Differential effects of a school-based obesity prevention program: A cluster randomized trial

Interventions to prevent obesity in children aged 5 to 11 years old

BACKGROUND

Prevention of obesity in children is an international public health priority given the prevalence of the condition (and its significant impact on health, development and well-being). Interventions that aim to prevent obesity involve behavioural change strategies that promote healthy eating or 'activity' levels (physical activity, sedentary behaviour and/or sleep) or both, and work by reducing energy intake and/or increasing energy expenditure, respectively. There is uncertainty over which approaches are more effective and numerous new studies have been published over the last five years, since the previous version of this Cochrane review.

OBJECTIVES

To assess the effects of interventions that aim to prevent obesity in children by modifying dietary intake or 'activity' levels, or a combination of both, on changes in BMI, zBMI score and serious adverse events.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was February 2023.

SELECTION CRITERIA

Randomised controlled trials in children (mean age 5 years and above but less than 12 years), comparing diet or 'activity' interventions (or both) to prevent obesity with no intervention, usual care, or with another eligible intervention, in any setting. Studies had to measure outcomes at a minimum of 12 weeks post baseline. We excluded interventions designed primarily to improve sporting performance.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our outcomes were body mass index (BMI), zBMI score and serious adverse events, assessed at short- (12 weeks to < 9 months from baseline), medium- (9 months to < 15 months) and long-term (≥ 15 months) follow-up. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

This review includes 172 studies (189,707 participants); 149 studies (160,267 participants) were included in meta-analyses. One hundred forty-six studies were based in high-income countries. The main setting for intervention delivery was schools (111 studies), followed by the community (15 studies), the home (eight studies) and a clinical setting (seven studies); one intervention was conducted by telehealth and 31 studies were conducted in more than one setting. Eighty-six interventions were implemented for less than nine months; the shortest was conducted over one visit and the longest over four years. Non-industry funding was declared by 132 studies; 24 studies were funded in part or wholly by industry. Dietary interventions versus control Dietary interventions, compared with control, may have little to no effect on BMI at short-term follow-up (mean difference (MD) 0, 95% confidence interval (CI) -0.10 to 0.10; 5 studies, 2107 participants; low-certainty evidence) and at medium-term follow-up (MD -0.01, 95% CI -0.15 to 0.12; 9 studies, 6815 participants; low-certainty evidence) or zBMI at long-term follow-up (MD -0.05, 95% CI -0.10 to 0.01; 7 studies, 5285 participants; low-certainty evidence). Dietary interventions, compared with control, probably have little to no effect on BMI at long-term follow-up (MD -0.17, 95% CI -0.48 to 0.13; 2 studies, 945 participants; moderate-certainty evidence) and zBMI at short- or medium-term follow-up (MD -0.06, 95% CI -0.13 to 0.01; 8 studies, 3695 participants; MD -0.04, 95% CI -0.10 to 0.02; 9 studies, 7048 participants; moderate-certainty evidence). Five studies (1913 participants; very low-certainty evidence) reported data on serious adverse events: one reported serious adverse events (e.g. allergy, behavioural problems and abdominal discomfort) that may have occurred as a result of the intervention; four reported no effect. Activity interventions versus control Activity interventions, compared with control, may have little to no effect on BMI and zBMI at short-term or long-term follow-up (BMI short-term: MD -0.02, 95% CI -0.17 to 0.13; 14 studies, 4069 participants; zBMI short-term: MD -0.02, 95% CI -0.07 to 0.02; 6 studies, 3580 participants; low-certainty evidence; BMI long-term: MD -0.07, 95% CI -0.24 to 0.10; 8 studies, 8302 participants; zBMI long-term: MD -0.02, 95% CI -0.09 to 0.04; 6 studies, 6940 participants; low-certainty evidence). Activity interventions likely result in a slight reduction of BMI and zBMI at medium-term follow-up (BMI: MD -0.11, 95% CI -0.18 to -0.05; 16 studies, 21,286 participants; zBMI: MD -0.05, 95% CI -0.09 to -0.02; 13 studies, 20,600 participants; moderate-certainty evidence). Eleven studies (21,278 participants; low-certainty evidence) reported data on serious adverse events; one study reported two minor ankle sprains and one study reported the incident rate of adverse events (e.g. musculoskeletal injuries) that may have occurred as a result of the intervention; nine studies reported no effect. Dietary and activity interventions versus control Dietary and activity interventions, compared with control, may result in a slight reduction in BMI and zBMI at short-term follow-up (BMI: MD -0.11, 95% CI -0.21 to -0.01; 27 studies, 16,066 participants; zBMI: MD -0.03, 95% CI -0.06 to 0.00; 26 studies, 12,784 participants; low-certainty evidence) and likely result in a reduction of BMI and zBMI at medium-term follow-up (BMI: MD -0.11, 95% CI -0.21 to 0.00; 21 studies, 17,547 participants; zBMI: MD -0.05, 95% CI -0.07 to -0.02; 24 studies, 20,998 participants; moderate-certainty evidence). Dietary and activity interventions compared with control may result in little to no difference in BMI and zBMI at long-term follow-up (BMI: MD 0.03, 95% CI -0.11 to 0.16; 16 studies, 22,098 participants; zBMI: MD -0.02, 95% CI -0.06 to 0.01; 22 studies, 23,594 participants; low-certainty evidence). Nineteen studies (27,882 participants; low-certainty evidence) reported data on serious adverse events: four studies reported occurrence of serious adverse events (e.g. injuries, low levels of extreme dieting behaviour); 15 studies reported no effect. Heterogeneity was apparent in the results for all outcomes at the three follow-up times, which could not be explained by the main setting of the interventions (school, home, school and home, other), country income status (high-income versus non-high-income), participants' socioeconomic status (low versus mixed) and duration of the intervention. Most studies excluded children with a mental or physical disability.

AUTHORS' CONCLUSIONS

The body of evidence in this review demonstrates that a range of school-based 'activity' interventions, alone or in combination with dietary interventions, may have a modest beneficial effect on obesity in childhood at short- and medium-term, but not at long-term follow-up. Dietary interventions alone may result in little to no difference. Limited evidence of low quality was identified on the effect of dietary and/or activity interventions on severe adverse events and health inequalities; exploratory analyses of these data suggest no meaningful impact. We identified a dearth of evidence for home and community-based settings (e.g. delivered through local youth groups), for children living with disabilities and indicators of health inequities.

Promoting healthy school food environments and nutrition in Canada: a systematic review of interventions, policies, and programs

CONTEXT

The school food environment is a critical interface for child and adolescent nutrition, and there is a need to understand existing literature on Canadian school food environments to identify equity gaps and opportunities, and empower decision-makers to plan for future action.

OBJECTIVE

Literature on Canadian school food and nutrition interventions, policies, programs, and their effects on diets and nutritional status are synthesized and appraised in this systematic review.

DATA SOURCES

A search strategy was developed for each database used (Medline, Embase, PsycINFO, ERIC, Cochrane Collaboration, Canadian Electronic Library, BiblioMap), with a combination of free text and controlled vocabulary, for articles published from 1990 to 2021. Unpublished data and grey literature were also searched.

DATA EXTRACTION

Quantitative and qualitative studies with an observational or intervention study design, reviews, or program evaluations conducted in Canadian schools with participants aged 5-19.9 years were included. Key study characteristics and risk of bias were extracted independently by 2 investigators using a standardized tool.

DATA ANALYSIS

A total of 298 articles were included (n = 192 peer reviewed and 106 from the grey literature), which were mostly conducted in Ontario (n = 52), British Columbia (n = 43), and Nova Scotia (n = 28). Twenty-four interventions, 5 nonevaluated programs, and 1 policy involved Indigenous populations. Overall, 86 articles measured and reported on effectiveness outcomes, including dietary intake; anthropometry; knowledge, attitudes, and practices; and physical activity. The literature remains largely heterogenous and primarily focused on nutrition education programs that use subjective assessments to infer changes in nutrition. A key facilitator to implementation and sustainability was community engagement, whereas key barriers were staff capacity, access to resources and funding, and consistent leadership.

CONCLUSIONS

This review provides insight into Canadian school food and nutrition interventions, programs, and policies and uncovers important evidence gaps that require careful examination for future evaluations. Governments must create supportive environments that optimize nutrition for children and adolescents through equitable policies and programs.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022303255.

A literature review of evidence for primary prevention of overweight and obesity in healthy weight children and adolescents: A report produced by a working group of the Danish Council on Health and Disease Prevention

Primary prevention targets development of overweight in individuals with healthy weight and is a great challenge. This paper summarizes the main findings of a working group of the Danish Council on Health and Disease Prevention that reviewed the literature on primary prevention of overweight and obesity among children and adolescents. The results were presented in a Danish report, in which a 2019 Cochrane review on childhood obesity prevention was complemented by searches in PubMed to include all relevant subsequent studies published from January 2018 until March 2020. In this paper, the review was updated until June 2023. Numerous childhood overweight prevention interventions have been developed during the past decades, primarily targeting diet and/or physical activity. Several of these interventions showed positive effects on diet and physical activity level but did not show effects on risk of developing overweight. The evidence foundation is inconsistent as four out of five interventions did not show positive effects. Previously observed intervention effects may not reflect excessive weight gain prevention among children with healthy weight but rather bodyweight reduction among those with overweight or obesity. We do not have sufficient knowledge about how to prevent children with healthy weight from developing overweight, and creative solutions are urgently needed.

Efficiency of an Alternative Physical Education Program for the Lower Grades of Elementary School Children

(1) Introduction: This research was conducted with the aim of assessing whether an alternative physical education (PE) program could effectively substitute for the traditional PE curriculum and aid in accomplishing the essential goals and objectives of PE among younger elementary school children. (2) Materials and Methods: This longitudinal 6-month study included third-grade elementary school children of both genders, who were healthy, lived in urban areas, and were involved in an alternative PE program, as well as the regular PE classes. The sample of participants comprised 214 students, with 105 participants in the experimental group and 109 participants in the control group, who underwent pre- and post-intervention measurements. For the purposes of this study, 11 variables were applied to assess the parameters of growth and development, motor abilities, and physical and health education. MANCOVA and ANCOVA methods were used to determine the effects resulting from the alternative and regular PE programs, and differences between the groups, respectively. The data are reported as the mean and standard deviations, and were analyzed using the statistical package SPSS version 20.0 (SPSS Inc., Armonk, NY, USA). (3) Results: Based on the research results obtained for motor abilities and physical and health education, it was concluded that both the alternative and regular PE programs had positive effects in achieving the goals and objectives of PE, but without statistical significance at the multivariate and univariate levels. The differences between the two groups were found to be negligible (effect size, ES < 0.2). (4) Discussion: Sports and PE have distinct objectives and approaches. While sports emphasize competition and winning, PE aims to impart fundamental skills and knowledge, prioritizing inclusivity among younger students. Success in PE is measured by the number of students meeting these goals, potentially affecting both talented and struggling learners. (5) Conclusions: The results obtained from the conducted research indicate that both the alternative PE program and the regular PE program influence changes in motor abilities and physical and health education to a limited extent. The alternative PE program proposed in this study, with its modifications to the structure of existing, regular PE program, can fully replace the latter in schools that do not meet the required spatial and material standards.

Impact of School-Based Interventions on Pediatric Obesity: A Systematic Review

Childhood obesity is a global public health problem with significant implications for the health and well-being of children. The prevalence of childhood obesity is increasing every decade, making it a recognized public health concern. This systematic review aims to explore and evaluate the impact of school-based interventions on reducing pediatric obesity among school-aged children. A systematic review of literature according to the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 was conducted. Google Scholar, PubMed, and Cochrane were the databases used. After screening for bias, inclusion and exclusion criteria, and quality, 27 studies were included in the systematic review, and data were synthesized. The results show that physical activity reduces obesity and improves cardiovascular health. The nutritional change reduces the risk of obesity more than physical activity alone. When blended, the two provide the most benefits for participants. Motivation, self-efficacy, and behavioral change could help maintain the improvements. Schools should adopt a blend of physical activity and nutritional change to reduce prevent, reduce, and manage obesity.

A Systematic Review of Healthy Nutrition Intervention Programs in Kindergarten and Primary Education

Childhood obesity and overweight rates are increasing in an exponential way. This type of diet-related health problem has consequences, not only at present but also for children's future lives. For these reasons, it is very important to find a solution, which could be nutrition intervention programs. The main objective of this article is to investigate the effectiveness of nutrition intervention programs in children aged 3-12 around the world. We used SCOPUS, Web of Science, and PubMed databases to carry out this systematic review and we followed the PRISMA statement. Two authors conducted literature searches independently, finding a total of 138 articles. Finally, after a thorough screening, a total of 19 articles were selected for detailed analysis. The results show that, in general, nutrition intervention programs are effective in improving knowledge and behaviors about healthy habits, and, consequently, that the body mass index value is reduced. However, it is true that we found differences between the incomes of families and geographical areas. In conclusion, we encourage school centers to consider including these types of programs in their educational program and bring awareness of the importance of families too.

The Health Education and Training (HEAT) Corps: A Medical-Community Collaboration Response during the COVID-19 Pandemic

With the declaration of the COVID-19 pandemic by the World Health Organization in March 2020, many elements of society were faced with attempting to assimilate public health recommendations for infectious control. Vital social organizations had to balance delivering their social services while attempting to stay up to date with COVID-19 information and comply with evolving regulations. In the realm of schools and school systems, guidance on how to best adapt to COVID-19 was often limited. School officials and staff had to assist with multiple public health crises as a consequence of the pandemic, from the pandemic's transmission prevention strategies (e.g., face masks and physical distancing) to the recognition that students would have personal tragedies related to COVID-19. In this review, we highlight the process and feasibility of implementing an international COVID-19 school-based initiative over two years of the pandemic, the Health Education and Training (HEAT) Corps program.

“When You Move You Have Fun”: Perceived Barriers, and Facilitators of Physical Activity From a Child's Perspective

In Northern Ireland (NI), many children do not meet the recommended levels of physical activity (PA). To reduce the prevalence of physical inactivity and associated health conditions, it is important to understand the influences on children's PA, which in turn has the potential to inform future intervention design. The purpose of this formative study was to examine the current views, barriers, facilitators, experiences, and perceptions of children in relation to PA in the classroom, school, and home environments, and to assess the acceptability of components for a school-based intervention. Write and draw tasks and semi-structured focus groups (n = 10) were conducted with 50 children aged 7–9 years (22 boys, 28 girls) from six primary schools. Focus groups were recorded, transcribed, and analyzed thematically. Pen profiles were constructed from the transcripts in a deductive manner and represent key emergent themes. Results indicated that children's perception and knowledge of PA was mainly structured and sport-based, while some referred to fun, play and health. Fun, social support and outdoor activity were identified as key facilitators. Barriers included parental restrictions, lack of time and space in the different environments. The acceptability of intervention components was examined, children recognized the potential benefits of additional movement in the classroom, but opinions differed on the sit-to-stand desks. Findings contribute to a more detailed understanding of children's perceptions of context specific PA, the barriers they face, in addition to factors that support them to lead a physically active lifestyle, which may inform future PA promotion strategies.

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-eight 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 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. Significant reductions were found between groups in BMI kg/m2 (-0.39; 95% CI = -0.47, -0.30) and BMI z-score (-0.05; 95% CI = -0.08, -0.02) in favour of the intervention. The findings have important implications for future intervention research in terms of the effectiveness of intervention components and characteristics.

Differential effects of a school-based obesity prevention program: A cluster randomized trial

School-based healthy living interventions are widely promoted as strategies for preventing obesity. The peer-led Healthy Buddies™ curriculum has been shown to improve obesity-related outcomes in school-aged children. We examined whether these improvements existed among subgroups of children stratified by sex, income level and urban/rural geography. In a cluster-randomized controlled trial, elementary schools in Manitoba, Canada, were randomly allocated to Healthy Buddies™ (10 schools, 340 students) or standard curriculum (10 schools, 347 students). Healthy Buddies™ participants had 21weekly lessons on healthy eating, physical activity and self-efficacy, delivered by children age 9-12 to children age 6-8. We assessed pre- and post-intervention body mass index (BMI) z-scores, waist circumference, healthy living knowledge, dietary intake and self-efficacy among the younger children. Compared to standard curriculum (n = 154), Healthy Buddies™ participants (n = 157) experienced a greater reduction in waist circumference (-1.7 cm; 95% confidence interval [CI][-2.8, -0.5 cm]) and improved dietary intake (4.6; 95% CI [0.9, 8.3]), healthy living knowledge (5.9; 95% CI [2.3, 9.5]) and self-efficacy (5.3; 95% CI [1.0, 9.5]) scores. In subgroup analyses, effects for waist circumference (-2.0 cm; 95% CI [-3.6, -0.5]), healthy living knowledge (9.1; 95% CI [4.4, 13.8]) and self-efficacy (8.3; 95% CI [3.3, 13.3]) were significant among boys. Dietary intake (10.5; 95% CI [5.5, 15.4]), healthy living knowledge (9.8; 95% CI [4.5, 15.0]) and self-efficacy (6.7; 95% CI [0.7, 12.7]) improved among urban-dwelling but not rural-dwelling children. Healthy Buddies™ was effective for boys and children living in urban settings. Enhanced curricula may be needed to improve program effectiveness for select subgroups of school-aged children.