School-based intervention on healthy behaviour among Ecuadorian adolescents: effect of a cluster-randomized controlled trial on screen-time

Effectiveness of Intervention Strategies to Increase Adolescents' Physical Activity and Reduce Sedentary Time in Secondary School Settings, Including Factors Related to Implementation: A Systematic Review and Meta-Analysis

BACKGROUND

Globally, just one in five adolescents meet physical activity guidelines and three-quarters of the school day is spent sitting. It is unclear which types of school-based interventions strategies increase physical activity and reduce sedentary time among adolescents, or how these interventions are implemented influences their effectiveness.

OBJECTIVE

The three aims of our systematic review were to (a) identify intervention strategies used within secondary school settings to improve students' movement behaviours throughout school-based initiatives, delivered at or by the school; (b) determine the overall effect of the interventions (meta-analysis) on physical activity (all intensities), sedentary time, cognitive/academic, physical health and/or psychological outcomes; and (c) describe factors related to intervention implementation.

METHODS

Searches were conducted in MEDLINE complete, EMBASE, CINAHL, SPORTDiscus, APA PsycINFO, and ERIC in January 2023 for studies that (a) included high school-aged adolescents; (b) involved a school-based intervention to increase physical activity and/or decrease sedentary time; and (c) were published in English. Reported effects were pooled in meta-analyses where sufficient data were obtained.

RESULTS

Eighty-five articles, representing 61 interventions, met the inclusion criteria, with 23 unique intervention strategies used. Interventions that involved whole-school approaches (i.e., physical activity sessions, environmental modifications, teacher training, peer support and/or educational resources) were favourably associated with most of the outcomes. The meta-analyses showed: (a) non-significant effects for sedentary time (Standardized mean difference [SMD] = -0.02; 95%CI, -0.14, 0.11), physical activity at all intensities (light: SMD= -0.01; 95%CI, -0.08, 0.05; moderate: SMD = 0.06; 95%CI, -0.09, 0.22; vigorous: SMD = 0.08; 95%CI, -0.02, 0.18; moderate-to-vigorous: SMD = 0.05; 95%CI, -0.01, 0.12) and waist circumference (SMD = 0.09; 95%CI, -0.03, 0.21), and (b) a small statistically significant decrease in body mass index (SMD= -0.09, 95%CI -0.16, -0.0). Factors related to intervention implementation were reported in 51% of the articles.

CONCLUSION

While some intervention approaches demonstrated promise, small or null effects were found in meta-analyses. Future school-based interventions should utilize a whole-school approach designed to increase adolescents' activity across the day. Consistent reporting of implementation will increase understanding of how interventions are adopted, implemented and sustained.

REGISTRATION

PROSPERO (CRD42020169988).

Effectiveness of multi-component modular intervention on screen-based and non-screen-based sedentary time among adolescents in an urban area of Mangalore: a school-based cluster randomised controlled trial-protocol

Background

Behavioural risk factors may often present during adolescence and account for 70% of premature deaths during adulthood. Excessive sedentary behaviour and screen time have become significant concerns, especially among adolescents, due to their potential negative impact on physical and mental health. Adolescents with a high screen-based sedentary time are more likely to be physically inactive, have unhealthy body structure and poor academic performance. The objective of our study is to assess the effect of multi-component modular educational intervention on screen-based sedentary time (SST) and non-screen-based Sedentary time (NSST) among adolescents.

Methods

Ethical approval for the study has been obtained from the institutional Ethics Committee of Kasturba Medical College in Mangalore, India. This cluster randomized control trial will be carried out in schools located in the urban area of Mangalore. Using simple randomization, the eligible schools will be randomized into intervention and control arms, each consisting of 10 clusters. A multi-component modular educational intervention will be administered to participants in the intervention group at baseline, second and fourth month. The control group will receive the standard curriculum. Both the groups will be assessed at baseline and at second month, fourth month and sixth month of follow up for SST, NSST and level of physical activity. Anthropometric measurements like height, weight, waist circumference and hip circumference will be taken at baseline and sixth month of follow up.

Results

A comprehensive school-based modular educational intervention can have cumulative advantages by reducing screen- and non-screen-based sedentary time, and encouraging physical activity. Similar modular teaching can be incorporated into the curriculum, which will promote healthy life-style among the adolescents.

Replacing screen time, with physical activity and sleep time: influence on cardiovascular indicators and inflammatory markers in Brazilian children

OBJECTIVE

To examine if the substitution of different screen time intervals with light physical activity (LPA), moderate to vigorous physical activity (MVPA) and sleep is associated with cardiovascular indicators and inflammatory markers in children.

METHODS

This is a cross-sectional study developed with 186 children aged between six and 11 years old from public schools in southern Brazil. CRF was measured with the 6-minute running and walking test, following the Brazil Sports Project procedures. The percentage of fat was evaluated through DXA. LPA and MVPA were measured using accelerometers. Sleep and screen time were assessed by questionnaires answered by parents. Leptin and C-reactive protein were measured by fasting blood collection. Systolic and diastolic blood pressure were determined through a digital sphygmomanometer. Isotemporal substitution models were used for statistical analysis.

RESULTS

Replacing 1 h of screen time with MVPA was associated with lower BMI, systolic and diastolic blood pressure, fat percentage, leptin, and C-reactive protein. When screen time was substituted for sleep time, lower waist circumference was observed. Regarding the substitution of 1 h of screen time with LPA, significant values were found only for leptin.

CONCLUSION

The replacement of screen time with physical activities of different intensities and sleep time was associated with benefits in cardiovascular indicators and inflammatory markers in childhood.

Effects of Excessive Screen Time on Child Development: An Updated Review and Strategies for Management

Children's heavy reliance on screen media has raised serious public health issues since it might harm their cognitive, linguistic, and social-emotional growth. This study examines the effects of screen time on many developmental domains and covers management and limitation techniques for kids' screen usage. Screen media has a wide range of cognitive consequences, with both beneficial and detrimental effects noted. Screens can improve education and learning; however, too much time spent in front of a screen and multitasking with other media has been related to worse executive functioning and academic performance. As screen time reduces the amount and quality of interactions between children and their caregivers, it can also have an impact on language development. Contextual elements like co-viewing and topic appropriateness are key in determining how language development is impacted. Additionally, excessive screen usage has detrimental effects on social and emotional growth, including a rise in the likelihood of obesity, sleep disorders, and mental health conditions including depression and anxiety. It can obstruct the ability to interpret emotions, fuel aggressive conduct, and harm one's psychological health in general. Setting boundaries, utilizing parental controls, and demonstrating good screen behavior are all techniques that parents may use to manage children's screen usage. We can reduce the possible negative impacts of excessive screen time and promote children's healthy development and well-being by increasing knowledge and encouraging alternative activities that stimulate development.

Overview of Systematic Reviews of Health Interventions for the Prevention and Treatment of Overweight and Obesity in Children

(1) Background: The importance of studying the health interventions used to prevent and treat overweight and obesity in school-aged children is imperative. This overview aimed to summarize systematic reviews that assess the effects of school-based, family, and mixed health interventions for preventing and treating overweight and obesity in school-aged children. (2) Methods: The Cochrane Collaboration methodology and PRISMA statement were followed. A search was conducted using terms adapted to 12 databases. Systematic reviews reporting interventions in children from six to 12 years old with an outcome related to preventing or treating obesity and overweight were included. Studies with pharmacological or surgical interventions and adolescents were excluded. (3) Results: A total of 15,226 registers were identified from databases and citation searching. Of those, ten systematic reviews published between 2013 and 2022 were included. After the overlap, 331 interventions for children between 6 and 12 years old were identified, and 61.6% involved physical activity and nutrition/diet intervention. Multicomponent intervention, combining physical activity with nutrition and behavioral change, school-based plus community-based interventions may be more effective in reducing overweight and obesity in children. (4) Conclusions: Plenty of interventions for childhood overweight and obesity aimed at prevention and treatment were identified, but there is a gap in the methodological quality preventing the establishment of a certain recommendation.

Interventions to Promote Physical Activity and Healthy Digital Media Use in Children and Adolescents: A Systematic Review

OBJECTIVES

To identify effective interventions that promote healthy screen time use and reduce sedentary behavior in school-age children and adolescents (SACA) in all settings, over the last 20 years.

METHODS

Searches were conducted from 2000 until March 2021 using PubMed, Embase, Medline, PsycINFO, Ovid SP, The Cochrane Library, Cochrane Central Register of Controlled Trials, Cochrane Methodology Register, and the WHO regional databases, including Google Scholar and reference lists of relevant articles and reviews. Randomized-controlled trials and quasi-experimental studies assessing interventions to reduce sedentary behaviors and screen time in healthy SACA (aged 5-19.9 years) globally. Data were extracted by 2 reviewers and where possible, pooled with a random-effects model.

RESULTS

The review included 51 studies, of which 23 were included in meta-analyses with 16 418 children and adolescents. Nondigital randomized-controlled trials reported a small, but significant reduction of TV-specific screen time (minutes per day) (mean difference, -12.46; 95% confidence interval, -20.82 to -4.10; moderate quality of evidence) and sedentary behavior (minutes per day) (mean difference, -3.86; 95% confidence interval, -6.30 to -1.41; participants = 8920; studies = 8; P = .002; moderate quality of evidence) as compared with control groups. For quasi-experimental studies, nondigital interventions may make little or no difference on screen time (minutes per day) or sedentary behavior (minutes per day), given the high uncertainty of evidence. Most studies were conducted in a high-income country. Generalizability of results to low- and middle- income countries remain limited.

CONCLUSIONS

Public health policies and programs will be necessary to reduce excessive sedentary behavior and screen time, especially in the post-coronavirus disease 2019 reality.

Media Awareness and Screen Time Reduction in Children, Youth or Families: A Systematic Literature Review

Excessive use of screen media is a global public health issue and especially extensive screen exposure during very early childhood. This review was conducted in order to update previous reviews on the effectiveness of interventions to reduce screen time. An electronic literature search was carried out in MEDLINE, COCHRANE LIBRARY and CINAHL for articles indexed from June 2011 until October 2019. The search identified 933 publications of which 11 publications were included in this review. There are studies showing interventions with a positive influence on reduction of screen time and the participants' awareness and behavior concerning the use of screen media, as well as studies without such effects. No intervention was identified to be superior. This warrants further investigation of potentially effective combinations of intervention components and long-term follow-up.

Effectiveness and moderators of a multicomponent school-based intervention on screen time devices: the Movimente cluster-randomized controlled trial

Background

Interventions targeting reduce screen time in adolescents are urgently needed, mainly in low and middle-income countries because of the lack of evidence. Thus, the aims of the study were to examine the effect of a cluster-randomized controlled trial on screen time (ST) devices among Brazilian adolescents and to identify possible moderators.

Methods

Movimente was a multicomponent school-based intervention that was performed in 2017 and consisted of teacher training, education curriculum, and environmental improvements. Baseline and post-intervention assessments (over one academic year) were conducted with students aged 10–16 years at baseline (baseline n = 921, [n = 538 intervention group; n = 383 control group]). A self-report questionnaire was used to measure daily minutes of device specific screen time (TV, computer, video games and smartphone) and demographic variables. Linear mixed models were used to examine intervention effects and an exploratory moderation analysis (sex, grade and socioeconomic status) was performed.

Results

The intervention had no significant effects on TV time (β = − 6.4, 95% CI: − 6.1;13.4), game time (β = − 8.2, 95% CI: − 7.2;10.8), computer time (β = 1.1, 95% CI: − 6.3;18.5), smartphone time (β = − 10.2, 95% CI: − 32.5;12.1), screen time (β = − 12.8, 95% CI: − 50.5;24.8), meeting screen time guidelines (OR: 1.29, 95% CI: 0.65,2.57) and meeting screen time guidelines with smartphone (OR: 1.66, 95% CI: 0.37,7.40). There was a significant intervention effect on reducing TV time (β = − 37.1, 95% CI: − 73.0, − 1.3) among 8th grade students only.

Conclusions

The Movimente intervention was effective only for TV time among 8th grade students. Understanding how school-based interventions can improve adolescents’ device specific screen time across age groups is needed. Future strategies should cover all screen-based devices. Further, there is a need for more studies in low- and-middle income countries to assist in the development of effective strategies.

Trial registration

Clinicaltrials.gov identifier NCT02944318 (25/10/2016).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11895-2.

School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6 to 18

BACKGROUND

Physical activity among children and adolescents is associated with lower adiposity, improved cardio-metabolic health, and improved fitness. Worldwide, fewer than 30% of children and adolescents meet global physical activity recommendations of at least 60 minutes of moderate to vigorous physical activity per day. Schools may be ideal sites for interventions given that children and adolescents in most parts of the world spend a substantial amount of time in transit to and from school or attending school.

OBJECTIVES

The purpose of this review update is to summarise the evidence on effectiveness of school-based interventions in increasing moderate to vigorous physical activity and improving fitness among children and adolescents 6 to 18 years of age. Specific objectives are: • to evaluate the effects of school-based interventions on increasing physical activity and improving fitness among children and adolescents; • to evaluate the effects of school-based interventions on improving body composition; and • to determine whether certain combinations or components (or both) of school-based interventions are more effective than others in promoting physical activity and fitness in this target population.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO, BIOSIS, SPORTDiscus, and Sociological Abstracts to 1 June 2020, without language restrictions. We screened reference lists of included articles and relevant systematic reviews. We contacted primary authors of studies to ask for additional information.

SELECTION CRITERIA

Eligible interventions were relevant to public health practice (i.e. were not delivered by a clinician), were implemented in the school setting, and aimed to increase physical activity among all school-attending children and adolescents (aged 6 to 18) for at least 12 weeks. The review was limited to randomised controlled trials. For this update, we have added two new criteria: the primary aim of the study was to increase physical activity or fitness, and the study used an objective measure of physical activity or fitness. Primary outcomes included proportion of participants meeting physical activity guidelines and duration of moderate to vigorous physical activity and sedentary time (new to this update). Secondary outcomes included measured body mass index (BMI), physical fitness, health-related quality of life (new to this update), and adverse events (new to this update). Television viewing time, blood cholesterol, and blood pressure have been removed from this update.  DATA COLLECTION AND ANALYSIS: Two independent review authors used standardised forms to assess each study for relevance, to extract data, and to assess risk of bias. When discrepancies existed, discussion occurred until consensus was reached. Certainty of evidence was assessed according to GRADE. A random-effects meta-analysis based on the inverse variance method was conducted with participants stratified by age (children versus adolescents) when sufficient data were reported. Subgroup analyses explored effects by intervention type.

MAIN RESULTS

Based on the three new inclusion criteria, we excluded 16 of the 44 studies included in the previous version of this review. We screened an additional 9968 titles (search October 2011 to June 2020), of which 978 unique studies were potentially relevant and 61 met all criteria for this update. We included a total of 89 studies representing complete data for 66,752 study participants. Most studies included children only (n = 56), followed by adolescents only (n = 22), and both (n = 10); one study did not report student age. Multi-component interventions were most common (n = 40), followed by schooltime physical activity (n = 19), enhanced physical education (n = 15), and before and after school programmes (n = 14); one study explored both enhanced physical education and an after school programme. Lack of blinding of participants, personnel, and outcome assessors and loss to follow-up were the most common sources of bias.  Results show that school-based physical activity interventions probably result in little to no increase in time engaged in moderate to vigorous physical activity (mean difference (MD) 0.73 minutes/d, 95% confidence interval (CI) 0.16 to 1.30; 33 studies; moderate-certainty evidence) and may lead to little to no decrease in sedentary time (MD -3.78 minutes/d, 95% CI -7.80 to 0.24; 16 studies; low-certainty evidence). School-based physical activity interventions may improve physical fitness reported as maximal oxygen uptake (VO₂max) (MD 1.19 mL/kg/min, 95% CI 0.57 to 1.82; 13 studies; low-certainty evidence). School-based physical activity interventions may result in a very small decrease in BMI z-scores (MD -0.06, 95% CI -0.09 to -0.02; 21 studies; low-certainty evidence) and may not impact BMI expressed as kg/m² (MD -0.07, 95% CI -0.15 to 0.01; 50 studies; low-certainty evidence). We are very uncertain whether school-based physical activity interventions impact health-related quality of life or adverse events.

AUTHORS' CONCLUSIONS

Given the variability of results and the overall small effects, school staff and public health professionals must give the matter considerable thought before implementing school-based physical activity interventions. Given the heterogeneity of effects, the risk of bias, and findings that the magnitude of effect is generally small, results should be interpreted cautiously.

Identifying effective intervention strategies to reduce children's screen time: a systematic review and meta-analysis

BACKGROUND

Excessive screen time ([Formula: see text] 2 h per day) is associated with childhood overweight and obesity, physical inactivity, increased sedentary time, unfavorable dietary behaviors, and disrupted sleep. Previous reviews suggest intervening on screen time is associated with reductions in screen time and improvements in other obesogenic behaviors. However, it is unclear what study characteristics and behavior change techniques are potential mechanisms underlying the effectiveness of behavioral interventions. The purpose of this meta-analysis was to identify the behavior change techniques and study characteristics associated with effectiveness in behavioral interventions to reduce children's (0-18 years) screen time.

METHODS

A literature search of four databases (Ebscohost, Web of Science, EMBASE, and PubMed) was executed between January and February 2020 and updated during July 2021. Behavioral interventions targeting reductions in children's (0-18 years) screen time were included. Information on study characteristics (e.g., sample size, duration) and behavior change techniques (e.g., information, goal-setting) were extracted. Data on randomization, allocation concealment, and blinding was extracted and used to assess risk of bias. Meta-regressions were used to explore whether intervention effectiveness was associated with the presence of behavior change techniques and study characteristics.

RESULTS

The search identified 15,529 articles, of which 10,714 were screened for relevancy and 680 were retained for full-text screening. Of these, 204 studies provided quantitative data in the meta-analysis. The overall summary of random effects showed a small, beneficial impact of screen time interventions compared to controls (SDM = 0.116, 95CI 0.08 to 0.15). Inclusion of the Goals, Feedback, and Planning behavioral techniques were associated with a positive impact on intervention effectiveness (SDM = 0.145, 95CI 0.11 to 0.18). Interventions with smaller sample sizes (n < 95) delivered over short durations (< 52 weeks) were associated with larger effects compared to studies with larger sample sizes delivered over longer durations. In the presence of the Goals, Feedback, and Planning behavioral techniques, intervention effectiveness diminished as sample size increased.

CONCLUSIONS

Both intervention content and context are important to consider when designing interventions to reduce children's screen time. As interventions are scaled, determining the active ingredients to optimize interventions along the translational continuum will be crucial to maximize reductions in children's screen time.

Latin American interventions in children and adolescents' sedentary behavior: a systematic review

OBJECTIVE To identify and evaluate the effects of community-based interventions on the sedentary behavior (SB) of Latin American children and adolescents. METHODS A systematic review on community-based trials to reduce and/or control SB in Latin American countries (Prospero: CRD42017072157). Five databases (PubMed, Web of Science, Scopus, SciELO and Lilacs) and a reference lists were searched. RESULTS Ten intervention studies met the eligibility criteria and composed the descriptive synthesis. These studies were conducted in Brazil (n=5), Mexico (n=3), Ecuador (n=1) and Colombia (n=1). Most interventions were implemented in schools (n=8) by educational components, such as meetings, lessons, and seminars, on health-related subjects (n=6). Only two studies adopted specific strategies to reduce/control SB; others focused on increasing physical activity and/or improving diet. Only one study used an accelerometer to measure SB. Seven studies investigated recreational screen time. Eight studies showed statistically significant effects on SB reduction (80%). CONCLUSIONS Latin America community-based interventions reduced children and adolescents' SB. Further studies should: define SB as a primary outcome and implement strategies to reduce such behaviour; focus in different SBs and settings, other than recreational screen time or at-home sitting time; and use objective tools together with questionnaires to measure sedentary behaviour in.

The effectiveness and complexity of interventions targeting sedentary behaviour across the lifespan: a systematic review and meta-analysis

BACKGROUND

Evidence suggests that sedentary behaviour (SB) is associated with poor health outcomes. SB at any age may have significant consequences for health and well-being and interventions targeting SB are accumulating. Therefore, the need to review the effects of multicomponent, complex interventions that incorporate effective strategies to reduce SB are essential.

METHODS

A systematic review and meta-analysis were conducted investigating the impact of interventions targeting SB across the lifespan. Six databases were searched and two review authors independently screened studies for eligibility, completed data extraction and assessed the risk of bias and complexity of each of the included studies.

RESULTS

A total of 77 adult studies (n=62, RCTs) and 84 studies (n=62, RCTs) in children were included. The findings demonstrated that interventions in adults when compared to active controls resulted in non-significant reductions in SB, although when compared to inactive controls significant reductions were found in both the short (MD -56.86; 95%CI -74.10, -39.63; n=4632; I2 83%) and medium-to-long term (MD -20.14; 95%CI -34.13, -6.16; n=4537; I2 65%). The findings demonstrated that interventions in children when compared to active controls may lead to relevant reductions in daily sedentary time in the short-term (MD -59.90; 95%CI -102.16, -17.65; n=267; I2 86%), while interventions in children when compared to inactive controls may lead to relevant reductions in the short-term (MD -25.86; 95%CI -40.77, -10.96; n=9480; I2 98%) and medium-to-long term (MD -14.02; 95%CI -19.49, -8.55; n=41,138; I2 98%). The assessment of complexity suggested that interventions may need to be suitably complex to address the challenges of a complex behaviour such as SB, but demonstrated that a higher complexity score is not necessarily associated with better outcomes in terms of sustained long-term changes.

CONCLUSIONS

Interventions targeting reductions in SB have been shown to be successful, especially environmental interventions in both children and adults. More needs to be known about how best to optimise intervention effects. Future intervention studies should apply more rigorous methods to improve research quality, considering larger sample sizes, randomised controlled designs and valid and reliable measures of SB.

The Role of Recreational Online Activities in School-Based Screen Time Sedentary Behaviour Interventions for Adolescents: A Systematic and Critical Literature Review

Sedentary behaviours are highly associated with obesity and other important health outcomes in adolescence. This paper reviews screen time and its role within school-based behavioural interventions targeting adolescents between the years 2007 and 2019. A systematic literature review following PRISMA guidelines was conducted across five major databases to identify interventions targeting screen time—in addition to TV/DVD viewing. The review identified a total of 30 papers analysing 15 studies across 16 countries aiming at addressing reduction of recreational screen time (internet use and gaming) in addition to television/DVD viewing. All of the interventions focused exclusively on behaviour change, targeting in the majority both reduction of sedentary behaviours along with strategies to increase physical activity levels. A mix of intervention effects were found in the reviewed studies. Findings suggest aiming only for reduction in time spent on screen-based behaviour within interventions could be a limited strategy in ameliorating excessive screen use, if not targeted, in parallel, with strategies to address other developmental, contextual and motivational factors that are key components in driving the occurrence and maintenance of adolescent online behaviours. Additionally, it raises the need for a differential treatment and assessment of each online activity within the interventions due to the heterogeneity of the construct of screen time. Recommendations for enhancing the effectiveness of school-based sedentary behaviour interventions and implications for public policy are discussed.

Associations between active commuting to school, sleep duration, and breakfast consumption in Ecuadorian young people

BACKGROUND

Daily behaviours such as active commuting to school (ACS) could be a source of physical activity, contributing to the improvement of youth cardiovascular health, however, the relationship between ACS and other aspects of a youth's health, such as sleep duration and breakfast consumption, require further clarification. The aims of this study were therefore: 1) to analyse the prevalence of modes of commuting to school, sleep duration, and breakfast consumption by age groups and gender, and 2) to analyse the association between ACS, sleep duration recommendations, and breakfast consumption by age groups and gender.

METHOD

This cross-sectional study included 732 school-aged students of low-middle socioeconomic status, categorised into children (10-12 yr), young adolescents (13-15 yr), and older adolescents (16-18 yr). Modes of commuting to/from school, sleep duration, and breakfast consumption were self-reported. Logistic regression models were fitted to examine the association between ACS, sleep duration and breakfast consumption, analysed according to age groups and gender.

RESULTS

The percentage of students meeting sleep duration and daily breakfast recommendations was lowest in older adolescents, and highest in children (6.3% versus 50.8% p < 0.001, and 62.1%, versus 76.8%, p = 0.001, respectively). Young adolescents and girls who met the sleep duration recommendations were more likely to be active commuters than their counterparts (OR = 4.25; 95% CI = 1.81 to 9.92, p = 0.001 and OR = 2.89; 95%CI = 1.01 to 8.27, p = 0.04, respectively).

CONCLUSION

Young adolescents (13-15 yr) and girls who met the sleep duration recommendations during school days displayed a positive association with ACS. There was no association between ACS and breakfast consumption for any of the age groups or gender. Children (10-12 yr) were those that best meet with the adequate sleep duration and breakfast consumption recommendations.

Regional Variations in Physical Fitness and Activity in Healthy and Overweight Ecuadorian Adolescents

Background: Insufficient physical activity (PA) and excessive sedentary behavior (SB) are the main contributors to adolescent obesity. However, it is uncertain whether recent economic growth and urbanization in Ecuador are contributing to an obesogenic environment. This study assessed the relationships among fitness, PA, SB, and perceived social support for PA in adolescents from urban (Quito) and rural (Loja) Ecuador. Methods: Fitness was estimated using 3-min step test and PA and SB participation and social support for PA were self-reported in 407 adolescents. T-tests and analysis of variance assessed differences by sex, obesity status, and region of Ecuador. Pearson correlations assessed relationships among PA, SB, fitness, and social support. Results: Males and rural adolescents (48.3 ± 9.4 and 47.1 ± 9.6 mL/kg/min) were more fit than females and urban adolescents (41.1 ± 7.5 and 39.7 ± 6.1 mL/kg/min). Fitness was negatively correlated with obesity only in rural Ecuador. Few adolescents reported ≥60 min/day of PA (8.4%) or ≤2 h/day of SB (30.2%), with greater SB participation in rural Ecuador. Weak correlations were observed among fitness, PA, SB, and parental/peer support for PA (r = -0.18 to 0.19; p < 0.05). Conclusion: While fitness varied by sex, weight status, and region, SB participation and parent/peer support for PA, not PA participation itself, predicted fitness in rural Ecuadorean adolescents.

Effects of School-based Health Promotion Intervention on Health Behaviors among School Adolescents in North Lima and Callao, Peru

Background

Multicomponent interventions that include both school and family or community involvements have the potential to cause significant changes in the levels of health in adolescents. To this end, KOICA and Yonsei Global Health Center implemented a school-based health promotion program from 2015 to 2016 in Northern Lima and Callao, Peru. The present study aimed to evaluate the effects of a school-based health promotion intervention on the health behaviors of school adolescents in Peru.

Methods

Health behaviors were measured using a standard self-administered questionnaire before and after the introduction of a school-based health promotion intervention in 2014 and 2016. The intervention was executed in secondary schools, specifically two schools from Lima and two from Callao, from April 2015 to November 2016. Two schools (one from each area) were selected as control schools. The interventions included health education, screening, and psychological counseling of vulnerable individuals as well as education for teachers and workshops with parents.

Results

Descriptive statistics, chi-square test results, and logistic regression values were computed. Sample sizes were 332 and 255 in 2014 and 933 and 599 in 2016 in the intervention and control schools, respectively. Logistic regression analysis revealed significant improvement in the consumption of vegetables and in depression in the intervention schools. Suicide attempts, television-watching, video game use, Internet use, consumption of chips and sugary drinks, and being in fights did not decrease in the intervention group but did increase in the control group. Thus, the intervention might have prevented the worsening of these behaviors in the intervention schools.

Conclusion

The intervention had a positive effect on vegetable consumption and feeling depressed as well as on preventing the increase in sedentary behaviors, fighting, and suicide attempts.

Tackling Youth Inactivity and Sedentary Behavior in an Entire Latin America City

Real-world interventions are fundamental to bridge the research-practice gap in healthy lifestyle promotion. This study aimed to assess the impact of a 7-month, intensive, city-wide intervention ("Life of Health") on tackling youth inactivity and sedentary behavior in an entire Latin-American city (Jaguariuna, Brazil). For youth, a program focused on tackling inactivity/sedentary behavior was delivered at every school (n = 18). Plausibility assessments (pre-to-post design) were performed with 3,592 youth (out of 8,300 individuals at school age in the city) to test the effectiveness of the intervention. Primary outcomes were physical activity and sedentary behavior. Secondary outcome was BMI z-score. Physical activity did not change (0; 95%CI:-2.7-2.8 min/day; p = 0.976), although physically inactive sub-group increased physical activity levels (11.2; 95%CI:8.8-13.6 min/day; p < 0.001). Weekday television and videogame time decreased, whereas computer time increased. Participants with overweight and obesity decreased BMI z-score (-0.08; 95%CI:-0.11-0.05; p < 0.001; -0.15; 95%CI:-0.19-0.11; p < 0.001). This intervention was not able to change the proportion of physical inactivity and sedentary behavior in youth at a city level. Nonetheless, physically inactive individuals increased PA levels and participants with overweight and obesity experienced a reduction in BMI z-score, evidencing the relevance of the intervention. Education-based lifestyle programs should be supplemented with environmental changes to better tackle inactivity/sedentary behavior in the real-world.

Intervention to reduce recreational screen-time in adolescents: Outcomes and mediators from the 'Switch-Off 4 Healthy Minds' (S4HM) cluster randomized controlled trial

INTRODUCTION

The primary objective was to evaluate the impact of the 'Switch-off 4 Healthy Minds' (S4HM) intervention on recreational screen-time in adolescents.

METHODS

Cluster randomized controlled trial with study measures at baseline and 6-months (post-intervention). Eligible participants reported exceeding recreational screen-time recommendations (i.e., >2h/day). In total, 322 adolescents (mean age=14.4±0.6years) from eight secondary schools in New South Wales, Australia were recruited. The S4HM intervention was guided by Self-Determination Theory and included: an interactive seminar, eHealth messaging, a behavioral contract and parental newsletters. The primary outcome was recreational screen-time. Secondary outcomes included mental health (i.e., well-being, psychological distress, self-perceptions), objectively measured physical activity, and body mass index (BMI). Outcome analyses were conducted using linear mixed models and mediation was examined using a product-of-coefficients test.

RESULTS

At post-intervention, significant reductions in screen-time were observed in both groups, with a greater reduction observed in the intervention group (-50min/day versus -29min, p<0.05 for both). However, the adjusted difference in change between groups was not statistically significant (mean=-21.3min/day, p=0.255). There were no significant intervention effects for mental health outcomes, physical activity or BMI. Significant mediation effects for autonomous motivation were found.

CONCLUSIONS

Participants in both the S4HM intervention and control groups significantly reduced their screen-time, with no group-by-time effects. Enhancing autonomous motivation might be a useful intervention target for trials aimed at reducing adolescents' recreational screen-time.

TRIAL REGISTRATION

ACTRN12614000163606.