Physical activity and dietary behaviour in a population-based sample of British 10-year old children: the SPEEDY study (Sport, Physical activity and Eating behaviour: environmental Determinants in Young people)

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.

The Challenge of Incomplete Data in Accelerometer Studies: Characteristics of Nonparticipation and Noncompliance in a Nationwide Sample of Adolescents and Young Adults in Germany

BACKGROUND

Incomplete data due to nonparticipation and noncompliance with the study protocol can bias the results of studies. We investigated how a nationwide accelerometer sample of adolescents and young adults is affected by such incomplete data.

METHODS

We analyzed cross-sectional data from 6465 participants (11-31 y old) who participated in a national health survey in Germany (KiGGS Wave 2; 2014-2017). The data included information about the participation in the measurement of physical activity using accelerometers, compliance with the wear-time protocol, and sociodemographic and health-related variables. Multivariable regression analyses were conducted to detect factors associated with incomplete data.

RESULTS

Of the total sample, 78.0% participated in the accelerometer part of the study, and 83.5% of the participants with data available complied with the wear-time protocol. In 11- to 17-year-olds, the likelihood of having incomplete accelerometer data was higher in boys, older adolescents, adolescents with a lower sociodemographic status, adolescents with overweight, adolescents not participating in organized sport, adolescents not speaking only German at home, current smokers, and adolescents having a higher soft drink consumption. In 18- to 31-year-olds, the likelihood of having incomplete accelerometer data was higher in men, adults with a lower educational level, adults not speaking only German at home, and adults who smoke.

CONCLUSIONS

Our results suggest that accelerometer samples are biased such that participants with more beneficial health behaviors provide complete accelerometer data more often. This knowledge should be used to design effective recruitment strategies and should be considered when interpreting results of accelerometer studies.

Associations between the built environment, policies and curriculum in schools and primary school children’s physical activity

Background: A large proportion of children in the UK do not engage in the recommended amount of physical activity. Schools are an environment where children spend a considerable portion of their time and have the potential to facilitate more physical activity. There has been little exploration of the specific school environment factors that are most pertinent to child physical activity and sedentary behaviour. This study was intended to fill this important gap. Methods: Data were collected between March 2017 and May 2018 from 50 schools and 1223 children who participated in the B-Proact1v cohort study. School level measures were the built environment (e.g. playground equipment, cycling parking, allotments), physical activity-related policies (e.g. policy to encourage active travel) and the use of physical activity in the curriculum (e.g. regular physical activity breaks throughout day). Children’s weekday moderate-to-vigorous physical activity (MVPA) was estimated via Actigraph GT3X accelerometers. Associations between school context measures and children’s weekday MVPA were analysed using linear multilevel models, with children nested within schools, adjusted for individual characteristics. Results: On average, children at schools with allotments, a larger amount of playground equipment and where cycle training was offered, engaged in higher levels of MVPA. PE being compromised due to space was associated with lower levels of MVPA. Conclusions: Whilst there is a need for further exploration, the findings suggest that school-based provision and policies for active travel, sport and active play may be important to encouraging more primary school children to be more active more regularly.

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.

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. Multinomial logistic regression investigated determinants. Some 38% of participants changed travel mode; 66% from active to passive. Passively traveling participants at follow-up showed a decrease in physical activity. Several social-ecological domains were associated with change. Findings suggest multicomponent interventions are required to support active travel in youth.

An online family-based self-monitoring and goal-setting intervention to improve children’s physical activity: the FRESH feasibility trial and three-arm pilot RCT

Background

Family-based physical activity promotion presents a promising avenue for promoting whole-family physical activity, but high-quality research is lacking.

Objectives

To assess the feasibility, acceptability and preliminary effectiveness of FRESH (Families Reporting Every Step to Health), a child-led online family-based physical activity intervention; and to identify effective and resource-efficient family recruitment strategies.

Design

The project consisted of (1) a randomised feasibility trial, (2) a randomised controlled pilot trial and (3) a systematic review and Delphi study.

Setting

Norfolk/Suffolk counties, UK.

Participants

Families, recruited from schools, workplaces and community settings, were eligible to participate if one child aged 7–11 years and one adult responsible for their care provided written consent; all family members could participate.

Interventions

The FRESH intervention, guided by self-determination theory, targeted whole families and was delivered via an online platform. All family members received pedometers and were given website access to select family step challenges to ‘travel’ to target cities around the world, log steps, and track progress as they virtually globetrotted. Families were randomised to FRESH intervention, pedometer-only or control arm.

Main outcome measures

Physical (e.g. blood pressure), psychosocial (e.g. family functioning) and behavioural (e.g. device-measured family physical activity) measures were collected at baseline and at 8- and 52-week follow-up. A mixed-methods process evaluation assessed the acceptability of the intervention and evaluation.

Data sources review

Systematic search of four databases (Cochrane Library, PubMed, PsycINFO and SCOPUS).

Review methods

Articles were screened in duplicate, and data extraction was fully checked. Academic experts participated in the three-round Delphi study. Data were combined to identify effective and resource-efficient family recruitment strategies.

Inclusion criteria

Included generally healthy school-aged children and at least one adult; intervention attempted to change physical activity, sedentary behaviour, screen use, diet, or prevent overweight/obesity in multiple family members; presented relevant measure of effect in children and adults.

Results

The feasibility study (12 families, 32 participants; 100% retention at 8 weeks) demonstrated the feasibility and acceptability of FRESH, but highlighted that adaptations were required. Of 41 families recruited in the pilot study (149 participants), 98% and 88% were retained at the 8-week and 52-week follow-up, respectively. More children in the FRESH arm self-reported doing more family physical activity, and they thought that FRESH was fun. There were no notable between-group differences in children’s outcomes. Change in moderate to vigorous physical activity at 8 weeks favoured FRESH intervention adults [vs. control: 9.4 minutes/week (95% confidence interval 0.4 to 18.4) vs. pedometer only: 15.3 (95% confidence interval 6.0 to 24.5)], and was stronger in fathers, but this was not maintained. In 49 included studies, apart from recruitment settings and strategies used (reported in 84% and 73% of the studies, respectively), recruitment details were scarce. School-based recruitment was predominant. The Delphi study identified a wide range of recruitment settings and strategies.

Limitations

Recruitment was the main limitation of the FRESH studies; generalisability of the proposed recruitment strategies may be limited.

Conclusions

This study has demonstrated the feasibility and acceptability of the FRESH intervention. However, we failed to recruit the target sample size and were unable to demonstrate a signal of effectiveness. Future research should employ a multifaceted recruitment approach.

Future work

Further refinements to intervention delivery and recruitment methods should be investigated.

Study registration

Current Controlled Trials ISRCTN12789422 and PROSPERO CRD42019140042.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 9, No. 9. See the NIHR Journals Library website for further project information.

Changes in Body Composition and Anthropomorphic Measurements in Children Participating in Swimming and Non-Swimming Activities

BACKGROUND

Physical activity is a well-known means of obesity prevention, but the relationship between exercise frequency and body composition in children has not been thoroughly investigated.

OBJECTIVE

The aim of this study was to compare the body composition of children aged 11-12 who regularly performed swimming and other sports as an organized extra-curricular physical activity for a 12-week period.

METHODS

The study included 46 students who attended swimming classes and 42 students who participated in training activities in other sports, including, but not limited to, football, basketball and athletics. Body height and body composition were measured using a Tanita BC 418 MA analyzer. The students individually reported their rate of perceived exertion during training using the Pictorial Children's Effort Rating Table PCERT scale.

RESULTS

The weekly volume of training was substantially higher in the group of swimmers than in that playing other sports (12.3 h/week vs. 5.2 h/week, p < 0.01). After 12 weeks of training, body height and weight significantly increased in both groups (p < 0.001). However, the BMI value and adipose tissue content only increased in the group of non-swimmers. Swimmers perceived greater exertion during training than non-swimmers (7.1 vs. 5.8 on the PCERT scale, p < 0.01).

CONCLUSIONS

In early pubescent children, engaging in vigorous exercise such as swimming for at least 10 h a week may restrain the growth of adipose tissue. However, the variety of exercises that are typical of team sports, if performed for no more than 5 h a week, may be insufficient to restrain adipose tissue growth.

Assessing Walking and Cycling around Schools

To encourage students to walk and cycle to school and ensure their health and safety, it is essential to provide safe and operationally efficient infrastructure around schools. This study used an audit tool to assess the infrastructure and environment around schools in the city of Doha, Qatar, with a particular emphasis on active transport (walking and cycling). The aim was to identify strengths, weaknesses, and areas for improvement. Twenty-two schools with varied education levels were assessed. Among all assessed categories, active transport items scored the lowest, requiring the most improvements. A detailed analysis was conducted based on school type (elementary, primary, high, and mixed-schools) and revealed similar results except for elementary schools (scored acceptable for active transport). The study revealed that adding bike lanes, installing bicycle parking, and providing good separation of travel modes are the most needed improvements at school sites. In summary, improving active transport could significantly improve the overall quality of the infrastructure around schools in Qatar. Such improvements could greatly encourage more school children to walk and cycle to school instead of being primarily dropped-off and picked up by their parents’ vehicles or school buses.

Tracking Children's Physical Activity Patterns across the School Year: A Mixed-Methods Longitudinal Case Study

Despite the breadth of health benefits associated with regular physical activity (PA), many children in the UK are not sufficiently active enough to meet health guidelines, and tend to become less active as they mature into and throughout adolescence. Research has indicated that children's school, home and neighbourhood environments can all significantly influence their opportunities to engage in moderate-to-vigorous physical activity (MVPA). However, less is known about how children's MVPA patterns within these key environments may change across the school year. The current mixed-methods case study aims to explore this issue by tracking key stage 2 (KS2) and key stage 3 (KS3) children's MVPA patterns across the school year. Fifty-eight children (29 boys, 29 girls, KS2 = 34, KS3 = 24) wore an integrated global positioning systems (GPS) and heart rate (HR) monitor over four consecutive days in the first term of school (autumn), before these measurements were repeated in the two remaining school terms (winter-summer). A subsample of children (n = 6-8 per group) were invited to take part in one of six focus groups each term to further explore their PA behaviours and identify the barriers and facilitators to PA. The children's MVPA was significantly lower (p = 0.046) in term 2 (winter/spring term) than during the warmer terms (autumn and summer). All the locations showed reductions in MVPA in term 2, except indoor MVPA, which increased, and MVPA on foot in the neighbourhood, which remained consistent. Focus groups revealed location, friends, and the variety of options to be associated with MVPA, and poor weather, parental permission, and time limitations to be barriers to MVPA. This mixed-methodological, repeated-measures design study highlights differences in the activity patterns and perceptions of children over the school year. Future studies should implement longitudinal, multi-method approaches to gain deeper insight into how children's PA behaviours differ over time. Consequently, this can inform future health policies promoting children's PA throughout the year.

A whole family-based physical activity promotion intervention: findings from the families reporting every step to health (FRESH) pilot randomised controlled trial

Introduction

This study assessed the feasibility and acceptability of FRESH (Families Reporting Every Step to Health), a theory-based child-led family physical activity (PA) intervention delivered online. We also assessed the preliminary effectiveness of the intervention on outcomes of interest and whether pre-specified criteria were met to progress to a full-scale definitive trial.

Methods

In a three-armed randomised pilot trial, 41 families (with a 7–11-year-old index child) were allocated to a: ‘family’ (FAM), ‘pedometer-only’ (PED), or a no-treatment control (CON) arm. The FAM arm received access to the FRESH website, allowing participants to select step challenges to ‘travel’ to target cities around the world, log their steps, and track progress as families virtually globetrot. FAM and PED arms also received family sets of pedometers. All family members could participate in the evaluation. Physical (e.g., fitness, blood pressure), psychosocial (e.g., social support), behavioural (e.g., objectively-measured PA), and economic (e.g., expenditure for PA) data were collected at baseline, 8- and 52-weeks.

Results

At 8- and 52-weeks, 98 and 88% of families were retained, respectively. Most children liked participating in the study (> 90%) and thought it was fun (> 80%). Compared to the PED (45%) and CON (39%) arms, a higher percentage of children in the FAM (81%) arm reported doing more activities with their family. Adults agreed that FRESH encouraged their family do more PA and made their family more aware of the amount of PA they do. No notable between-group differences were found for childrens’ minutes in moderate-to-vigorous PA. Sizeable changes of 9.4 (95%CI: 0.4, 18.4) and 15.3 (95%CI: 6.0, 24.5) minutes in moderate-to-vigorous PA was found for adults in the FAM group compared to those in the PED or CON groups, respectively. No other notable differences were found.

Conclusion

This study demonstrates feasibility and acceptability of the FRESH intervention. All progression criteria were at least partially satisfied. However, we failed to recruit the target sample size and did not find a signal of effectiveness on PA particularly long-term or in children. Further refinements are required to progress to a full-scale trial.

Trial registration

This study was prospectively registered (ISRCTN12789422) on 16/03/2016.

Birth weight, cardiometabolic risk factors and effect modification of physical activity in children and adolescents: pooled data from 12 international studies

Objectives

Low and high birth weight is associated with higher levels of cardiometabolic risk factors and adiposity in children and adolescents, and increases the risk of cardiovascular diseases, obesity, and early mortality later in life. Moderate-to-vigorous physical activity (MVPA) is associated with lower cardiometabolic risk factors and may mitigate the detrimental consequences of high or low birth weight. Thus, we examined whether MVPA modified the associations between birth weight and cardiometabolic risk factors in children and adolescents.

Methods

We used pooled individual data from 12 cohort- or cross-sectional studies including 9,100 children and adolescents. Birth weight was measured at birth or maternally reported retrospectively. Device-measured physical activity (PA) and cardiometabolic risk factors were measured in childhood or adolescence. We tested for associations between birth weight, MVPA, and cardiometabolic risk factors using multilevel linear regression, including study as a random factor. We tested for interaction between birth weight and MVPA by introducing the interaction term in the models (birth weight x MVPA).

Results

Most of the associations between birth weight (kg) and cardiometabolic risk factors were not modified by MVPA (min/day), except between birth weight and waist circumference (cm) in children (p = 0.005) and HDL-cholesterol (mmol/l) in adolescents (p = 0.040). Sensitivity analyses suggested that some of the associations were modified by VPA, i.e., the associations between birth weight and diastolic blood pressure (mmHg) in children (p = 0.009) and LDL- cholesterol (mmol/l) (p = 0.009) and triglycerides (mmol/l) in adolescents (p = 0.028).

Conclusion

MVPA appears not to consistently modify the associations between low birth weight and cardiometabolic risk. In contrast, MVPA may mitigate the association between higher birth weight and higher waist circumference in children. MVPA is consistently associated with a lower cardiometabolic risk across the birth weight spectrum. Optimal prenatal growth and subsequent PA are both important in relation to cardiometabolic health in children and adolescents.

Tracking of total sedentary time and sedentary patterns in youth: a pooled analysis using the International Children's Accelerometry Database (ICAD)

Background

To gain more understanding of the potential health effects of sedentary time, knowledge is required about the accumulation and longitudinal development of young people’s sedentary time. This study examined tracking of young peoples’ total and prolonged sedentary time as well as their day-to-day variation using the International Children’s Accelerometry Database.

Methods

Longitudinal accelerometer data of 5991 children (aged 4-17y) was used from eight studies in five countries. Children were included if they provided valid (≥8 h/day) accelerometer data on ≥4 days, including ≥1 weekend day, at both baseline and follow-up (average follow-up: 2.7y; range 0.7–8.2). Tracking of total and prolonged (i.e. ≥10-min bouts) sedentary time was examined using multilevel modelling to adjust for clustering of observations, with baseline levels of sedentary time as predictor and follow-up levels as outcome. Standardized regression coefficients were interpreted as tracking coefficients (low: < 0.3; moderate: 0.3–0.6; high: > 0.6).

Results

Average total sedentary time at study level ranged from 246 to 387 min/day at baseline and increased annually by 21.4 min/day (95% confidence interval [19.6–23.0]) on average. This increase consisted almost entirely of prolonged sedentary time (20.9 min/day [19.2–22.7]). Total (standardized regression coefficient (B) = 0.48 [0.45–0.50]) and prolonged sedentary time (B = 0.43 [0.41–0.45]) tracked moderately. Tracking of day-to-day variation in total (B = 0.04 [0.02–0.07]) and prolonged (B = 0.07 [0.04–0.09]) sedentary time was low.

Conclusion

Young people with high levels of sedentary time are likely to remain among the people with highest sedentary time as they grow older. Day-to-day variation in total and prolonged sedentary time, however, was rather variable over time.

GIS-modelled built-environment exposures reflecting daily mobility for applications in child health research

Background

Inaccurately modelled environmental exposures may have important implications for evidence-based policy targeting health promoting or hazardous facilities. Travel routes modelled using GIS generally use shortest network distances or Euclidean buffers to represent journeys with corresponding built-environment exposures calculated along these routes. These methods, however, are an unreliable proxy for calculating child built-environment exposures as child route choice is more complex than shortest network routes.

Methods

We hypothesised that a GIS model informed by characteristics of the built-environment known to influence child route choice could be developed to more accurately model exposures. Using GPS-derived walking commutes to and from school we used logistic regression models to highlight built-environment features important in child route choice (e.g. road type, traffic light count). We then recalculated walking commute routes using a weighted network to incorporate built-environment features. Multilevel regression analyses were used to validate exposure predictions to the retail food environment along the different routing methods.

Results

Children chose routes with more traffic lights and residential roads compared to the modelled shortest network routes. Compared to standard shortest network routes, the GPS-informed weighted network enabled GIS-based walking commutes to be derived with more than three times greater accuracy (38%) for the route to school and more than 12 times greater accuracy (92%) for the route home.

Conclusions

This research advocates using weighted GIS networks to accurately reflect child walking journeys to school. The improved accuracy in route modelling has in turn improved estimates of children’s exposures to potentially hazardous features in the environment. Further research is needed to explore if the built-environment features are important internationally. Route and corresponding exposure estimates can be scaled to the population level which will contribute to a better understanding of built-environment exposures on child health and contribute to mobility-based child health policy.

Variations in accelerometry measured physical activity and sedentary time across Europe - harmonized analyses of 47,497 children and adolescents

Background

Levels of physical activity and variation in physical activity and sedentary time by place and person in European children and adolescents are largely unknown. The objective of the study was to assess the variations in objectively measured physical activity and sedentary time in children and adolescents across Europe.

Methods

Six databases were systematically searched to identify pan-European and national data sets on physical activity and sedentary time assessed by the same accelerometer in children (2 to 9.9 years) and adolescents (≥10 to 18 years). We harmonized individual-level data by reprocessing hip-worn raw accelerometer data files from 30 different studies conducted between 1997 and 2014, representing 47,497 individuals (2–18 years) from 18 different European countries.

Results

Overall, a maximum of 29% (95% CI: 25, 33) of children and 29% (95% CI: 25, 32) of adolescents were categorized as sufficiently physically active. We observed substantial country- and region-specific differences in physical activity and sedentary time, with lower physical activity levels and prevalence estimates in Southern European countries. Boys were more active and less sedentary in all age-categories. The onset of age-related lowering or leveling-off of physical activity and increase in sedentary time seems to become apparent at around 6 to 7 years of age.

Conclusions

Two third of European children and adolescents are not sufficiently active. Our findings suggest substantial gender-, country- and region-specific differences in physical activity. These results should encourage policymakers, governments, and local and national stakeholders to take action to facilitate an increase in the physical activity levels of young people across Europe.

Exploring Children's Physical Activity Behaviours According to Location: A Mixed-Methods Case Study

The school environment is ideally placed to facilitate physical activity (PA) with numerous windows of opportunity from break and lunch times, to lesson times and extracurricular clubs. However, little is known about how children interact with the school environment to engage in PA and the other locations they visit daily, including time spent outside of the school environment i.e., evening and weekend locations. Moreover, there has been little research incorporating a mixed-methods approach that captures children’s voices alongside objectively tracking children’s PA patterns. The aim of this study was to explore children’s PA behaviours according to different locations. Sixty children (29 boys, 31 girls)—35 key stage 2 (aged 9–11) and 25 key stage 3 (aged 11–13)—wore an integrated global positioning systems (GPS) and heart rate (HR) monitor over four consecutive days. A subsample of children (n = 32) were invited to take part in one of six focus groups to further explore PA behaviours and identify barriers and facilitators to PA. Children also completed a PA diary. The KS2 children spent significantly more time outdoors than KS3 children (p = 0.009). Boys engaged in more light PA (LPA) when on foot and in school, compared with girls (p = 0.003). KS3 children engaged in significantly more moderate PA (MPA) at school than KS2 children (p = 0.006). Focus groups revealed fun, enjoyment, friends, and family to be associated with PA, and technology, costs, and weather to be barriers to PA. This mixed methodological study highlights differences in the PA patterns and perceptions of children according to age and gender. Future studies should utilize a multi-method approach to gain a greater insight into children’s PA patterns and inform future health policies that differentiate among a range of demographic groups of children.

Development, Validation, and Application of School Audit Tool (SAT): An Effective Instrument for Assessing Traffic Safety and Operation around Schools

There is a need for a reliable school audit tool with well-defined scales to convert qualitative evaluation of existing school sites into a quantitative assessment in order to help public agencies to improve schools’ safety and efficiency. In this study, a new, simple, and versatile School Audit Tool (SAT) was developed and tested. SAT was formed using a 30-item checklist categorized into four domains: school site assessment, road network assessment, parking/loading assessment, and active transport assessment. The tool was applied on a sample of 22 schools. Then, categorical and item-by-item Intraclass Correlation Coefficients (ICC) were calculated to validate the tool. The results showed acceptable overall test-retest (ICC = 0.919) and inter-rater reliability (ICC = 0.843) across all items and domains. SAT’s adaptable framework to assess and compare the safety and efficiency of schools is reliable, easy-to-use, and comprehensive. The tool is also effective in ranking schools and identifying items that may require upgrades or modifications.

Association of BMI category with change in children's physical activity between ages 6 and 11 years: a longitudinal study

BACKGROUND/OBJECTIVES

To examine the association of body mass index (BMI) with change in children's physical activity and sedentary time between ages 6 and 11.

PARTICIPANTS

A total of 2132 children participated from 57 schools in Southwest England, from the B-PROACT1V study.

METHODS

Mean minutes of MVPA and sedentary time per day were derived from accelerometer-based measurements at ages 6, 9 and 11. Linear multilevel models examined the association of BMI categories with MVPA and sedentary time between 6 and 11, adjusting for seasonality, wear time, gender and household education. Differences in change over time were examined using interaction terms.

RESULTS

Average weekday MVPA decreased between ages 6 and 11 by 2.2 min/day/year (95% CI: 1.9 to 2.5), with a steeper decline at weekends. Average sedentary time increased at a rate of 12.9 min/day/year (95% CI: 12.2 to 13.6). There were no differences in mean levels of MVPA by BMI categories at age 6, but differences emerged as children aged, with the gap between children who were healthy weight and overweight increasing by 1.7 min/day (95% CI: 0.8-2.6) every year, and between healthy and obese by 2.0 min/day (95% CI: 0.9-3.1) each year. Children who were overweight/obese engaged in less average weekday sedentary time at age 6 than those of healthy weight, but the gap closed by age 11.

CONCLUSION

MVPA declines and sedentary time increases on average for all children between ages 6 and 11. While there are no differences in activity levels by BMI category at age 6, differences in MVPA emerge over time for those who are overweight and obese. Developing interventions that support children to retain activity levels as they approach older childhood, particularly those who are overweight/obese could improve public health.

How socio-demographic and familiar circumstances are associated with total and domain-specific sedentary behaviour in youth? The UP&DOWN study

Objective: The aims of the present study were to analyze the associations between the socio-demographic and familiar circumstances with: (i) the total leisure-time sedentary behavior (SB) assessed by accelerometry, and (ii) the domain-specific leisure-time SB (i.e., screen-based, educational-based, social-based, and other-based SB), in a sample of Spanish youth. Method: The sample consisted of 1,543 youth (12.02 ± 2.51 years) included in the UP&DOWN study. SB was evaluated by accelerometry and questionnaire. Nationality, location of school, type of school, socio-economic status, parental educational level, parental occupation status, family structure, number of siblings and position among siblings were self-reported by participants or their parents. Linear mixed models, including school and city as random effects, were performed. Results: Several associations were found; however, socio-demographic and family circumstances differently associated with SB according to the domain-specific SB, the sex and the type of day. For example, participants with a father holding a high-skilled occupation spent lower time in screen-based SB during weekdays; and mother occupation status of high qualification was related to higher educational-based SB in boys. Having three or more sibling was associated with lower total SB in boys, while having an obese mother was related to higher screen-based SB on weekends both in boys and girls. Conclusions: Socio-demographic and familiar circumstances are associated with SB in young people, so future interventions should consider multiple and sex-specific factors for reduce SB of young people, focusing especially on youth with a low number of siblings and with parents holding low-skilled employments.

Substituting prolonged sedentary time and cardiovascular risk in children and youth: a meta-analysis within the International Children's Accelerometry database (ICAD)

BACKGROUND

Evidence on the association between sitting for extended periods (i.e. prolonged sedentary time (PST)) and cardio-metabolic health is inconsistent in children. We aimed to estimate the differences in cardio-metabolic health associated with substituting PST with non-prolonged sedentary time (non-PST), light (LIPA) or moderate-to-vigorous physical activity (MVPA) in children.

METHODS

Cross-sectional data from 14 studies (7 countries) in the International Children's Accelerometry Database (ICAD, 1998-2009) was included. Accelerometry in 19,502 participants aged 3-18 years, together with covariate and outcome data, was pooled and harmonized. Iso-temporal substitution in linear regression models provided beta coefficients (95%CI) for substitution of 1 h/day PST (sedentary time accumulated in bouts > 15 min) with non-PST, LIPA or MVPA, for each study, which were meta-analysed.

RESULTS

Modelling substitution of 1 h/day of PST with non-PST suggested reductions in standardized BMI, but estimates were > 7-fold greater for substitution with MVPA (- 0.44 (- 0.62; - 0.26) SD units). Only reallocation by MVPA was beneficial for waist circumference (- 3.07 (- 4.47; - 1.68) cm), systolic blood pressure (- 1.53 (- 2.42; - 0.65) mmHg) and clustered cardio-metabolic risk (- 0.18 (- 0.3; - 0.1) SD units). For HDL-cholesterol and diastolic blood pressure, substitution with LIPA was beneficial; however, substitution with MVPA showed 5-fold stronger effect estimates (HDL-cholesterol: 0.05 (0.01; 0.10) mmol/l); diastolic blood pressure: - 0.81 (- 1.38; - 0.24) mmHg).

CONCLUSIONS

Replacement of PST with MVPA may be the preferred scenario for behaviour change, given beneficial associations with a wide range of cardio-metabolic risk factors (including adiposity, HDL-cholesterol, blood pressure and clustered cardio-metabolic risk). Effect estimates are clinically relevant (e.g. an estimated reduction in waist circumference of ≈1.5 cm for 30 min/day replacement). Replacement with LIPA could be beneficial for some of these risk factors, however with substantially lower effect estimates.

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.

Visualisation and network analysis of physical activity and its determinants: Demonstrating opportunities in analysing baseline associations in the Let's Move It trial

Background: Visualisations and readily-accessible web-based supplementary files can improve data reporting and transparency. In this paper, we make use of recent developments in software and psychological network analysis to describe the baseline cohort of a trial testing the Let's Move It intervention, which aimed to increase physical activity (PA) and reduce sedentary behaviours (SB) among vocational school students. Methods: At baseline, 1166 adolescents, distributed across 6 school clusters and four educational tracks, completed measures of PA and SB, theoretical predictors of these behaviours, and body composition. Within a comprehensive website supplement, which includes all code and analyses, data were tabulated and visualised, and network analyses explored relations between predictor variables and outcomes. Results: Average daily moderate-to-vigorous PA was 65 min (CI95: 57min-73 min), and SB 8h44 min (CI95: 8h04min-9h24 min), with 25.8 (CI95: 23.5-28.0) interruptions to sitting. Cluster randomisation appeared to result in balanced distributions for baseline characteristics between intervention and control groups, but differences emerged across the four educational tracks. Self-reported behaviour change technique (BCT) use was low for many but not all techniques. A network analysis revealed direct relationships between PA and behavioural experiments, planning and autonomous motivation, and several BCTs were connected to PA via autonomous motivation. Visualisation uncovered a case of Simpson's paradox. Conclusions: Data-visualisation and data exploration techniques (e.g. network analysis) can help reveal the dynamics involved in complex multi-causal systems - a challenging task with traditional data presentations. The benefits of presenting complex data visually should encourage researchers to publish extensive analyses and descriptions as website supplements, which would increase the speed and quality of scientific communication, as well as help to address the crisis of reduced confidence in research findings. We hope that this example will serve as a template for other investigators to improve upon in the future.

The development and feasibility of a randomised family-based physical activity promotion intervention: the Families Reporting Every Step to Health (FRESH) study

Background

There is a need for high-quality research aiming to increase physical activity in families. This study assessed the feasibility and acceptability of FRESH (Families Reporting Every Step to Health), a child-led family-based physical activity intervention delivered online.

Methods

In a two-armed randomised feasibility study, 12 families (with an 8–10-year-old index child) were allocated to a ‘child-only’ (CO) or ‘family’ arm (FAM) of the theory-based FRESH intervention. Both received access to the FRESH website, allowing participants to select step challenges to ‘travel’ to target cities around the world, log their steps, and track their progress as they virtually globetrot. Only index children wore pedometers in CO; in FAM, all family members wore pedometers and worked towards collective goals. All family members were eligible to participate in the evaluation. Mixed-methods process evaluation (questionnaires and family focus groups) at 6-week follow-up consisted of completing questionnaires assessing acceptability of the intervention and accompanying effectiveness evaluation, focussed on physical (e.g. fitness, blood pressure), psychosocial (e.g. social support), and behavioural (e.g. objectively-measured family physical activity) measures.

Results

All families were retained (32 participants). Parents enjoyed FRESH and all children found it fun. More FAM children wanted to continue with FRESH, found the website easy to use, and enjoyed wearing pedometers. FAM children also found it easier to reach goals. Most CO families would have preferred whole family participation. Compared to CO, FAM exhibited greater website engagement as they travelled to more cities (36 ± 11 vs. 13 ± 8) and failed fewer challenges (1.5 ± 1 vs. 3 ± 1). Focus groups also revealed that most families wanted elements of competition. All children enjoyed being part of the evaluation, and adults disagreed that there were too many intervention measures (overall, 2.4 ± 1.3) or that data collection took too long (overall, 2.2 ± 1.1).

Conclusion

FRESH was feasible and acceptable to participating families; however, findings favoured the FAM group. Recruitment, intervention fidelity and delivery and some measurement procedures are particular areas that require further attention for optimisation. Testing the preliminary effectiveness of FRESH on family physical activity is a necessary next step.

Trial registration

This study was registered and given an International Standard Randomised Controlled Trials Number (ISRCTN12789422). Registered 16 March 2016. http://www.isrctn.com/ISRCTN12789422

The effects of the London 2012 Olympics and related urban regeneration on physical and mental health: the ORiEL mixed-methods evaluation of a natural experiment

Background

There is limited evidence for public health policy-makers on the health impacts of urban regeneration programmes.

Objectives

To assess whether or not the London 2012 Olympic and Paralympic Games, and related urban regeneration, were associated with an increase in physical activity and mental health and well-being; to assess whether or not any benefits were sustained over time; and to capture the experiences of residents of the Olympic host boroughs.

Design

Quasi-experimental prospective cohort study of adolescents and their parents/carers, with a nested qualitative longitudinal study of families.

Setting

London boroughs of Newham, Barking and Dagenham, Tower Hamlets and Hackney.

Participants

A cohort of 2254 adolescents in 25 schools; a repeat cross-sectional study of parents/carers and a sample of 20 families for the qualitative study.

Intervention

The London 2012 Olympic and Paralympic Games, and urban regeneration primarily associated with the redevelopment of the Olympic Park for legacy use.

Primary outcome measures

Change in the proportion of respondents meeting physical activity recommendations (using self-reported physical activity); change in the proportion of respondents reporting depression and anxiety and change in well-being score.

Main results

At 6 months, adolescents who became inactive were less likely to come from the intervention borough (Newham) than from comparison boroughs [risk ratio (RR) = 0.69, 95% confidence interval (CI) 0.51 to 0.93]. At 18 months, there were no statistically significant differences between intervention and comparison boroughs for all adolescent physical activity and screen-time transitions. Those who visited the Olympic Park more than once a month were the least likely to remain inactive (RR 0.11, 95% CI 0.02 to 0.48) and the least likely to become inactive (RR 0.38, 95% CI 0.24 to 0.60) compared with those who were active at baseline and at the 18-month follow-up. No impacts on parental/carer physical activity were observed. Adolescents who were ‘no longer depressed’ (RR 1.53, 95% CI 1.07 to 2.20) or ‘remained depressed’ (RR 1.78, 95% CI 1.12 to 2.83) at 6 months were more likely to be from the intervention borough. For well-being, there was no association between boroughs and change in well-being between baseline and the 6-month follow-up. At 18 months’ follow-up, adolescents who ‘remained depressed’ (RR 1.93, 95% CI 1.01 to 3.70) were more likely to be from the intervention borough than from comparison boroughs. No associations were observed for well-being at 18 months. There was limited evidence of change for parental mental health and well-being. The qualitative study found that residents generally welcomed the unexpected chance to live in a cleaner, safer and more unified environment. The findings suggested that the Games temporarily alleviated certain stressors in the social and physical environment. Overall, the Games lessened participants’ sense of social exclusion and appeared to generate a sense of inclusion and respite, even if this was only temporary. Study limitations include the potential for adolescents to not be assigned the correct level of exposure to urban regeneration and the effect of reductions in central and local public budgets owing to the UK Government’s deficit reduction programme.

Conclusions

This study provided the highest quality data to date on the short- and medium-term social and health impacts of sporting mega-events. We found limited evidence that the London 2012 Olympic and Paralympic Games had a positive effect on adolescent or parental physical activity, mental health or well-being.

Funding

The National Institute for Health Research Public Health Research programme.

Physical activity intensity, bout-duration, and cardiometabolic risk markers in children and adolescents

OBJECTIVES

To determine the role of physical activity intensity and bout-duration in modulating associations between physical activity and cardiometabolic risk markers.

METHODS

A cross-sectional study using the International Children's Accelerometry Database (ICAD) including 38,306 observations (in 29,734 individuals aged 4-18 years). Accelerometry data was summarized as time accumulated in 16 combinations of intensity thresholds (≥500 to ≥3000 counts/min) and bout-durations (≥1 to ≥10 min). Outcomes were body mass index (BMI, kg/m2), waist circumference, biochemical markers, blood pressure, and a composite score of these metabolic markers. A second composite score excluded the adiposity component. Linear mixed models were applied to elucidate the associations and expressed per 10 min difference in daily activity above the intensity/bout-duration combination. Estimates (and variance) from each of the 16 combinations of intensity and bout-duration examined in the linear mixed models were analyzed in meta-regression to investigate trends in the association.

RESULTS

Each 10 min positive difference in physical activity was significantly and inversely associated with the risk factors irrespective of the combination of intensity and bout-duration. In meta-regression, each 1000 counts/min increase in intensity threshold was associated with a -0.027 (95% CI: -0.039 to -0.014) standard deviations lower composite risk score, and a -0.064 (95% CI: -0.09 to -0.038) kg/m2 lower BMI. Conversely, meta-regression suggested bout-duration was not significantly associated with effect-sizes (per 1 min increase in bout-duration: -0.002 (95% CI: -0.005 to 0.0005) standard deviations for the composite risk score, and -0.005 (95% CI: -0.012 to 0.002) kg/m2 for BMI).

CONCLUSIONS

Time spent at higher intensity physical activity was the main determinant of variation in cardiometabolic risk factors, not bout-duration. Greater magnitude of associations was consistently observed with higher intensities. These results suggest that, in children and adolescents, physical activity, preferably at higher intensities, of any bout-duration should be promoted.

Defining Accelerometer Nonwear Time to Maximize Detection of Sedentary Time in Youth

PURPOSE

The present study examined various accelerometer nonwear definitions and their impact on detection of sedentary time using different ActiGraph models, filters, and axes.

METHODS

In total, 61 youth (34 children and 27 adolescents; aged 5-17 y) wore a 7164 and GT3X+ ActiGraph on a hip-worn belt during a 90-minute structured sedentary activity. Data from GT3X+ were downloaded using the Normal filter (N) and low-frequency extension (LFE), and vertical axis (V) and vector magnitude (VM) counts were examined. Nine nonwear definitions were applied to the 7164 model (V), GT3X+LFE (V and VM), and GT3X+N (V and VM), and sedentary estimates were computed.

RESULTS

The GT3X+LFE-VM was most sensitive to movement and could accurately detect observed sedentary time with the shortest nonwear definition of 20 minutes of consecutive "0" counts for children and 40 minutes for adolescents. The GT3X+N-V was least sensitive to movement and required longer definitions to detect observed sedentary time (40 min for children and 90 min for adolescents). VM definitions were 10 minutes shorter than V definitions. LFE definitions were 40 minutes shorter than N definitions in adolescents.

CONCLUSION

Different nonwear definitions are needed for children and adolescents and for different model-filter-axis types. Authors need to consider nonwear definitions when comparing prevalence rates of sedentary behavior across studies.

Multilevel Analysis of the Risk Factors in High-Risk Health Behavior among Korean Adolescents

Objectives

To examine health behaviors among Korean adolescents with a focus on both individual and school-based factors, specifically in relation to predictors of high-risk groups.

Methods

Secondary data analysis was conducted with data from the 8th Korea Youth Risk Behavior Web-Based Survey, using descriptive statistics, t tests, χ² test, and multilevel logistic regression analysis. Health Practice Index was calculated and a range of 0 to 2 was classified as a high-risk group.

Results

The results revealed that the individual-level variables of sex, age, stress, depression, subjective health status, school performance, health education, father’s level of education, and living situation were significant predictors of high-risk behaviors. The risk was greater in girls, greater with higher age and higher stress scores, greater in adolescents with depression, greater with lower paternal educational level, and greater in adolescents who did not live with both parents, as were the school-level variables of school grade and school affluence score. The possibility of being in the high-risk group in health behavior was greater if a student attended a school where the Family Affluence Score (FAS) was lower.

Conclusion

School health education should be expanded to manage students’ high-risk health behaviors, especially in schools that have many students from families with a low affluence status.

Comparison of two methods to assess physical activity prevalence in children: an observational study using a nationally representative sample of Scottish children aged 10-11 years

OBJECTIVES

To describe the objectively measured levels of physical activity (PA) and sedentary time in a nationally representative sample of 10-11-year-old children, and compare adherence estimates to the UK PA guidelines using two approaches to assessing prevalence.

DESIGN

Nationally representative longitudinal cohort study.

SETTING

Scotland wide in partnership with the Growing up in Scotland (GUS) study. Data collection took place between May 2015 and May 2016.

PARTICIPANTS

The parents of 2402 GUS children were approached and 2162 consented to contact. Consenting children (n=1096) wore accelerometers for 8 consecutive days and 774 participants (427 girls, 357 boys) met inclusion criteria.

PRIMARY AND SECONDARY OUTCOME MEASURES

Total PA (counts per minute, cpm); time spent sedentary and in moderate-to-vigorous PA (MVPA); proportion of children with ≥60 min MVPA on each day of wear (daily approach); proportion of children with ≥60 min of MVPA on average across days of wear (average approach)-presented across boys and girls, index of multiple deprivation and season.

RESULTS

Mean PA level was 648 cpm (95% CI, 627 to 670). Children spent 7.5 hours (7.4-7.6) sedentary/day and 72.6 min (70.0-75.3) in MVPA/day. 11% (daily) and 68% (average) of children achieved the recommended levels of PA (P<0.05 for difference); a greater proportion of boys met the guidelines (12.5% vs 9.8%, NS; 75.9% vs 59.5%, P<0.001); guideline prevalence exhibited seasonal variation. No significant socioeconomic patterning existed across any outcome measure.

CONCLUSIONS

PA estimates are significantly influenced by the analytical method used to assess prevalence. This could have a substantial impact on the evaluation of interventions, policy objectives and public health investment. Existing guidelines, which focus on daily PA only may not further our understandings about the underlying construct itself. Gender differences exist within this age-group, suggesting greater investment, with particular consideration of seasonality, is needed for targeted intervention work in younger children.

Harmonising data on the correlates of physical activity and sedentary behaviour in young people: Methods and lessons learnt from the international Children's Accelerometry database (ICAD)

Background

Large, heterogeneous datasets are required to enhance understanding of the multi-level influences on children’s physical activity and sedentary behaviour. One route to achieving this is through the pooling and co-analysis of data from multiple studies. Where this approach is used, transparency of the methodology for data collation and harmonisation is essential to enable appropriate analysis and interpretation of the derived data. In this paper, we describe the acquisition, management and harmonisation of non-accelerometer data in a project to expand the International Children’s Accelerometry Database (ICAD).

Method

Following a consultation process, ICAD partners were requested to share accelerometer data and information on selected behavioural, social, environmental and health-related constructs. All data were collated into a single repository for cataloguing and harmonisation. Harmonised variables were derived iteratively, with input from the ICAD investigators and a panel of invited experts. Extensive documentation, describing the source data and harmonisation procedure, was prepared and made available through the ICAD website.

Results

Work to expand ICAD has increased the number of studies with longitudinal accelerometer data, and expanded the breadth of behavioural, social and environmental characteristics that can be used as exposure variables. A set of core harmonised variables, including parent education, ethnicity, school travel mode/duration and car ownership, were derived for use by the research community. Guidance documents and facilities to enable the creation of new harmonised variables were also devised and made available to ICAD users. An expanded ICAD database was made available in May 2017.

Conclusion

The project to expand ICAD further demonstrates the feasibility of pooling data on physical activity, sedentary behaviour and potential determinants from multiple studies. Key to this process is the rigorous conduct and reporting of retrospective data harmonisation, which is essential to the appropriate analysis and interpretation of derived data. These documents, made available through the ICAD website, may also serve as a guide to others undertaking similar projects.

Feasibility of an incentive scheme to promote active travel to school: a pilot cluster randomised trial

Background

In Great Britain, 19% of trips to primary school within 1 mile, and 62% within 1-2 miles, are by car. Active travel to school (ATS) offers a potential source of moderate-to-vigorous physical activity (MVPA). This study tested the feasibility of an intervention to promote ATS in 9-10 year olds and associated trial procedures.

Methods

A parallel cluster randomised pilot trial was conducted over 9 weeks in two schools from a low-income area in northeast England. Measures included daily parental ATS reports (optionally by SMS) and child ATS reports, as well as accelerometry (ActiGraph GT3X+). At baseline, all children were asked to wear the accelerometer for the same week; in the post-randomisation phase, small subsamples were monitored each week. In the 2 weeks when a child wore the accelerometer, parents also reported the start and finish times of the journey to school. The intervention consisted of a lottery-based incentive scheme; every ATS day reported by the parent, whether by paper or SMS, corresponded to one ticket entered into a weekly £5 voucher draw. Before each draw session, the researcher prepared the tickets and placed them into an opaque bag, from which one was randomly picked by the teacher at the draw session.

Results

Four schools replied positively (3.3%, N = 123) and 29 participants were recruited in the two schools selected (33.0%, N = 88). Participant retention was 93.1%. Most materials were returned on time: accelerometers (81.9%), parental reports (82.1%) and child reports (97.9%). Draw sessions lasted on average 15.9 min (IQR 10-20) and overall session attendance was 94.5%. Parent-child report agreement regarding ATS was moderate (k = 0.53, CI 95% 0.45; 0.60). Differences in minutes of accelerometer-assessed MVPA between parent-reported ATS and non-ATS trips were assessed during two timeframes: during the journey to school based on the times reported by the parent (U = 390.5, p < 0.05, 2.46 (n = 99) vs 0.76 (n = 13)) and in the hour before classes (U = 665.5, p < 0.05, 4.99 (n = 104) vs 2.55 (n = 19)). Differences in MVPA minutes between child-reported ATS and non-ATS trips were also significant for each of the timeframes considered (U = 596.5, p < 0.05, 2.40 (n = 128) vs 0.81 (n = 15) and U = 955.0, p < 0.05, 4.99 (n = 146) vs 2.59 (n = 20), respectively).

Conclusions

Data suggest the feasibility of an ATS incentive scheme and of most trial procedures. School recruitment stood out as requiring further piloting.

Trial registration

ClinicalTrials.gov: NCT02282631. Registered 5th September 2014.

Is School Type Associated with Objectively Measured Physical Activity in 15-Year-Olds?

The main aims of this study were: (1) to determine the objectively assessed physical activity (PA) patterns in urban 15-year-old male and female adolescents according to school type and (2) to assess the differences in PA between school days and weekend days. In this cross-sectional study, participants were 187 secondary-school male and female adolescents (61.4% females) attending grammar and vocational schools. Patterns of PA were objectively evaluated using a multi-sensor body monitor for 5 consecutive days. Confounders assessed included biological age, socio-economic status, sum of 4 skinfolds, maximal temperature and the amount of rainfall. Males and females from grammar schools achieved higher total daily energy expenditure (TEE) and active energy expenditure (AEE) compared to their peers from vocational schools (TEE: 50 ± 12 kcal/kg/day vs. 47 ± 12 kcal/kg/day, p = 0.02; AEE: 23 ± 5 kcal/kg/day vs. vocational = 21 ± 6 kcal/kg/day, p = 0.04). No differences in time spent in light (LPA), moderate (MPA) or vigorous (VPA) physical activity were noted between the two groups (p = 0.16-0.43). Next, a significant decline in TEE and MPA between school days and weekends was observed (p< 0.001 and p = 0.02, respectively), while VPA remained the same throughout the week (p = 0.76). Weekly patterns of PA did not show differences by school type or gender (p for interactions = 0.21-0.50). In addition, significantly lower amount of MPA was accumulated during weekends compared to school days, resulting in lower TEE, regardless of school type or gender. Policies and strategies on PA in adolescents should focus vocational schools and weekend days.

Effects of a multi-level intervention on the pattern of physical activity among in-school adolescents in Oyo state Nigeria: a cluster randomised trial

Background

Physical inactivity contributes to the global burden of non-communicable diseases. The pattern of physical activity in adulthood are often established during adolescence and sedentary behaviours in the early years could influence the development of diseases later in life. Studies on physical activity in Nigeria have focused largely on individual behaviours and the effects of school-based interventions have not been well investigated. The aim of the proposed study is to identify factors influencing; and evaluate the effects of a multi-level intervention on the physical activity behaviours of in-school adolescents in Oyo state, Nigeria.

Methods

The study will adopt a cluster randomised controlled trial design and schools will serve as the unit of randomisation. The sample size is 1000 in-school adolescents aged 10–19 years. The study will be guided by the socio-ecological model and theory of reasoned action and baseline data will be obtained through a mixed methods approach comprising a cross sectional survey to document the self-reported physical activity levels coupled with objectively measured physical activity levels using pedometers for a subset of the sample. Other measurements including weight, height, waist and hip circumferences, fitness level using the 20-m shuttle run test (20-mSRT) and blood pressure will be obtained. The schools’ built environment and policy support for physical activity will be assessed using structured questionnaires coupled with key informant interviews and focus group discussions with the school authorities. Baseline findings will guide the design and implementation of a 12-week multi-level intervention. The primary outcome measures are self–reported and 7-day objectively measured physical activity. Other secondary outcome measures are body-mass-index for age, waist-to-hip ratio, cardioresiratory fitness and blood pressure. The association between behavioural factors and physical activity levels will be assessed. Follow-up measurements will be taken immediately after the intervention and 3-months post intervention.

Discussion

Physical activity behaviours of adolescents in Nigeria are influenced by multiple factors. There is an urgent need for effective school-based interventions with a potential to improve the physical activity behaviours of adolescents in Nigeria and other low and middle income countries.

Trial registration

Pan African Clinical Trial Registry. Trial registration number: PACTR201706002224335, registered 26 June 2017.

A cluster randomised controlled trial to evaluate the effectiveness and cost-effectiveness of the GoActive intervention to increase physical activity among adolescents aged 13-14 years

INTRODUCTION

Adolescent physical activity promotion is rarely effective, despite adolescence being critical for preventing physical activity decline. Low adolescent physical activity is likely to last into adulthood, increasing health risks. The Get Others Active (GoActive) intervention is evidence-based and was developed iteratively with adolescents and teachers. This intervention aims to increase physical activity through increased peer support, self-efficacy, group cohesion, self-esteem and friendship quality, and is implemented using a tiered-leadership system. We previously established feasibility in one school and conducted a pilot randomised controlled trial (RCT) in three schools.

METHODS AND ANALYSIS

We will conduct a school-based cluster RCT (CRCT) in 16 secondary schools targeting all year 9 students (n=2400). In eight schools, GoActive will run for two terms: weekly facilitation support from a council-funded intervention facilitator will be offered in term 1, with more distant support in term 2. Tutor groups choose two weekly activities, encouraged by older adolescent mentors and weekly peer leaders. Students gain points for trying new activities; points are entered into a between-class competition. Outcomes will be assessed at baseline, interim (week 6), postintervention (week 14-16) and 10-month follow-up (main outcome). The primary outcome will be change from baseline in daily accelerometer-assessed moderate-to-vigorous physical activity. Secondary outcomes include accelerometer-assessed activity intensities on weekdays/weekends; self-reported physical activity and psychosocial outcomes; cost-effectiveness and cost-utility analyses; mixed-methods process evaluation integrating information from focus groups and participation logs/questionnaires.

ETHICS AND DISSEMINATION

Ethical approval for the conduct of the study was gained from the University of Cambridge Psychology Research Ethics Committee. Given the lack of rigorously evaluated interventions, and the inclusion of objective measurement of physical activity, long-term follow-up and testing of causal pathways, the results of a CRCT of the effectiveness and cost-effectiveness of GoActive are expected to add substantially to the limited evidence on adolescent physical activity promotion. Workshops will be held with key stakeholders including students, parents, teachers, school governors and government representatives to discuss plans for wider dissemination of the intervention.

TRIAL REGISTRATION NUMBER

ISRCTN31583496.

Changes in diet from age 10 to 14 years and prospective associations with school lunch choice

BACKGROUND

There is limited evidence on how diet changes over the transition from primary to secondary school. In this study we investigated changes in diet from age 10 (2007) to age 14 years (2011) and the contribution of school-time consumption and school lunch choice to such changes.

METHODS

The 351 participants with dietary data (4 day food record) available at baseline (age 10 years) and follow-up (age 14 years) were included. Multi-level regression models were fitted for absolute or change in food and nutrient intake, cross-classified by primary and secondary school attended as appropriate, with adjustment for covariates and mis-reporting.

RESULTS

From age 10 to age 14 years, children decreased energy intake from sugars (-2.6% energy (%E)) (standard error (SE) 0.44) and from saturated fats (-0.54%E (SE 0.18)), decreased fruit (-3.13 g/MJ (SE 1.04)) and vegetables (-1.55 g/MJ (SE 0.46)) consumption and increased sugar sweetened beverage (SSB) (4.66  g/MJ (SE 1.87)) and fries (1.31  g/MJ (SE 0.39)) consumption. Intake of snack foods, SSBs, and fries, but also fruits and vegetables was higher outside school hours. Prospective change from non-school lunch to school lunch, compared to maintaining non-school lunch consumption, was associated with decreased consumption of savoury snacks (-8.32 g/day (SE 2.03)), increased consumption of fries (12.8 g/day (SE 4.01)) and decreased consumption of fruit (-25.16 g/day (SE 11.02)) during school hours.

CONCLUSIONS

Changes in diet from age 10 to age 14 years differed within and outside of school hours. Consumption of a school lunch, compared to lunch obtained elsewhere, was associated with negative as well as positive changes in diet, suggesting that any efforts to encourage school lunch take-up need to be accompanied by further efforts to improve school lunch provision to meet nutritional guidelines.

Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis

BACKGROUND

Although the scientific community has acknowledged modest improvements can be made to weight status and obesogenic behaviors (i.e., physical activity, sedentary/screen time, diet, and sleep) during the school year, studies suggests improvements are erased as elementary-age children are released to summer vacation. Emerging evidence shows children return to school after summer vacation displaying accelerated weight gain compared to the weight gained occurring during the school year. Understanding how summer days differ from when children are in school is, therefore, essential.

DISCUSSION

There is limited evidence on the etiology of accelerated weight gain during summer, with few studies comparing obesogenic behaviors on the same children during school and summer. For many children, summer days may be analogous to weekend days throughout the school year. Weekend days are often limited in consistent and formal structure, and thus differ from school days where segmented, pre-planned, restrictive, and compulsory components exist that shape obesogenic behaviors. The authors hypothesize that obesogenic behaviors are beneficially regulated when children are exposed to a structured day (i.e., school weekday) compared to what commonly occurs during summer. This is referred to as the 'Structured Days Hypothesis' (SDH). To illustrate how the SDH operates, this study examines empirical data that compares weekend day (less-structured) versus weekday (structured) obesogenic behaviors in U.S. elementary school-aged children. From 190 studies, 155 (~80%) demonstrate elementary-aged children's obesogenic behaviors are more unfavorable during weekend days compared to weekdays.

CONCLUSION

In light of the SDH, consistent evidence demonstrates the structured environment of weekdays may help to protect children by regulating obesogenic behaviors, most likely through compulsory physical activity opportunities, restricting caloric intake, reducing screen time occasions, and regulating sleep schedules. Summer is emerging as the critical period where childhood obesity prevention efforts need to be focused. The SDH can help researchers understand the drivers of obesogenic behaviors during summer and lead to innovative intervention development.

Childhood predictors of adolescent behaviour: The prospective association of familial factors with meeting physical activity guidelines

Little is known about the longitudinal association of familial socio-demographic factors, behaviours, attitudes, or home environment with meeting physical activity guidelines. Our objective was to a) describe 4-year change in the prevalence of meeting guidelines, and characteristics of participants across categories of physical activity maintenance, and b) identify familial factors in childhood that are longitudinally associated with meeting guidelines in adolescence. Data on 17 parent- and child-reported family variables and objectively measured physical activity (ActiGraph GT1M) were available from 406 children (10.3 ± 0.3 years, 53.5% female) participating in the SPEEDY study. Average duration of week- and weekend day moderate-to-vigorous physical activity (MVPA, ≥ 2000 cpm) at baseline and follow-up (14.3 ± 0.3 years) were calculated to determine whether participants met 60 min MVPA/day guidelines at each assessment. Descriptives were calculated across four MVPA change categories. Multi-level logistic regression examined the association of baseline familial factors with meeting guidelines at follow-up, adjusting for sex, baseline physical activity, family socio-economic position, and school clustering. At follow-up, 51.5% and 36.1% of adolescents met guidelines on weekdays and weekend days, respectively (baseline: 68.0%, 67.2%). Girls were less likely than boys to remain sufficiently active, particularly on weekdays. Family social support was positively associated with adolescents meeting guidelines at weekends (OR 1.2; 95% CI 1.0-1.4). The presence of play equipment at home was negatively associated with meeting guidelines on weekdays (OR 0.5; 95% CI 0.3-0.8). Interventions that foster parent's facilitation of physical activity may help to encourage the upkeep of healthy behaviours during the transition from childhood to adolescence.

Exploring childhood obesity prevention among diverse ethnic groups in schools and places of worship: Recruitment, acceptability and feasibility of data collection and intervention components

Small-scale, detailed exploration of the recruitment, assessment, and evaluation processes of obesity intervention among minority ethnic children. The study took place in schools and places of worship during 2008–2010 in London, UK. Measures included 3-day food diaries, 24 h dietary recalls, the Youth Physical Activity Questionnaire, accelerometry, and diet and physical activity self-efficacy questionnaires. Potential intervention components were evaluated via observation, questionnaires, and focus group discussions. Schools and places of worship that reflected the ethnic and religious diversity of inner city London populations (Hindus, Muslims and Christians) were targeted. Telephone invitations to 12 schools achieved recruitment of five schools (42% response); 181 invitations to 94 places of worship, recruited eight organisations (9%). Multi-strategy approaches were required to build relationships with faith organisations. Sixty-five children aged 8–13 years participated in the testing of measures. High completion rates were achieved for 24 h recalls, diet and PA self-efficacy questionnaires (ranging from 89% to 100%), with more consistent quality in schools. Dietary assessment highlighted inadequacies in composition data for minority ethnic foods. Intervention sessions were tested among 155 children in all five schools, and 33 children in a church, temple and mosque. Evaluation coverage was more consistent in these places of worship than in schools. Schools may logistically be more straightforward settings for delivery of interventions but, despite complex issues (engagement strategies; cultural foodways), places of worship provide opportunities for effective reach of children, families and communities. We suggest community based participatory research between researchers, schools and community organisations to harness culturally-specific support.

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Diverse strategies were required to recruit places of worship.

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Schools were logistically more straightforward for intervention delivery.

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Evaluation coverage was more consistent in places of worship.

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Places of worship also provide opportunities to reach children's families.

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Findings will be built on in a pilot trial in school-faith organisation coalitions.

An evaluation of outdoor school environments to promote physical activity in Delhi, India

Background

Increasing physical activity in children is an important public health goal in India. Schools may be a target for physical activity promotion, but little is known about outdoor school environments. The purpose of this study was to describe characteristics of the surrounding outdoor school environments that may promote children’s physical activity in Delhi, India.

Methods

For this cross-sectional study, we conducted a structured observation of outdoor school environments in a random sample of 16 private schools in Delhi, India using the Sport, Physical activity and Eating behavior: Environmental Determinants in Young people (SPEEDY) audit tool. The SPEEDY school audit measured six categories, including (1) access to the school; (2) surrounding area; (3) school grounds; (4) aesthetics; (5) usage; and (6) overall environment. Six trained data collectors conducted the audit independently in the summer of 2012 while schools were in session.

Results

Of the 16 schools, one had cycle lanes separated from the road while two schools had cycle lanes on the road. Two schools had pavement on both sides of the road for pedestrians. One school had marked pedestrian crossings. No schools had school warning signs, road safety signs, or route signs for cyclists that would help calm vehicular traffic. Fifteen schools had playground equipment and nine had courts, an assault course (a sequence of equipment designed to be used together), and a quadrangle (an enclosed or semi-enclosed courtyard) for outdoor physical activity. The majority of schools were shielded from the surrounding area by hedges, trees, or fences (n = 13) and were well maintained (n = 10). One school had evidence of vandalism. Two schools had graffiti, seven had litter, and 15 had murals or art.

Conclusions

The majority of schools did not have infrastructure to support physical activity, such as cycle lanes, marked pedestrian crossings, or traffic calming mechanisms such as school warning signs. However, most had playground equipment, courts, and outdoor play areas. Nearly all were free from vandalism and many had murals or art. These results provide preliminary data for future work examining outdoor school environments, active transport to school, and children’s physical activity in India.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3987-8) contains supplementary material, which is available to authorized users.

Determinants of Three-Year Change in Children's Objectively Measured Sedentary Time

BACKGROUND

Sedentary behaviours (SB) are highly prevalent in young people and may be adversely associated with physical and mental health. Understanding of the modifiable determinants of SB is necessary to inform the design of behaviour change interventions but much of the existing research is cross-sectional and focussed upon screen-based behaviours.

PURPOSE

To examine the social, psychological and environmental determinants of change in children's objectively measured sedentary time from age 11 to 14 years.

METHODS

Data are from the second (2008) and third (2011) waves of assessment in the Sport, Physical Activity, and Eating Behaviour: Environmental Determinants in Young People (SPEEDY) study, conducted in the county of Norfolk, United Kingdom. Longitudinal data on accelerometer assessed sedentary time were available for 316 (53.5% female, 11.2±0.3 years at baseline) and 264 children after-school and at the weekend respectively. Information on 14 candidate determinants, including school travel mode and electronic media ownership, was self-reported. Change in the proportion of registered time spent sedentary was used as the outcome variable in cross-classified linear regression models, adjusted for age, sex, body mass index and baseline sedentary time. Simple and multiple models were run and interactions with sex explored.

RESULTS

Daily sedentary time increased by 30-40 minutes after-school and at the weekend from baseline to follow-up. Participants who travelled to school by cycle exhibited smaller increases in after-school sedentary time (beta; 95%CI for change in % time spent sedentary: -3.3;-6.7,-0.07). No significant determinants of change in weekend sedentary time were identified.

CONCLUSIONS

Time spent sedentary increased during the three-year duration of follow-up but few of the variables examined were significantly associated with changes in sedentary time. Children's mode of school travel may influence changes in their sedentary time over this period and should be examined further, alongside broader efforts to identify modifiable determinants of SB during childhood.

Age-related patterns of vigorous-intensity physical activity in youth: The International Children's Accelerometry Database

Physical activity declines during youth but most evidence reports on combined moderate and vigorous-intensity physical activity. We investigated how vigorous-intensity activity varies with age. Cross-sectional data from 24,025 participants (5.0-18.0 y; from 20 studies in 10 countries obtained 2008-2010) providing ≥ 1 day accelerometer data (International Children's Accelerometry Database (ICAD)). Linear regression was used to investigate age-related patterns in vigorous-intensity activity; models included age (exposure), adjustments for monitor wear-time and study. Moderate-intensity activity was examined for comparison. Interactions were used to investigate whether the age/vigorous-activity association differed by sex, weight status, ethnicity, maternal education and region. A 6.9% (95% CI 6.2, 7.5) relative reduction in mean vigorous-intensity activity with every year of age was observed; for moderate activity the relative reduction was 6.0% (5.6%, 6.4%). The age-related decrease in vigorous-intensity activity remained after adjustment for moderate activity. A larger age-related decrease in vigorous activity was observed for girls (- 10.7%) versus boys (- 2.9%), non-white (- 12.9% to - 9.4%) versus white individuals (- 6.1%), lowest maternal education (high school (- 2.0%)) versus college/university (ns) and for overweight/obese (- 6.1%) versus healthy-weight participants (- 8.1%). In addition to larger annual decreases in vigorous-intensity activity, overweight/obese individuals, girls and North Americans had comparatively lower average vigorous-intensity activity at 5.0-5.9 y. Age-related declines in vigorous-intensity activity during youth appear relatively greater than those of moderate activity. However, due to a higher baseline, absolute moderate-intensity activity decreases more than vigorous. Overweight/obese individuals, girls, and North Americans appear especially in need of vigorous-intensity activity promotion due to low levels at 5.0-5.9 y and larger negative annual differences.

Feasibility study and pilot cluster-randomised controlled trial of the GoActive intervention aiming to promote physical activity among adolescents: outcomes and lessons learnt

OBJECTIVES

Assess the feasibility of implementing the GoActive intervention in secondary schools, to identify improvements, test study procedures, determine preliminary effectiveness to increase moderate-to-vigorous physical activity (MVPA), and inform power calculations to establish programme effectiveness.

SETTING

Feasibility study (1 school) and pilot cluster-randomised controlled trial (CRCT; 2 intervention; 1 control school(s)).

PARTICIPANTS

460 participants (46.6% female; 13.2 (0.4) years old).

INTERVENTIONS

8-week intervention (2013) involved: classes choosing weekly activities encouraged by mentors (older adolescents) and in-class peer leaders. Students gain points for trying activities which are entered into an intramural competition.

PRIMARY AND SECONDARY OUTCOME MEASURES

Planned quantitative (questionnaire) and qualitative (focus groups) process evaluation addressed enjoyment, confidence, participation, suggested improvements. Outcomes were assessed at baseline and follow-up (week 8) in pilot CRCT and included accelerometer-assessed MVPA; adolescent-reported activity type, well-being, peer support, shyness, sociability. Analysis of covariance was used to assess preliminary effectiveness as change in MVPA adjusted for baseline.

RESULTS

All year 9 students in intervention schools were exposed to the intervention; over all schools 77% of eligible students were measured. 71% boys and 74% girls found GoActive 'fun'; 38% boys and 32% girls said it increased confidence, and 64% boys and 59% girls said they would continue with a GoActive activity. Suggested improvements included more mentorship; improved training; streamlined points recording. Pilot results indicated potential effectiveness ((adjusted mean difference (95% CI) p value; MVPA mins; 5.1 (1.1 to 9.2) p=0.014)) and suggest recruitment of 16 schools (2400 adolescents) for a full trial. Compared with control, intervention students reported greater peer support 0.5 (0.1 to 0.9) p=0.03, well-being 1.8 (0.1 to 3.4) p=0.04 but no difference in shyness/sociability. Participation in activity types approached significance (intervention group 2.3 (-0.2 to 4.7) p=0.07 more activity types).

CONCLUSIONS

Results suggest feasibility and indicate potential effectiveness of GoActive to increase MVPA and support a fully powered evaluation of effectiveness and cost-effectiveness. Process evaluation data were used to refine GoActive prior to a full trial.

TRIAL REGISTRATION NUMBER

ISRCTN31583496; pre-results.

The effect of a classroom activity break on physical activity levels and adiposity in primary school children

AIM

Despite recognition that regular physical activity is essential for good health, many children do not accumulate sufficient daily physical activity. The aim of this study was to examine the effect of a classroom-based activity break on accelerometer-determined moderate-to-vigorous intensity physical activity (MVPA) and adiposity in primary school children.

METHODS

One hundred twenty children from seven primary schools in Northern Ireland participated in the study. In each school, one class of children was randomly assigned to an intervention group and another class to a control group. Teachers of the intervention classes led a 5-min activity break three times per day for 12 weeks. Accelerometer-determined MVPA, height, weight and four skinfolds were measured at baseline and post-intervention.

RESULTS

Compared with the control group, the intervention group significantly increased weekday MVPA (+9.5 min) from baseline to post-intervention. There were no significant changes in BMI; however, an increase in sum-of-skinfolds of the intervention group was observed.

CONCLUSIONS

Classroom-based activity breaks led by the teacher are successful in increasing children's physical activity levels. The programme shows a positive step in improving overall physical activity levels and contributing to the goal of 60 min daily MVPA.

Gamification of active travel to school: A pilot evaluation of the Beat the Street physical activity intervention

Beat the Street aims to get children more active by encouraging them to walk and cycle in their neighbourhood using tracking technology with a reward scheme. This pilot study evaluates the impact of Beat the Street on active travel to school in Norwich, UK. Eighty children 8-10 yrs were recruited via an intervention and control school. They wore an accelerometer for 7 days at baseline, mid-intervention and post-intervention (+20 weeks), and completed a travel diary. Physical activity overall was not higher at follow-up amongst intervention children compared to controls. However, there was a positive association between moderate-to-vigorous physical activity (MVPA) during school commute times and the number of days on which children touched a Beat the Street sensor. This equated to 3.46min extra daily MVPA during commute times for children who touched a sensor on 14.5 days (the mean number of days), compared to those who did not engage. We also found weekly active travel increased at the intervention school (+10.0% per child) while it decreased at the control (-7.0%), p=0.056. Further work is needed to understand how improved engagement with the intervention might impact outcomes.

School polices, programmes and facilities, and objectively measured sedentary time, LPA and MVPA: associations in secondary school and over the transition from primary to secondary school

Background

There is increasing policy interest in ensuring that the school environment supports healthy behaviours. We examined the cross-sectional and longitudinal associations between schools’ policies, programmes and facilities for physical activity (PA) and adolescents’ objectively-measured activity intensity during the school day and lunchtime.

Methods

Accelerometer-derived PA (proportion of time spent in sedentary (SED), light PA (LPA) and moderate-to-vigorous PA (MVPA)) during school hours and lunchtime from 325 participants in the SPEEDY study were obtained from baseline measurements (primary school, age 9/10 years) and +4y follow-up (secondary school). School environment characteristics were assessed by teacher questionnaire. Multivariable multi-level linear regression analyses accounting for school and adjusted for sex, age, BMI and family socio-economic status assessed cross-sectional associations with lunchtime and school-day SED, LPA and MVPA; effect modification by sex was investigated. The association of changes in school environment with changes in outcomes was examined using multivariable cross-classified linear regression models.

Results

There were significant differences between primary and secondary schools for 6/10 school environment characteristics investigated (including secondary schools reporting shorter breaks, more lunchtime PA opportunities, and higher number of sports facilities). Cross-sectional analyses showed that boys attending secondary schools with longer breaks spent significantly less time in SED and more time in MVPA during the school day. Longitudinally, an increase in break-time duration between primary and secondary school was associated with smaller reductions in MVPA during the school day. Moreover, participants who moved from a primary school that did not provide opportunities for PA at lunchtime to a secondary school that did provide such opportunities exhibited smaller increases in SED and smaller reductions in MVPA at lunchtime.

Conclusions

Schools should consider the potential negative impact of reducing break time duration on students’ MVPA and SED during the school day. School-based interventions that combine longer breaks and more PA opportunities during lunchtime may be a fruitful direction for future research. Further research should also explore other factors in the school environment to explain the school-level clustering observed, and study sex differences in the way that the school environment influences activity intensity for adolescent populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-016-0378-6) contains supplementary material, which is available to authorized users.

School grounds and physical activity: Associations at secondary schools, and over the transition from primary to secondary schools

This paper aims to further understanding of the physical environments of secondary schools and their associations with young peoples' physical activity. Accelerometer-derived physical activity measurements from 299 participants in the SPEEDY study (Norfolk, UK) were obtained from baseline measurements (age 9-10y) and +4y follow-up. These were linked to objective measures of primary and secondary school environments as measured by the SPEEDY grounds audit tool. We saw considerable differences in the nature of school grounds between primary and secondary schools. Cross-sectional associations were seen between active travel provision scores and commuting time moderate-to-vigorous physical activity (MVPA) for 13-14 year old boys and adolescents living further from school. However, few associations were seen between changes in school grounds scores and changes in school-based MVPA.

Where does the time go? Patterns of physical activity in adolescent youth

OBJECTIVES

To explore daily patterns of physical activity in early adolescent youth, and identify whether patterns differed across varying activity levels.

DESIGN

Cross-sectional observational study.

METHODS

Adolescent youth (n=715, 11.8-14.4 years) were asked to wear an Actigraph accelerometer for a 9-day period. Average daily and hourly minutes spent in moderate-vigorous physical activity (MVPA) were calculated for each participant. Participants were grouped into sex-specific quartiles (Q) based on average daily MVPA accumulation (Q4 most active, Q1 least active). Principal components analysis was used to identify, from hourly MVPA data, distinct time blocks for Weekday and Weekend days. Mixed between-within ANOVA's were conducted separately by gender to assess the impact of Quartile grouping on minutes of MVPA across the distinct time blocks.

RESULTS

Males accumulated significantly more minutes of MVPA daily than females (55.3±21.6min, versus 47.4±18.1min). Principal Components Analysis revealed three distinct time components for MVPA during weekdays, and weekend days. The total difference between Q4 and Q1 was greatest 'Weekend Afternoons' for Males (22min), and 'Weekend Midday' for females (12.8min); with Q4 accumulating significantly more MVPA in these time periods than the other three Quartiles (p<0.05).

CONCLUSIONS

This study points to the weekend midday and afternoon periods as particular time blocks to target for intervening with inactive youth. Future research should examine the reasons why some youth choose to be active during these particular periods while others do not, with a view to developing appropriate strategies for intervention.

The independent prospective associations of activity intensity and dietary energy density with adiposity in young adolescents

There is limited evidence on the prospective association of time spent in activity intensity (sedentary (SED), moderate (MPA) or vigorous (VPA) physical activity) and dietary intake with adiposity indicators in young people. This study aimed to assess associations between (1) baseline objectively measured activity intensity, dietary energy density (DED) and 4-year change in adiposity and (2) 4-year change in activity intensity/DED and adiposity at follow-up. We conducted cohort analyses including 367 participants (10 years at baseline, 14 years at follow-up) with valid data for objectively measured activity (Actigraph), DED (4-d food diary), anthropometry (waist circumference (WC), %body fat (%BF), fat mass index (FMI), weight status) and covariates. Linear and logistic regression models were fit, including adjustment for DED and moderate-to-vigorous physical activity. Results showed that baseline DED was associated with change in WC (β for 1kJ/g difference: 0·71; 95% CI 0·26, 1·17), particularly in boys (1·26; 95% CI 0·41, 2·16 v. girls: 0·26; 95% CI −0·34, 0·87), but not with %BF, FMI or weight status. In contrast, baseline SED, MPA or VPA were not associated with any of the outcomes. Change in DED was negatively associated with FMI (β for 1kJ/g increase: −0·86; 95% CI −1·59, −0·12) and %BF (−0·86; 95% CI −1·25, −0·11) but not WC (−0·27; 95% CI −1·02, 0·48). Change in SED, MPA and VPA did not predict adiposity at follow-up. In conclusion, activity intensity was not prospectively associated with adiposity, whereas the directions of associations with DED were inconsistent. To inform public health efforts, future studies should continue to analyse longitudinal data to further understand the independent role of different energy-balance behaviours in changes in adiposity in early adolescence.

Development and reliability of an audit tool to assess the school physical activity environment across 12 countries

OBJECTIVES

Schools are an important setting to enable and promote physical activity. Researchers have created a variety of tools to perform objective environmental assessments (or 'audits') of other settings, such as neighborhoods and parks; yet, methods to assess the school physical activity environment are less common. The purpose of this study is to describe the approach used to objectively measure the school physical activity environment across 12 countries representing all inhabited continents, and to report on the reliability and feasibility of this methodology across these diverse settings.

METHODS

The International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) school audit tool (ISAT) data collection required an in-depth training (including field practice and certification) and was facilitated by various supporting materials. Certified data collectors used the ISAT to assess the environment of all schools enrolled in ISCOLE. Sites completed a reliability audit (simultaneous audits by two independent, certified data collectors) for a minimum of two schools or at least 5% of their school sample. Item-level agreement between data collectors was assessed with both the kappa statistic and percent agreement. Inter-rater reliability of school summary scores was measured using the intraclass correlation coefficient.

RESULTS

Across the 12 sites, 256 schools participated in ISCOLE. Reliability audits were conducted at 53 schools (20.7% of the sample). For the assessed environmental features, inter-rater reliability (kappa) ranged from 0.37 to 0.96; 18 items (42%) were assessed with almost perfect reliability (κ=0.80-0.96), and a further 24 items (56%) were assessed with substantial reliability (κ=0.61-0.79). Likewise, scores that summarized a school's support for physical activity were highly reliable, with the exception of scores assessing aesthetics and perceived suitability of the school grounds for sport, informal games and general play.

CONCLUSIONS

This study suggests that the ISAT can be used to conduct reliable objective audits of the school physical activity environment across diverse, international school settings.

Do specific parenting practices and related parental self-efficacy associate with physical activity and screen time among primary schoolchildren? A cross-sectional study in Belgium

OBJECTIVES

To assess the association between specific parenting practices and related parental self-efficacy with children's physical activity (PA) and screen time. Parental body mass index (BMI), family socioeconomic status (SES), and child's age and gender were examined as possible influencing factors.

DESIGN

Cross-sectional.

SETTING

January 2014, Flanders (Belgium).

PARTICIPANTS

207 parents (87.4% mothers) of children aged 6-12 years.

OUTCOME MEASURES

Specific parenting practices, related parental self-efficacy, and children's PA and screen time.

RESULTS

The majority of investigated parenting practices and related parental self-efficacy were not significantly associated with children's PA or screen time. However, children were more physically active if sports equipment was available at home (p<0.10) and if parents did not find it difficult to motivate their child to be physically active (p<0.05). Children had a lower screen time if parents limited their own gaming (p<0.01). The associations between parenting practices and related parental self-efficacy with children's PA or screen time were significant for parents with a normal BMI, for medium-high SES families and for parents of younger children. Furthermore, the association between the parenting relating factors and children's PA and screen time differed for boys and girls.

CONCLUSIONS

In contrast to what we expected, the findings of the current study show that only a very few specific parenting practices and related parental self-efficacy were associated with children's PA and screen time. It was expected that parental self-efficacy would play a more important role. This can be due to the fact that parental self-efficacy was already high in this group of parents. Therefore, it is possible that parents do not realise how difficult it is to perform certain parenting practices until they are faced with it in an intervention.

TRIAL REGISTRATION NUMBER

EC/2012/317.

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.