Primary prevention of overweight and obesity in adolescents: An overview of systematic reviews

Dietary Strategies in the Prevention and Treatment of Hypertension in Children and Adolescents: A Narrative Review

This study aims to gather information on effective dietary strategies for the prevention and treatment of hypertension (HTN) in children and adolescents. It discusses specific nutritional models such as the Diet Approaches to Stop Hypertension (DASH diet), traditional Asian diets, plant-based diets, the Southern European traditional Atlantic diet, and the Mediterranean diet, highlighting the benefits of these approaches. The manuscript also addresses dehydration resulting from insufficient fluid intake among children, as well as the consumption of inappropriate beverages, like soft drinks and energy drinks, which contributes to the development of HTN. Additionally, it examines the role of oxidative stress in the pathomechanism of HTN in children, particularly in relation to the antioxidant potential of food components such as selenium, magnesium, and selected vitamins. The relationship between sodium and potassium intake from food and the development of HTN in children is also explored. Finally, this study discusses public health strategies for the prevention of HTN in children. A comprehensive search was performed across multiple databases, such as PubMed/MEDLINE, the Cochrane Library, Science Direct, and EBSCO. This search focused on locating English-language meta-analyses, systematic reviews, randomized clinical trials, and observational studies from around the globe.

The centrality of food in Norwegian adolescents' life; a photo elicitation study among Norwegian youth

The purpose of the study was to explore how adolescents from a high school in Viken county define and interact with food systems in their immediate environments to understand if and how health and sustainability affect their food choices. A qualitative case study design and a participatory approach were employed. Data were collected through photo elicitation combined with group interviews. Pictures were analyzed in collaboration with participants, and the group interview through systematic text condensation. Results indicate that adolescents perceive food systems as being a substantial part of their everyday life, that they care about their health and that of the planet, and they wish to take sustainability and health into consideration when making food choices. Their food choices are affected by aspects such as family, friends, marketing, price, time, availability and accessibility. They perceive that their agency to influence their own diet and food systems is limited. Adolescents hold unique and important knowledge of their food-related behaviors and value their autonomy to make food choices. Future research and policies aiming to help adolescents make healthy and sustainable food choices should therefore actively include adolescents.

Interventions to prevent obesity in children aged 12 to 18 years old

BACKGROUND

Prevention of obesity in adolescents is an international public health priority. The prevalence of overweight and obesity is over 25% in North and South America, Australia, most of Europe, and the Gulf region. Interventions that aim to prevent obesity involve strategies that promote healthy diets 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 adolescents 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 adolescents (mean age 12 years and above but less than 19 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 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 74 studies (83,407 participants); 54 studies (46,358 participants) were included in meta-analyses. Sixty studies were based in high-income countries. The main setting for intervention delivery was schools (57 studies), followed by home (nine studies), the community (five studies) and a primary care setting (three studies). Fifty-one interventions were implemented for less than nine months; the shortest was conducted over one visit and the longest over 28 months. Sixty-two studies declared non-industry funding; five were funded in part by industry. Dietary interventions versus control The evidence is very uncertain about the effects of dietary interventions on body mass index (BMI) at short-term follow-up (mean difference (MD) -0.18, 95% confidence interval (CI) -0.41 to 0.06; 3 studies, 605 participants), medium-term follow-up (MD -0.65, 95% CI -1.18 to -0.11; 3 studies, 900 participants), and standardised BMI (zBMI) at long-term follow-up (MD -0.14, 95% CI -0.38 to 0.10; 2 studies, 1089 participants); all very low-certainty evidence. Compared with control, dietary interventions may have little to no effect on BMI at long-term follow-up (MD -0.30, 95% CI -1.67 to 1.07; 1 study, 44 participants); zBMI at short-term (MD -0.06, 95% CI -0.12 to 0.01; 5 studies, 3154 participants); and zBMI at medium-term (MD 0.02, 95% CI -0.17 to 0.21; 1 study, 112 participants) follow-up; all low-certainty evidence. Dietary interventions may have little to no effect on serious adverse events (two studies, 377 participants; low-certainty evidence). Activity interventions versus control Compared with control, activity interventions do not reduce BMI at short-term follow-up (MD -0.64, 95% CI -1.86 to 0.58; 6 studies, 1780 participants; low-certainty evidence) and probably do not reduce zBMI at medium- (MD 0, 95% CI -0.04 to 0.05; 6 studies, 5335 participants) or long-term (MD -0.05, 95% CI -0.12 to 0.02; 1 study, 985 participants) follow-up; both moderate-certainty evidence. Activity interventions do not reduce zBMI at short-term follow-up (MD 0.02, 95% CI -0.01 to 0.05; 7 studies, 4718 participants; high-certainty evidence), but may reduce BMI slightly at medium-term (MD -0.32, 95% CI -0.53 to -0.11; 3 studies, 2143 participants) and long-term (MD -0.28, 95% CI -0.51 to -0.05; 1 study, 985 participants) follow-up; both low-certainty evidence. Seven studies (5428 participants; low-certainty evidence) reported data on serious adverse events: two reported injuries relating to the exercise component of the intervention and five reported no effect of intervention on reported serious adverse events. Dietary and activity interventions versus control Dietary and activity interventions, compared with control, do not reduce BMI at short-term follow-up (MD 0.03, 95% CI -0.07 to 0.13; 11 studies, 3429 participants; high-certainty evidence), and probably do not reduce BMI at medium-term (MD 0.01, 95% CI -0.09 to 0.11; 8 studies, 5612 participants; moderate-certainty evidence) or long-term (MD 0.06, 95% CI -0.04 to 0.16; 6 studies, 8736 participants; moderate-certainty evidence) follow-up. They may have little to no effect on zBMI in the short term, but the evidence is very uncertain (MD -0.09, 95% CI -0.2 to 0.02; 3 studies, 515 participants; very low-certainty evidence), and they may not reduce zBMI at medium-term (MD -0.05, 95% CI -0.1 to 0.01; 6 studies, 3511 participants; low-certainty evidence) or long-term (MD -0.02, 95% CI -0.05 to 0.01; 7 studies, 8430 participants; low-certainty evidence) follow-up. Four studies (2394 participants) reported data on serious adverse events (very low-certainty evidence): one reported an increase in weight concern in a few adolescents and three reported no effect.

AUTHORS' CONCLUSIONS

The evidence demonstrates that dietary interventions may have little to no effect on obesity in adolescents. There is low-certainty evidence that activity interventions may have a small beneficial effect on BMI at medium- and long-term follow-up. Diet plus activity interventions may result in little to no difference. Importantly, this updated review also suggests that interventions to prevent obesity in this age group may result in little to no difference in serious adverse effects. Limitations of the evidence include inconsistent results across studies, lack of methodological rigour in some studies and small sample sizes. Further research is justified to investigate the effects of diet and activity interventions to prevent childhood obesity in community settings, and in young people with disabilities, since very few ongoing studies are likely to address these. Further randomised trials to address the remaining uncertainty about the effects of diet, activity interventions, or both, to prevent childhood obesity in schools (ideally with zBMI as the measured outcome) would need to have larger samples.

Prevalence of obesity and associated health risks in soldiers of the German Armed Forces

BACKGROUND

Obesity rates are rising in the armed forces of Western democratic countries, impacting military readiness and health. This highlights the need for preventive health risk assessments and countermeasures.

METHODS

Using mandatory health examination data from 2018 to 2022, we analyzed the prevalence of obesity, health risks, and associated specific military risk factors (rank and unit) in 43,214 soldiers of the German Armed Forces. Statistical methods included χ2 contingencies and binary logistic regressions.

RESULTS

The prevalence of obesity (BMI ≥ 30) was 18.0%. Male soldiers (OR = 3.776) and those with an officer's rank (OR = 1.244) had an increased chance for obesity. Serving in a combat unit reduced the chance of being obese (OR = .886). Considering BMI and waist circumference, 2.4% of the total sample faced extremely high cardiovascular and metabolic health risks, while 11.0% and 11.6% had very high or high health risks, respectively.

CONCLUSIONS

Our data underscore the importance of targeting obesity-related health risk factors in soldiers to ensure their well-being and deployment readiness.

Nutrition Interventions for Pediatric Obesity Prevention: An Umbrella Review of Systematic Reviews

Nutrition interventions to prevent pediatric obesity can help to establish healthy habits to improve current and future health. The objective of this umbrella review of systematic reviews (SRs) is to examine the impact of obesity prevention interventions with a nutrition component on body mass index measures, overweight/obesity prevalence, and cost-effectiveness in participants 2-17 years old. Grading of Recommendations Assessment, Development and Evaluation (GRADE) methods were used, and this umbrella review was registered on PROSPERO (CRD42023443033). Included SRs were required to search ≥2 databases and to assess the risk of bias (RoB) of primary studies, and they were published 2017-June 2023. Database searches identified 4776 articles, and 31 SRs were included. In all age groups combined, interventions with both nutrition and physical activity were effective and cost-effective in all settings combined, and in the community setting specifically. In children ≤5 years old, interventions in the home and family, community, and healthcare settings demonstrated some efficacy, whereas in children 6-12 years old, school interventions were most effective. Evidence with individuals 13-17 years was limited. The certainty of evidence was generally low due to RoB in included studies, inconsistency, and imprecision. Pediatric obesity prevention interventions with nutrition should be tailored to the developmental stage to ensure appropriateness and efficacy.

System dynamics simulation models on overweight and obesity in children and adolescents: A systematic review

It has increasingly been recognized that developing successful obesity prevention policies and interventions requires understanding of the complex mechanisms driving the obesity pandemic and that models could be useful tools for simulating policies. This paper reviews system dynamics simulation models of mechanisms driving childhood overweight and obesity and/or testing of preventive interventions. A systematic literature search was conducted in six databases from inception to January 2023 using terms related to overweight/obesity, children, and system dynamics. Study descriptives, mechanisms, and where to intervene (the leverage points), as well as quality assessments of the simulation models were extracted by two researchers into a predetermined template and narratively synthesized. Seventeen papers describing 15 models were included. Models describing the mechanisms ranged from only intrapersonal factors to models cutting across multiple levels of the ecological model, but mechanisms across levels were lacking. The majority of interventions tested in the simulation models were changes to existing model parameters with less emphasis on models that alter system structure. In conclusion, existing models included mechanisms driving youth obesity at multiple levels of the ecological model. This is useful for developing an integrated simulation model combining mechanisms at multiple levels and allowing for testing fundamental system changes.

Adolescents' capacity to take action on obesity: A concurrent controlled before-and-after study of the European CO-CREATE project

This study evaluated the effect on reported readiness for action and attitudes toward obesity prevention among older adolescents (mean age 17) who took part in a youth-led participatory action research European initiative (CO-CREATE Youth Alliances) compared with a comparison group that acted as controls. This was a concurrent before-and-after controlled study across five countries and took place between September 2019 and October 2020. Adolescents (n = 159) recruited from schools and youth organizations came together with researchers and formed 15 Youth Alliances. An online questionnaire measuring their readiness for action and attitudes toward obesity prevention was administered. Alliance members (n = 62) who filled in the questionnaire at both baseline and postinitiative, and adolescents from the comparison group (n = 132) who completed the questionnaire twice were included in the main analysis. Two-level linear mixed models controlling for country-related variance were fitted. Alliance members scored significantly higher than the comparison group on two factors in each of the readiness for action, responsibility, and drivers of behavior concepts. The findings suggest that involving youth in co-creating policies to prevent obesity may increase adolescents' readiness for action and promote a shift in adolescents' conceptualization of obesity from an individual perspective to a societal responsibility and drivers of behavior.

Youth involvement in policy processes in public health, education, and social work: Protocol for a scoping review

The objective of this scoping review is to understand the extent and impact of youth involvement in policy processes within public health, education, and social work. Youth involvement in policy processes may enhance the relevance of policies and strengthen democratic practices. This scoping review aims to explore the nature, extent, and impact of youth involvement in policy processes in public health, education, and social work, with a focus on health, well-being, and obesity prevention. Empirical studies published from 1989 and evaluating involvement of youth aged 10 to 19 years old from all socioeconomic backgrounds and countries. Studies will be searched in seven databases. Data will be extracted and synthesized narratively by rights-based perspectives on youth involvement, practical processes of the involvement, and social experiences using descriptive statistics and visuals.

Assessing adolescents' readiness for action and attitudes toward obesity prevention: Instrument development and psychometric properties

Engaging adolescents in obesity prevention is a main objective of the CO-CREATE project. This paper presents the development of a questionnaire to assess readiness for action and attitudes toward obesity prevention among adolescents. The questionnaire was developed based on literature searches and internal discussions with experts in the CO-CREATE consortium. The questionnaire was translated, back translated, and pretested for time and comprehensiveness by adolescents from five countries (the Netherlands, Norway, Poland, Portugal, and the United Kingdom). Exploratory factor analysis was performed, and internal reliability of the resulting factors was determined using baseline data from Poland and Norway. Furthermore, test-retest reliability was assessed in a sample of Norwegian adolescents. The exploratory factor analysis on readiness for action identified four factors. Analysis on attitudes toward obesity prevention identified four factors on responsibility and five factors on drivers of behavior. Six of the factors had a Cronbach's alpha value above 0.70, five factors had a value between 0.60-0.70, whereas the remaining two factors were below 0.60. The test-retest correlation ranged from 0.46 to 0.87. The exploratory factor analyzes on readiness for action identified the same factors as hypothesized in the development of the questionnaire, whereas attitudes toward obesity prevention identified more factors than initially assumed. The questionnaire is considered reliable as a tool for measuring adolescents' readiness for action and attitudes toward obesity prevention.

Overweight and obesity prevention for and with adolescents: The "Confronting obesity: Co-creating policy with youth" (CO-CREATE) project

The CO-CREATE project focuses on the need for research on obesity prevention in adolescents to move away from studies of single interventions, toward the investigation of systems-based research incorporating youth involvement. This paper provides an overview of the project, presenting the objectives, design, and novel methodologies applied, as well as findings to date and anticipated outcomes. Adolescents (16-18 years old) in five European countries participated. Methods applied in the project include monitoring and benchmarking of policies, systematic literature reviews, epidemiological surveillance, linking observed overweight and obesity trends to observed policy landscapes, group model building to identify perceived drivers of obesity, alliance building with adolescents, dialog with stakeholders, and system dynamics modelling to explore the potential impact of policy options. Outcomes include tools for developing policy ideas and investigation of prevention strategies with adolescents, including policy databases, system maps of drivers of obesity, protocols for organizing youth alliances, an intergenerational policy dialog tool, and system dynamic models exploring the impacts of cocreated policy ideas. These outcomes make an important contribution to building a pan-European infrastructure for designing and evaluating policies and for providing youth with the opportunity to make their voices heard in the development and implementation of obesity prevention measures.

System mapping with adolescents: Using group model building to map the complexity of obesity

Public health research and practice is increasingly employing systems thinking to help grapple with complex issues, from obesity to HIV treatment. At the same time, there is growing recognition that to address a given problem it is essential collaborate with those most at risk of or affected by it. Group model building (GMB), a process grounded in system dynamics, combines systems thinking and participatory methods to structure and address complex issues. As part of the CO-CREATE project we conducted GMB sessions with young people in six countries to create causal loop diagrams showing the factors that they believe drive obesity. This paper describes the background to GMB and the process we used to construct causal loop diagrams; it discusses how GMB contributed to generating noteworthy and useful findings, and the strengths and limitations of the method. Using GMB, we identified areas of concern to adolescents in relation to obesity that have so far had little attention in obesity research and policy: mental health and online activity. In using GMB, we also helped answer calls for a more participatory approach to youth involvement in research and policy development.

Recruiting and engaging adolescents in creating overweight and obesity prevention policies: The CO-CREATE project

The CO-CREATE project aims to collaborate with adolescents across Europe in developing policy ideas that contribute to overweight and obesity prevention. In this paper, we present the theoretical basis and methodological approach to recruitment and engagement in the project. The principles of youth-led participatory action research were employed to design Youth Alliances in which adolescents and adults could collaborate. These Alliances should serve to promote and support adolescent participation and to develop policy ideas that would contribute to obesity prevention. Alliance members were recruited in two local geographical areas per country with a focus on reaching out to underrepresented youth. We started with fieldwork to assess locally relevant forms of inclusion and exclusion. The methodology entailed a handbook combining existing tools which could be used flexibly, a collaborative organization, and budgets for the alliances. Engagement started in local organizations, that is, schools and scouts, and with peers. Health- and overweight-related challenges were addressed in their immediate surroundings and supported the inclusion of experiential knowledge. Adolescents were then supported to address the wider obesogenic system when designing policy ideas. The CO-CREATE Alliances provide a concrete example of how to engage youth in public health, in a manner that strives to be participatory, transformative, and inquiry based.

A Community-Based, Participatory, Multi-Component Intervention Increased Sales of Healthy Foods in Local Supermarkets-The Health and Local Community Project (SoL)

Project SoL was a 19-month (September 2012 to April 2014) community-based multi-component intervention based on the supersetting approach that was designed to promote healthier eating and physical activity among children and their families. The aim of this study was to examine the effects of a multi-component intervention (level 1) and a mass media intervention alone (level 2) compared to a control area (level 3) on food sales. The design was quasi-experimental. Weekly sales data for all Coop supermarkets in the intervention and control areas were analysed via longitudinal linear mixed-effects analyses. Significant increases in the sales of fish (total) (29%; p = 0.003), canned fish (31%; p = 0.025) and oatmeal (31%; p = 0.003) were found for the level 1 intervention area compared to the control area. In the level 2 intervention area, significant increases in the sales of vegetables (total) (17%; p = 0.038), fresh vegetables (20%; p = 0.01), dried fruit (51%; p = 0.022), oatmeal (19%; p = 0.008) and wholegrain pasta (58%; p = 0.0007) were found compared to the control area. The sales of canned fish increased by 30% in the level 1 area compared to the level 2 area (p = 0.025). This study demonstrated significant increases in the sales of healthy foods, both in the areas with multi-component and mass media interventions alone compared to the control area.

Nutritional status of school-age children and adolescents in low- and middle-income countries across seven global regions: a synthesis of scoping reviews

OBJECTIVE

To summarise available evidence on the nutritional status of school-age children and adolescents (5-19 years) from seven global regions and on interventions implemented to improve malnutrition in this population.

SETTING

Global.

DESIGN

Findings were compiled from seven scoping literature reviews, including data from low- and middle-income countries within the following UNICEF-defined global regions: East Asia and Pacific; Europe and Central Asia; South Asia; West and Central Africa; Eastern and Southern Africa; Middle East and North Africa and Latin America and the Caribbean.

RESULTS

A double burden of malnutrition was evident across the world regions reviewed: stunting, thinness, anaemia and other micronutrient deficiencies persisted, alongside rising overweight and obesity prevalence. Transitions towards diets increasingly high in energy-dense, processed and micronutrient-poor foods were observed. Evidence from intervention studies was limited, but suggested that providing multiple micronutrient-fortified foods or beverages at school may effectively target micronutrient deficiencies and facilitate weight gain in undernourished populations. Interventions to prevent or manage overweight and obesity were even more limited. There was minimal evidence of using novel technological approaches to engage school-age children and adolescents, or of involving them in designing interventions.

CONCLUSION

The limited data available on nutrition of school-age children and adolescents are neither standardised nor comparable. Consensus on methods for assessing nutritional status and its determinants for this age group is urgently needed to set targets and monitor progress. Additionally, strategies are required to ensure that nutritious, safe and sustainable diets are available, affordable and appealing.

Improving the health of adolescents: the Nordic countries can help fill the evidence gap

While in the Nordic countries we have well-developed welfare policies and several structural, statutory measures in place aiming to promote public health, studies from these countries are often absent from systematic reviews of research literature assessing the effects of policy measures designed to promote health. Using adolescent health promotion and efforts related to primary prevention of obesity as an example, this short commentary aims to illustrate the paucity of well-designed studies investigating the effects of public health policies affecting adolescents. This paper argues that the Nordic research community is in a good position to help fill this gap, and to contribute more widely to the international literature on evaluation of policy interventions.

A Theoretical Perspective on Why Socioeconomic Health Inequalities Are Persistent: Building the Case for an Effective Approach

Despite policy intentions and many interventions aimed at reducing socioeconomic health inequalities in recent decades in the Netherlands and other affluent countries, these inequalities have not been reduced. Based on a narrative literature review, this paper aims to increase insight into why socioeconomic health inequalities are so persistent and build a way forward for improved approaches from a theoretical perspective. Firstly, we present relevant theories focusing on individual determinants of health-related behaviors. Thereafter, we present theories that take into account determinants of the individual level and the environmental level. Lastly, we show the complexity of the system of individual determinants, environmental determinants and behavior change for low socioeconomic position (SEP) groups and describe the next steps in developing and evaluating future effective approaches. These steps include systems thinking, a complex whole-system approach and participation of all stakeholders in system change.

Controlling the obesity pandemic: Geoffrey Rose revisited

The ongoing obesity pandemic threatens the health of hundreds of millions globally. However, to date, no country has had much success in limiting its growth, let alone reversing it. This commentary demonstrates the relevance to the obesity pandemic of the public health conceptual framework of epidemiologist Geoffrey Rose, first published as "Sick Individuals and Sick Populations" in 1985. That framework provides a useful way to analyze the pandemic's prevention and control options, based on the notions of primordial, primary, secondary and tertiary prevention-the full spectrum of "more upstream and more downstream" approaches, each with its pros and cons. Based on an analysis of key studies to date, this commentary argues strongly that only the primordial prevention approach is likely to be successful against the obesity pandemic-but its onerous requirements for society-wide behavioural and cultural change may make that public health struggle a long one.

The potential of food environment policies to reduce socioeconomic inequalities in diets and to improve healthy diets among lower socioeconomic groups: an umbrella review

Socioeconomic inequalities in diets need to be tackled to improve population diets and prevent obesity and diet-related non-communicable diseases. The potential of food environment policies to reduce such inequalities has to date however not been appraised. The objective of this umbrella review was to assess the impact of food environment policies on socioeconomic inequalities in diets and to identify knowledge gaps in the existing literature, using the Healthy Food Environment Policy Index as a conceptual framework. The policies considered in the umbrella review are within six domains: 1) food composition 2) food labelling 3) food promotion 4) food provision 5) food retail 6) food pricing. A systematic search for systematic literature reviews on the effect of food environment policies on dietary-related outcomes across socioeconomic groups and published in English between 2004 and 2019 was conducted. Sixteen systematic literature reviews encompassing 159 primary studies were included, covering food composition (n = 2), food labelling (n = 3), food provision (n = 2), food prices (n = 13) and food in retail (n = 4). Quality assessment using the "Assessing the Methodological Quality of Systematic Reviews" quality rating scale showed that review quality was mainly low or critically low. Results suggest that food taxation may reduce socioeconomic inequalities in diets. For all other policy areas, the evidence base was poor. Current research largely fails to provide good quality evidence on impacts of food environment policies on socioeconomic inequalities in diets. Research to fill this knowledge gap is urgently needed.

Effect of the multicomponent healthy high school intervention on meal frequency and eating habits among high school students in Denmark: a cluster randomized controlled trial

BACKGROUND

Previous studies have shown that multicomponent interventions may improve meal frequency and eating habits in children, but evidence among young people is limited. This study evaluated the effect of the Healthy High School (HHS) intervention on daily intake of breakfast, lunch, water, fruit, and vegetables at 9-month follow-up.

METHODS

The study included first-year students (≈16 years) attending high school in Denmark. Participating schools were randomized into the HHS intervention (N = 15) or control group (operating as usual) (N = 15). The intervention was designed to promote well-being (primary outcome) by focusing on healthy habits including meals, stress prevention, and strong peer relations. It included a curriculum, structural and organisational initiatives, a workshop, and a smartphone application. Students completed self-administered online questionnaires at the beginning of the school year and nine months later. To account for clustering of data, we used multilevel logistic regression analyses to estimate odds ratios (OR). We applied an intention-to-treat approach with multiple imputations of missing data.

RESULTS

At baseline 4577 of 5201 students answered the questionnaire and 4512 at follow-up. In both groups the proportion of students eating breakfast decreased from approximately 50% to 40% from baseline to follow-up, and lunch frequency decreased from approximately 50% to 47%. Daily water intake, intake of fresh fruit and intake of vegetables remained unchanged from baseline to follow-up. There were no significant between group differences on any of the outcomes at first follow-up: breakfast: OR = 0.85 (95% CI: 0.65;1.10), lunch: OR = 0.96 (95% CI: 0.75;1.22), water intake: OR = 1.14 (95% CI: 0.92;1.40), intake of fresh fruit: (OR = 1.07, 95% CI: 0.84;1.37), vegetables: (OR = 1.01, 95% CI: 0.77;1.33).

CONCLUSION

No evidence of an effect of the HHS intervention was found for any of the outcomes. Future studies are warranted to explore how health promoting interventions can be integrated in further education to support educational goals. Moreover, how to fit interventions to the lives and wishes of young people, by also including systems outside of the school setting.

TRIAL REGISTRATION

ISRCTN, ISRCTN43284296 . Registered 28 April 2017 - retrospectively registered.

How effects on health equity are assessed in systematic reviews of interventions

BACKGROUND

Enhancing health equity is endorsed in the Sustainable Development Goals. The failure of systematic reviews to consider potential differences in effects across equity factors is cited by decision-makers as a limitation to their ability to inform policy and program decisions.  OBJECTIVES: To explore what methods systematic reviewers use to consider health equity in systematic reviews of effectiveness.

SEARCH METHODS

We searched the following databases up to 26 February 2021: MEDLINE, PsycINFO, the Cochrane Methodology Register, CINAHL, Education Resources Information Center, Education Abstracts, Criminal Justice Abstracts, Hein Index to Foreign Legal Periodicals, PAIS International, Social Services Abstracts, Sociological Abstracts, Digital Dissertations and the Health Technology Assessment Database. We searched SCOPUS to identify articles that cited any of the included studies on 10 June 10 2021. We contacted authors and searched the reference lists of included studies to identify additional potentially relevant studies.

SELECTION CRITERIA

We included empirical studies of cohorts of systematic reviews that assessed methods for measuring effects on health inequalities. We define health inequalities as unfair and avoidable differences across socially stratifying factors that limit opportunities for health. We operationalised this by assessing studies which evaluated differences in health across any component of the PROGRESS-Plus acronym, which stands for Place of residence, Race/ethnicity/culture/language, Occupation, Gender or sex, Religion, Education, Socioeconomic status, Social capital. "Plus" stands for other factors associated with discrimination, exclusion, marginalisation or vulnerability such as personal characteristics (e.g. age, disability), relationships that limit opportunities for health (e.g. children in a household with parents who smoke) or environmental situations which provide limited control of opportunities for health (e.g. school food environment).

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data using a pre-tested form. Risk of bias was appraised for included studies according to the potential for bias in selection and detection of systematic reviews.  MAIN RESULTS: In total, 48,814 studies were identified and the titles and abstracts were screened in duplicate. In this updated review, we identified an additional 124 methodological studies published in the 10 years since the first version of this review, which included 34 studies. Thus, 158 methodological studies met our criteria for inclusion. The methods used by these studies focused on evidence relevant to populations experiencing health inequity (108 out of 158 studies), assess subgroup analysis across PROGRESS-Plus (26 out of 158 studies), assess analysis of a gradient in effect across PROGRESS-Plus (2 out of 158 studies) or use a combination of subgroup analysis and focused approaches (20 out of 158 studies). The most common PROGRESS-Plus factors assessed were age (43 studies), socioeconomic status in 35 studies, low- and middle-income countries in 24 studies, gender or sex in 22 studies, race or ethnicity in 17 studies, and four studies assessed multiple factors across which health inequity may exist. Only 16 studies provided a definition of health inequity. Five methodological approaches to consider health equity in systematic reviews of effectiveness were identified: 1) descriptive assessment of reporting and analysis in systematic reviews (140 of 158 studies used a type of descriptive method); 2) descriptive assessment of reporting and analysis in original trials (50 studies); 3) analytic approaches which assessed differential effects across one or more PROGRESS-Plus factors (16 studies); 4) applicability assessment (25 studies) and 5) stakeholder engagement (28 studies), which is a new finding in this update and examines the appraisal of whether relevant stakeholders with lived experience of health inequity were included in the design of systematic reviews or design and delivery of interventions. Reporting for both approaches (analytic and applicability) lacked transparency and was insufficiently detailed to enable the assessment of credibility.

AUTHORS' CONCLUSIONS

There is a need for improvement in conceptual clarity about the definition of health equity, describing sufficient detail about analytic approaches (including subgroup analyses) and transparent reporting of judgments required for applicability assessments in order to consider health equity in systematic reviews of effectiveness.

Effectiveness of Nutritional Strategies on Improving the Quality of Diet of Children from 6 to 12 Years Old: A Systematic Review

Dietary habits, that are formed during childhood and consolidated in adulthood, are known to influence the development of future chronic diseases such as metabolic syndrome or type 2 diabetes. The aim of this review was to evaluate the effectiveness of nutritional interventions carried out in recent years focused on improving the quality of the diet of the child population. A systematic search of the PubMed and Scopus databases was performed from January 2011 until September 2021. A total of 910 articles were identified and screened based on their title, abstract and full text. Finally, 12 articles were included in the current systematic review. Of those, in six studies the intervention was based on the provision of healthy meals and in the other six studies the intervention focused on modifying the school environment. Six of the studies selected included other components in their intervention such as nutritional education sessions, physical activity and/or families. A wide variety of methods were used for diet assessments, from direct method to questionnaires. The results suggest that interventions that modify the school environment or provide different meals or snacks may be effective in improving children’s dietary patterns, both in the short and long term. Further research is necessary to evaluate the real effectiveness of strategies with multidisciplinary approach (nutritional sessions, physical activity and family’s involvement).

Preventing Childhood Obesity in Primary Schools: A Realist Review from UK Perspective

Childhood obesity is a global public health concern. While evidence from a recent comprehensive Cochrane review indicates school-based interventions can prevent obesity, we still do not know how or for whom these work best. We aimed to identify the contextual and mechanistic factors associated with obesity prevention interventions implementable in primary schools. A realist synthesis following the Realist And Meta-narrative Evidence Syntheses-Evolving Standards (RAMESES) guidance was with eligible studies from the 2019 Cochrane review on interventions in primary schools. The initial programme theory was developed through expert consensus and stakeholder input and refined with data from included studies to produce a final programme theory including all of the context-mechanism-outcome configurations. We included 24 studies (71 documents) in our synthesis. We found that baseline standardised body mass index (BMIz) affects intervention mechanisms variably as a contextual factor. Girls, older children and those with higher parental education consistently benefitted more from school-based interventions. The key mechanisms associated with beneficial effect were sufficient intervention dose, environmental modification and the intervention components working together as a whole. Education alone was not associated with favourable outcomes. Future interventions should go beyond education and incorporate a sufficient dose to trigger change in BMIz. Contextual factors deserve consideration when commissioning interventions to avoid widening health inequalities.

The set point: weight destiny established before adulthood?

PURPOSE OF REVIEW

Although the set point is one of the best understood weight defense mechanisms, how and when a set point is established and what causes its disruption are not well understood. The purpose of this review is to address these gaps in the literature by exploring studies on the establishment of the set point theory and the underlying metabolic processes that support its existence.

RECENT FINDINGS

Research suggests that weight loss achieved through restricted energy intake and increased energy expenditure is difficult to maintain and is often followed by greater weight gain over time. It is hypothesized that such weight gain is driven by an individual's set point, a weight range in which the body seeks to remain by adjusting metabolism (e.g. by moderating energy expenditure based on energy intake in times of diet or energy fluctuation). Similar to adults, weight loss in adolescence results in decreased resting metabolic rate (RMR), and that the RMR remains suppressed even with weight restoration.

SUMMARY

Recommending weight loss in youth results in metabolic adaptations to restore weight and weight inclusive approaches may be more appropriate to protect their health and wellbeing.

Understanding obesity-related behaviors in youth from a systems dynamics perspective: The use of causal loop diagrams

This paper reports how we applied systems dynamics methods to gain insight into the complexity of obesity-related behaviors in youth, including diet, physical activity, sedentary behavior, and sleep, by integrating a literature review into causal loop diagrams (CLDs). Results showed that the CLDs consisted of multiple subsystems and three types of dynamics appeared, including (1) feedback loops, (2) connections between feedback loops and subsystems, and (3) mechanisms. We observed clear similarities in the dynamics for the four behaviors in that they relate to "traditional" subsystems, such as home and school environments, as well as to newly added subsystems, including macroeconomics, social welfare, and urban systems. The CLDs provided insights that can support the development of intervention strategies, including (1) the confirmation that a range of mechanisms cover and connect multiple levels and settings, meaning that there is no silver bullet to address obesity; (2) understanding of how interventions in one particular setting, such as school, might be influenced by the interactions with other settings, such as urban systems; and (3) a comprehensive view of (un)intended consequences. This way of framing the problem will assist moving towards public health interventions that respond to and operate in the complexity of the real world.

A secondary analysis of the childhood obesity prevention Cochrane Review through a wider determinants of health lens: implications for research funders, researchers, policymakers and practitioners

BACKGROUND

Randomised controlled trials (RCTs) are often regarded as the gold standard of evidence, and subsequently go on to inform policymaking. Cochrane Reviews synthesise this type of evidence to create recommendations for practice, policy, and future research. Here, we critically appraise the RCTs included in the childhood obesity prevention Cochrane Review to understand the focus of these interventions when examined through a wider determinants of health (WDoH) lens.

METHODS

We conducted a secondary analysis of the interventions included in the Cochrane Review on "Interventions for Preventing Obesity in Children", published since 1993. All 153 RCTs were independently coded by two authors against the WDoH model using an adaptive framework synthesis approach. We used aspects of the Action Mapping Tool from Public Health England to facilitate our coding and to visualise our findings against the 226 perceived causes of obesity.

RESULTS

The proportion of interventions which targeted downstream (e.g. individual and family behaviours) as opposed to upstream (e.g. infrastructure, environmental, policy) determinants has not changed over time (from 1993 to 2015), with most intervention efforts (57.9%) aiming to change individual lifestyle factors via education-based approaches. Almost half of the interventions (45%) targeted two or more levels of the WDoH. Where interventions targeted some of the wider determinants, this was often achieved via upskilling teachers to deliver educational content to children. No notable difference in design or implementation was observed between interventions targeting children of varying ages (0-5 years, 6-12 years, 13-18 years).

CONCLUSIONS

This study highlights that interventions, evaluated via RCTs, have persisted to focus on downstream, individualistic determinants of obesity over the last 25 years, despite the step change in our understanding of its complex aetiology. We hope that the findings from our analysis will challenge research funders, researchers, policymakers and practitioners to reflect upon, and critique, the evidence-based paradigm in which we operate, and call for a shift in focus of new evidence which better accounts for the complexity of obesity.