The impact of social media interventions on eating behaviours and diet in adolescents and young adults: a mixed methods systematic review protocol

INTRODUCTION

Adolescents and young adults are susceptible population when it comes to healthy eating and dietary behaviours. The increasing use of social media by this age group presents a unique opportunity to promote healthy eating habits. Social media has become a popular platform for promoting health interventions, particularly among young people. However, there is a lack of consensus on the effectiveness of social media interventions in this population. This mixed-method systematic review aims to synthesise the available evidence on the impact of social media interventions on healthy eating behaviours among young people, their qualitative views and user experiences, and the intervention characteristics, behaviour change theories and techniques used to promote healthy eating.

METHODS AND ANALYSIS

We will conduct a comprehensive search of seven electronic databases, including ASSIA, Cochrane Library, Embase, MEDLINE, PsycINFO, Scopus and Web of Science. The search strategy will use a combination of Medical Subject Headings terms and keywords covering three domains: social media, eating behaviours and young people. The search will be limited to peer-reviewed published papers in any language, published from 2000. Three independent reviewers will screen studies based on predetermined eligibility criteria. Data will be extracted and analysed using a convergent segregated mixed-method approach. We will use random-effect meta-analysis or Synthesis Without Meta-analysis for quantitative data and thematic synthesis for qualitative data. Finally, narrative synthesis using concurrent triangulation will be used to bring together the results of the mixed-method data analysis to provide a comprehensive and integrated understanding of the impact and other features of social media interventions. This systematic review will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

ETHICS AND DISSEMINATION

Ethical approval is not required since this systematic review will not collect original data. The outcomes of this review will be shared through peer-reviewed publications and conference presentations and will contribute to the PhD thesis of the primary author.

PROSPERO REGISTRATION NUMBER

CRD42023414476.

Gender Differences in Caregivers' Attitudes to Risky Child Play in Britain: A Cross-Sectional Study

BACKGROUND

This study examines gender differences in parental attitudes toward risky play for 5- to 11-year-old boys and girls in Britain.

METHODS

Analyses use data from the cross-sectional, nationally representative British Child Play Survey. Survey respondents were caregivers of primary-school-aged children living in Britain. Parent self-reported their risk tolerance in play via the Tolerance for Risk in Play Scale (TRiPS) and the Risk Engagement and Protection Survey (REPS). The REPS includes subscales that assess caregiver attitudes around "Protection from Injury" (PFI) and "Engagement with Risk" (EWR) in relation to children's play. Multiple linear regression compared caregiver gender differences in TRiPS, REPS-PFI, and REPS-EWR at the item level, and overall. Associations between child gender and these scales were also examined.

RESULTS

Among 1919 caregivers, no significant gender differences emerged in mean TRiPS (P = .72), REPS-EWR (P = .58), and REPS-PFI (P = .34) scores. Activity-specific differences were evident in caregivers' tolerance for individual risky play activities (15/31 activities). Parents of boys exhibited higher risk tolerance (B = -4.48, P < .01) and willingness for their child to engage in risky play (B = -0.63, P < .01) than parents of girls.

CONCLUSIONS

While there was no difference between male and female caregivers overall attitudes, gender differences were prominent for specific play activities and attitudes, with male caregivers demonstrating higher tolerance for the riskiest activities. Parents of boys expressed more permissive attitudes toward engagement in risky play. Further work is needed to identify why there is gender-related variation in these attitudes and should be considered in interventions that support parents in enabling adventurous play opportunities for children.

Are school uniforms associated with gender inequalities in physical activity? A pooled analysis of population-level data from 135 countries/regions

BACKGROUND

We assessed whether school uniforms are associated with population-level gender inequalities in physical activity, and whether associations differ by school level, country/region income, and assessment method.

METHODS

An ecological study design was employed. We collected data about global uniform practices using an online survey. We searched for country/region-level estimates of school-aged youth meeting physical activity guidelines from international surveillance studies. Study selection was conducted in duplicate using a systematic process, and a random sample of all data was checked to ensure extraction and pooling processes were accurate. We calculated absolute and relative gender inequalities in physical activity for each country. Linear regression examined associations between country/region-level uniform practices (binary yes/no exposure variable) and country/region-level gender inequalities in physical activity guideline compliance (absolute and relative inequalities). We investigated moderation by school level, stratified analyses by income group, and repeated primary analyses using device-measured data.

RESULTS

Pooling data from 135 countries/regions (n = 1,089,852), we found no association between population-level uniform practices and gender inequalities in physical activity across all ages (absolute: β = -0.2; 95% confidence interval (95%CI): -1.7 to 1.3, p = 0.74; relative: β = 0.1; 95%CI: -0.1 to 0.2, p = 0.51). Subgroup analysis suggested a positive association in primary school settings (absolute: β = 4.3; 95%CI: -0.0 to 8.6, p = 0.05). Among high-income countries, absolute inequalities were significantly greater in countries/regions with uniform practices (N = 37) compared to those without (N = 48) (9.1 (SD = 3.6) vs. 7.8 percentage points (SD = 4.3)). Repeating analyses using device-measured data (n = 32,130; N = 24) did not alter our primary finding. From initial descriptive statistics, we found that in countries/regions where a majority of schools (>50%) reportedly use uniforms, there was lower compliance with physical activity guidelines among all genders (median: 16.0%, interquartile range: 13.2-19.9, N = 103) compared to generally non-uniform countries/regions (median: 19.5%, interquartile range: 16.4-23.5, N = 32) (z = 3.04, p = 0.002). (N = countries, regions and studies represented; n = sample size or participants included).

CONCLUSION

School uniforms are associated with greater gender inequalities in physical activity in primary school settings and in high-income countries. Our population-level findings warrant testing using individual-level data across contexts.

Investigating the impact of London's ultra low emission zone on children's health: children's health in London and Luton (CHILL) protocol for a prospective parallel cohort study

BACKGROUND

Air pollution harms health across the life course. Children are at particular risk of adverse effects during development, which may impact on health in later life. Interventions that improve air quality are urgently needed both to improve public health now, and prevent longer-term increased vulnerability to chronic disease. Low Emission Zones are a public health policy intervention aimed at reducing traffic-derived contributions to urban air pollution, but evidence that they deliver health benefits is lacking. We describe a natural experiment study (CHILL: Children's Health in London and Luton) to evaluate the impacts of the introduction of London's Ultra Low Emission Zone (ULEZ) on children's health.

METHODS

CHILL is a prospective two-arm parallel longitudinal cohort study recruiting children at age 6-9 years from primary schools in Central London (the focus of the first phase of the ULEZ) and Luton (a comparator site), with the primary outcome being the impact of changes in annual air pollutant exposures (nitrogen oxides [NOx], nitrogen dioxide [NO2], particulate matter with a diameter of less than 2.5micrograms [PM2.5], and less than 10 micrograms [PM10]) across the two sites on lung function growth, measured as post-bronchodilator forced expiratory volume in one second (FEV1) over five years. Secondary outcomes include physical activity, cognitive development, mental health, quality of life, health inequalities, and a range of respiratory and health economic data.

DISCUSSION

CHILL's prospective parallel cohort design will enable robust conclusions to be drawn on the effectiveness of the ULEZ at improving air quality and delivering improvements in children's respiratory health. With increasing proportions of the world's population now living in large urban areas exceeding World Health Organisation air pollution limit guidelines, our study findings will have important implications for the design and implementation of Low Emission and Clean Air Zones in the UK, and worldwide.

CLINICALTRIALS

GOV: NCT04695093 (05/01/2021).

Real-world application of a scalable school-based physical activity intervention: A cross-sectional survey of the implementation of The Daily Mile in Greater London primary schools

School-based physical activity interventions are considered ideal given their potential to reach most children. They can help children achieve the recommended guidelines of 60 minutes of moderate-to-vigorous physical activity per day. The Daily Mile is a popular school-based active mile intervention with a global reach. It recommends ten core principles for successful implementation, three of which are key for effectiveness: that it is quick (15 minutes), the whole school participates, and that it takes place in the school day during lessons (excluding physical education lessons and scheduled breaks). Studies assessing the impacts of The Daily Mile do not often report implementation of the ten core principles which is crucial to identifying the potential impact and feasibility of scalable interventions in real-world settings. Our aim was to assess adherence to The Daily Mile's ten core principles in Greater London primary schools. We created and distributed a survey to 1717 primary schools during September 2020 and achieved a 21% (n = 369/1717) response rate by September 2021. Our sample was representative of Greater London primary schools with responses from every London borough. A total of 196/369 (53%) schools reported implementing The Daily Mile but none of them reported adherence to all ten core principles. Adherence to at least 6/10 principles in various combinations was reported by 54/196 (28%) schools. Only 19/196 (10%) schools that reported implementing The Daily Mile reported adherence to the three key principles recommended for effectiveness. Despite its popularity and global reach, our findings suggest that an implementation gap exists when The Daily Mile is adopted in real-world settings which is likely to challenge its intended purpose. Further research in school settings is needed to understand factors that can improve adherence to increase the potential public health impact of The Daily Mile and other similar interventions.

Device-Measured Change in Physical Activity in Primary School Children During the UK COVID-19 Pandemic Lockdown: A Longitudinal Study

BACKGROUND

Lockdown measures, including school closures, due to the COVID-19 pandemic have caused widespread disruption to children's lives. The aim of this study was to explore the impact of a national lockdown on children's physical activity using seasonally matched accelerometry data.

METHODS

Using a pre/post observational design, 179 children aged 8 to 11 years provided physical activity data measured using hip-worn triaxial accelerometers worn for 5 consecutive days prepandemic and during the January to March 2021 lockdown. Multilevel regression analyses adjusted for covariates were used to assess the impact of lockdown on time spent in sedentary and moderate to vigorous physical activity.

RESULTS

A 10.8-minute reduction in daily time spent in moderate to vigorous physical activity (standard error: 2.3 min/d, P < .001) and a 33.2-minute increase in daily sedentary activity (standard error: 5.5 min/d, P < .001) were observed during lockdown. This reflected a reduction in daily moderate to vigorous physical activity for those unable to attend school (-13.1 [2.3] min/d, P < .001) during lockdown, with no significant change for those who continued to attend school (0.4 [4.0] min/d, P < .925).

CONCLUSION

These findings suggest that the loss of in-person schooling was the single largest impact on physical activity in this cohort of primary school children in London, Luton, and Dunstable, United Kingdom.

Incomplete reporting of complex interventions: a call to action for journal editors to review their submission guidelines

Reporting of intervention research has been inadequate for many years. The development and promotion of freely available checklists aims to address this problem by providing researchers with a list of items that require reporting to enable study interpretation and replication. In this commentary, we present evidence from a recent systematic review of 51 randomised controlled trials published 2015-2020 that inadequate intervention reporting remains a widespread issue and that checklists are not being used to describe all intervention components. In 2022, we assessed the submission guidelines of 33 journals that published articles included in our review and found that just one at the time encouraged the use of reporting checklists for all intervention components. To drive progress, we contacted the editors of the other 32 journals and requested that they update their submission guidelines in response. We conclude by highlighting the waste associated with current practices and encourage journals from all fields to urgently review their submission guidelines. Only through collective action can we build an evidence base that is fit for purpose.

Do socioeconomic inequities arise during school-based physical activity interventions? An exploratory case study of the GoActive trial

OBJECTIVE

To investigate socioeconomic inequities in the intervention and evaluation process of the GoActive school-based physical activity intervention and demonstrate a novel approach to evaluating intervention-related inequalities.

DESIGN

Exploratory post-hoc secondary data analysis of trial data.

SETTING

The GoActive trial was run in secondary schools across Cambridgeshire and Essex (UK), between September 2016 and July 2018.

PARTICIPANTS

13-14 years old adolescents (n=2838, 16 schools).

METHODS

Socioeconomic inequities across six stages in the intervention and evaluation process were evaluated: (1) provision of and access to resources; (2) intervention uptake; (3) intervention effectiveness (accelerometer-assessed moderate-to-vigorous physical activity (MVPA)); (4) long-term compliance; (5) response in evaluation; and (6) impact on health. Data from self-report and objective measures were analysed by individual-level and school-level socioeconomic position (SEP) using a combination of classical hypothesis tests and multilevel regression modelling.

RESULTS

Stage: (1) There was no difference in the provision of physical activity resources by school-level SEP (eg, quality of facilities (0-3), low=2.6 (0.5); high=2.5 (0.4). (2) Students of low-SEP engaged significantly less with the intervention (eg, website access: low=37.2%; middle=45.4%; high=47.0%; p=0.001). (3) There was a positive intervention effect on MVPA in adolescents of low-SEP (3.13 min/day, 95% CI -1.27 to 7.54, but not middle/high (-1.49; 95% CI -6.54 to 3.57). (4) At 10 months post-intervention, this difference increased (low SEP: 4.90; 95% CI 0.09 to 9.70; middle/high SEP: -2.76; 95% CI -6.78 to 1.26). (5) There was greater non-compliance to evaluation measures among adolescents of low-SEP (eg, % accelerometer compliance (low vs high): baseline: 88.4 vs 92.5; post-intervention: 61.6 vs 69.2; follow-up: 54.5 vs 70.2. (6) The intervention effect on body mass index (BMI) z-score was more favourable in adolescents of low-SEP (low SEP: -0.10; 95% CI -0.19 to 0.00; middle/high: 0.03; 95% CI -0.05 to 0.12).

CONCLUSIONS

These analyses suggest the GoActive intervention had a more favourable positive effect on MVPA and BMI in adolescents of low-SEP, despite lower intervention engagement. However, differential response to evaluation measures may have biassed these conclusions. We demonstrate a novel way of evaluating inequities within young people's physical activity intervention evaluations.

TRIAL REGISTRATION NUMBER

ISRCTN31583496.

Natural experimental study of no car zones implemented outside schools: potential and lessons learnt

INTRODUCTION

Walking and cycling can be beneficial to health. Restrictions for motor vehicles outside schools could be one way to encourage activity but few evaluations exist. We aimed to explore the potential of such a scheme on children's active commuting, intervention mechanisms, and the utility of routinely collected data for evaluation.

METHODS

Restricted access for motor vehicles on road sections directly outside two Cambridge schools (one primary school [5-11 years] and one secondary school [11-16 years]) were implemented in April 2021. Teachers conducted hands-up travel surveys in March and May, 2021. All schools had facilities for storing bikes. Online surveys were distributed to parents, staff, local residents, and business owners between May and July, 2021, to assess travel behaviours and perceptions. We conducted observations at schools and interviews with a survey subsample to gain insights into intervention mechanisms, analysed using a thematic approach. Data for air quality and traffic volumes were available from February to September, 2021.

FINDINGS

457 respondents completed the online survey, 13 interviews were conducted, and 40 classes completed both hands-up surveys. 18 (15%) of 117 primary school children and 30 (68%) of 44 secondary school children travelled to school without adult supervision according to parental reports. Hands-up survey data indicated no change in active commuting at the secondary school and a 2% increase at the primary school. The schemes improved perceptions of safety for pedestrians and cyclists at the primary school; however, residents still had concerns as motorists' compliance and safety were highlighted as key issues in both schools. Routinely collected, continuous air quality data were found to be particularly useful, but traffic volume data were less useful because of the timing of data collection and cost of sensors.

INTERPRETATION

It is possible that such schemes implemented with enforcement are necessary but not sufficient to encourage changes in commuting. Before a larger study could be done, the scheme design needs refinement to improve potential effectiveness.

FUNDING

UK Medical Research Council.

Shifting towards healthier transport: carrots or sticks? Systematic review and meta-analysis of population-level interventions

BACKGROUND

Promoting active travel can be beneficial for both health and the environment. However, evidence about the most effective strategies is inconsistent. We aimed to compare the effectiveness of interventions with positive (ie, carrot), negative (ie, stick), or a combination of strategies on changing population-level travel behaviour. We also aimed to identify which intervention functions, or mechanisms of how interventions seek to alter behaviour (eg, by addressing safety or accessibility), affect transport outcomes.

METHODS

For this systematic review and meta-analysis, we searched eight online databases for studies published before March 28, 2022: Web of Science, MEDLINE, Scopus, Applied Social Sciences Index and Abstracts, Global Health, PsycINFO, CINAHL, and Transport Research International Documentation. We did not restrict searches by language or publication date. We included controlled before-and-after studies of population-level interventions and travel behaviours (ie, driving, public transport, walking, and cycling) from adults in the general population. We categorised interventions according to their function. Depending on whether gains or losses due to intervention function could occur, we classified interventions as carrot (eg, new bike-share programmes), stick (eg, congestion charging), or combined carrot-and-stick interventions (eg, pedestrianising areas by use of reallocated parking space). We used harvest plots to summarise the findings and guide narrative synthesis. Where possible, we converted outcomes into standardised mean differences and did random-effects meta-analyses.

FINDINGS

From 38 916 records screened, 102 reports describing 121 interventions met the inclusion criteria. 79 interventions were carrots, 22 were carrot-and-sticks, and 20 were sticks. Results for carrot interventions were less consistent than for stick or combined interventions. Findings from the meta-analysis (64 reports describing 67 interventions) agreed with those in the narrative synthesis; although effects were statistically non-significant, for driving outcomes, interventions with stick strategies (standardised mean difference [SMD] -0·17, 95% CI -0·36 to 0·02) and combined carrot-and-stick strategies (-0·13, -0·47 to 0·20) had point estimates of greater magnitude than those for interventions with carrot strategies (-0·10, -0·23 to 0·03). Likewise, for active travel outcomes, combined carrot-and-stick strategies had a higher point estimate (0·33, -0·01 to 0·68) compared with carrot interventions (0·08, -0·05 to 0·21). Functions thought to change behaviour using financial means were effective at decreasing driving behaviour, whereas those improving access, safety, and space were effective for increasing active travel outcomes.

INTERPRETATION

This Article found that, although transport interventions with only positive strategies are more commonly evaluated, interventions that combine both positive and negative strategies might be more effective at encouraging alternatives to driving at the population level. Further research is needed for interventions involving a stick strategy, which remain less widely implemented or well studied than those with only carrot strategies.

FUNDING

Medical Research Council, Cambridge Trust.

Developing a core outcome set for physical activity interventions in primary schools: a modified-Delphi study

OBJECTIVES

To develop a core outcome set (COS) for physical activity interventions in primary schools.

DESIGN

Modified-Delphi study.

SETTING

The UK and international.

PARTICIPANTS

104 participants from four stakeholder groups (educators, public health professionals, health researchers, parents); 16 children (aged 8-9 years) from 1 London primary school.

INTERVENTIONS

Physical activity interventions.

METHODS

Four-stage process: (1) outcomes extracted from relevant studies identified from an umbrella review and a focus group; (2) list of outcomes produced and domains established; (3) stakeholders completed a two-round Delphi survey by rating (Round 1) and re-rating (Round 2) each outcome on a nine-point Likert Scale from 'not important' to 'critical': a>70% participant threshold identified the outcomes rated 'critical' to measure, and outcomes important to children were identified through a workshop; and (4) a stakeholder meeting to achieve consensus of the outcomes to include in the COS.

RESULTS

In total, 74 studies were extracted from 53 reviews. A list of 50 outcomes was produced and three domains were established: 'physical activity and health' (16 outcomes), 'social and emotional health' (22 outcomes) and 'educational performance' (12 outcomes). 104 participants completed survey Round 1; 65 participants completed both rounds. In total, 13 outcomes met the threshold; children identified 8 outcomes. Fourteen outcomes achieved consensus to produce the COS: five outcomes for physical activity and health (diet (varied and balanced), energy, fitness, intensity of physical activity, sleep (number of hours)); seven outcomes for social and emotional health (anxiety, depression, enjoyment, happiness, self-esteem, stress, well-being); and two outcomes for educational performance (concentration, focus).

CONCLUSIONS

We have developed the first COS for physical activity interventions in primary schools in consultation with those interested in the development and application of an agreed standardised set of outcomes. Future studies including these outcomes will reduce heterogeneity across studies.

TRIAL REGISTRATION NUMBER

Core Outcome Measures in Effectiveness Trials Initiative registration number 1322; Results.

Features of effective staff training programmes within school-based interventions targeting student activity behaviour: a systematic review and meta-analysis

BACKGROUND

Evaluations of school-based activity behaviour interventions suggest limited effectiveness on students' device-measured outcomes. Teacher-led implementation is common but the training provided is poorly understood and may affect implementation and student outcomes. We systematically reviewed staff training delivered within interventions and explored if specific features are associated with intervention fidelity and student activity behaviour outcomes.

METHODS

We searched seven databases (January 2015-May 2020) for randomised controlled trials of teacher-led school-based activity behaviour interventions reporting on teacher fidelity and/or students' device-measured activity behaviour. Pilot, feasibility and small-scale trials were excluded. Study authors were contacted if staff training was not described using all items from the Template for Intervention Description and Replication reporting guideline. Training programmes were coded using the Behaviour Change Technique (BCT) Taxonomy v1. The Effective Public Health Practice Project tool was used for quality assessment. Promise ratios were used to explore associations between BCTs and fidelity outcomes (e.g. % of intended sessions delivered). Differences between fidelity outcomes and other training features were explored using chi-square and Wilcoxon rank-sum tests. Random-effects meta-regressions were performed to explore associations between training features and changes in students' activity behaviour.

RESULTS

We identified 68 articles reporting on 53 eligible training programmes and found evidence that 37 unique teacher-targeted BCTs have been used (mean per programme = 5.1 BCTs; standard deviation = 3.2). The only frequently identified BCTs were 'Instruction on how to perform the behaviour' (identified in 98.1% of programmes) and 'Social support (unspecified)' (50.9%). We found moderate/high fidelity studies were significantly more likely to include shorter (≤6 months) and theory-informed programmes than low fidelity studies, and 19 BCTs were independently associated with moderate/high fidelity outcomes. Programmes that used more BCTs (estimated increase per additional BCT, d: 0.18; 95% CI: 0.05, 0.31) and BCTs 'Action planning' (1.40; 0.70, 2.10) and 'Feedback on the behaviour' (1.19; 0.36, 2.02) were independently associated with positive physical activity outcomes (N = 15). No training features associated with sedentary behaviour were identified (N = 11).

CONCLUSIONS

Few evidence-based BCTs have been used to promote sustained behaviour change amongst teachers in school-based activity behaviour interventions. Our findings provide insights into why interventions may be failing to effect student outcomes.

TRIAL REGISTRATION

PROSPERO registration number: CRD42020180624.

Associations between socioeconomic position and young people's physical activity and sedentary behaviour in the UK: a scoping review

OBJECTIVE

To examine the evidence on the associations between socioeconomic position and young people's physical activity and sedentary behaviours in the UK.

DESIGN

Scoping review.

DATA SOURCES

PubMed, SCOPUS and Web of Science databases were searched for articles published up to and including January 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Observational studies in children and adolescents (aged 5-18 years) from the UK that had assessed associations between at least one indicator of socioeconomic position and at least one outcome of physical activity and/or sedentary behaviour.

DATA EXTRACTION AND SYNTHESIS

Data were extracted by one reviewer and 20% were double checked. Indicators of socioeconomic position were tabulated with domains of physical activity and sedentary behaviour.

RESULTS

Fifty-seven publications were included in the review; 37 publications from 19 studies (k=23) of children and 21 publications from 15 studies (k=23) of adolescents. Most studies were cross-sectional. 63% of studies of children, and 40% of studies of adolescents assessed Index of Multiple Deprivation. Eighteen studies measured physical activity in children, 13 measured sedentary behaviour. Eleven studies of adolescents included a measure of physical activity, 10 included a measure of sedentary behaviour. Among children and adolescents, the association between socioeconomic position and measures of either physical activity or sedentary behaviour was highly variable depending on the measure of both socioeconomic position used and the behavioural outcome, with the exception of higher family affluence which was consistently associated with higher reported physical activity among adolescents.

CONCLUSION

Physical activity and sedentary behaviours of children and adolescents in the UK are complex and influenced by multiple indicators of socioeconomic position that are, in most cases, different across age stages, outcomes examined and measurement tools. Greater consistency in the use and measures of socioeconomic position as well as outcomes of behaviour are required for robust country-specific meta-analyses.

Cross-sectional and longitudinal associations of active travel, organised sport and physical education with accelerometer-assessed moderate-to-vigorous physical activity in young people: the International Children's Accelerometry Database

BACKGROUND

Physical activity (PA) declines during childhood. Important sources of PA are active travel, organised sport and physical education (PE), but it is unclear how these domain-specific PA sources contribute to (changes in) daily moderate-to-vigorous PA (MVPA) in young people. This study aimed to examine (1) the cross-sectional association between domain-specific physical activity (i.e., active travel, organised sport and PE) and daily minutes in accelerometer-assessed MVPA; and (2) the longitudinal association between domain-specific physical activity at baseline and change in daily minutes in MVPA.

METHODS

Participants (baseline age 11.3 ± .1.2 years) were drawn from three studies in the International Children's Accelerometry Database. The contribution of self-reported standardised active travel, organised sport and PE to accelerometer-measured daily minutes in MVPA was examined using linear regression. In cross-sectional analyses, MVPA was regressed on each PA domain in separate models, adjusted for study, age, sex, maternal education, season, and monitor wear time. In longitudinal analyses, change in MVPA was regressed on each of the baseline PA domains, additionally adjusting for changes in season and wear time, follow-up duration, and baseline MVPA. R-squared was used to compare variance explained by each PA domain.

RESULTS

In the cross-sectional analyses (n = 3871), organised sport (standardised β = 3.81, 95% confidence interval [95%CI] = 3.06, 4.56) and active travel (β = 3.46, 95%CI = 2.73, 4.19) contributed more to daily MVPA than PE (β = 0.82, 95%CI = -0.02, 1.66). Compared to the base model which included only covariates (R2 = 21.5%), organised sport (absolute change: + 1.9%) and active travel (+ 1.7%) models explained more of the variance than the PE model (± < 0.1%). Associations followed a similar pattern in the longitudinal analyses (n = 2302), but none of the PA domains predicted change in MVPA (organised sport: standardised β = 0.85, 95%CI = -0.03, 1.72; active travel: β = 0.68, 95%CI = -0.14, 1.50; PE: β = 0.02, 95%CI = -0.87, 0.91).

CONCLUSIONS

A multi-sectoral approach covering a wide range of PA domains should be promoted to minimise the age-related decline in MVPA during childhood.

Do adolescents' experiences of the barriers to and facilitators of physical activity differ by socioeconomic position? A systematic review of qualitative evidence

This review aims to systematically identify and synthesize qualitative data on adolescents' experiences of the barriers to and facilitators of physical activity to understand whether these differ by socioeconomic position. Multiple databases (MEDLINE, Web of Science Core Collection, PsycINFO, and ERIC) were searched in August 2020. Duplicate title/abstract and full text screening was conducted. Studies were included if they reported qualitative data collected from adolescents (aged 10-19), a measure of socioeconomic position and focused on physical activity. Studies not published in English or published before 2000 were excluded. Relevant data were extracted and methodological quality assessed (in duplicate). Data were analyzed using Thomas and Harden's methods for the thematic synthesis. Four analytical themes emerged from the 25 included studies: (1) social support, (2) accessibility and the environment, (3) other behaviors and health, and (4) gendered experiences. These themes appeared across socioeconomic groups; however, their narratives varied significantly. For example, provision and access to local facilities was discussed as a facilitator to middle and high socioeconomic adolescents, but was a barrier to low socioeconomic adolescents. These findings can be used to inform how different socioeconomic groups may benefit from, or be disadvantaged by, current interventions.

Impact of risk of generalizability biases in adult obesity interventions: A meta-epidemiological review and meta-analysis

Biases introduced in early-stage studies can lead to inflated early discoveries. The risk of generalizability biases (RGBs) identifies key features of feasibility studies that, when present, lead to reduced impact in a larger trial. This meta-study examined the influence of RGBs in adult obesity interventions. Behavioral interventions with a published feasibility study and a larger scale trial of the same intervention (e.g., pairs) were identified. Each pair was coded for the presence of RGBs. Quantitative outcomes were extracted. Multilevel meta-regression models were used to examine the impact of RGBs on the difference in the effect size (ES, standardized mean difference) from pilot to larger scale trial. A total of 114 pairs, representing 230 studies, were identified. Overall, 75% of the pairs had at least one RGB present. The four most prevalent RGBs were duration (33%), delivery agent (30%), implementation support (23%), and target audience (22%) bias. The largest reductions in the ES were observed in pairs where an RGB was present in the pilot and removed in the larger scale trial (average reduction ES -0.41, range -1.06 to 0.01), compared with pairs without an RGB (average reduction ES -0.15, range -0.18 to -0.14). Eliminating RGBs during early-stage testing may result in improved evidence.

CHoosing Active Role Models to INspire Girls (CHARMING): protocol for a cluster randomised feasibility trial of a school-based, community-linked programme to increase physical activity levels in 9-10-year-old girls

Background

In the UK, there is evidence that girls’ physical activity tends to decline to a greater extent than boys as they enter adolescence. ‘Role models’ could play a vital role in inspiring girls to become or remain physically active. The CHARMING Programme is a primary school-based community linked role-model programme, co-developed in 2016, with children, parents, schools and wider stakeholders. It involves different types of physical activity delivered for 1-h each week by a community provider and peer role models (e.g. older girls from secondary schools) joining in with the sessions. The programme ultimately aims to increase and sustain physical activity levels among 9–10-year-old girls. This study aims to assess the feasibility and acceptability of the CHARMING Programme and of evaluating it using a randomised trial.

Methods

This study is a feasibility cluster randomised controlled trial, with embedded process evaluation and health economic evaluation. Approximately 90 Year 5 (i.e. 9–10-year-old) girls will be recruited across six primary schools in Mid-South Wales. Participating schools will be allocated to the programme: control on a 2:1 basis; four intervention schools will run the CHARMING Programme and two will continue with usual practice. A survey and accelerometer will be administered at baseline and repeated at 12 months. Interviews and focus groups will be conducted post-intervention delivery. The primary aim is to assess feasibility of a future randomised trial via the recruitment of schools, participants and role models; randomisation; retention; reach; data collection completion rates; programme adherence; and programme fidelity, views on intervention acceptability and programme barriers and facilitators. Secondary aims are to evaluate established physical activity outcome measures for children plus additional health economic outcomes for inclusion in a future full-scale trial.

Discussion

The results of this study will inform decisions on whether and how to proceed to a full-scale evaluation of the effectiveness and cost-effectiveness of the CHARMING Programme to improve or sustain physical activity.

Trial registration

ClinicalTrials.gov ISRCTN36223327. Registered March 29, 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00961-6.

Impact of The Daily Mile on children's physical and mental health, and educational attainment in primary schools: iMprOVE cohort study protocol

INTRODUCTION

School-based active mile initiatives such as The Daily Mile (TDM) are widely promoted to address shortfalls in meeting physical activity recommendations. The iMprOVE Study aims to examine the impact of TDM on children's physical and mental health and educational attainment throughout primary school. METHODS AND ANALYSIS: iMprOVE is a longitudinal quasi-experimental cohort study. We will send a survey to all state-funded primary schools in Greater London to identify participation in TDM. The survey responses will be used for non-random allocation to either the intervention group (Daily Mile schools) or to the control group (non-Daily Mile schools). We aim to recruit 3533 year 1 children (aged 5-6 years) from 77 primary schools and follow them up annually until the end of their primary school years. Data collection taking place at baseline (children in school year 1) and each primary school year thereafter includes device-based measures of moderate-to-vigorous physical activity (MVPA) and questionnaires to measure mental health (Strengths and Difficulties Questionnaire) and educational attainment (ratings from 'below expected' to 'above expected levels'). The primary outcome is the mean change in MVPA minutes from baseline to year 6 during the school day among the intervention group compared with controls. We will use multilevel linear regression models adjusting for sociodemographic data and participation in TDM. The study is powered to detect a 10% (5.5 min) difference between the intervention and control group which would be considered clinically significant.

ETHICS AND DISSEMINATION

Ethics has been approved from Imperial College Research Ethics Committee, reference 20IC6127. Key findings will be disseminated to the public through research networks, social, print and media broadcasts, community engagement opportunities and schools. We will work with policy-makers for direct application and impact of our findings.

Cycle training and factors associated with cycling among adolescents in England

BACKGROUND

Cycling has the potential to encourage physical activity as well as advancing societal goals such as reducing carbon emissions; encouraging cycling is therefore a policy goal in many contexts. We analysed individual level data from the whole of England on factors associated with cycling among adolescents, including cycle training delivered by the age of 11 years in primary schools.

METHODS

Data came from the nationally representative Millennium Cohort Study collected when participants were aged 13-15 years (adolescents). We assessed frequency of cycling at least once per week (regular cycling) and used logistic regression to assess how this differed across characteristics including demographic, health and environmental factors, as well as receiving cycle training ('Bikeability') in primary school.

RESULTS

We found that 21.0% of adolescents cycled at least once per week. In fully adjusted analyses, this was more common among boys than girls (32.5% vs. 9.4%, p < 0.001), and those in rural areas than urban areas (24.9% vs. 20.3%, p < 0.001). Adolescents in areas with higher prevalence of adult cycle commuting were more likely to cycle regularly (26.1% in high cycling areas vs. 19.3% in low cycling areas, p < 0.001). Participants offered cycle training in primary school were not more likely to cycle regularly as adolescents (21.7% vs. 22.3%, p = 0.528).

DISCUSSION

Approximately one in five adolescents in England cycles regularly, although being offered cycle training in primary school was not linked to greater cycling. Many of the factors associated with adolescent cycling are similar to those for adults and adolescents are more likely to cycle in areas with higher levels of adult cycling.

Identification and evaluation of risk of generalizability biases in pilot versus efficacy/effectiveness trials: a systematic review and meta-analysis

BACKGROUND

Preliminary evaluations of behavioral interventions, referred to as pilot studies, predate the conduct of many large-scale efficacy/effectiveness trial. The ability of a pilot study to inform an efficacy/effectiveness trial relies on careful considerations in the design, delivery, and interpretation of the pilot results to avoid exaggerated early discoveries that may lead to subsequent failed efficacy/effectiveness trials. "Risk of generalizability biases (RGB)" in pilot studies may reduce the probability of replicating results in a larger efficacy/effectiveness trial. We aimed to generate an operational list of potential RGBs and to evaluate their impact in pairs of published pilot studies and larger, more well-powered trial on the topic of childhood obesity.

METHODS

We conducted a systematic literature review to identify published pilot studies that had a published larger-scale trial of the same or similar intervention. Searches were updated and completed through December 31st, 2018. Eligible studies were behavioral interventions involving youth (≤18 yrs) on a topic related to childhood obesity (e.g., prevention/treatment, weight reduction, physical activity, diet, sleep, screen time/sedentary behavior). Extracted information included study characteristics and all outcomes. A list of 9 RGBs were defined and coded: intervention intensity bias, implementation support bias, delivery agent bias, target audience bias, duration bias, setting bias, measurement bias, directional conclusion bias, and outcome bias. Three reviewers independently coded for the presence of RGBs. Multi-level random effects meta-analyses were performed to investigate the association of the biases to study outcomes.

RESULTS

A total of 39 pilot and larger trial pairs were identified. The frequency of the biases varied: delivery agent bias (19/39 pairs), duration bias (15/39), implementation support bias (13/39), outcome bias (6/39), measurement bias (4/39), directional conclusion bias (3/39), target audience bias (3/39), intervention intensity bias (1/39), and setting bias (0/39). In meta-analyses, delivery agent, implementation support, duration, and measurement bias were associated with an attenuation of the effect size of - 0.325 (95CI - 0.556 to - 0.094), - 0.346 (- 0.640 to - 0.052), - 0.342 (- 0.498 to - 0.187), and - 0.360 (- 0.631 to - 0.089), respectively.

CONCLUSIONS

Pre-emptive avoidance of RGBs during the initial testing of an intervention may diminish the voltage drop between pilot and larger efficacy/effectiveness trials and enhance the odds of successful translation.

Using a multi-stakeholder experience-based design process to co-develop the Creating Active Schools Framework

BACKGROUND

UK and global policies recommend whole-school approaches to improve childrens' inadequate physical activity (PA) levels. Yet, recent meta-analyses establish current interventions as ineffective due to suboptimal implementation rates and poor sustainability. To create effective interventions, which recognise schools as complex adaptive sub-systems, multi-stakeholder input is necessary. Further, to ensure 'systems' change, a framework is required that identifies all components of a whole-school PA approach. The study's aim was to co-develop a whole-school PA framework using the double diamond design approach (DDDA).

METHODOLOGY

Fifty stakeholders engaged in a six-phase DDDA workshop undertaking tasks within same stakeholder (n = 9; UK researchers, public health specialists, active schools coordinators, headteachers, teachers, active partner schools specialists, national organisations, Sport England local delivery pilot representatives and international researchers) and mixed (n = 6) stakeholder groupings. Six draft frameworks were created before stakeholders voted for one 'initial' framework. Next, stakeholders reviewed the 'initial' framework, proposing modifications. Following the workshop, stakeholders voted on eight modifications using an online questionnaire.

RESULTS

Following voting, the Creating Active Schools Framework (CAS) was designed. At the centre, ethos and practice drive school policy and vision, creating the physical and social environments in which five key stakeholder groups operate to deliver PA through seven opportunities both within and beyond school. At the top of the model, initial and in-service teacher training foster teachers' capability, opportunity and motivation (COM-B) to deliver whole-school PA. National policy and organisations drive top-down initiatives that support or hinder whole-school PA. To the authors' knowledge, this is the first time practitioners, policymakers and researchers have co-designed a whole-school PA framework from initial conception. The novelty of CAS resides in identifying the multitude of interconnecting components of a whole-school adaptive sub-system; exposing the complexity required to create systems change. The framework can be used to shape future policy, research and practice to embed sustainable PA interventions within schools. To enact such change, CAS presents a potential paradigm shift, providing a map and method to guide future co-production by multiple experts of PA initiatives 'with' schools, while abandoning outdated traditional approaches of implementing interventions 'on' schools.

Protocol for developing a core outcome set for evaluating school-based physical activity interventions in primary schools

INTRODUCTION

Primary school-based physical activity interventions, such as The Daily Mile initiative, have the potential to increase children's physical activity levels over time, which is associated with a variety of health benefits. Comparing interventions or combining results of several studies of a single intervention is challenging because previous studies have examined different outcomes or used different measures that are not feasible or relevant for researchers in school settings. The development and implementation of a core outcome set (COS) for primary school-based physical activity interventions would ensure outcomes important to those involved in implementing and evaluating interventions are standardised.

METHODS AND ANALYSIS

Our aim is to develop a COS for studies of school-based physical activity interventions. We will achieve this by undertaking a four-stage process:(1) identify a list of outcomes assessed in studies through a systematic review of international literature; (2) establish domains from these outcomes to produce questionnaire items; (3) prioritise outcomes through a two-stage Delphi survey with four key stakeholder groups (researchers, public health professionals, educators and parents), where stakeholders rate the importance of each outcome on a 9-point Likert scale (consensus that the outcomes should be included in the COS will be determined as 70% or more of all stakeholders scoring the outcome 7%-9% and 15% or less scoring 1 to 3); (4) achieve consensus on a final COS in face-to-face meetings with a sample of stakeholders and primary school children.

ETHICS AND DISSEMINATION

We have received ethical approval from Imperial College London (ref: 19IC5428). The results of this study will be disseminated via conference presentations/public health meetings, peer-reviewed publications and through appropriate media channels.

TRIAL REGISTRATION NUMBER

Core Outcome Measures in Effectiveness Trials Initiative (COMET) number: 1322.

Whole family-based physical activity promotion intervention: the Families Reporting Every Step to Health pilot randomised controlled trial protocol

INTRODUCTION

Family-based physical activity (PA) interventions present a promising avenue to promote children's activity; however, high-quality experimental research is lacking. This paper describes the protocol for the FRESH (Families Reporting Every Step to Health) pilot trial, a child-led family-based PA intervention delivered online.

METHODS AND ANALYSIS

FRESH is a three-armed, parallel-group, randomised controlled pilot trial using a 1:1:1 allocation ratio with follow-up assessments at 8 and 52 weeks postbaseline. Families will be eligible if a minimum of one child in school Years 3-6 (aged 7-11 years) and at least one adult responsible for that child are willing to participate. Family members can take part in the intervention irrespective of their participation in the accompanying evaluation and vice versa.Following baseline assessment, families will be randomly allocated to one of three arms: (1) FRESH; (2) pedometer-only or (3) no-intervention control. All family members in the pedometer-only and FRESH arms receive pedometers and generic PA promotion information. FRESH families additionally receive access to the intervention website; allowing participants to select step challenges to 'travel' to target cities around the world, log steps and track progress as they virtually globetrot. Control families will receive no treatment. All family members will be eligible to participate in the evaluation with two follow-ups (8 and 52 weeks). Physical (eg, fitness and blood pressure), psychosocial (eg, social support) and behavioural (eg, objectively measured family PA) measures will be collected at each time point. At 8-week follow-up, a mixed methods process evaluation will be conducted (questionnaires and family focus groups) assessing acceptability of the intervention and evaluation. FRESH families' website engagement will also be explored.

ETHICS AND DISSEMINATION

This study received ethical approval from the Ethics Committee for the School of the Humanities and Social Sciences at the University of Cambridge. Findings will be disseminated via peer-reviewed publications, conferences and to participating families.

TRIAL REGISTRATION NUMBER

ISRCTN12789422.

Cost-effectiveness of physical activity interventions in adolescents: model development and illustration using two exemplar interventions

OBJECTIVE

To develop a model to assess the long-term costs and health outcomes of physical activity interventions targeting adolescents.

DESIGN

A Markov cohort simulation model was constructed with the intention of being capable of estimating long-term costs and health impacts of changes in activity levels during adolescence. The model parameters were informed by published literature and the analysis took a National Health Service perspective over a lifetime horizon. Univariate and probabilistic sensitivity analyses were undertaken.

SETTING

School and community.

PARTICIPANTS

A hypothetical cohort of adolescents aged 16 years at baseline.

INTERVENTIONS

Two exemplar school-based: a comparatively simple, after-school intervention and a more complex multicomponent intervention compared with usual care.

PRIMARY AND SECONDARY OUTCOME MEASURES

Incremental cost-effectiveness ratio as measured by cost per quality-adjusted life year gained.

RESULTS

The model gave plausible estimates of the long-term effect of changes in physical activity. The use of two exemplar interventions suggests that the model could potentially be used to evaluate a number of different physical activity interventions in adolescents. The key model driver was the degree to which intervention effects were maintained over time.

CONCLUSIONS

The model developed here has the potential to assess long-term value for money of physical activity interventions in adolescents. The two applications of the model indicate that complex interventions may not necessarily be the ones considered the most cost-effective when longer-term costs and consequences are taken into account.

Socioeconomic and ethnic differences in children's vigorous intensity physical activity: a cross-sectional analysis of the UK Millennium Cohort Study

OBJECTIVE

To investigate if daily vigorous physical activity (VPA), adjusted for minutes of moderate physical activity (MPA) performed, differs by socioeconomic position or ethnicity in a large sample of UK children with objectively measured physical activity.

DESIGN

Nationally representative prospective cohort study.

SETTING

UK children born between 2000 and 2002.

PARTICIPANTS

5172 children aged 7-8 with valid accelerometer data for ≥10 hour on ≥3 days, including 1 weekend day.

MAIN OUTCOME MEASURES

Time spent in VPA (>3841 counts per min).

EXPLANATORY MEASURES

Maternal education, annual household Organisation for Economic Co-Operation and Development equivalised income, ethnicity.

RESULTS

Multivariable linear regression models fitted to explore differences in average daily minutes of VPA (adjusted for MPA, mean accelerometer wear time, season of measurement, age and sex), revealed significantly higher amounts of VPA accumulated as a child's socioeconomic position increased (highest vs lowest level of maternal education: β: 2.96, p: 0.00; annual household equivalised income: β: 0.58, p: 0.00, per £10 000 annual increase). Additionally, children from certain minority ethnicities (Bangladeshi and Pakistani: β: -3.34, p: 0.00; other ethnic groups: β:-2.27, p: 0.02) accrued less daily VPA compared with their white British counterparts.

CONCLUSIONS

The socioeconomic and ethnic patterning of vigorous activity observed in this study mirrors parallel inequalities in rates of childhood obesity. Given the stronger association of VPA with adiposity than of MPA, intensity specific differences may be contributing to widening inequalities in obesity. Accordingly, these findings suggest that the current global focus on overall moderate-to-vigorous intensity activity may mask important behavioural inequalities.

Introducing physically active lessons in UK secondary schools: feasibility study and pilot cluster-randomised controlled trial

OBJECTIVES

Assess feasibility, acceptability and costs of delivering a physically active lessons (PAL) training programme to secondary school teachers and explore preliminary effectiveness for reducing pupils' sedentary time.

DESIGN AND SETTING

Secondary schools in East England; one school participated in a pre-post feasibility study, two in a pilot cluster-randomised controlled trial. In the pilot trial, blinding to group assignment was not possible.

PARTICIPANTS

Across studies, 321 randomly selected students (51% male; mean age: 12.9 years), 78 teachers (35% male) and 2 assistant head teachers enrolled; 296 (92%) students, 69 (88%) teachers and 2 assistant head teachers completed the studies.

INTERVENTION

PAL training was delivered to teachers over two after-school sessions. Teachers were made aware of how to integrate movement into lessons; strategies included students collecting data from the environment for class activities and completing activities posted on classroom walls, instead of sitting at desks.

PRIMARY AND SECONDARY OUTCOMES

Quantitative and qualitative data were collected to assess feasibility and acceptability of PAL training and delivery. Outcomes were assessed at baseline and ~8 weeks post-training; measures included accelerometer-assessed activity, self-reported well-being and observations of time-on-task. Process evaluation was conducted at follow-up.

RESULTS

In the feasibility study, teachers reported good acceptability of PAL training and mixed experiences of delivering PAL. In the pilot study, teachers' acceptability of training was lower and teachers identified aspects of the training in need of review, including the outdoor PAL training and learning challenge of PAL strategies. In both studies, students and assistant head teachers reported good acceptability of the intervention. Preliminary effectiveness for reducing students' sedentary time was not demonstrated in either study.

CONCLUSIONS

No evidence of preliminary effectiveness on the primary outcome and mixed reports of teachers' acceptability of PAL training suggest the need to review the training. The results do not support continuation of research with the current intervention.

TRIAL REGISTRATION NUMBER

ISRCTN38409550.

Network Interventions for Changing Physical Activity Behaviour in Preadolescents

Network interventions can help achieve behavioural change by inducing peer-pressure in the network. However, inducing peer-pressure without considering the structure of the existing social network may render the intervention ineffective or weaker. In a 7-week school-based field experiment using preadolescents' physical activity (PA) as a proxy for estimating behavioural change, we test the hypothesis that boys' and girls' distinct networks are susceptible to different social incentives. We run three different social-rewards schemes, in which classmates' rewards depend on the PA of two friends either reciprocally (directly or indirectly) or collectively. Compared to a random-rewards control, social-rewards schemes had an overall significantly positive effect on PA (51.8% increase), with females being more receptive to the direct reciprocity scheme (76.4%) and males to team (collective) rewards (131.5%). Differences in the sex-specific sub-networks can explain these findings. Network interventions adapted to the network-specific characteristics may constitute a powerful tool for behavioural change.

Change in physical activity from adolescence to early adulthood: a systematic review and meta-analysis of longitudinal cohort studies

Objective

To systematically review and meta-analyse how physical activity (PA) changes from adolescence to early adulthood (13–30 years).

Data sources

Seven electronic databases were searched: Medline, Embase, PsycInfo, SCOPUS, ASSIA, SPORTdiscus and Web of Science.

Eligibility criteria for selecting studies

English-language, longitudinal studies (from 01/1980 to 01/2017) assessing PA ≥twice, with the mean age of ≥1 measurement in adolescence (13–19 years) and ≥1 in young adulthood (16–30 years) were included. Where possible, data were converted to moderate-to-vigorous physical activity (MVPA) min/day, and meta-analyses were conducted between weighted mean differences (WMDs) in adolescence and adulthood. Heterogeneity was explored using meta-regression.

Results

Of 67 included studies, 49 were eligible for meta-analysis. PA was lower during adulthood than adolescence WMD (95% CI) −5.2 (−7.3 to –3.1) min/day MVPA over mean (SD) 3.4 (2.6) years; heterogeneity was high (I² >99.0%), and no predictors explained this variation (all p>0.05). When we restricted analysis to studies with data for males (n=29) and females (n=30) separately, there were slightly larger declines in WMD (−6.5 (−10.6 to –2.3) and −5.5 (−8.4 to −2.6) min/day MVPA) (both I² >99.0%). For studies with accelerometer data (n=9), the decline was −7.4 (−11.6 to –3.1) and longer follow-up indicated more of a decline in WMD (95% CI) (−1.9 (−3.6 to –0.2) min/day MVPA), explaining 27.0% of between-study variation. Of 18 studies not eligible for meta-analysis, nine statistically tested change over time: seven showed a decline and two showed no change.

Conclusion

PA declines modestly between adolescence and young adulthood. More objective longitudinal PA data (eg, accelerometry) over this transition would be valuable, as would investigating how PA change is associated with contemporaneous social transitions to better inform PA promotion interventions.

Registration

PROSPERO ref:CRD42015030114.

Association between birth weight and objectively measured sedentary time is mediated by central adiposity: data in 10,793 youth from the International Children's Accelerometry Database

BACKGROUND

Birth weight is an early correlate of disease later in life, and animal studies suggest that low birth weight is associated with reduced activity and increased sedentary time. Whether birth weight predicts later sedentary time in humans is uncertain.

OBJECTIVES

We examined the relation between birth weight and sedentary time in youth and examined whether this association was mediated by central adiposity.

DESIGN

We used pooled cross-sectional data from 8 observational studies conducted between 1997 and 2007 that consisted of 10,793 youth (boys: 47%) aged 6-18 y from the International Children's Accelerometry Database. Birth weight was measured in hospitals or maternally reported, sedentary time was assessed by using accelerometry (<100 counts/min), and abdominal adiposity (waist circumference) was measured according to WHO procedures. A mediation analysis with bootstrapping was used to analyze data.

RESULTS

The mean (±SD) time spent sedentary was 370 ± 91 min/d. Birth weight was positively associated with sedentary time (B = 4.04, P = 0.006) and waist circumference (B = 1.59, P < 0.001), whereas waist circumference was positively associated with sedentary time (B = 0.82, P < 0.001). Results of the mediation analysis showed a significant indirect effect of birth weight on sedentary time through waist circumference (B: 1.30; 95% bias-corrected CI: 0.94, 1.72), and when waist circumference was controlled for, the effect of birth weight on sedentary time was attenuated by 32% (B = 2.74, P = 0.06).

CONCLUSION

The association between birth weight and sedentary time appears partially mediated by central adiposity, suggesting that both birth weight and abdominal adiposity may be correlates of sedentary time in youth.

Family-based interventions to increase physical activity in children: a meta-analysis and realist synthesis protocol

INTRODUCTION

Despite the established relationship between physical activity and health, data suggest that many children are insufficiently active, and that levels decline into adolescence. Engaging the family in interventions may increase and maintain children's physical activity levels at the critical juncture before secondary school. Synthesis of existing evidence will inform future studies, but the heterogeneity in target populations recruited, behaviour change techniques and intervention strategies employed, and measurement conducted, may require a multifaceted review method. The primary objective of this work will therefore be to synthesis evidence from intervention studies that explicitly engage the family unit to increase children's physical activity using an innovative dual meta-analysis and realist approach.

METHODS AND ANALYSIS

Peer-reviewed studies will be independently screened by two authors for inclusion based on (1) including 'healthy' participants aged 5-12 years; (2) having a substantive intervention aim of increasing physical activity, by engaging the family and (3) reporting on physical activity. Duplicate data extraction and quality assessment will be conducted using a specially designed proforma and the Effective Public Health Practice Project Quality Assessment Tool respectively. STATA software will be used to compute effect sizes for meta-analyses, with subgroup analyses conducted to identify moderating characteristics. Realist syntheses will be conducted according to RAMESES quality and publication guidelines, including development of a programme theory and evidence mapping.

DISSEMINATION

This review will be the first to use the framework of a traditional review to conduct a dual meta-analysis and realist synthesis, examining interventions that engage the family to increase physical activity in children. The results will be disseminated through peer-reviewed publications, conferences, formal presentations to policy makers and practitioners and informal meetings. Evidence generated from this synthesis will also be used to inform the development of theory-driven, evidence-based interventions aimed at engaging the family to increase physical activity levels in children.

PROTOCOL REGISTRATION

International Prospective Register for Systematic Reviews (PROSPERO): number CRD42013005780.

Changes in household, transport and recreational physical activity and television viewing time across the transition to retirement: longitudinal evidence from the EPIC-Norfolk cohort

Background

Retirement is associated with an increase in recreational physical activity but its impact on other domains of activity (at home, for transport) and sedentary behaviour, such as time spent watching television (TV) is unknown. We examined the association between retirement and changes in domain-specific and overall activity and TV viewing.

Methods

Data were derived from the population-based EPIC (European Prospective Investigation into Cancer)–Norfolk cohort. Physical activity and TV viewing time were self-reported at baseline (1997–2000) and follow-up 2 (2006–2007) by 3334 participants employed at baseline, of whom 785 (24%) were retired at follow-up 1 (2002–2006). Multivariable regression models were fitted to estimate the association between retirement and changes in physical activity and weekly TV viewing time.

Results

Compared with continued employment, retirement was associated with a decline in overall activity (men: non-manual, −40.9 MET h/wk; manual, −49.6 MET h/wk; women: non-manual, −26.9 MET h/wk; manual, −31.6 MET h/wk; all p<0.001 (MET, metabolic equivalent of task)). Domain-specific activity declined for transport and occupational (p<0.001) and increased for recreational (p<0.02) and household (p≤0.002) activity. We observed significant interaction between retirement and social class in respect of overall and domain-specific activity apart from household activity. Retirement was associated with a mean increase in TV viewing time, with the largest increase among manual social classes (men: +3.9 h/wk; women: +2.8 h/wk; both p<0.001).

Conclusions

Interventions should aim to promote household and transport as well as recreational activity. Further research on the impact of retirement on sedentary behaviour is needed.

Protocol for systematic reviews of determinants/correlates of obesity-related dietary and physical activity behaviors in young children (preschool 0 to 6 years): evidence mapping and syntheses

BACKGROUND

The aim of these reviews is to inform the design and content of interventions to reduce obesity in young children. The behaviors that are associated with obesity/overweight have been studied extensively; however, the factors associated with these behaviors in young children (0 to 6 years) have not been systematically reviewed. Over the past few years the focus of obesity prevention has shifted to preschool children because of the high prevalence of obesity at school entry and recognition that habits formed in early life could track into adulthood. In order to develop effective interventions and change behavior, it is important to understand the factors that are associated with those behaviors. For example, we need to understand whether it would be more important to target the family, childcare settings or the wider environment and identify the most effective way of changing these energy balance related behaviors.

METHODS/DESIGN

Quantitative (intervention and observational) and qualitative literature on determinants/correlates of fruit and vegetable intake, sugar sweetened beverage and other unhealthy diet intake, and physical activity and sedentary behaviors in young children will be systematically identified, mapped and reviewed. A common search strategy (no language or period restrictions) will be used to identify papers from eight electronic databases and this will be supplemented by hand-searching. Next, studies in developed countries that examine the factors associated with these behaviors in children aged 0 to 6 years (at baseline) will be screened and mapped descriptively followed by in-depth data extraction, quality assessment and synthesis. Data from quantitative studies will be summarized using either forest plots or harvest plots and narrative synthesis, and qualitative studies using thematic analysis. Qualitative evidence will be integrated with the quantitative evidence, using a parallel synthesis approach, to provide a deeper understanding of effective strategies to influence these energy balance related behaviors.

DISCUSSION

In addition to updating and mapping current research, these reviews will be the first to comprehensively synthesize and integrate both the quantitative and qualitative evidence pertaining to determinants/correlates/barriers/facilitators of obesity related behaviors in this young age group (0 to 6 years) with the aim of informing future interventions.

TRIAL REGISTRATION

International Prospective Register for Systematic Reviews (PROSPERO) Registration number: CRD42012002881.

Is environmental setting associated with the intensity and duration of children's physical activity? Findings from the SPEEDY GPS study

Using a sample of English school children, we use accelerometery and global positioning systems to identify whether different intensities of activity (light, moderate, and vigorous) occur in different environments, and whether environments for bouts of moderate to vigorous activity (MVPA) vary from those for non-bout MVPA. We find that land uses such as buildings and roads and pavements were generally used for light activity, whilst green environments such as gardens, parks, grassland and farmland appear supportive of vigorous activity. Built land uses such as hard surface play areas were particularly used for activity of short duration. Future work may consider differentiating light activity from moderate and vigorous, and separating bout and non-bout MVPA to better identify environmental supportiveness for activity in children.

Is a change in mode of travel to school associated with a change in overall physical activity levels in children? Longitudinal results from the SPEEDY study

Background

Children who use active modes of travel (walking or cycling) to school are more physically active than those who use passive (motorised) modes. However, less is known on whether a change in mode of travel to school is associated with a change in children’s physical activity levels. The purpose of this analysis was to investigate the association between change in mode of travel to school and change in overall physical activity levels in children.

Methods

Data from 812 9–10 year old British children (59% girls) who participated in the SPEEDY study were analysed. During the summer terms of 2007 and 2008 participants completed a questionnaire and wore an accelerometer for at least three days. Two-level multiple linear regression models were used to explore the association between change in usual mode of travel to school and change in objectively measured time spent in MVPA.

Results

Compared to children whose reported mode of travel did not change, a change from a passive to an active mode of travel was associated with an increase in daily minutes spent in MVPA (boys: beta 11.59, 95% CI 0.94 to 22.24; girls: beta 11.92, 95% CI 5.00 to 18.84). This increase represented 12% of boys’ and 13% of girls’ total daily time spent in MVPA at follow-up.

Conclusion

This analysis provides further evidence that promoting active travel to school may have a role in contributing to increasing physical activity levels in children.

Is active travel to non-school destinations associated with physical activity in primary school children?

OBJECTIVE

To examine associations between mode of travel to non-school destinations and physical activity in schoolchildren.

METHOD

Analyses of data from SPEEDY, an observational study of 9-10 year old British children. In summer 2007, children reported their usual mode of travel to four destinations (to visit family, friends, the park or the shops) and wore accelerometers for at least three days. Time spent in moderate to vigorous physical activity (MVPA) was computed for the following time segments: daily, after school, weekend and out-of-school. Associations between mode of travel and physical activity were assessed using adjusted two-level multiple regression models stratified by sex.

RESULTS

1859 pupils provided valid data. Boys who used active modes of travel spent significantly more time in MVPA in all time segments than boys who used passive modes. The median daily time spent in MVPA was 87 minutes (IQR 68-106) for active travellers and 76 minutes (IQR 60-93) for passive travellers. In girls, median time spent in MVPA after school was significantly higher in the active (34 minutes (IQR 27-44)) than the passive travellers (29 minutes (IQR 22-37)).

CONCLUSION

Active travel to non-school destinations is associated with higher overall physical activity levels in 9-10 year old schoolchildren.