1.40-3.50, respectively). Moderate IA users had 1.81 times higher odds of screen use before sleep (aOR = 1.81, 95 % CI: 1.26-2.64). Sleep quality was not associated with IA in main analyses, but in some sensitivity analyses higher IA was associated lower odds of fair/poor sleep quality. CONCLUSIONS:These results suggest IA is unfavourably associated with several key sleep outcomes. Further experimental or longitudinal studies could confirm the directionality of these associations. Policies aimed at reducing screen time overall, preventing screen time before bed, and preventing late sleep timing in general could contribute towards reducing the risk of developing or worsening IA, while improving sleep health overall.

Background The actions required to achieve higher-quality and harmonised global surveillance of child and adolescent movement behaviours (physical activity, sedentary behaviour including screen time, sleep) are unclear. Objective To identify how to improve surveillance of movement behaviours, from the perspective of experts. Methods This Delphi Study involved 62 experts from the SUNRISE International Study of Movement Behaviours in the Early Years and Active Healthy Kids Global Alliance (AHKGA). Two survey rounds were used, with items categorised under: (1) funding, (2) capacity building, (3) methods, and (4) other issues (e.g., policymaker awareness of relevant WHO Guidelines and Strategies). Expert participants ranked 40 items on a five-point Likert scale from 'extremely' to 'not at all' important. Consensus was defined as > 70% rating of 'extremely' or 'very' important. Results We received 62 responses to round 1 of the survey and 59 to round 2. There was consensus for most items. The two highest rated round 2 items in each category were the following; for funding (1) it was greater funding for surveillance and public funding of surveillance; for capacity building (2) it was increased human capacity for surveillance (e.g. knowledge, skills) and regional or global partnerships to support national surveillance; for methods (3) it was standard protocols for surveillance measures and improved measurement method for screen time; and for other issues (4) it was greater awareness of physical activity guidelines and strategies from WHO and greater awareness of the importance of surveillance for NCD prevention. We generally found no significant differences in priorities between low-middle-income (n = 29) and high-income countries (n = 30) or between SUNRISE (n = 20), AHKGA (n = 26) or both (n = 13) initiatives. There was a lack of agreement on using private funding for surveillance or surveillance research. Conclusions This study provides a prioritised and international consensus list of actions required to improve surveillance of movement behaviours in children and adolescents globally.

Background: Investigators from low-, middle-, and high-income countries representing 6 continents contributed to the development of the Global Adolescent and Child Physical Activity Questionnaire (GAC-PAQ). The GAC-PAQ is designed to assess physical activity (PA) across all key domains (i.e., school, chores, work/volunteering, transport, free time, outdoor time). It aimed to address multiple gaps in global PA surveillance (e.g., omission of important PA domains, insufficient cultural adaptation, underrepresentation of rural areas in questionnaire validation studies). The purpose of this study was to assess the content validity of the GAC-PAQ among PA experts, 8-to 17-year-olds, and one of their parents/ guardians, and to discuss changes made to the questionnaire based on participants' feedback. Methods: Sixty-two experts in PA measurement and/or surveillance from 24 countries completed an online survey that included both closed-and open-ended questions about the content validity of the GAC-PAQ. The proportion of experts who agreed or strongly agreed with the items was calculated. Child-parent/guardian dyads from 15 countries (n = 250; 10-40 per country) participated in a structured cognitive interview to assess the clarity of the questions and response options, and they were encouraged to provide suggestions to improve clarity and facilitate completion of the questionnaire. Participating countries are: Aotearoa New Zealand, Brazil, Canada, China, Colombia, Czech Republic, India, Malawi, Mexico, Nepal, Nigeria, Spain, Sweden, Thailand, and the United Arab Emirates. Interviews were conducted in 13 different languages and structured by PA domain. Generic images were included to help participants in answering questions about PA intensity. Results: Expert agreement with the items for each domain exceeded 75%, and their qualitative feedback was used to revise the questionnaire before cognitive interviews. In general, participants found the questionnaire to be comprehensive. Adolescents (12-17 years) found it easier than children (8-11 years) to answer the questions. Several children struggled to answer questions about the duration and intensity of activities and/or concepts related to travel modes, active trips, and organized activities. Many parents/guardians were unsure about the frequency, duration, and intensity of their children's or adolescents' PA at school and/or recommended using more culturally relevant and appropriate images. Some participants misunderstood the concept of activities that "make you stronger" (intended to assess resistance activities) and/or struggled to differentiate between work, volunteering, and chores. Conclusion: Participants' feedback was used to develop a revised, simplified, and culturally adapted GAC-PAQ, which will be pilot-tested in all 15 countries in an App that will include country-specific images and narration in local languages. Further research is needed to assess the reliability and validity of the revised GAC-PAQ.

Background:Canada has produced 16 national Report Cards on the Physical Activity of Children and Youth over the past 20 years. This manuscript details the impact of the most recent Report Cards released between 2015 and 2024, updating evidence since the publication of the impact paper focused on the first 10 years (2005-2014). Methods:Various quantitative and qualitative approaches were employed to catalogue the developmental history and background of the Report Card, its leadership and sources of funding; consolidate and discuss the various evaluations and assessments that have been performed on the Report Card from 2015 to 2024; describe the distribution and reach of the Report Card from 2015 to 2024; and, examine the multi-dimensional impact of the Report Card on propelling the movement to get children and youth moving over the past 10 years in Canada and internationally. Results:Leadership by ParticipACTION has led to replicating the Children and Youth Report Card in over 70 jurisdictions, with many examples of beneficial cross-fertilization of ideas across jurisdictions and sectors. The multisectoral impact of the Report Card in Canada continues to be substantial, though sustained funding remains a challenge. There is modest evidence that grades for some indicators are drifting upwards. Deliberate efforts have been made to better integrate evidence and gaps related to the physical activity of equity-denied groups. Conclusions:Over the past 10 years, the ParticipACTION Children and Youth Report Card has continued to have a measurable, positive impact on the pediatric physical activity field in Canada (and beyond).

Importance:Approximately half of all youths with concussions report sleep disturbance, including short and long sleep durations, in the first week of recovery. Limited longitudinal research exists regarding the association between sleep duration and symptom burden during acute pediatric concussion recovery. Objective:To investigate the association between mean nightly sleep duration over 1 week (days 1 to 7) and 2 weeks (days 1 to 14) postinjury and subsequent symptom burden at 1, 2, and 4 weeks following pediatric concussion. Design, Setting, and Participants:This cohort study used data from a randomized clinical trial conducted in 3 emergency pediatric departments in Ontario, Canada, from March 2017 to December 2019 (with secondary analysis conducted between September 2022 and September 2024). Eligible participants were between ages 10 years and 18 years who received treatment for a concussion within 48 hours. Exposure:Sleep postinjury was measured with waist-worn accelerometers 24 hours per day for 2 weeks and daily sleep logs. Main Outcomes and Measures:Symptom burden was measured with the Health and Behavior Inventory at 1 week, 2 weeks, and 4 weeks postconcussion. A nonlinear mixed-effects model was applied that estimated symptom burden at 1, 2, and 4 weeks from mean sleep duration over days 1 to 7 and days 1 to 14. Logistic regressions were performed to assess the odds of being reliably symptomatic at 2 and 4 weeks by mean sleep duration. Conservative (z ≥ 1.65) and liberal (z ≥ 1.28) definitions of reliable change in symptoms were evaluated. All models compared 10th vs 50th, 25th vs 75th, and 50th vs 90th percentile contrasts, and were adjusted for prognostic pre-injury demographic and baseline injury variables. Results:A total of 291 participants (median [IQR] age, 13.2 [11.6-14.9] years; 128 female [44.0%]) were included in the main analysis. Mean nightly sleep duration beyond 9.5 hours in the first week postconcussion was associated with higher symptom burden at 1 week (75th percentile [10.5 h] vs 25th percentile [9.5 h]: estimate, 1.3 [95% CI, 0.25-2.28]; 90th percentile [11.3 h] vs 50th percentile [10.0 h]: estimate, 2.9 [95% CI, 1.22-4.69]). Mean sleep duration beyond 9.9 hours in the first 2 weeks postconcussion was associated with higher symptom burden at 2 weeks (90th percentile [10.9 h] vs 50th percentile [9.9 h]: estimate, 2.2 [95% CI, 0.85-3.47]) and 4 weeks (estimate, 2.2 [95% CI, 0.85-3.47]), and increased odds of persisting symptoms at 4 weeks (conservative: odds ratio [OR], 1.73 [95% CI, 0.91-3.26]; liberal: OR, 1.93 [95% CI, 1.07-3.47]). Conclusions and Relevance:In this observational study of adolescents, average nightly sleep durations beyond 9.9 hours over the first 2 weeks of concussion recovery were associated with high symptom burden and persistent symptoms. Clinicians should monitor youths' sleep after concussions.

ImportanceDetermining the optimal volume of early moderate-to-vigorous-intensity physical activity (MVPA) after concussion and its association with subsequent symptom burden is important for early postinjury management recommendations.ObjectivesTo investigate the association between cumulative MVPA (cMVPA) over 2 weeks and subsequent symptom burden at 1 week, 2 weeks, and 4 weeks postinjury in children and examine the association between cMVPA and odds of persisting symptoms after concussion (PSAC) at 2 weeks and 4 weeks postinjury.Design, Setting, and ParticipantsThis multicenter cohort study used data from a randomized clinical trial that was conducted from March 2017 to December 2019 at 3 Canadian pediatric emergency departments in participants aged 10.00 to 17.99 years with acute concussion of less than 48 hours. Data were analyzed from July 2022 to December 2023.ExposurecMVPA postinjury was measured with accelerometers worn on the waist for 24 hours per day for 13 days postinjury, with measurements deemed valid if participants had 4 or more days of accelerometer data and 3 or fewer consecutive days of missing data. cMVPA at 1 week and 2 weeks postinjury was defined as cMVPA for 7 days and 13 days postinjury, respectively. Multiple imputations were carried out on missing MVPA days.Main Outcomes and measuresSelf-reported postconcussion symptom burden at 1 week, 2 weeks, and 4 weeks postinjury using the Health and Behavior Inventory (HBI). PSAC was defined as reliable change on the HBI. A linear mixed-effect model was used for symptom burden at 1 week, 2 weeks, and 4 weeks postinjury with a time × cMVPA interaction. Logistic regressions assessed the association between cMVPA and PSAC. All models were adjusted for prognostically important variables.ResultsIn this study, 267 of 456 children (119 [44.6%] female; median [IQR] age, 12.9 [11.5 to 14.4] years) were included in the analysis. Participants with greater cMVPA had significantly lower HBI scores at 1 week (75th percentile [258.5 minutes] vs 25th percentile [90.0 minutes]; difference, −5.45 [95% CI, −7.67 to −3.24]) and 2 weeks postinjury (75th percentile [565.0 minutes] vs 25th percentile [237.0 minutes]; difference, −2.85 [95% CI, −4.74 to −0.97]) but not at 4 weeks postinjury (75th percentile [565.0 minutes] vs 25th percentile [237.0 minutes]; difference, −1.24 [95% CI, −3.13 to 0.64]) (P = .20). Symptom burden was not lower beyond the 75th percentile for cMVPA at 1 week or 2 weeks postinjury (1 week, 259 minutes; 2 weeks, 565 minutes) of cMVPA. The odds ratio for the association between 75th and 25th percentile of cMVPA and PSAC was 0.48 (95% CI, 0.24 to 0.94) at 2 weeks.Conclusions and RelevanceIn children and adolescents with acute concussion, 259 minutes of cMVPA during the first week postinjury and 565 minutes of cMVPA during the second week postinjury were associated with lower symptom burden at 1 week and 2 weeks postinjury. At 2 weeks postinjury, higher cMVPA volume was associated with 48% reduced odds of PSAC compared with lower cMVPA volume.

OBJECTIVE:We aimed to analyze the associations between movement behaviors (physical activity, screen time, and sleep), independently and jointly, and suicidal thoughts/ideation among Brazilian adolescents according to race/ethnicity.METHODS:This cross-sectional study surveyed 4,081 adolescents aged 15-19 years (49.9% females) across all Brazilian geographic regions. Data were collected using a self-administered questionnaire. Within the sample, 31.0% (n = 1,264) self-reported as White and 69.0% (n = 2,817) as Black. Adolescents who declared one or more times/week suicidal thoughts/ideation were considered as a risk group. Accruing moderate-to-vigorous physical activity during leisure time, reduced recreational screen time, and good sleep quality were the exposures investigated. We evaluated both additive and multiplicative interactions between race/ethnicity and movement behaviors. Binary logistic regression was used to estimate the odds ratio (OR), marginal means effects, and 95% confidence intervals (95% CIs).RESULTS:Black adolescents who met 1 (OR: 0.34; [95% CI: 0.22-0.52]), 2 (OR: 0.17 [0.11-0.27]), or 3 (OR: 0.13 [0.07-0.26]), and White adolescents who met 1 (OR: 0.35 [0.21-0.57]), 2 (OR: 0.14 [0.08-0.26]), or 3 (OR: 0.11 [0.04-0.31]) of the movement behavior targets had lower odds of suicidal thoughts/ideation than Black adolescents who did not meet any of the movement behavior targets. Black adolescents who did not meet any of the movement behavior targets had higher suicidal thoughts/ideation odds than the other adolescent's groups.CONCLUSIONS:We identified an inverse association between meeting individuals and combinations of movement behavior targets with suicidal thoughts/ideation. Among Black adolescents who did not meet any targets, these associations were more evident.

Primary objectives were to examine: (1) changes in movement behaviours (i.e., outdoor play (OP), organized physical activity (PA), screen time (ST), sleep) across the first 2 years of coronavirus disease-2019 (COVID-19) among Canadian toddlers and preschoolers, and (2) intrapersonal, interpersonal, community, and policy moderators of change in movement behaviors. Participants were 341 Canadian parents of children (start of study: 1–4 years; 48% female). Participants completed online questionnaires regarding their children’s movement behaviours and intrapersonal, interpersonal, and community factors at five time-points before and throughout the pandemic (T1–T5). Data from government websites were also used for some community and policy factors. Linear mixed models were conducted. Compared to pre-COVID-19 (T1): OP was on average 30 min/day higher at T2 and T3; organized PA was on average 62, 44, and 37 min/day lower at T2, T3, and T4, respectively; ST was on average 67, 17, 38, and 52 min/day higher at T2, T3, T4, and T5, respectively; and sleep was on average 30, 36, and 82 min/day lower at T3, T4, and T5, respectively. Significant moderating variables were observed for OP (parental education, parental work inside home, COVID-19 restriction severity), organized PA (children’s sex, started kindergarten, nonparental care, parental education, household income, parental employment status, house type, indoor home space and support for PA), ST (nonparental care, parental marital status) and sleep (children’s T1 age group, started kindergarten, parental place of birth, parental employment status). All movement behaviors changed across the first 2 years of COVID-19 but patterns and moderators were behaviour-specific. Children from lower socioeconomic status families had the least optimal patterns.

This study examined the variability, convergent validity and correlates of outdoor play (OP) in preschool-aged children. Participants were 107 preschool-aged children (3-5 years) and their parents from Edmonton, Canada, and surrounding areas. Children's OP was measured via a parental questionnaire and the lux feature of ActiGraph accelerometers (n=98). Correlates from various levels of the socioecological framework were measured. Children had significantly higher OP in summer/fall months (versus winter months), on weekend days (versus weekdays), and when parental-reported (versus device-measured). Parental age was positively associated with children's parental-reported OP on weekend days, and temperature was positively associated with children's parental-reported OP in summer/fall months. Higher temperature was associated with a higher likelihood of children participating in >= 30 minutes/day of device-based measured OP (versus <30 minutes/day). Implementing interventions to promote OP in all weather, and days of the week, may help reverse the declining trend of children's OP.

Canada, Australia, the World Health Organization and other countries have released 24-hour movement guidelines for the early years which integrate physical activity, sedentary behaviour, and sleep, focusing on supporting children to achieve a healthy 24-hour day. The guideline evidence synthesis, however, highlighted the dearth of high-quality evidence, particularly from large-scale studies. The Sleep and Activity Database for the Early Years (SADEY) project aims to assemble a large, pooled database of 24-hour movement behaviours and health indicators in young children (birth to 5.99 years), to advance knowledge in these areas. This paper describes the SADEY design and methods. Data sets were identified with > 100 children and device-measured (hip-worn ActiGraph accelerometers) physical activity and sedentary behaviour, parent-reported or device-measured sleep, and at least one health outcome: physical (BMI, waist circumference, blood pressure), social-emotional (Strength and Difficulties Questionnaire), cognitive (Early Years Toolbox), or motor development (Test of Gross Motor Development 2). Led by the University of Wollongong co-ordinating centre, the SADEY project collates the datasets to create a pooled database. To date, 13 studies from 7 countries have been included in the database. Ethics clearance and data sharing agreements have been secured for all studies and the SADEY 1.0 database is being assembled including ~ 8,000 participants. SADEY will be used to address questions of global importance to public health policy and practice, for example – Is the mix of movement behaviours across the 24-hour day associated with healthy development?, What is the optimal mix of these behaviours?, and; What factors can be targeted to support young children in achieving the optimal mix of 24-hour movement behaviours? Additionally, SADEY seeks to develop and disseminate protocols, develop capacity on the device-based measurement of movement behaviours, and seeks partnerships with stakeholders that promote knowledge translation on movement behaviours to support healthy development among young children.

Purpose: Examine in preschool-aged children: (1) the associations between parental-reported and device-measured outdoor play (OP) and health indicators of physical, cognitive, and social–emotional development and (2) whether associations were independent of outdoor moderate- to vigorous-intensity physical activity (MVPA). Methods: This cross-sectional study included 107 participants. Children’s OP was measured via a parental questionnaire and the lux feature of accelerometers. Children’s growth, adiposity, and motor skills were assessed as physical development indicators. Visual–spatial working memory, response inhibition, and expressive language were assessed as cognitive development indicators. Sociability, prosocial behavior, internalizing, externalizing, and self-regulation were assessed as social–emotional development indicators. Regression models were conducted that adjusted for relevant covariates. Additional models further adjusted for outdoor MVPA. Results: Parental-reported total OP, OP in summer/fall months, and OP on weekdays were negatively associated (small effect sizes) with response inhibition and working memory. After adjusting for outdoor MVPA, these associations were no longer statistically significant. OP on weekdays was negatively associated with externalizing (B = −0.04; 95% confidence interval, −0.08 to −0.00; P = .03) after adjusting for outdoor MVPA. A similar pattern was observed for device-based measured total OP (B = −0.49; 95% confidence interval, −1.05 to 0.07; P = .09). Conclusions: Future research in preschool-aged children should take into account MVPA and contextual factors when examining the association between OP and health-related indicators.

•Movement behaviours consisted of sleep, physical activity, and screen time.•Mental health measures included flourishing, resiliency, anxiety and depression.•Best day scenarios maximized sleep and physical activity while minimizing screen.•For transgender youth small difference in activity associated better mental health.•Screen use associated with less severe poor mental health in boys.

Early menarche has been associated with adverse health outcomes, such as depressive symptoms. Discovering effect modifiers across these conditions in the pediatric population is a constant challenge. We tested whether movement behaviours modified the effect of the association between early menarche and depression symptoms among adolescents. This crosssectional study included 2031 females aged 15-19 years across all Brazilian geographic regions. Data were collected using a self-administered questionnaire; 30.5% (n = 620) reported having experienced menarche before age 12 years (i.e., early menarche). We used the Patient Health Questionnaire (PHQ-9) to evaluate depressive symptoms. Accruing any moderate-vigorous physical activity during leisure time, limited recreational screen time, and having good sleep quality were the exposures investigated. Adolescents who experienced early menarche and met one (B: -4.45, 95% CI: (-5.38, -3.51)), two (B: -6.07 (-7.02, -5.12)), or three (B: -6.49 (-7.76, -5.21)), and adolescents who experienced not early menarche and met one (B: -5.33 (-6.20; -4.46)), two (B: -6.12 (-6.99; -5.24)), or three (B: -6.27 (-7.30; -5.24)) of the movement behaviour targets had lower PHQ-9 scores for depression symptoms than adolescents who experienced early menarche and did not meet any of the movement behaviours. The disparities in depressive symptoms among the adolescents (early menarche vs. not early menarche) who adhered to all three target behaviours were not statistically significant (B: 0.41 (-0.19; 1.01)). Adherence to movement behaviours modified the effect of the association between early menarche and depression symptoms.