Background:Reviews have highlighted a lack of evidence on how successful intervention strategies for adolescent smoking prevention can be effectively adapted for low-middle income countries (LMICs). The MECHANISMS study compared behavioral mechanisms between two school-based smoking prevention programs for adolescents in Northern Ireland (NI; a high-income setting) and Bogotá, Colombia (middle-income). ASSIST works via peer education and diffusion. Dead Cool uses conventional classroom pedagogy. Both interventions were previously trialed in the UK and were culturally adapted for Bogotá. We investigated whether changes in smoking/vaping outcomes differed by intervention or setting. Mediation analyses were conducted to test the hypothesized intervention mechanisms. Methods:Full school year groups in 12 secondary schools participated during one semester (n = 1,344, target age 12-13 years). Outcomes included willingness to pay (WTP) to support anti-smoking norms, self-report and objectively measured smoking behavior, smoking intentions, susceptibility, knowledge, and attitudes. Mediators included injunctive and descriptive smoking/vaping norms, self-efficacy to resist tobacco, perceived risks and benefits, perceived behavioral control, and exposure to advertising. Structural equation models examined intervention and setting effects on outcomes. Multiple mediator models were conducted using the product-of-coefficients approach. Results:Most significant intervention effects showed more anti-smoking outcomes for Dead Cool compared to ASSIST, although exposure to advertising was lower for ASSIST (media: unstandardized coefficient (b) = -1.19, p < 0.0001, shops: b = -0.14, p = 0.04). ASSIST peer supporters also improved their knowledge (b = 0.31, p = 0.03), self-report smoking behavior (b = 0.10, p = 0.07), and perceived addiction risks (b = 0.31, p = 0.01) compared to Dead Cool. Most significant setting effects showed more anti-smoking outcomes for NI versus Bogotá. However, WTP to support anti-smoking norms (b = 0.48, p = 0.01), self-report descriptive smoking norms (b = 0.23, p = 0.01), and exposure to advertising in shops (b = -0.34, p < 0.0001) were more anti-smoking in Bogotá. Several significant mediators showed suppressive mediating effects, suggesting there were important but unmeasured mediators. Conclusion:Our results suggest school-based programs may be an appealing target for adolescent smoking prevention in LMICs and support using social norms strategies. Future research should identify additional mediating constructs for adolescent smoking prevention in LMICs (integrating intrapersonal, social, environmental, cultural, and political factors), investigate how to optimize the communication channels in peer education and diffusion programs, and provide empirically testable mechanisms.

Abstract Background Participatory systems mapping (PSM) methods are increasingly applied in population health research to understand and address complex challenges. Despite their growing use, there remains limited understanding of how these approaches are implemented in practice. This systematic scoping review aimed to explore the application of PSM in population health research, identify methodological gaps and highlight opportunities for advancing methods development and reporting standards, with particular attention to participatory approaches. Methods A systematic search of OVID MEDLINE and Scopus identified peer-reviewed papers published in English between January 2000 and September 2023 that: (1) applied and presented the results of PSM related to population health or health improvement questions and (2) incorporated a participatory design. Two reviewers screened and assessed papers, extracting data on study characteristics, participatory approaches, map features and integration of conceptual frameworks and methods not directly related to PSM. Results In the 123 included studies, involving stakeholders in building causal loop diagrams was the most commonly used approach. Variability was evident in geographical focus, study design, application and reporting. Participant involvement was mostly limited to map building, with less engagement in map validation. Significant gaps in reporting study samples and procedures were identified. A small number of studies involved end users or people with lived experiences in mapping processes. Only a few studies evaluated stakeholders’ experience with participatory processes. Lessons learnt on participatory processes include: PSM in population health benefits from cross-disciplinary, inclusive collaboration and capacity-building efforts that support meaningful involvement, shared ownership and trust among diverse stakeholders. Adaptability in the design of PSM approaches, continuous reflection and long-term partnerships are essential to maintaining relevance, enhancing impact and fostering systemic change over time. Conclusions To advance participatory systems mapping in population health, there is a need for further methodological innovation, stronger stakeholder engagement and more transparent, reflexive reporting practices. Building capacity through training, practical guidance and cross-disciplinary communities of practice will also be essential to support rigorous and inclusive application of these methods.

Participatory systems mapping methods are increasingly used to explore complex population health challenges by involving diverse stakeholders in co-producing causal diagrams. However, the field lacks tools that support thoughtful design and selection of methods. This paper introduces the Participatory Systems Mapping Design Framework, developed within a wider methodological research programme through evidence synthesis, case study development and international expert consultation. The Framework is intended to support researchers, practitioners and policymakers with varied systems mapping experience and is structured around three core considerations: (1) What is the scope of the project? (2) What is the added value of a participatory approach? and (3) Which factors may affect capacity to use a participatory systems mapping method? Each is supported by scaffolded questions and an open-access tool, alongside a comprehensive guidance document, to enable reflective, context-sensitive design and use. As a deliberative design resource rather than a prescriptive decision aid, the Framework encourages broader use of underused methods and supports greater transparency, inclusivity and methodological rigour. It also aims to strengthen the design and reporting of participatory processes and highlights the importance of planning for the use and value of system maps beyond the lifespan of projects. By addressing gaps in design rationale and stakeholder involvement, the Framework aims to enhance the relevance, coherence and impact of participatory systems mapping in population health. This deliberative tool provides a foundation for continued methodological development, and we invite testing and refinement to strengthen its contribution in understanding and generating solutions for complex population health problems.

Background:Peer influence is central to adolescent smoking initiation, yet its impact varies depending on individual and contextual factors. Understanding which moderators (personality, contextual, cultural, and environmental traits) shape these processes can inform more effective prevention strategies. We investigated hypothesized moderators of peer influence for adolescent smoking/vaping norms and other smoking-related outcomes in high and low-middle-income countries (LMICs): Northern Ireland and Bogotá. Methods:Across 12 schools (n = 1,344, age 12-13 years), participants completed novel behavioral economics experiments measuring social norms, and self-report surveys, before and after school-based prevention interventions (ASSIST and Dead Cool). We examined how peer influence effects were moderated by setting, intervention type, gender, school socio-economic status (SES), personality traits, social network positions, and self-efficacy. Moderation was examined using regressions with interactions between peer-group means (friends, school classes, school year groups) of the outcome variables and moderators (p ≤ 0.01). Results:Peer influence was moderated by study setting, intervention, gender, school SES, personality characteristics (pro-sociality, fear of negative evaluation, extraversion), and social network structure. Effects were stronger among girls and in schools with lower SES. ASSIST schools showed greater peer influence effects than Dead Cool, reflecting the programs' distinct mechanisms, as ASSIST operates primarily through network diffusion and Dead Cool through teacher-led instruction and skills-building. Network measures highlighted that peer influence was stronger amongst more central individuals and more homogenous networks. Conclusion:Susceptibility to peer influence depends on contextual, individual, and network factors. Future social norms interventions should provide information on both injunctive and descriptive norms and highlight the social consequences of smoking, particularly in LMICs. Gender-tailored approaches are needed to address heightened susceptibility among girls. Future intervention research should combine peer-led diffusion approaches with teacher-led instruction to maximize reach and sustainability in different contexts. Social influence-based interventions may be particularly beneficial for schools with lower SES or in LMICs without tobacco control legislation, where smoking remains largely normalized. Network-based interventions like ASSIST could benefit from careful consideration of which network metrics are used to select peer leaders (e.g., eigenvector or closeness centralities) and exploring alternative approaches for more heterogeneous networks (e.g., 'segmentation', which targets clusters of individuals within social networks).

INTRODUCTION:Around 80% of the world's smokers live in lower-middle income countries and smoking rates in China, Philippines and Indonesia are very high. Evidence suggests that most people begin smoking or become habitual smokers before reaching adulthood. This highlights the need for a smoking prevention intervention focused on young people. ASSIST (A Stop Smoking In Schools Trial) is a 'peer-led', school-based smoking prevention intervention, shown to be effective in the UK. The aim of the study is to assess the feasibility of conducting a full-scale effectiveness evaluation of an adapted version of the ASSIST intervention in China, Indonesia or the Philippines. However, due to issues with obtaining relevant approvals, China was removed from the trial with the approval of the funder and Trial Steering Committee, and the study will only be completed in Indonesia and the Philippines. METHODS AND ANALYSIS:A feasibility mixed-methods cluster randomised controlled trial in 10 schools (six intervention, four control) in each of the two countries. Participants will be students aged c13-14 in mainstream ('lower secondary') schools. In addition to their usual education on smoking, intervention schools will receive the ASSIST intervention which is based on 'diffusion of innovation' theory, with new norms and behaviours promoted through: (1) peer modelling by locally influential individuals; and (2) information disseminated by them through their social networks. Control schools will continue with their usual education around smoking prevention.The key outcome of the study is whether prespecified progression criteria relating to recruitment, retention, acceptability and feasibility have been met in order to progress to a larger cluster randomised controlled effectiveness trial in one or more of the countries. A mixed-methods process evaluation will assess acceptability, feasibility and fidelity of intervention delivery, exposure to and reach of the intervention. The feasibility of trial processes including outcome measurement will be assessed. An economic evaluation will estimate the costs of the ASSIST intervention. Statistical analyses will focus on feasibility criteria, and qualitative data will be analysed using a framework approach. Outcomes assessed will include self-reported smoking behaviour (own and that of friends and family); vaping and other forms of nicotine use; smoking-related attitudes and knowledge; smoking norms; self-esteem; self-efficacy; (all at baseline and 7 month follow-up) and exhaled carbon monoxide concentration (at follow-up only). ETHICS AND DISSEMINATION:The trial has been approved by the University of Glasgow College of Medical, Veterinary and Life Sciences (MVLS) Ethics Committee (ref: 200210204), the De La Salle University Research Ethics Review Committee (ref: 2023-012C) and the Medical and Health Research Ethics Committee (MHREC); Faculty of Medicine, Public Health and Nursing; Universitas Gadjah Mada (ref: KE/FK/1205/EC/2022). The trial is sponsored by the University of Glasgow (Head of Research Regulation and Compliance-debra.stuart@glasgow.ac.uk). The sponsor will not have input in data collection, management, analysis and interpretation; write up and submissions for publication.The study findings will be disseminated through peer-reviewed publications in expert journals and conference presentations and targeted communications to schools, policymakers and the public. TRIAL REGISTRATION NUMBER:ISRCTN99140476.

Background:Early childhood education and care (ECEC) provision is widespread. NAPSACC UK is an intervention in ECECs designed to improve nutrition and physical activity policies, practice and provision through ECEC staff workshops, self-assessment and assistance over one year. It was adapted for the UK from the USA and we tested whether it reduced energy consumption and increased physical activity. Methods:Repeated cross-sectional, multicentre, two-arm, single-blind, parallel-group, cluster-randomised controlled trial including ECEC providers in the UK. The randomisation was conducted by a statistician who was blinded to ECEC provider identity, with allocation within each local authority area and by ECEC Index of Multiple Deprivation scores to minimise differences between arms. Participants were not blind to allocation. Co-primary outcomes after 12-months were child average total energy consumed per eating occasion in the ECEC (lunch or snack) and child accelerometer-assessed total physical activity on ECEC days. Secondary outcomes were moderate-to-vigorous physical activity, sedentary time, energy served and consumed at lunch and snacks, diet quality, and Body Mass Index z-score. The senior statistician and majority of co-investigators were blinded. Analysis was intention-to-treat. Trial registration is ISRCTN33134697 and is completed. Findings:Between 14 March 2022 and 25 March 2024 we enrolled 52 ECEC providers (25 intervention; 27 control) and 835 2-5 year-olds (401 intervention, 434 control). The co-primary outcomes were assessed 12 months after baseline with data provided by 382 children for nutrition and 244 children for physical activity. There was no evidence of a difference in the co-primary outcomes compared to control of average kcal per eating occasion in ECEC (adjusted geometric mean ratio 0.86 (95% CI 0.72-1.03; p = 0.09)) or total physical activity (adjusted mean difference (aMD) -2.13 min (95% CI -10.96 to 6.70; p = 0.64)). There was evidence of lower lunch energy served (aMD -69.1 kcal per occasion (95% CI -116 to -22.2; p = 0.004)) and consumed (aMD -67.7 kcal per occasion (95% CI -118.6 to -18.7, p = 0.009)) with the intervention. There was no evidence of differences in other secondary outcomes. No adverse events were reported. Interpretation:NAPSACC UK did not improve average kcal per eating occasion in ECEC or physical activity. Lower lunch energy servings and consumption closer to recommendations were observed as secondary outcomes. The lower fidelity to the intervention than intended and staffing pressures give insight into interpretation of the null result. Therefore, we recommend that policy-level and statutory changes, which require low agency by individual ECEC settings are research and policy priorities for nutrition and physical activity in ECEC. Funding:National Institute for Health and Care Research (NIHR):127551.

Background‘Inhalants’ have been associated with poorer mental health in adolescence, but little is known of associations with specific types of inhalants.AimsWe aimed to investigate associations of using volatile substances, nitrous oxide and alkyl nitrates with mental health problems in adolescence.MethodWe conducted a cross-sectional analysis using data from 13- to 14-year-old adolescents across England and Wales collected between September 2019 and March 2020. Multilevel logistic regression examined associations between lifetime use of volatile substances, nitrous oxide and alkyl nitrates with self-reported symptoms of probable depression, anxiety, conduct disorder and auditory hallucinations.ResultsOf the 6672 adolescents in the study, 5.1% reported use of nitrous oxide, 4.9% volatile solvents and 0.1% alkyl nitrates. After accounting for multiple testing, adolescents who had used volatile solvents were significantly more likely to report probable depressive (odds ratio = 4.59, 95% CI 3.58, 5.88), anxiety (odds ratio = 3.47, 95% CI 2.72, 4.43) or conduct disorder (odds ratio = 7.52, 95% CI 5.80, 9.76) and auditory hallucinations (odds ratio = 5.35, 95% CI 4.00, 7.17) than those who had not. Nitrous oxide use was significantly associated with probable depression and conduct disorder but not anxiety disorder or auditory hallucinations. Alkyl nitrate use was rare and not associated with mental health outcomes. Adjustment for use of other inhalants, tobacco and alcohol resulted in marked attenuation but socioeconomic disadvantage had little effect.ConclusionTo our knowledge, this study provides the first general population evidence that volatile solvents and nitrous oxide are associated with probable mental health disorders in adolescence. These findings require replication, ideally with prospective designs.

OBJECTIVES:Physical activity is associated with a greater quantity and quality of social connections. Participating in physical activity with others (co-engagement) has dual physical and social benefits that can promote healthy ageing. We aimed to understand the social network characteristics of mid-to-older aged adults associated with co-engagement in physical activity. METHODS:Adults aged 55-75 years completed a social network survey (3679 social contacts reported by 140 participants). Multilevel modelling was used to identify the characteristics of participants, social contacts, and relationships that were predictive of co-engagement in physical activity. RESULTS:Network size and relationship quality were not associated with co-engagement. Similarity in age, greater interaction frequency, closer geographic proximity, and shorter relationship length were associated with higher odds of co-engagement. DISCUSSION:For co-engagement, the quality and quantity of relationships were less important than the convenience and accessibility of relationships, particularly newer relationships. As such, co-engagement ties can be understood as part of a dynamic social convoy which fulfil a specific function at a specific life stage. An understanding of naturally occurring tendencies for co-engagement may be utilised to identify leverage points for the development of interventions.

INTRODUCTION:Equally Safe at School (ESAS) is a whole-school intervention to reduce gender-based violence (GBV) in secondary school. ESAS comprises self-assessment, student-led action group, two-tier staff training, curriculum enhancement and policy review. Schools set up key activities in Year 1 and embed them in Year 2. GBV, including sexual harassment, is common in secondary schools and disproportionately affects young women and lesbian, gay, bisexual, transgender and queer youth. METHODS AND ANALYSIS:We will evaluate the effectiveness, cost-effectiveness, mechanisms of action and implementation of ESAS. We will recruit 36 schools across Scotland. The evaluation comprises three linked studies:Study 1: Pragmatic cluster randomised trial with 1:1 school allocation to either immediate ESAS intervention start (intervention schools) or 12-month delayed intervention start (control schools). Our primary outcome of student experience of sexual harassment will be measured at 12 months post-randomisation. Analysis of primary and secondary outcomes (student and school level) will be conducted on an intention to treat (ITT) basis comparing schools according to their original allocation.Study 2: Mixed-methods evaluation. Study 2A: Longitudinal follow-up will assess primary, secondary and intermediate outcomes at baseline, 12 months and 24 months of follow-up. Study 2B: Systems and realist-informed process evaluation will assess intervention and control school context, fidelity, dose and reach, acceptability and actor response, and how this varies by school and students. We will also assess implementation processes and mechanisms of action (beneficial or harmful), including if and how change is embedded over time, and if and how ESAS helps schools leverage other assets and resources.Study 3: Economic evaluation to assess the within-trial and longer term cost-effectiveness of ESAS.The methods include surveys in three out of six year groups (Years 2, 4 and 6) in all schools (baseline, 12 months and 24 months of follow-up); interviews with staff, students and other stakeholders; activity observations; brief surveys with key actors and analysis of trial documentation. ETHICS AND DISSEMINATION:Ethical approval by University of Glasgow MVLS Ethics Committee (200220268). Findings will be disseminated via multiple channels to researchers, GBV and education sector stakeholders, study participants and the public. TRIAL REGISTRATION NUMBER:ISRCTN29792495.

A range of health behavior interventions demonstrate efficacy in controlled settings, but face challenges when it comes to real-world implementation. These challenges arise due to the variation in participant, implementation staff, and implementation organization needs and resources which influence intervention delivery and effectiveness outcomes of these evidence-based interventions. We present potential approaches and considerations to prevent common pitfalls throughout the process of evidence-based intervention adoption, implementation, and sustainment. This includes using program theory, active engagement, cultural considerations, and understanding the connection between strategies, mechanisms, and outcomes right from the beginning to diligently develop, evaluate, implement, and disseminate evidence-based interventions. These approaches will help behavioral medicine/health psychology implementation researchers to get one step closer to the holy grail: To integrate evidence-based interventions sustainably into programs, systems, policy, and environments to facilitate long-term health behavior change and better health.

This invited discussion paper highlights key updates in the MRC/NIHR's revised framework for the development and evaluation of complex nursing interventions and reflects on the implications for nursing research.

Background: Sexual harassment in secondary school is common but only recently acknowledged as a widespread problem in the United Kingdom. There is limited research on how schools respond to incidents of sexual harassment. The aim of this study was to understand how school systems shape the dynamics of disclosure, reporting and handling of sexual harassment in school (including behaviours, processes, norms), and to identify opportunities for effecting systems change. Methods: We used participatory systems mapping to elicit school stakeholders' perspectives on systems factors and their connections. Researchers built the map based on in-person workshops with students (n = 18) and staff (n = 4) from three schools in Scotland. Survey data (n = 638 students; n = 119 staff) was used to augment participant perspectives. The map was validated via three workshops (two online, one in-person) involving students and staff from seven schools. Results: The final map (causal loop diagram) represents a hypothesised system of 25 causally connected factors and three feedback loops shaping the disclosure, reporting and handling of sexual harassment. We grouped these factors into four interlinked themes: 1] Knowledge and confidence; 2] Trust in reporting system and processes; 3] Communication, confidentiality and safeguarding; and, 4] Prioritisation of sexual harassment. Conclusions and implications: This study highlights the interconnectedness of factors shaping disclosure, reporting and handling of sexual harassment within secondary schools. The map surfaces key challenges for schools and provides a foundation for learning and discussions on where to focus efforts in future.

Adolescent health-related behaviours and outcomes are shaped by their peers through various social processes. Research using network data on friendship ties has uncovered evidence for processes such as peer influence and imitation. Much less is known about how the structure of small groups within a network, network communities that represents its meso level, affect individuals. The structure and composition of peer groups could play an important role in shaping health behaviour but knowledge of the effects of groups is limited. We used data from The Peers and Levels of Stress study, a cross-sectional social network study conducted in 2006 of 22 secondary schools in Glasgow, Scotland. Students from one year group (15-16 yrs., N = 3148; 50.8% women) provided information on socio-demographics, health behaviour and friendships via a questionnaire. Dependent variables were substance use and general mental wellbeing measured via principal components. We used a series of multilevel models with students (level 1), network communities (peer groups) identified by the Walktrap algorithm (level 2), and schools (level 3). We found substantial and moderate clustering at the peer group level for substance use and mental wellbeing, respectively. Larger and more transitive groups were associated with less substance use, but worse mental wellbeing. Addressing the methodological gap regarding the influence of the choice of group detection method on findings, we repeated our analysis using nine additional methods. The choice of the method somewhat influenced peer group variance and greatly influenced association of peer group properties with health. This study makes two key contributions to school-health improvement research. Beyond describing peer group clustering health outcomes, this is the first demonstration that structural and compositional characteristics of peer groups are associated with individual health, while highlighting the sensitivity of findings to group detection method used.

What is participatory systems mapping? Participatory systems mapping engages stakeholders with varied knowledge and perspectives in creating a visual representation of a complex system. Its purpose is to explore, and document perceived causal relations between elements in the system. This guidance focuses on six causal systems mapping methods: systems-based theory of change maps; causal loop diagrams; CECAN participatory systems mapping; fuzzy cognitive maps; systems dynamics models; and Bayesian belief networks. What is the purpose of this guidance? This guidance includes a Framework that aids the choice and design of participatory systems mapping approaches for population health research, policy and practice. It offers insights on different systems mapping approaches, by comparing them and highlighting their applications in the population health domain. This guidance also includes case studies, signposting to further reading and resources, and recommendations on enhancing stakeholder involvement in systems mapping. Who is this guidance for? This guidance is designed for anyone interested in using participatory systems mapping, regardless of prior knowledge or experience. It primarily responds to calls to support the growing demand for systems mapping (and systems-informed approaches more broadly) in population health research, policy and practice. This guidance can however also be applied to other disciplines. How was it developed? The guidance was created by an interdisciplinary research team through an iterative, rigorous fivestage process that included a scoping review, key informant interviews, and a consultation exercise with subject experts. What is the ‘Participatory Systems Design Framework’ included in this guidance? The Design Framework supports users to choose between different methods and enhance the design of participatory systems mapping projects. Specifically, it encourages users to consider: 1) the added value of adopting a participatory approach to systems mapping; 2) the differences between methods, including their relative advantages and disadvantages; and 3) the feasibility of using particular methods for a given purpose. An editable version of the Framework is available to download as a supplementary file. How will this guidance support future use of these methods? Participatory systems mapping is an exciting and evolving field. This guidance clarifies and defines the use of these methods in population health research, policy and practice, to encourage more thoughtful and purposeful project design, implementation, and reporting. The guidance also identifies several aspects for future research and development: methodological advancements; advocating for and strengthening participatory approaches; strengthening reporting; understanding and demonstrating the use of maps; and developing skills for the design and use of these methods.

Background: Among older people, walking is a popular and prevalent activity. Walking is key to increasing physical activity levels and resulting physical and mental health. In the context of rapidly ageing populations, it is important to better understand what factors are associated with walking among older people, based on the socioecological model of health. Methods: We used data from Understanding Society (n:6450), a national panel survey of UK adults aged 65 years and over living in Great Britain. Slope Indices of Inequality (SII) were calculated for weekly walking hours for older people according to individual, social and area characteristics. These include health, loneliness and social isolation, previous walking and sporting activity, residential self-selection, contact with neighbours, number of close friends and social activity. Spatial area-level data described local area crime, walkability, and proximity to retail, greenspace, and public transport amenities. Results: Multivariable models indicated that poor health, particularly requiring help with walking, was the strongest predictor of weekly walking hours (SII (95% CI) comparing those needing help vs. no help: -3.58 (-4.30, -2.87)). However, both prior sporting activity (most vs. least active: 2.30 (1.75, 2.88)) and walking for pleasure (yes vs. no: 1.92 (1.32, 2.53)) were strongly associated with increased walking several years later. Similarly having close friends (most vs. fewest, 1.18 (0.72, 1.77)) and local retail destinations (any vs. none: 0.93 (0.00, 1.86)) were associated with more weekly walking. Conclusions: Past engagement in physical activity and walking for pleasure are strong predictors of walking behaviour in older people, underscoring the importance of implementing and sustaining walking interventions across the lifespan to ensure continued engagement in later years and the associated health benefits. However, poor health significantly impedes walking in this demographic, emphasising the need for interventions that offer both physical assistance and social support to promote this activity.