Optimal levels of sleep, sedentary behaviour, and physical activity needed to support cognitive function in children of the early years.

Background: Sleep, sedentary behaviour, physical activity, and the composition of these movement behaviours across the 24-h day are associated with cognitive function in early years children. This study used a Goldilocks day compositional data analysis approach to identify the optimal duration of sleep, sedentary behaviour, light physical activity, and moderate-to-vigorous physical activity associated with desired cognitive function outcomes in early years children.

Methods: This cross-sectional study included 858 children aged 2.

Consideration of Young People's Active Travel in National Urban Policy Documents in Asia: A Documentary Analysis.

Background: Active travel to school faces challenges in urbanized and car-centric Asian regions. The UN-Habitat supports global governments in formulating National Urban Policies (NUPs) for sustainable urban development. This study examined how young people's active travel is discussed in NUP documents in selected Asian countries.

Family Car Ownership: Driving Inactivity in Young People? Cross-Sectional and Longitudinal Analyses in the International Children's Accelerometry Database.

Background: Ubiquitous car ownership may affect children's activity and health. We assessed the cross-sectional and longitudinal associations between household car ownership and children's daily time spent sedentary (SED) and in moderate to vigorous physical activity (MVPA).

Methods: Pooled cohort data were from the International Children's Accelerometry Database.

Cross-sectional associations of gender identity and sexual orientation, with co-occurrence and clustering of health-related behaviours among British adolescents: Millennium cohort study.

Purpose: We examined whether gender identity and sexual orientation were associated with seven health-related behaviours, and with co-occurrence and clustering of these behaviours among British adolescents.

Methods: Millennium Cohort Study (age 17 wave) provided data on the exposures, gender identity (male, female, genderqueer) and sexual orientation (heterosexual, bisexual, gay or lesbian, or other), and seven self-reported health-related behaviours (binge drinking, drug use, no consumption of breakfast, no consumption of fruits or vegetables, physical inactivity, poor sleep, and smoking or vaping). Poisson regressions examined associations between the exposures and single behaviours (reporting prevalence ratios (PRs)); and multinomial logistic regressions were used for behavioural cumulative co-occurrence score (reporting PRs).

Consolidated guidance for behavioral intervention pilot and feasibility studies.

Background: In the behavioral sciences, conducting pilot and/or feasibility studies (PFS) is a key step that provides essential information used to inform the design, conduct, and implementation of a larger-scale trial. There are more than 160 published guidelines, reporting checklists, frameworks, and recommendations related to PFS. All of these publications offer some form of guidance on PFS, but many focus on one or a few topics.

Total and temporal patterning of physical activity in adolescents and associations with mental wellbeing.

Background: There is limited understanding of the extent to which differences in physical activity across the day and week may be associated with mental wellbeing. Such an understanding is needed for better targeting of interventions. In this study, we describe total and temporal patterning of physical activity across the week in adolescents (age 13-14y) and assess their prospective associations with mental wellbeing.

Activity Behaviors Before and During Pregnancy Are Associated With Women's Device-Measured Physical Activity and Sedentary Time in Later Parenthood: A Longitudinal Cohort Analysis.

Purpose: To explore how activity behaviors before/during pregnancy relate to those in later parenthood, we assessed associations between sitting and moderate-/strenuous exercise before/during pregnancy, and sedentary time (SED) and moderate to vigorous physical activity (MVPA) 4-7 years postpartum ("later parenthood").

Methods: Longitudinal data were from the Southampton Women's Survey, United Kingdom. Women reported time spent sitting (in hours per day), in moderate-strenuous exercise (hours per week), and in strenuous exercise (hours per week) at 3 time points before/during pregnancy (ie, preconception, at ∼12-wk and ∼34-wk gestation).

Conducting school-based health surveys with secondary schools in England: advice and recommendations from school staff, local authority professionals, and wider key stakeholders, a qualitative study.

Background: Improving the health and well-being of young people is a public health priority. Schools present an ideal setting to implement strategies to improve young people's health and well-being. A key strategy involves conducting surveys to assess student health needs, inform interventions, and monitor health over time.

Pre-pubertal accelerometer-assessed physical activity and timing of puberty in British boys and girls: the Millennium Cohort Study.

Background: Early puberty timing is associated with adverse health outcomes. We aimed to examine prospective associations between objectively measured physical activity and puberty timing in boys and girls.

Methods: In the UK Millennium Cohort Study, physical activity volume and intensities at 7 years were measured using accelerometers.

Time spent on social media use and BMI z-score: A cross-sectional explanatory pathway analysis of 10798 14-year-old boys and girls.

Background: The association between adolescent time spent on social media use and body mass index z-score (BMI z-score) is unclear. Pathways of association and sex differences are also unclear. This study examined the association between time spent on social media use and BMI z-score (primary objective) and potential explanatory pathways (secondary objective) for boys and girls.

Shorter sleep among adolescents is associated with lower fruit and vegetable consumption the following day.

Background: Insufficient sleep has been associated with weight gain and metabolic dysregulation, with one suggested mechanism being through reduction in diet quality. Experimental evidence supports a causal effect of sleep timings on diet but this may not be applicable to a free-living adolescent population. In this analysis we use daily measures of sleep timings and diet quality, to examine the effect of sleep duration and timing on diet quality the following day among free-living adolescents.

Recruitment and retention into longitudinal health research from an adolescent perspective: a qualitative study.

Background: High quality longitudinal studies investigating changes in health behaviours over the transition into early adulthood are critical. However, recruiting and retaining adolescents is challenging. This study explored adolescents' perspectives of signing up to and continuing involvement in a hypothetical longitudinal health research study.

The association between number and ages of children and the physical activity of mothers: Cross-sectional analyses from the Southampton Women's Survey.

Background: Physical activity (PA) has many health benefits, but motherhood is often associated with reduced PA. Considering that ages and number of children may be associated with maternal PA, and that PA patterns may change as children transition to formal schooling, we aimed to investigate the associations between ages and number of children and device-measured maternal PA.

Methods: Cross-sectional analyses were conducted using data from 848 mothers from the Southampton Women's Survey at two different timepoints.

Creation of a Pilot School Health Research Network in an English Education Infrastructure to Improve Adolescent Health and Well-Being: A Study Protocol.

Schools play a significant role in promoting health and well-being and the reciprocal links between health and educational attainment are well-evidenced. Despite recognition of the beneficial impact of school-based health improvement programmes, significant barriers to improving health and well-being within schools remain. This study pilots a School Health Research Network in the South West of England (SW-SHRN), a systems-based health intervention bringing together schools, academic health researchers and public health and/or education teams in local authorities to share knowledge and expertise to improve the health and well-being of young people.

Activity Behaviors in British 6-Year-Olds: Cross-Sectional Associations and Longitudinal Change During the School Transition.

Background: To explore activity behaviors at school entry, we describe temporal/demographic associations with accelerometer-measured physical activity in a population-based sample of British 6-year-olds, and examine change from ages 4 to 6.

Methods: A total of 712 six-year-olds (308 at both ages) wore Actiheart accelerometers for ≥3 (mean 6.0) days.

Impacts of new cycle infrastructure on cycling levels in two French cities: an interrupted time series analysis.

Background: Cities globally have started to make substantial investment in more sustainable forms of transportation. We aimed to evaluate whether the construction of new cycling infrastructure in Paris and Lyon, France, affected population cycling activity along new or improved routes.

Methods: Routinely collected cycle count data from January 2014 to March 2020 were acquired for the cities of Paris and Lyon.

Device-measured sleep onset and duration in the development of depressive symptoms in adolescence.

Background: Sleep deprivation in adolescence is increasing in prevalence and may be linked to subsequent depression. Findings regarding associations between sleep duration, sleep onset time, and the development of depressive symptoms over time in adolescents are mixed, and rely on subjective measures of sleep.

Methods: Sleep onset and duration were assessed using a combined heart rate monitor and accelerometer and self-report in 688 participants from the ROOTS study at age 15.

Descriptive epidemiology of the prevalence of adolescent active travel to school in Asia: a cross-sectional study from 31 countries.

Objective: This study aimed to examine the prevalence of adolescent active travel to school (ATS) across 31 countries and territories in Asia, overall and by age group, sex and body mass index (BMI) category.

Design: Cross-sectional study.

Setting: 31 Asian countries.

Influence of Guideline Operationalization on Youth Activity Prevalence in the International Children's Accelerometry Database.

Introduction: The United Kingdom and World Health Organization recently changed their youth physical activity (PA) guidelines from 60 min of moderate- to vigorous-intensity PA (MVPA) every day, to an average of 60 min of MVPA per day, over a week. The changes are based on expert opinion due to insufficient evidence comparing health outcomes associated with different guideline definitions. This study used the International Children's Accelerometry Database to compare approaches to calculating youth PA compliance and associations with health indicators.

Aerobic fitness mediates the intervention effects of a school-based physical activity intervention on academic performance. The school in Motion study - A cluster randomized controlled trial.

Little information exists on the mechanism of how physical activity interventions effects academic performance. We examined whether the effects of a school-based physical activity intervention on academic performance were mediated by aerobic fitness. The School in Motion study was a nine-month cluster randomized controlled trial between September 2017 and June 2018.

Perceptions of the South African 24-Hour Movement Guidelines for Birth to 5 Years: A Qualitative Study.

Background: South Africa launched 24-hour movement guidelines for birth to 5 years in 2018. Perceptions of these guidelines were assessed as part of the dissemination process with community-based organizations in 2019.

Methods: Fifteen dissemination workshops were held with community-based organization representatives and a range of stakeholders.

Cross-sectional and prospective associations of sleep duration and bedtimes with adiposity and obesity risk in 15 810 youth from 11 international cohorts.

Objectives: To investigate associations of bedtimes and sleep durations with adiposity levels in children and adolescents.

Methods: Individual data were pooled for 12 247 children (5819 with follow-up adiposity at 2.3 ± 1.

Association of change in the school travel mode with changes in different physical activity intensities and sedentary time: A International Children's Accelerometry Database Study.

Our aim was to assess the association between changes in active travel to school and changes in different intensities of physical activity (i.e. moderate - MPA and vigorous - VPA) and time spent sedentary (SED) among adolescents and assess the moderating effect of children's sex, age and weight status.

The socio-ecological determinants of change in school travel mode over the transition from childhood to adolescence and the association with physical activity intensity.

School active travel contributes to young people's physical activity levels, yet the prevalence is low, and declines with age. Based on determinants from the social-ecological model we investigated changes in school travel behaviour over the transition from childhood to adolescence in participants from the baseline and four-year follow-up of the SPEEDY cohort. Descriptive analysis examined how travel behaviours changed and were related to physical activity.

Early adulthood socioeconomic trajectories contribute to inequalities in adult cardiovascular health, independently of childhood and adulthood socioeconomic position.

Background: Cardiovascular health shows significant socioeconomic inequalities, however there is little understanding of the role of early adulthood in generation of these inequalities. We assessed the contribution of socioeconomic trajectories during early adulthood (16-24 years) to cardiovascular health in mid-adulthood (46 years).

Methods: Participants from the 1970 British Cohort Study with socioeconomic data available in early adulthood were included (n=12 423).