For whom and under what circumstances do school-based energy balance behavior interventions work? Systematic review on moderators

Mediators and moderators of the effects of a school-based intervention on adolescents' fruit and vegetable consumption: the HEIA study

OBJECTIVE

To examine whether targeted determinants mediated the effects of the HEalth In Adolescents (HEIA) intervention on fruit and vegetable (FV) consumption and explore if these mediating effects were moderated by sex, parental education or weight status.

DESIGN

Cluster-randomised controlled trial.

SETTING

The HEIA study (2007-2009) was a Norwegian 20-month multi-component school-based intervention to promote healthy weight development. FV consumption and targeted determinants were self-reported at baseline, mid-way (8 months) and post-intervention (20 months).

PARTICIPANTS

Adolescents (11-13-year-old) in twenty-five control schools (n 746) and twelve intervention schools (n 375).

RESULTS

At post-intervention, more adolescents in the intervention group compared with the control group had knowledge of the FV recommendations (OR: 1·4, 95 % CI 1·1, 1·9) and reported a decreased availability of vegetables at home (β: -0·1, 95 % CI -0·2, 0·0). Availability/accessibility of FV at home, availability of vegetables at dinner, taste preferences for different types of FV and knowledge of the FV recommendations were positively associated with the consumption of FV. However, none of the post-intervention determinants significantly mediated the intervention effects on FV consumption. Although no moderating influences by sex, parental education or weights status were observed on the mediating effects, exploratory analyses revealed significant moderations in the b-paths.

CONCLUSIONS

Since none of the targeted determinants could explain the increase in FV consumption, it remains unclear why the intervention was effective. Reporting on a wide range of mediators and moderators in school-based interventions is needed to reveal the pathways through which intervention effects are achieved.

Psychosocial mediators and moderators of a school-based physical activity intervention among Brazilian adolescents

School-based interventions are needed due to the low levels of physical activity (PA) in adolescents. The aim is to examine the mediation effects of psychosocial factors (attitude, self-efficacy, social support from parents, friends, general teachers, and PE teachers, and environment school perception) and moderation by sex, school grade, and socioeconomic level of a school-based PA intervention on the PA practice among adolescents. The Movimente Programme is a randomised controlled trial at schools in southern Brazil (n = 921 adolescents). Strategies included teacher training, educational actions, and environmental changes. Adolescents self-reported their weekly PA. Potential psychosocial mediators and moderators were investigated through validated questionnaires in a Brazilian sample. The product of the coefficients with percentile bootstrapping 95% confidence interval was performed. The Movimente Programme was related to positive changes in adolescents' perception of the school environment and social support from general and physical education teachers. Most psychosocial variables (attitude, self-efficacy, social support from friends, and social support from teachers) were associated with PA, but none mediated the impact of the Movimente Programme on PA. Results varied according to sex and school grade. The Movimente Programme increased the adolescents' perception of the school environment and social support from teachers, but no mediators were confirmed.

Mediators and moderators of physical activity changes in a school-based intervention targeting childhood obesity

This study identifies mediators and moderators of changes in physical activity (PA) following a school-based pilot intervention. Students from two Lebanese schools were randomly allocated into intervention (n = 191) and control (n = 183) groups. The multiple-mediation analysis revealed that active self-identity and perceived barriers mediated the intervention's effect on PA changes. Baseline intention, attitude, PBC, and age moderated PA changes at post-intervention. The youngest participants and those reporting the lowest PA scores at baseline benefited most from the intervention. Future interventions with students should target these mediators and moderators to promote positive change in PA behavior.

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.

Associations between the School Environment and Physical Activity Pattern during School Time in Swedish Adolescents

Knowledge about associations between school-based initiatives and physical activity patterns is limited. The purpose of this paper was to examine associations between factors in the school environment, physical activity and sedentary time during school time. The cross-sectional study included 1139 adolescents aged 13–14 from 34 schools. Physical activity and sedentary time were measured using hip-worn accelerometers. Factors in the school environment included health policy, a mobile phone ban during breaks, organized physical activities during breaks and activity breaks during lessons reported by teachers. The frequency and duration of breaks and physical education (PE) lessons were collected from school schedules. The results showed significant associations between health policy (β = 3.87, 95% confidence interval (CI): 2.37, 5.23), the mobile phone ban (β = 2.51, 95% CI: 1.29, 3.94) and PE; total duration (β = 0.08, 95% CI: 0.05, 0.11), average duration (β = 0.08, 95% CI: 0.01, 0.13) and frequency (β = 1.73, 95% CI: 0.50, 3.04) and moderate-vigorous physical activity. There were negative associations between health policy (β = −6.41, 95% CI: −10.24, −2.67), the mobile phone ban (β = −3.75, 95% CI: −7.25, −0.77) and PE; total duration (β = −0.15, 95% CI: −0.23, −0.08) and average duration (β = −0.14, 95% CI: −0.27, −0.03) and time spent sedentary. Adolescents attending schools with health policies, mobile phone bans and more time for PE showed higher levels of physical activity and lower sedentary time.

Tackling risk factors for type 2 diabetes in adolescents: PRE-STARt study in Euskadi

INTRODUCTION

Obesity in the child population and its effect in the development of metabolic diseases are a public health issue. One of the aims of the European Project in a health system, is the evaluation of the effectiveness of a multidisciplinary health promotion program directed at adolescents with risk factors associated with the development of type 2 Diabetes Mellitus (T2DM).

PATIENTS AND METHODS

Randomised clinical trial with two groups of 12-14 year-old overweight adolescents. The intervention group took part in a multidisciplinary program for 24 months. This program was based on 11 group sessions (8 main sessions and 3 additional support ones) for adolescents and their guardians. The control group received usual care at primary care level. Longitudinal regression models were adjusted to assess the evolution of anthropometric measures and living habits at baseline, 3, 6, 12, and 24 months in both groups.

RESULTS

There were 92 participants, equally distributed by group. Statistically significant differences were observed between intervention and control groups in several results: evolution of the body mass index; increase in the consumption of fruits and vegetables; decrease in the consumption of snacks and sweetened drinks; and increase in the number of days per week with more than one hour of physical activity.

CONCLUSIONS

The results confirm the effectiveness of this multidisciplinary program, both in the evolution of the body mass index, and in the improvement of the eating and physical activity habits, all of them risk factors for the future development of metabolic diseases, such as T2DM.

Effect of a Scalable School-Based Intervention on Cardiorespiratory Fitness in Children: A Cluster Randomized Clinical Trial

IMPORTANCE

Cardiorespiratory fitness is an important marker of childhood health and low fitness levels are a risk factor for disease later in life. Levels of children's fitness have declined in recent decades. Whether school-based physical activity interventions can increase fitness at the population level remains unclear.

OBJECTIVE

To evaluate the effect of an internet-based intervention on children's cardiorespiratory fitness across a large number of schools.

DESIGN, SETTING, AND PARTICIPANTS

In this cluster randomized clinical trial, 22 government-funded elementary schools (from 137 providing consent) including 1188 students stratified from grades 3 and 4 in New South Wales, Australia, were randomized. The other schools received the intervention but were not included in the analysis. Eleven schools received the internet-based intervention and 11 received the control intervention. Recruitment and baseline testing began in 2016 and ended in 2017. Research assistants, blinded to treatment allocation, completed follow-up outcome assessments at 12 and 24 months. Data were analyzed from July to August 2020.

INTERVENTIONS

The internet-based intervention included standardized online learning for teachers and minimal in-person support from a project mentor (9-10 months).

MAIN OUTCOMES AND MEASURES

Multistage 20-m shuttle run test for cardiorespiratory fitness.

RESULTS

Of 1219 participants (49% girls; mean [SD] age, 8.85 [0.71] years) from 22 schools, 1188 students provided baseline primary outcome data. At 12 months, the number of 20-m shuttle runs increased by 3.32 laps (95% CI, 2.44-4.20 laps) in the intervention schools and 2.11 laps (95% CI, 1.38-2.85 laps) in the control schools (adjusted difference = 1.20 laps; 95% CI, 0.17-2.24 laps). By 24 months, the adjusted difference was 2.22 laps (95% CI, 0.89-3.55 laps). The cost per student was AUD33 (USD26).

CONCLUSIONS AND RELEVANCE

In this study, a school-based intervention improved children's cardiorespiratory fitness when delivered in a large number of schools. The low cost and sustained effect over 24 months of the intervention suggests that it may have potential to be scaled at the population level.

TRIAL REGISTRATION

http://anzctr.org.au Identifier: ACTRN12616000731493.

The Effectiveness of School-Based Interventions on Obesity-Related Behaviours in Primary School Children: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

School-based interventions are promising for targeting a change in obesity-related behaviours in children. However, the efficacy of school-based interventions to prevent obesity remains unclear. This review examined the effectiveness of school-based interventions at changing obesity-related behaviours (increased physical activity, decreased sedentary behaviour and improved nutrition behaviour) and/or a change in BMI/BMI z-score. Following PRISMA guidelines, seven databases were systematically searched from 1 January 2009 to 31 December 2020. Two review authors independently screened studies for eligibility, completed data extraction and assessed the risk of bias of each of the included studies. Forty-eight studies met the inclusion criteria and were included in a narrative synthesis. Thirty-seven studies were eligible for inclusion in a meta-analysis. The findings demonstrate that interventions in children when compared to controls resulted in a small positive treatment effect in MVPA in the control group (2.14; 95% CI = 0.77, 3.50). There was no significant effect on sedentary behaviour, energy intake, and fruit and vegetable intake, and BMI kg/m2. A small significant reduction was found between groups in BMI z-score (-0.04; 95% CI = -0.07, -0.01) in favour of the intervention. The findings have important implications for future intervention research in terms of the effectiveness of intervention components and characteristics.

The effect of a one-year vigorous physical activity intervention on fitness, cognitive performance and mental health in young adolescents: the Fit to Study cluster randomised controlled trial

Background

Physical activity (PA) may positively stimulate the brain, cognition and mental health during adolescence, a period of dynamic neurobiological development. High-intensity interval training (HIIT) or vigorous PA interventions are time-efficient, scalable and can be easily implemented in existing school curricula, yet their effects on cognitive, academic and mental health outcomes are unclear. The primary aim of the Fit to Study trial was to investigate whether a pragmatic and scalable HIIT-style VPA intervention delivered during school physical education (PE) could improve attainment in maths. The primary outcome has previously been reported and was null. Here, we report the effect of the intervention on prespecified secondary outcomes, including cardiorespiratory fitness, cognitive performance, and mental health in young adolescents.

Methods

The Fit to Study cluster randomised controlled trial included Year 8 pupils (n = 18,261, aged 12–13) from 104 secondary state schools in South/Mid-England. Schools were randomised into an intervention condition (n = 52), in which PE teachers delivered an additional 10 min of VPA per PE lesson for one academic year (2017–2018), or into a “PE as usual” control condition. Secondary outcomes included assessments of cardiorespiratory fitness (20-m shuttle run), cognitive performance (executive functions, relational memory and processing speed) and mental health (Strength and Difficulties Questionnaire and self-esteem measures). The primary intention-to-treat (ITT) analysis used linear models and structural equation models with cluster-robust standard errors to test for intervention effects. A complier-average causal effect (CACE) was estimated using a two-stage least squares procedure.

Results

The HIIT-style VPA intervention did not significantly improve cardiorespiratory fitness, cognitive performance (executive functions, relational memory or processed speed), or mental health (all p > 0.05). Subgroup analyses showed no significant moderation of intervention effects by sex, socioeconomic status or baseline fitness levels. Changes in cardiorespiratory fitness were not significantly related to changes in cognitive or mental health outcomes. The trial was marked by high drop-out and low intervention compliance. Findings from the CACE analysis were in line with those from the ITT analysis.

Conclusion

The one-academic year HIIT-style VPA intervention delivered during regular school PE did not significantly improve fitness, cognitive performance or mental health, but these findings should be interpreted with caution given low implementation fidelity and high drop-out. Well-controlled, large-scale, school-based trials that examine the effectiveness of HIIT-style interventions to enhance cognitive and mental health outcomes are warranted.

Trial registration

ISRCTN registry, 15,730,512. Trial protocol and analysis plan for primary outcome prospectively registered on 30th March 2017.

ClinicalTrials.gov, NCT03286725. Secondary measures (focus of current manuscript) retrospectively registered on 18 September 2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-021-01113-y.

Examining moderators of the effectiveness of a web- and video-based computer-tailored physical activity intervention

Understanding for whom behaviour change interventions work is important, however there is a lack of studies examining potential moderators in such interventions. This study investigated potential moderators on the effectiveness of a computer-tailored intervention to increase physical activity among Australian adults. People who had <150 min of moderate-vigorous physical activity (MVPA) a week, able to speak and read English, aged ≥18 years, lived in Australia, and had internet access were eligible to participate. Participants recruited through social media, emails, and third-party databases, were randomly assigned to either the control (n = 167) or intervention groups (n = 334). Physical activity was measured objectively by ActiGraph GT3X and also by self-report at baseline and three months. Three-way interaction terms were tested to identify moderators (i.e., demographic characteristics, BMI, and perceived neighbourhood walkability). The results showed that the three-way interaction was marginally significant for sex on accelerometer measured MVPA/week (p = 0.061) and steps/day (p = 0.047). The intervention appeared to be more effective for women compared to men. No significant three-way interactions were found for the other potential moderators. Strategies to improve levels of personalisation may be needed so that physical activity interventions can be better tailored to different subgroups, especially sex, and therefore improve intervention effectiveness.

[Tackling risk factors for type 2 diabetes in adolescents: PRE-STARt study in Euskadi]

INTRODUCTION

Obesity in the child population and its effect in the development of metabolic diseases are a public health issue. One of the aims of the European Project PRE-STARt in Euskadi, is the evaluation of the effectiveness of a multidisciplinary health promotion program directed at adolescents with risk factors associated with the development of type 2 Diabetes Mellitus (T2DM).

PATIENTS AND METHODS

Randomised clinical trial with two groups of 12-14 year-old overweight adolescents. The intervention group took part in a multidisciplinary program for 24 months. This program was based on 11 group sessions (8 main sessions and 3 additional support ones) for adolescents and their guardians. The control group received usual care at primary care level. Longitudinal regression models were adjusted to assess the evolution of anthropometric measures and living habits at baseline, 3, 6, 12, and 24 months in both groups.

RESULTS

There were 92 participants, equally distributed by group. Statistically significant differences were observed between intervention and control groups in several results: evolution of the body mass index; increase in the consumption of fruits and vegetables; decrease in the consumption of snacks and sweetened drinks; and increase in the number of days per week with more than one hour of physical activity.

CONCLUSIONS

The results confirm the effectiveness of this multidisciplinary program, both in the evolution of the body mass index, and in the improvement of the eating and physical activity habits, all of them risk factors for the future development of metabolic diseases, such as T2DM.

The role of income and neighbourhood poverty in the association between the 2009 Special Supplemental Nutrition Program for Women, Infants and Children (WIC) food package change and child obesity among WIC-participating children in Los Angeles County, 2003-2016

OBJECTIVE

To determine whether a previously reported association between the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) food package change and reduced child obesity risk among WIC-participating children in Los Angeles County holds across levels of family income and neighbourhood poverty.

DESIGN

Analysis of prospectively collected WIC administrative data. The outcome was obesity at age 4 years (BMI-for-age ≥ 95th percentile). Poisson regression was applied to a matched sample (n 79 502) to determine if the association between the WIC food package change and child obesity was modified by family income (<50 % federal poverty level (FPL), 50-100 % FPL, >100 % but <185 % FPL) and neighbourhood poverty.

SETTING

Los Angeles County, California.

PARTICIPANTS

Children who participated in WIC in Los Angeles County between 2003 and 2016; children were grouped as receiving the old WIC food package (2003-2009) or the new WIC food package (2010-2016).

RESULTS

Receiving the new WIC food package (i.e., post-2009) was associated with 7-18 % lower obesity risk across all family income categories. Neither family income nor neighbourhood poverty significantly modified the association between the WIC food package and child obesity. However, certain sub-groups seemed to benefit more from the food package change than others. In particular, boys from families with income above poverty but residing in the poorest neighbourhoods experienced the greatest reductions in obesity risk (relative risk = 0·77; 95 % CI 0·66, 0·88).

CONCLUSIONS

The WIC food package revisions were associated with reduced childhood obesity risk among all WIC-participating families in Los Angeles County, across levels of income eligibility and neighbourhood poverty.

Changing activity behaviours in vocational school students: the stepwise development and optimised content of the 'let's move it' intervention

Background: School-based interventions that increase physical activity (PA) in a sustainable way are lacking. Systematic and participatory, theory and evidence-based intervention development may enhance the effectiveness of complex behavioural interventions in the long term. However, detailed descriptions of the intervention development process are rarely openly published, hindering transparency and progress in the field. Aims: To illustrate a stepwise process to develop intervention targeting PA and sedentary behaviour (SB) among older adolescents, and to describe the final, optimised version of the intervention, detailing content of sessions by theoretical determinants and techniques. Methods: Two established intervention development frameworks (Intervention Mapping and Behaviour Change Wheel) were integrated, leading to a comprehensive evidence and theory-based process. It was informed by empirical studies, literature reviews, expert and stakeholder consultation, including scenario evaluation and component pre-testing. In all steps, contextual fit and potential for sustainability were ensured by stakeholder engagement. Results: As a large majority of youth opposed decreasing screen time, increasing PA and decreasing SB were defined as target behaviours, with peers and the school context including classroom practices as key social environments in influencing youth PA (problem specification, step 1). Behavioural diagnosis (step 2) identified a variety of determinants in the domains of capability (e.g. self-regulation skills), motivation (e.g. outcome expectations) and environmental opportunities. These were organised into an intervention theory integrating several formal theories, including Self-Determination Theory. Theory-aligned principles guided material design (Step 3). Feasibility RCT allowed optimisation into a final intervention protocol (step 4). Conclusions: Intervention elements target students directly, and indirectly by changing teacher behaviour and the school and wider environment. A systematic development and optimisation led to a high potential for sustainability. The detailed intervention content, with specification of the hypothesised mechanisms, allows for other researchers to replicate, adapt or refine parts or the whole intervention, considering specific target groups and (sub-)cultures.

Weight-related quality of life and temperament as predictors and moderators of outcomes among treatment-seeking, low-income, ethnically diverse children with obesity

Within any childhood obesity treatment program, some children have better outcomes than others. Little is known about predictors or moderators of more positive outcomes. We aimed to identify whether child temperament and weight-related quality of life predict or moderate childhood obesity treatment outcomes at 6 months. From 2015 to 2016, children (n = 97) ages 5-11 years old with obesity were randomized to a clinic-community (Bull City Fit) or a clinic-only treatment program. Linear regression was used to explore whether dimensions of child temperament and weight-related quality of life predicted or moderated 6-month anthropometric and physical activity outcomes. Children who had more social avoidance due to their weight at baseline had significantly better improvements in body fat percent in the clinic-community model compared with the clinic-only model at 6 months. Across programs, better baseline social quality of life predicted greater increases in waist circumference; conversely, better physical quality of life predicted a decrease in percent of the 95th percentile. Also, children with longer attention spans had greater increases in physical activity. Our findings suggest that children who have social avoidance due to their weight may benefit most from comprehensive clinic-community treatment. Weight-related quality of life may influence outcomes across all treatments, and practitioners need to carefully counsel children experiencing weight negatively.

'Jump start' childcare-based intervention to promote physical activity in pre-schoolers: six-month findings from a cluster randomised trial

BACKGROUND

Participation in adequate levels of physical activity during the early years is important for health and development. We report the 6-month effects of an 18-month multicomponent intervention on physical activity in early childhood education and care (ECEC) settings in low-income communities.

METHODS

A cluster randomised controlled trial was conducted in 43 ECEC settings in disadvantaged areas of New South Wales, Australia. Three-year-old children were recruited and assessed in the first half of 2015 with follow-up 6 months later. The intervention was guided by Social Cognitive Theory and included five components. The primary outcome was minutes per hour in total physical activity during ECEC hours measured using Actigraph accelerometers. Intention-to-treat analysis of the primary outcome was conducted using a generalized linear mixed model.

RESULTS

A total of 658 children were assessed at baseline. Of these, 558 (85%) had valid accelerometer data (mean age 3.38y, 52% boys) and 508 (77%) had valid accelerometry data at 6-month follow-up. Implementation of the intervention components ranged from 38 to 72%. There were no significant intervention effects on mins/hr. spent in physical activity (adjusted difference = - 0.17 mins/hr., 95% CI (- 1.30 to 0.97), p = 0.78). A priori sub-group analyses showed a greater effect among overweight/obese children in the control group compared with the intervention group for mins/hr. of physical activity (2.35mins/hr., [0.28 to 4.43], p = 0.036).

CONCLUSIONS

After six-months the Jump Start intervention had no effect on physical activity levels during ECEC. This was largely due to low levels of implementation. Increasing fidelity may result in higher levels of physical activity when outcomes are assessed at 18-months.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry  ACTRN12614000597695.

Childcare Center Characteristics Moderate the Effects of a Physical Activity Intervention

Center-based early childhood education and care (ECEC) programs are well-positioned to create positive impacts on the health and development of large numbers of young children by promoting physical activity using evidence-based programs. Studies testing physical activity programs for young children should examine the circumstances under which programs are most effective by assessing the role of contextual factors on program outcomes. The purpose of this study was to examine the moderating effects of baseline ECEC center characteristics on the relationship between the Study of Health and Activity in Preschool Environments (SHAPES) intervention and moderate-to-vigorous physical activity (MVPA). MVPA was assessed via accelerometry; center characteristics, practices, and social and physical environments were assessed by director interview and observation; and center quality was assessed using the Early Childhood Environment Rating Scale-Revised Edition. Mixed-model analyses of covariance (ANCOVAs) examined intervention effects on MVPA during the school day; interactions between baseline center variables and group assignment (intervention vs. control) tested for moderation. Two center instructional practices, two social environment characteristics, and one physical environment characteristic at baseline moderated the effects of SHAPES on MVPA outcomes. Assessing baseline practices and center characteristics may aid efforts to match centers with interventions likely to increase physical activity as well as suggest additional intervention strategies to test.

The effect of the 2009 WIC food package change on childhood obesity varies by gender and initial weight status in Los Angeles County

OBJECTIVE

To assess whether the effect of the 2009 women, infants, and children (WIC) food package change on obesity outcomes varies by initial weight status and gender.

METHODS

Using 2003 to 2016 data from Los Angeles County, we compared growth trajectories and obesity at age 4 years among children exposed to WIC after the food package change (n = 53 075) vs children exposed before (n = 53 075). Analyses were stratified by gender and initial weight status: low weight-for-height z-score (WHZ ≤ 25th percentile), average WHZ (25th < WHZ < 75th percentile), and high WHZ (WHZ ≥ 75th percentile). Within strata, children exposed to the new vs old packages were matched on sociodemographic characteristics and compared using growth models and Poisson regression.

RESULTS

Mean WHZ trajectories for children exposed to the new food package, compared with the old, tended to be lower during ages 1 to 5 years. For boys, the new food package was associated with 10% to 14% lower obesity risk at age 4 years in all initial weight status strata. For girls, the new package was associated with 16% lower obesity risk at age 4 years only for those with average WHZ at baseline.

CONCLUSIONS

The change in WIC food packages appears to be associated with obesity prevention benefits for boys regardless of initial weight status, with more limited benefits for girls.

Factors affecting the dose of intervention received and the participant satisfaction in a school-based obesity prevention intervention

This study assessed factors associated with the perceived dose of intervention received and with the participant satisfaction in a school-based obesity prevention intervention. It also explored the variance in the dose of intervention received that was at the school level. Process evaluation data from a school-based intervention study conducted in Oslo in 2007-2009 were used. A total of 542 11-year-olds from 12 intervention schools were included. A web-based questionnaire was used to collect data. Descriptive analyses and multilevel regression analyses were conducted. Females and those with medium (vs. low) parental education had higher odds of reporting a high vs. low dose of intervention received at mid-way (8 months after baseline). Perceived social capital and perceived social support for physical activity from friends at baseline were positively associated with the dose of intervention received at mid-way. Perceived social capital at mid-way was positively associated with the dose of intervention reported post-intervention (20 months after baseline). Around 20% of the variance in the perceived dose of intervention received was at the school level. Satisfaction with the intervention was high overall and higher for females for several intervention components at mid-way and at post-intervention. The factors identified in this study should be taken into consideration when planning future obesity prevention interventions among youth.

School-based physical activity intervention for older adolescents: rationale and study protocol for the Burn 2 Learn cluster randomised controlled trial

INTRODUCTION

This trial aims to investigate the impact of a school-based physical activity programme, involving high-intensity interval training (HIIT), on the physical, mental and cognitive health of senior school students.

METHODS AND ANALYSIS

The Burn 2 Learn (B2L) intervention will be evaluated using a two-arm parallel group cluster randomised controlled trial with allocation occurring at the school level (to treatment or wait-list control). Schools will be recruited in two cohorts from New South Wales, Australia. The trial will aim to recruit ~720 senior school students (aged 16-18 years) from 20 secondary schools (ie, 10 schools per cohort). A range of implementation strategies will be provided to teachers (eg, training, equipment and support) to facilitate the delivery of HIIT sessions during scheduled classes. In phase I and II (3 months each), teachers will facilitate the delivery of at least two HIIT sessions/week during lesson-time. In phase III (6 months), students will be encouraged to complete sessions outside of lesson-time (teachers may continue to facilitate the delivery of B2L sessions during lesson-time). Study outcomes will be assessed at baseline, 6 months (primary end point) and 12 months. Cardiorespiratory fitness (shuttle run test) is the primary outcome. Secondary outcomes include: vigorous physical activity, muscular fitness, cognition and mental health. A subsample of students will (i) provide hair samples to determine their accumulated exposure to stressful events and (ii) undergo multimodal MRI to examine brain structure and function. A process evaluation will be conducted (ie, recruitment, retention, attendance and programme satisfaction).

ETHICS AND DISSEMINATION

This study has received approval from the University of Newcastle (H-2016-0424) and the NSW Department of Education (SERAP: 2017116) human research ethics committees.

TRIAL REGISTRATION NUMBER

ACTRN12618000293268; Pre-results.

Effects of 1 y of free school fruit on intake of fruits, vegetables, and unhealthy snacks: 14 y later

Background

There are not many studies evaluating the long-term effects of fruit and vegetable interventions.

Objective

We examined the effects of 1 y of free fruit in elementary school on long-term consumption of fruit, vegetables, and unhealthy snacks, according to sex and educational attainment, 14 y after the intervention period.

Design

In 2001, the baseline survey of the longitudinal cohort, Fruits and Vegetables Make the Marks (FVMM), included 1950 children (mean age: 11.8 y) attending 38 randomly drawn elementary schools from 2 counties in Norway. In the following 10 mo, 9 schools served as intervention schools by participating in the Norwegian School Fruit Program for free, whereas 29 schools served as control schools. A follow-up survey conducted in 2016 included 982 participants (50%) from the original study sample (mean age: 26.5 y). The consumption of fruit and vegetables was measured by a 24-h recall (portions per day), and the consumption of unhealthy snacks was measured by food-frequency questions (portions per week). Linear mixed models were performed to test possible intervention effects on the consumption of fruit, vegetables, and unhealthy snacks 14 y after the intervention period.

Results

No overall intervention effects after 14 y due to the free-fruit scheme on the consumption of fruit, vegetables, and unhealthy snacks were observed, but significant interactions showed a sustained higher frequency of fruit consumption among females in the intervention group compared with the control group [mean difference (MD): 0.38 portions/d; P = 0.023] and that this effect was only significant among less-educated females (MD: 0.73 portions/d; P = 0.043). No significant long-term intervention effects were observed in the consumption of fruit among highly educated females and males nor in the consumption of vegetables or unhealthy snacks.

Conclusion

Results from the present study indicate that receiving free fruit at school for 1 y may have positive long-term effects for females without higher education.

Implementing Resistance Training in Secondary Schools: A Cluster Randomized Controlled Trial

PURPOSE

Guidelines recommend that young people engage in muscle-strengthening activities on at least 3 d·wk. The purpose of this study was to examine the effect of a school-based intervention focused on resistance training (RT) for adolescents.

METHODS

The "Resistance Training for Teens" intervention was evaluated using a cluster-randomized, controlled trial with 607 adolescents (50.1% girls; 14.1 ± 0.5 yr) from 16 secondary schools. Teachers were trained to deliver the intervention, which included the following: (i) an interactive student seminar; (ii) a structured physical activity program, focused on RT; (iii) lunchtime fitness sessions; and (iv) Web-based smartphone apps. The primary outcome was muscular fitness (MF) and secondary outcomes included body mass index, RT skill competency, flexibility, physical activity, self-efficacy, and motivation. Assessments were conducted at baseline, 6 months (postprogram; primary end point), and 12 months (follow-up). Outcomes were assessed using linear mixed models, with three potential moderators tested using interaction terms (and subgroup analyses where appropriate).

RESULTS

For the primary outcome (MF), a group-time effect was observed at 6 months for the upper body (2.0 repetitions; 95% confidence interval (CI), 0.8-3.2), but not the lower body (-1.4 cm; 95% CI, -4.7-1.9). At 6 months, there were intervention effects for RT skill competency and self-efficacy, but no other secondary outcomes. Effects for upper body MF and RT skill competency were sustained at 12 months. Despite overall no effect for body mass index, there was a group-time effect at 12 months among students who were overweight/obese at baseline (-0.55 kg·m; 95% CI, -1.01 to -0.08).

CONCLUSIONS

The school-based RT intervention resulted in immediate and sustained improvements in upper body MF and RT skill competency, demonstrating an effective and scalable approach to delivering RT within secondary schools.

Does the distribution frequency matter? A subgroup specific analysis of the effectiveness of the EU School Fruit and Vegetable Scheme in Germany comparing twice and thrice weekly deliveries

OBJECTIVE

The present study aimed to examine the effectiveness of two different implementation forms of the EU School Fruit and Vegetable Scheme (SFVS).

DESIGN

A quasi-experimental design was applied including a thrice as well as a twice weekly intervention group. Repeated 24 h dietary recalls were used to measure children's fruit and vegetable (F&V) intake. Effects were analysed on days with and without F&V deliveries using hierarchical linear regression models.

SETTING

Twelve primary schools in North Rhine-Westphalia, Germany.

SUBJECTS

Third and fourth graders (n 664).

RESULTS

Average daily F&V intake at pre-intervention was 0·84 frequencies in the thrice weekly intervention group, 0·90 frequencies in the twice weekly intervention group and 1·25 frequencies in the control group. Providing children thrice weekly with F&V increased children's F&V intake on average by 0·96 (P<0·001) frequencies/d. The effects were higher on days with (1·07; P<0·001) than on days without (0·75; P<0·001) F&V deliveries. Distributing F&V twice weekly resulted in an increase of 0·75 (P<0·001) frequencies/d on average, again with higher effects on days with (1·30; P<0·001) than without (0·48; P<0·003) F&V deliveries. Subgroup analysis revealed some indications for differential effectiveness only in the twice weekly intervention group.

CONCLUSIONS

The SFVS with thrice or twice weekly deliveries of F&V led to a significant increase in children's F&V intake on days with and without deliveries. The latter might provide an indication of positive long-term effects of the scheme. The scheme shows equal efficiency for almost all subgroups.

Impact and Moderating Variables of an Intervention Promoting Physical Activity Among Children: Results From a Pilot Study

This pilot study pursued three objectives: to assess the effect of a 1-month multilevel intervention on the PA of children, to assess the impact of the intervention on the theory of planned behavior (TPB) variables, and to evaluate the extent to which the impact of the intervention on PA and TPB variables varied according to personal (i.e., gender and age) and situational (i.e., class and school) moderating variables. Children were aged 7 to 11 years ( n = 306). Analyses revealed a significant increase of PA practice and TPB variables ( ps < .001). Age (i.e., being a younger child) was associated with a higher increase on attitude and perceived control ( ps < .01). The class or the school levels explained a meaningful variance in the evolution of PA or TPB variables (intraclass correlation coefficients > .10). The present study reports the interest and feasibility of a multilevel intervention to increase PA and TPB variables in children.

A Mixed-Methods Comparison of Classroom Context During Food, Health & Choices, a Childhood Obesity Prevention Intervention

BACKGROUND

Schools are frequent settings for childhood obesity prevention; however, intervention results are mixed. Classroom context may hold important clues to improving these interventions.

METHODS

We used mixed methods to examine classroom context during a curriculum intervention taught by trained instructors in fifth grade classrooms. We identified classrooms with high and low buy-in using cluster analysis and compared intervention delivery and reception, student energy balance-related behavior, and student perceptions about supports and barriers to energy balance.

RESULTS

Delivery and reception did not differ between the groups. Between-group differences in unhealthy behaviors were smaller at posttest, due to improvement in low buy-in classes. Although student perceptions of supports and barriers to energy balance were similar across groups, students in high buy-in classes indicated food preferences as a support while students in low buy-in classes indicated food preferences as a barrier. Neighborhood environment emerged as a universal barrier.

CONCLUSIONS

Trained instructors may improve intervention delivery and reception regardless of classroom context. Social norms could explain high levels of unhealthy behavior in low buy-in classes at baseline; improvement at posttest suggests that the curriculum may have motivated change. All children need more strategies and supportive policies to overcome a challenging food environment.

A school-based rope skipping program for adolescents: Results of a randomized trial

Despite physical education's health enhancing potential, students' activity levels in lessons are low. We evaluated a school-based intervention that involved rope skipping on students' moderate-to-vigorous physical activity (MVPA) in physical education. The intervention was evaluated using a clustered randomized controlled trial in 24 classes (N=731 students; M=14.38years; all from Secondary 2) from 12 Hong Kong schools during September to December 2013. The primary outcome was percentage of lesson time spent in MVPA. Secondary outcomes included students' vigorous activity, counts per minute, perceived autonomy support and motivation for physical education. Accelerometer-based activity measures were taken from a sub-sample of 168 students during lessons 1 to 3 (baseline) and lessons 5 to 7 (treatment phase). Participants self-reported motivation variables at lessons 4 and 8. Teachers allocated to the experimental group included an intervention during treatment phase; those in the control group continued usual practices. The intervention involved a 15-minute rope skipping activity where students completed intervals of skipping with rests in between. Using multilevel modeling, we examined the intervention effects on measured outcomes, and whether effects differed for boys and girls. Overall intervention effects were not found. However, girls in the intervention group spent more time in MVPA (β=0.25) and had higher counts per minute (β=0.32) than control group counterparts at treatment phase. Perceived autonomy support and motivation variables were similar across groups. The intervention increased activity levels of girls, but not boys. Implementation of the intervention may reduce differences between boys' and girls' physical education activity levels.

TRIAL REGISTRATION

ANZCTR: ACTRN12613000968774.

Effectiveness of a Playground Intervention for Antisocial, Prosocial, and Physical Activity Behaviors

BACKGROUND

We examined the effectiveness of Peaceful Playgrounds™ (P2) to decrease antisocial behaviors (ASB) while increasing physical activity (PA) and prosocial behaviors (PSB) in elementary school children.

METHODS

A longitudinal, cluster-randomized design was employed in 4 elementary school playgrounds where students (third to fifth) from 2 intervention and 2 control schools were observed during recess periods. The intervention included environmental changes (eg, marked surfaces) and student education. Data were collected using systematic observations of youth behavior and semistructured interviews conducted with key informants. Mixed-effects regression models controlling for scans nested within days nested within schools estimated the interaction of measurement period and treatment condition on children's PA, PSB, and ASB. It was hypothesized that children in intervention, but not control schools, would demonstrate increased PA/PSB and decreased ASB.

RESULTS

Contrary to the hypotheses, intervention and control schools showed favorable changes for all dependent variables except for PSB, but 1 intervention and 1 control school drove these effects. Follow-up interviews indicated variability in implementation and lack of adherence to the control condition.

CONCLUSIONS

P2 may promote increased PA during recess, but these results demonstrate the complexity of intervention implementation and the need for rigor when measuring intervention fidelity in real-world settings.

The effect of an online video intervention 'Movie Models' on specific parenting practices and parental self-efficacy related to children's physical activity, screen-time and healthy diet: a quasi experimental study

Background

In children, being sufficiently physically active, having low levels of screen-time and having a healthy diet are largely influenced by parenting practices. Children of parents applying positive parenting practices are at lower risk for overweight and obesity. Therefore, we investigated the effect of a health promoting online video intervention for parents (‘Movie Models’) on children’s physical activity (PA), screen-time and healthy diet, and on specific parenting practices and parental self-efficacy related to these parenting practices. The online videos are delivered to parents of primary schoolchildren, and were based on real-life scenarios.

Methods

A two-armed, quasi experimental design was used. Parents of primary schoolchildren were recruited between November and December 2013 by spreading an appeal in social media, and by contacting primary schools. Participating parents were predominantly of high socio-economic status (SES) (83.1%), and only 6.8% of children were overweight/obese. Intervention group participants were invited to watch online videos for 4 weeks. Specific parenting practices, parental self-efficacy, PA, screen-time and healthy diet of the child were assessed at baseline (T0), at one (T1) and at four (T2) months post baseline. Repeated Measures (Multivariate) ANOVAs were used to examine intervention effects. The potential moderating effect of age and gender of the child and parental SES was also examined.

Results

Between T0 and T2, no significant intervention effects were found on children’s PA, screen-time or healthy diet. Most significant intervention effects were found for more complex parenting practices (e.g., an increase in motivating the child to eat fruit). Subgroup analyses showed that the intervention had more effect on the actual parenting practices related to PA, screen-time and healthy diet in parents of older children (10–12 years old), whereas intervention effects on parental self-efficacy related to those behaviors were stronger in parents of younger children (6–9 years old).

Conclusions

‘Movie Models’ was effective in increasing some important parenting practices and parental self-efficacy related to PA, screen-time and healthy diet in children. Therefore, the current study is an important first step in promoting effective parenting-related factors, and possibly increasing children’s healthy diet and PA, and decreasing screen-time.

Trial registration

NCT02278809 in ClinicalTrials.gov on October 28, 2014 (retrospectively registered).

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4264-1) contains supplementary material, which is available to authorized users.

"For whom was it effective?" Moderators of the effect of a school-based intervention on potential physical activity determinants among Brazilian students

Knowledge about the effects of school-based interventions on modifiable physical activity (PA) determinants (e.g., social support), and whether the intervention effect differs according to students' characteristics (e.g., age and gender) are relevant PA promotion topics. This study aims to answer these topics among Brazilian students. This cluster-randomized controlled trial was conducted with 548 students in the intervention group and 537 in the control group (51.5% of boys; aged 11-18years). The four-month intervention included strategies focused on training teachers, opportunities for PA in the school environment, and health education. Potential PA determinants (attitude, self-efficacy, support of friends, parents, and teachers, perceived neighborhood environment and PA facilities in school) and moderators (gender, age, socioeconomic status (SES), and PA level at baseline) were assessed using self-reported instrument. Height and weight were measured to estimate the students' body mass index (BMI) status. Generalized linear models were used. In general, there was a significant and positive intervention effect for attitude, support of friends and teachers for PA, as well as PA facilities in school; effect size was 0.29, 0.24, 0.34, and 0.29, respectively (P<0.05). Age (support of friends, parents and teachers, and PA facilities in school), SES (support of friends and PA facilities in school), and BMI status (support of friends) were moderators of the intervention effect on some outcomes. In conclusion, the intervention improved potential PA determinants, but some changes occurred differently according to students' characteristics. These findings should be considered in PA policies in the school context.

TRIAL REGISTRATION

This study is registered at Clinicaltrials.govNCT02439827.

Curricular activities and change in determinants of fruit and vegetable intake among adolescents: Results from the Boost intervention

Knowledge of the association between implementation of different intervention components and the determinants they are tailored to change may contribute to evaluating the effects and working mechanisms of multi-component interventions. This study examined 1) the effect of a Danish multi-component school-based intervention (2010 − 2011) on key determinants of adolescents' fruit and vegetable intake and 2) if dose of curricular activities was positively associated with change in these determinants. Using multi-level linear and logistic regression analyses stratified by gender and socioeconomic position, we analyzed survey data from the cluster-randomized Boost study targeting Danish 13-year-olds' fruit and vegetable intake. We examined 1) differences in knowledge of recommendations, taste preferences and situational norms between students from 20 intervention (n = 991) and 20 control (n = 915) schools at follow-up; and 2) associations between curriculum dose received and delivered (student and teacher data aggregated to school- and class-level) and these determinants among students at intervention schools only. At follow-up, more students from intervention than control schools knew the recommendation for vegetable intake (OR 1.56, CI:1.18, 2.06) and number of fruits liked (taste preferences) increased by 0.22 (CI:0.04, 0.41). At class-level, curriculum dose received was positively associated with proportion of students knowing the recommendation for vegetable intake (OR 1.06, CI:1.002, 1.13). In stratified analyses, this association was only significant among students from high social class (OR 1.17, CI:1.04, 1.31). The Boost intervention succeeded in improving students' taste preferences for fruit and knowledge of recommendation for vegetable intake, but only the latter determinant was positively associated with curriculum dose.

Trial registration: ISRCTN11666034

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Positive change in knowledge of recommendation for vegetable intake

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Positive change in taste preferences for fruit

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Knowledge of recommendation for vegetable intake was associated with curriculum dose

The Physical Activity 4 Everyone Cluster Randomized Trial: 2-Year Outcomes of a School Physical Activity Intervention Among Adolescents

INTRODUCTION

Few interventions have been successful in reducing the physical activity decline typically observed among adolescents. The aim of this paper is to report the 24-month effectiveness of a multicomponent school-based intervention (Physical Activity 4 Everyone) in reducing the decline in moderate to vigorous physical activity (MVPA) among secondary school students in disadvantaged areas of New South Wales, Australia.

STUDY DESIGN

A cluster RCT was conducted in five intervention and five control schools with follow-up measures taken at 24 months post-randomization.

SETTING/PARTICIPANTS

The trial was undertaken within secondary schools located in disadvantaged communities in New South Wales, Australia.

INTERVENTION

A multicomponent school-based intervention based on the Health Promoting Schools Framework was implemented. The intervention consisted of seven physical activity promotion strategies that targeted the curriculum (teaching strategies to increase physical activity in physical education lessons, student physical activity plans, and modification of school sport program); school environment (recess/lunchtime activities, school physical activity policy); parents (parent newsletters); and community (community physical activity provider promotion). Six additional strategies supported school implementation of the physical activity intervention strategies.

MAIN OUTCOME MEASURE

Minutes per day spent in MVPA, objectively measured by accelerometer.

RESULTS

Participants (N=1,150, 49% male) were a cohort of students aged 12 years (Grade 7) at baseline (March-June 2012) and 14 years (Grade 9) at follow-up (March-July 2014). At 24-month follow-up, there were significant effects in favor of the intervention group for daily minutes of MVPA. The adjusted mean difference in change in daily MVPA between groups was 7.0 minutes (95% CI=2.7, 11.4, p<0.002) (analysis conducted December 2014-February 2015). Sensitivity analyses based on multiple imputation were consistent with the main analysis (6.0 minutes, 95% CI=0.6, 11.3, p<0.031).

CONCLUSIONS

The intervention was effective in increasing adolescents' minutes of MVPA, suggesting that implementation of the intervention by disadvantaged schools has the potential to slow the decline in physical activity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12612000382875.

A school-based intervention incorporating smartphone technology to improve health-related fitness among adolescents: rationale and study protocol for the NEAT and ATLAS 2.0 cluster randomised controlled trial and dissemination study

INTRODUCTION

Physical inactivity has been described as a global pandemic. Interventions aimed at developing skills in lifelong physical activities may provide the foundation for an active lifestyle into adulthood. In general, school-based physical activity interventions targeting adolescents have produced modest results and few have been designed to be 'scaled-up' and disseminated. This study aims to: (1) assess the effectiveness of two physical activity promotion programmes (ie, NEAT and ATLAS) that have been modified for scalability; and (2) evaluate the dissemination of these programmes throughout government funded secondary schools.

METHODS AND ANALYSIS

The study will be conducted in two phases. In the first phase (cluster randomised controlled trial), 16 schools will be randomly allocated to the intervention or a usual care control condition. In the second phase, the Reach, Effectiveness, Adoption, Implementation and Maintenance (Re-AIM) framework will be used to guide the design and evaluation of programme dissemination throughout New South Wales (NSW), Australia. In both phases, teachers will be trained to deliver the NEAT and ATLAS programmes, which will include: (1) interactive student seminars; (2) structured physical activity programmes; (3) lunch-time fitness sessions; and (4) web-based smartphone apps. In the cluster RCT, study outcomes will be assessed at baseline, 6 months (primary end point) and 12-months. Muscular fitness will be the primary outcome and secondary outcomes will include: objectively measured body composition, cardiorespiratory fitness, flexibility, resistance training skill competency, physical activity, self-reported recreational screen-time, sleep, sugar-sweetened beverage and junk food snack consumption, self-esteem and well-being.

ETHICS AND DISSEMINATION

This study has received approval from the University of Newcastle (H-2014-0312) and the NSW Department of Education (SERAP: 2012121) human research ethics committees. This study is funded by the Australian Research Council (FT140100399) and the NSW Department of Education.

TRIAL REGISTRATION NUMBER

ACTRN12615000360516; Pre-results.

'Let's Move It' - a school-based multilevel intervention to increase physical activity and reduce sedentary behaviour among older adolescents in vocational secondary schools: a study protocol for a cluster-randomised trial

Background

Physical activity (PA) has been shown to decline during adolescence, and those with lower education have lower levels of activity already at this age, calling for targeted efforts for them. No previous study has demonstrated lasting effects of school-based PA interventions among older adolescents. Furthermore, these interventions have rarely targeted sedentary behaviour (SB) despite its relevance to health. The Let’s Move It trial aims to evaluate the effectiveness and the cost-effectiveness of a school-based, multi-level intervention, on PA and SB, among vocational school students. We hypothesise that the intervention is effective in increasing moderate-to-vigorous-intensity physical activity (MVPA), particularly among those with low or moderate baseline levels, and decreasing SB among all students.

Methods

The design is a cluster-randomised parallel group trial with an internal pilot study. The trial is conducted in six vocational schools in the Helsinki Metropolitan area, Finland. The intervention is carried out in 30 intervention classes, and 27 control classes retain the standard curriculum. The randomisation occurs at school-level to avoid contamination and to aid delivery.

Three of the six schools, randomly allocated, receive the ‘Let’s Move It’ intervention which consists of 1) group sessions and poster campaign targeting students’ autonomous PA motivation and self-regulation skills, 2) sitting reduction in classrooms via alterations in choice architecture and teacher behaviour, and 3) enhancement of PA opportunities in school, home and community environments. At baseline, student participants are blind to group allocation. The trial is carried out in six batches in 2015–2017, with main measurements at pre-intervention baseline, and 2-month and 14-month follow-ups. Primary outcomes are for PA, MVPA measured by accelerometry and self-report, and for SB, sedentary time and breaks in sedentary time (accelerometry).

Key secondary outcomes include measured body composition, self-reported well-being, and psychological variables. Process variables include measures of psychosocial determinants of PA (e.g. autonomous motivation) and use of behaviour change techniques. Process evaluation also includes qualitative interviews. Intervention fidelity is monitored.

Discussion

The study will establish whether the Let’s Move It intervention is effective in increasing PA and reducing SB in vocational school students, and identify key processes explaining the results.

Trial registration

ISRCTN10979479. Registered: 31.12.2015

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3094-x) contains supplementary material, which is available to authorized users.

Effects of a Theory-Based Education Program to Prevent Overweightness in Primary School Children

The effectiveness of the “Extra Fit!” (EF!) education program in promoting healthy diet and physical activity to prevent and reduce overweightness among primary school children aged 9 to 11 was evaluated. A randomized controlled design was carried out in 45 primary schools (n = 1112) in the Netherlands, 23 intervention and 22 control schools. The intervention schools received the education program for two successive school years in grades (U.S. system) 4, 5, and 6 (mean 7.6 h during 16 weeks per school per year). The control schools followed their usual curriculum. No positive effects of EF! were found with regard to behavior and anthropometric measures when follow-up measurements were compared to the baseline. However, from baseline to follow-up after one and two school years, the intervention group improved their knowledge score significantly compared to the control group. Moreover, an effect was observed for mean time spent inactively that increased more in the control group than in the intervention group. In conclusion, limited intervention effects were found for the intervention on knowledge and inactivity. To improve the effectiveness of education programs, we advise focusing on parental involvement, attractive lessons to enlarge the acceptability of the program, and multi-component environmental strategies.

A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents

Lack of physical activity (PA) and high levels of sedentary behaviour (SB) have been associated with health problems. This systematic review evaluates the effectiveness of school-based interventions to increase PA and decrease SB among 15-19-year-old adolescents, and examines whether intervention characteristics (intervention length, delivery mode and intervention provider) and intervention content (i.e. behaviour change techniques, BCTs) are related to intervention effectiveness. A systematic search of randomised or cluster randomised controlled trials with outcome measures of PA and/or SB rendered 10 results. Risk of bias was assessed using the Cochrane risk of bias tool. Intervention content was coded using Behaviour Change Technique Taxonomy v1. Seven out of 10 studies reported significant increases in PA. Effects were generally small and short-term (Cohen's d ranged from 0.132 to 0.659). Two out of four studies that measured SB reported significant reductions in SB. Interventions that increased PA included a higher number of BCTs, specific BCTs (e.g., goal setting, action planning and self-monitoring), and were delivered by research staff. Intervention length and mode of delivery were unrelated to effectiveness. More studies are needed that evaluate long-term intervention effectiveness and target SBs among older adolescents.

Physical activity and nutrition education at the school environment aimed at preventing childhood obesity: evidence from systematic reviews

OBJECTIVE

To organize the main findings and list the most frequent recommendations from systematic reviews of interventions developed at the school environment aimed at reducing overweight in children and adolescents.

DATA SOURCE

Searches for systematic reviews available until December 31, 2014 were conducted in five electronic databases: Cochrane, PubMed, SciELO, SPORTDiscus, and Web of Science. Manual search for cross-references were also performed.

SUMMARY OF THE FINDINGS

Of the initial 2139 references, 33 systematic reviews adequately met the inclusion criteria and were included in the descriptive summary. In this set, interventions with periods of time greater than six months in duration (nine reviews), and parental involvement in the content and/or planned actions (six reviews) were identified as the most frequent and effective recommendations. Additionally, it was observed that boys respond more effectively to structural interventions, whereas girls respond to behavioral interventions. None of the included reviews was able to make inferences about the theoretical basis used in interventions as, apparently, those in charge of the interventions disregarded this component in their preparation.

CONCLUSIONS

Although the summary identified evidence with important applications in terms of public health, there are still gaps to be filled in this field of knowledge, such as the effectiveness of different theoretical models, the identification of the best strategies in relation to gender and age of participants and, finally, the identification of moderating variables to maximize the benefits provided by the interventions.

'Physical Activity 4 Everyone' school-based intervention to prevent decline in adolescent physical activity levels: 12 month (mid-intervention) report on a cluster randomised trial

BACKGROUND

Adolescence is a recognised period of physical activity decline, particularly among low-income communities. We report the 12-month (midpoint) effects of a 2-year multicomponent physical activity intervention implemented in disadvantaged secondary schools.

METHODS

A cluster randomised trial was undertaken in 10 secondary schools located in disadvantaged areas in New South Wales, Australia. Students in Grade 7 were recruited, with follow-up in Grade 8. The intervention was guided by socioecological theory and included seven physical activity strategies, and six implementation adoption strategies. The primary outcome was mean minutes of moderate-to-vigorous physical activity (MVPA) per day assessed using Actigraph GT3X accelerometers. Outcome data were analysed using repeated measures linear mixed models.

RESULTS

At baseline, 1150 (93%) students participated in the data collection (mean age 12 years, 48% boys) and 1050 (79%) students participated at 12-month follow-up. By the 12-month follow-up, the six implementation adoption strategies had been used to support schools to deliver four of the seven physical activity elements. There was a significant group-by-time interaction for mean minutes of MVPA per day in favour of the intervention group (adjusted difference between groups at follow-up=3.85 min, 95% CI (0.79 to 6.91), p ≤ 0.01), including significantly more vigorous physical activity (2.45 min, p ≤ 0.01), equating to 27 min more MVPA per week.

SUMMARY

At 12-month follow-up, the intervention had reduced the decline in physical activity among adolescents from disadvantaged schools. The intervention may assist students to meet physical activity guidelines.

Effect of School-based Interventions to Control Childhood Obesity: A Review of Reviews

Effectiveness of school-based interventions to prevent or control overweight and obesity among school children was reviewed for a 11-year period (January 2001 to December 2011). All English systematic reviews, meta-analyses, reviews of reviews, policy briefs and reports targeting children and adolescents which included interventional studies with a control group and aimed to prevent or control overweight and/or obesity in a school setting were searched. Four systematic reviews and four meta-analyses met the eligibility criteria and were included in the review. Results of the review indicated that implementation of multi-component interventions did not necessarily improve the anthropometric outcomes. Although intervention duration is a crucial determinant of effectiveness, studies to assess the length of time required are lacking. Due to existing differences between girls and boys in responding to the elements of the programs in tailoring of school-based interventions, the differences should be taken into consideration. While nontargeted interventions may have an impact on a large population, intervention specifically aiming at children will be more effective for at-risk ones. Intervention programs for children were required to report any unwanted psychological or physical adverse effects originating from the intervention. Body mass index was the most popular indicator used for evaluating the childhood obesity prevention or treatment trials; nonetheless, relying on it as the only indicator for adiposity outcomes could be misleading. Few studies mentioned the psychological theories of behavior change they applied. Recommendations for further studies on school-based interventions to prevent or control overweight/obesity are made at the end of this review.

The role of curriculum dose for the promotion of fruit and vegetable intake among adolescents: results from the Boost intervention

Background

Multi-component interventions combining educational and environmental strategies have proved effective in increasing children and adolescents’ fruit and vegetable intake. However such interventions are complex and difficult to implement and several studies report poor implementation. There is a need for knowledge on the role of dose for behaviour change and for assessment of intervention dose to avoid conclusions that intervention components which are not implemented are ineffective. This study aimed to examine 1) the association between dose of a class curriculum and adolescents’ fruit and vegetable intake in a school-based multi-component intervention, 2) if gender and socioeconomic position modify this association.

Methods

We carried out secondary analysis of data from intervention schools in the cluster-randomized Boost study targeting 13-year-olds’ fruit and vegetable intake. Teacher- and student data on curriculum dose delivered and received were aggregated to the school-level and class-level (only possible for student data). We analysed the association between curriculum dose and students’ (n 995) self-reported fruit and vegetable intake (24-h recall questionnaire) after finalization of the intervention using multi-level analyses. Potential moderation was examined by analyses stratified by gender and socioeconomic position.

Results

Average dose received at class-level was significantly associated with students’ fruit and vegetable intake (10 g (CI: 0.06, 20.33) per curricular activity received). In stratified analyses the association remained significant among boys only (14 g (CI: 2.84, 26.76) per curricular activity received). The average dose delivered and received at the school-level was not significantly associated with students’ intake.

Conclusions

We found a dose—response relationship between number of curricular activities received and adolescents’ fruit and vegetable intake. The results indicate that curriculum dose received only mattered for promotion of fruit and vegetable intake among boys. Future studies should explore this gender difference in larger samples to guide the planning of school-based curricular interventions with regards to the optimal number of curricular activities required to promote behavioural change in subgroups with low fruit and vegetable intake at baseline.

Trial registration

Current Controlled Trials ISRCTN11666034.

Changes in adolescents' and parents' intakes of sugar-sweetened beverages, fruit and vegetables after 20 months: results from the HEIA study - a comprehensive, multi-component school-based randomized trial

Background

Interventions conducted in school-aged children often involve parents, but few studies have reported effects on parents’ own behaviour as a result of these interventions.

Objective

To determine if a multi-component, cluster randomized controlled trial targeting 11–13 year olds influenced their consumption of fruit, vegetables, sugar-sweetened soft drinks and fruit drinks, and to explore whether the results varied by gender, adolescent weight status or parental educational level. A final aim was to assess whether the parents’ intakes were affected by the intervention.

Design

Participants were 1,418 adolescents, 849 mothers and 680 fathers. Baseline and post-intervention data from the 20 months intervention study HEIA (HEalth In Adolescents) were included. Data were collected assessing frequency (and amounts; beverages only).

Results

No significant differences were found at baseline between the intervention and control groups, except for the parental groups (educational level and intakes). At post-intervention, the adolescents in the intervention group consumed fruit more frequently (P<0.001) and had a lower intake of sugar-sweetened fruit drinks compared to the control group (P=0.02). The parental educational level moderated the effect on intake of sugar-sweetened fruit drinks in adolescents. The intake was less frequent in the intervention groups compared to the control groups (P=0.02) for those who had parents with low and medium educational level. Furthermore, the intervention may have affected mothers’ fruit intake and the vegetable intake in higher educated fathers.

Conclusion

Favourable effects in favour of the intervention group were found for intake of fruit and sugar-sweetened fruit drinks among the adolescents in the HEIA study. Our results indicate that it is possible to reduce adolescents’ intake of sugar-sweetened fruit drinks across parental education, and potentially affect sub-groups of parents.

The impact of playworks on boys' and girls' physical activity during recess

BACKGROUND

School-based programs, such as Playworks, that guide students in organized activities during recess and make improvements to the recess play yard may lead to significant increases in physical activity-especially for girls. This study builds on past research by investigating the impact of Playworks separately for girls and boys.

METHODS

Twenty-nine schools were randomly assigned to receive Playworks for 1 school year or serve as a control group. Postintervention physical activity data were collected via accelerometers and recess observations. Impacts were estimated separately for girls and boys using regression models.

RESULTS

Girls in Playworks schools had significantly higher accelerometer intensity counts and spent more time in vigorous physical activity than girls in control schools. No significant differences based on accelerometer data were found for boys. A significant impact was also found on the types of activities in which girls engaged during recess; girls in the treatment group were less likely than those in the control group to be sedentary and more likely to engage in jumping, tag, and playground games.

CONCLUSIONS

The current findings suggest that Playworks had a significant impact on some measures of girls' physical activity, but no significant impact on measures of boys' physical activity.

Implementation of strategies to increase adolescents' access to fruit and vegetables at school: process evaluation findings from the Boost study

Background

Access to fruit and vegetables (FV) is associated with adolescents’ FV consumption. However, little is known about implementation of strategies to increase access to FV at schools. We examined the implementation of two environmental components designed to increase access to FV at Danish schools.

Methods

We used data from 20 intervention schools involved in the school-based multicomponent Boost trial targeting 13-year-olds’ FV consumption. The environmental components at school included daily provision of free FV and promotion of a pleasant eating environment.

Questionnaire data was collected by the end of the nine-month intervention period among 1,121 pupils (95%), from all school principals (n = 20) and half way through the intervention period and by the end of the intervention among 114 teachers (44%).

The implementation of the components was examined descriptively using the following process evaluation measures; fidelity, dose delivered, dose received and reach. Schools with stable high implementation levels over time were characterised by context, intervention appreciation and implementation of other components.

Results

For all process evaluation measures, the level of implementation varied by schools, classes and over time. Dose received: 45% of pupils (school range: 13-72%, class range: 7-77%) ate the provided FV daily; 68% of pupils (school range: 40-93%, class range: 24-100%) reported that time was allocated to eating FV in class. Reach: The intake of FV provided did not differ by SEP nor gender, but more girls and low SEP pupils enjoyed eating FV together. Dose delivered: The proportion of teachers offering FV at a daily basis decreased over time, while the proportion of teachers cutting up FV increased over time. Schools in which high proportions of teachers offered FV daily throughout the intervention period were characterized by being: small; having a low proportion of low SEP pupils; having a school food policy; high teacher- and pupil intervention appreciation; having fewer teachers who cut up FV; and having high implementation of educational components.

Conclusions

The appliance of different approaches and levels of analyses to describe data provided comprehension and knowledge of the implementation process. This knowledge is crucial for the interpretation of intervention effect.

Trial registration

Current Controlled Trials ISRCTN11666034

The Dutch Obesity Intervention in Teenagers (DOiT) cluster controlled implementation trial: intervention effects and mediators and moderators of adiposity and energy balance-related behaviours

Background

The Dutch Obesity Intervention in Teenagers (DOiT) programme is an evidence-based obesity prevention programme tailored to adolescents attending the first two years of prevocational education in the Netherlands. The initial programme showed promising results during an effectiveness trial. The programme was adapted and prepared for nationwide dissemination. To gain more insight into the process of translating evidence-based approaches into ‘real world’ (i.e., ‘natural’) conditions, our research aims were to evaluate the impact of the DOiT-implementation programme on adolescents’ adiposity and energy balance-related behaviours during natural dissemination and to explore the mediating and moderating factors underlying the DOiT intervention effects.

Methods

We conducted a cluster-controlled implementation trial with 20 voluntary intervention schools (n=1002 adolescents) and 9 comparable control schools (n = 484 adolescents). We measured adolescents’ body height and weight, skinfold thicknesses, and waist circumference. We assessed adolescents’ dietary and physical activity behaviours by means of self-report. Data were collected at baseline and at 20-months follow-up. We used multivariable multilevel linear or logistic regression analyses to evaluate the intervention effects and to test the hypothesised behavioural mediating factors. We checked for potential effect modification by gender, ethnicity and education level.

Results

We found no significant intervention effects on any of the adiposity measures or behavioural outcomes. Furthermore, we found no mediating effects by any of the hypothesised behavioural mediators. Stratified analyses for gender showed that the intervention was effective in reducing sugar-containing beverage consumption in girls (B = -188.2 ml/day; 95% CI = -344.0; -32.3). In boys, we found a significant positive intervention effect on breakfast frequency (B = 0.29 days/week; 95% CI = 0.01; 0.58). Stratified analyses for education level showed an adverse intervention effect (B = 0.09; 95% CI = 0.02; 0.16) on BMI z-scores for adolescents attending the vocational education track.

Conclusions

Although not successful in changing adolescents’ adiposity, the DOiT-implementation programme had some beneficial effects on specific obesity-related behaviours in subgroups. This study underlines the difficulty of translating intervention effectiveness in controlled settings to real world contexts. Adaptations to the implementation strategy are needed in order to promote implementation as intended by the teachers.

Trial registration

Current Controlled Trials ISRCTN92755979.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-014-0158-0) contains supplementary material, which is available to authorized users.

Evidence update on the treatment of overweight and obesity in children and adolescents

Childhood obesity is associated with increased medical and psychosocial consequences and mortality and effective interventions are urgently needed. Effective interventions are urgently needed. This article reviews the evidence for psychological treatments of overweight and obesity in child and adolescent populations. Studies were identified through searches of online databases and reference sections of relevant review articles and meta-analyses. Treatment efficacy was assessed using established criteria, and treatments were categorized as well-established, probably efficacious, possibly efficacious, experimental, or of questionable efficacy. Well-established treatments included family-based behavioral treatment (FBT) and Parent-Only Behavioral Treatment for children. Possibly efficacious treatments include Parent-Only Behavioral Treatment for adolescents, FBT-Guided Self-Help for children, and Behavioral Weight Loss treatment with family involvement for toddlers, children, and adolescents. Appetite awareness training and regulation of cues treatments are considered experimental. No treatments are considered probably efficacious, or of questionable efficacy. All treatments considered efficacious are multicomponent interventions that include dietary and physical activity modifications and utilize behavioral strategies. Treatment is optimized if family members are specifically targeted in treatment. Research supports the use of multicomponent lifestyle interventions, with FBT and Parent-Only Behavioral Treatment being the most widely supported treatment types. Additional research is needed to test a stepped care model for treatment and to establish the ideal dosage (i.e., number and length of sessions), duration, and intensity of treatments for long-term sustainability of healthy weight management. To improve access to care, the optimal methods to enhance the scalability and implementability of treatments into community and clinical settings need to be established.

Effect of changes to the school food environment on eating behaviours and/or body weight in children: a systematic review

Previous school obesity-prevention reviews have included multi-component interventions. Here, we aimed to review the evidence for the effect of isolated food environment interventions on both eating behaviours (including food purchasing) and/or body weight. Five electronic databases were searched (last updated 30 November 2013). Of the 1,002 unique papers identified, 55 reported on school food environment changes, based on a review of titles and abstracts. Thirty-seven further papers were excluded, for not meeting the inclusion criteria. The final selection consisted of 18 papers (14 United States, 4 United Kingdom). Two studies had a body mass index (BMI) outcome, 14 assessed purchasing or eating behaviours and two studies assessed both weight and behaviour. Seventeen of 18 papers reported a positive outcome on either BMI (or change in BMI) or the healthfulness of food sold or consumed. Two studies were rated as strong quality and 11 as weak. Only three studies included a control group. A school environment supportive of healthy eating is essential to combat heavy marketing of unhealthy food. Modification of the school food environment (including high-level policy changes at state or national level) can have a positive impact on eating behaviours. A need exists, however, for further high-quality studies.

Predictors of child weight loss and maintenance among family-based treatment completers

OBJECTIVE

To examine general and treatment-specific predictors of children's weight outcomes during a pediatric weight management trial.

METHOD

One hundred fifty overweight children-69.3% female; M body mass index (BMI) z score (z-BMI) = 2.21 ± 0.30-completed family-based behavioral weight loss treatment (FBT), followed by randomization to social facilitation maintenance (SFM) treatment addressing social support and body image; behavioral skills maintenance treatment (BSM), which extended FBT skills to maintenance; or a control condition with no maintenance treatment. Regression and mixed-effects repeated-measures analysis of covariance (ANCOVA) examined child and parent anthropometric, demographic, and psychosocial variables in predicting relative weight outcomes over short- and long-term follow-ups.

RESULTS

Among FBT completers, lower child baseline z-BMI and age, and greater parent BMI reductions during FBT and baseline self-efficacy, predicted better child relative weight loss following FBT, F(6, 137) = 7.77, p < .001. Higher child-reported post-FBT eating pathology predicted greater relative weight loss in SFM than BSM or control from post-FBT to 2-year follow-up, F(4,255.88) = 3.48, p = .009, whereas higher parent-reported post-FBT social support predicted greater relative weight loss in BSM than control, F(2,141.65) = 3.28, p = .04. Lower parent-reported post-FBT behavioral problems predicted greater relative weight loss in SFM and BSM versus control, F(2,147.84) = 7.37, p < .001; higher problems predicted equivalent outcome across treatments.

CONCLUSION

SFM may improve weight outcomes for FBT completers with initially higher eating pathology, whereas extending FBT skills may be effective for those with higher familial support. These results suggest that certain pretreatment variables moderate the effectiveness of different pediatric weight control interventions. Further understanding these findings may help optimally match families to treatments.

Do school-based physical activity interventions increase or reduce inequalities in health?

Little is known about the effectiveness of school-based health promotion on physical activity inequalities among children from low-income areas. This study compared the two-year change in physical activity among 10-11 year-old children attending schools with and without health promotion programs by activity level, body weight status, and socioeconomic backgrounds to assess whether health promotion programs reduce or exacerbate health inequalities. This was a quasi-experimental trial of a Comprehensive School Health (CSH) program implemented in schools located in socioeconomically disadvantaged neighbourhoods in Edmonton, Alberta, Canada. In the spring of 2009 and 2011, pedometer (7 full days) and demographic data were collected from cross-sectional samples of grade five children from 10 intervention and 20 comparison schools. Socioeconomic status was determined from parent self-report. Low-active, active, and high-active children were defined according to step-count tertiles. Multilevel linear regression methods adjusted for potential confounders were used to assess the relative inequity in physical activity and were compared between groups and over-time. In 2009, a greater proportion of students in the intervention schools were overweight (38% vs. 31% p = 0.03) and were less active (10,827 vs. 12,265 steps/day p < 0.001). Two years later, the relative difference in step-counts between intervention and comparison schools reduced from -15.5% to 0% among low-active students, from -13.4% to 0% among active students, and from -15.1% to -2.7% among high-active students. The relative difference between intervention and comparison schools reduced from -11.1% to -1.6% among normal weight students, from -16.8% to -1.4% among overweight students, and was balanced across socioeconomic subgroups. These findings demonstrate that CSH programs implemented in socioeconomically disadvantaged neighbourhoods reduced inequalities in physical activity. Investments in school-based health promotion are a viable, promising, and important approach to improve physical activity and prevent childhood obesity, and may also reduce inequalities in health.

Moderators of the effectiveness of a web-based tailored intervention promoting physical activity in adolescents: the HELENA Activ-O-Meter

BACKGROUND

The aim of this study was to examine the moderation effects of sex, age, and psychosocial determinants (intention, social support, and modeling) of physical activity (PA) in the relationship between an Internet-based computer-tailored intervention program (Activ-O-Meter) and modes of PA and commuting.

METHODS

The Activ-O-Meter with intervention and control condition was delivered to 555 adolescents (boys 50.5%, mean age: 14.4 years) in 6 European cities. Data on different modes of PA and commuting, sex, age, and psychosocial determinants were collected at baseline and at 3-months follow-up, using questionnaires. The moderation effects of psychosocial determinants, sex, and age on the association between condition and modes of PA and commuting were tested with linear regression.

RESULTS

Moderation analysis showed that the following increased adolescents' responsiveness to the intervention: male sex, older age, higher baseline intention to increase PA, higher perceived social support or modeling level by siblings, and low perceived social support by friends.

CONCLUSIONS

These findings should be taken into consideration when planning PA interventions in adolescents. Future intervention studies should also include moderation analysis in order to get a deeper understanding of why interventions are not effective for certain individuals and how this unresponsiveness could be overcome.

Post-intervention effects on screen behaviours and mediating effect of parental regulation: the HEalth In Adolescents study--a multi-component school-based randomized controlled trial

Background

To improve effectiveness of future screen behaviour interventions, one needs to know whether an intervention works via the proposed mediating mechanisms and whether the intervention is equally effective among subgroups. Parental regulation is identified as a consistent correlate of screen behaviours, but prospective evidence as well as the mediation role of parental regulation is largely lacking. This study investigated post-intervention main effects on screen behaviours in the HEIA-intervention – a Norwegian school-based multiple-behaviour study, as well as mediation effects of parental regulation by adolescents’ and parents’ report. In addition, moderating effects of gender and weight status on the intervention and mediating effects were explored.

Methods

Participating schools were randomized to control (n = 25) or intervention (n = 12) condition. Adolescents (n = 908 Control; 510 Intervention) self-reported their weekday and weekend TV-viewing and computer/game-use. Change in adolescents’ behaviours was targeted through school and parents. Adolescents, mothers (n = 591 Control; 244 Interventions) and fathers (n = 469 Control; 199 Intervention) reported parental regulation of the screen behaviours post-intervention (at 20 month). The product-of-coefficient test using linear regression analysis was conducted to examine main and mediating effects.

Results

There was no intervention effect on the screen behaviours in the total sample. Gender moderated effect on weekend computer/game-use, while weight status moderated the effect on weekday TV-viewing and computer/game-use. Stratified analyses showed a small favourable intervention effect on weekday TV-viewing among the normal weight. Parental regulation did not mediate change in the screen behaviours. However, stronger parental regulation was associated with less TV-viewing and computer/game-use with effects being conditional on adolescents’ versus parental reports. Parental regulation of the screen behaviours, primarily by the parental report, was associated with change in the respective behaviours.

Conclusion

Multiple behaviour intervention may not affect all equally well, and the effect may differ by weight status and gender. In future interventions parents should be encouraged to regulate their adolescents’ TV-viewing and computer/game-use on both weekdays and weekends as parental regulation was identified as a determinant of these screen behaviours. However, future intervention studies may need to search for more effective intervention strategies targeting parental regulation.

Trial registration

Current Controlled Trials ISRCTN98552879