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.

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.

Young people's experiences of physical activity insecurity: a qualitative study highlighting intersectional disadvantage in the UK.

BACKGROUND: Intersecting socioeconomic and demographic reasons for physical activity (PA) inequalities are not well understood for young people at risk of experiencing marginalisation and living with disadvantage. This study explored young people's experiences of PA in their local area, and the associated impacts on opportunities for good physical and emotional health and wellbeing. METHODS: Seven local youth groups were purposefully sampled from disadvantaged areas across urban, rural and coastal areas of England, including two that were specifically for LGBTQ + young people. Each group engaged in three interlinked focus groups which explored young people's perceptions and lived experience of PA inequalities. Data were analysed using an inductive, reflexive thematic approach to allow for flexibility in coding. RESULTS: Fifty five young people aged 12-21 years of different sexualities, gender and ethnicity took part. Analysis yielded four themes: PA experiences across spaces; resigned to a lack of inclusivity and 'belonging'; safety first; complexities in access and accessibility. Young people felt more comfortable to be active in spaces that were simpler to navigate, particularly outdoor locations largely based in nature. In contrast, local gyms and sports clubs, and the school environment in general, were spoken about often in negative terms and as spaces where they experienced insecurity, unsafety or discomfort. It was common for these young people to feel excluded from PA, often linked to their gender and sexuality. Lived experiences or fears of being bullied and harassed in many activity spaces was a powerful message, but in contrast, young people perceived their local youth club as a safe space. Intersecting barriers related to deprivation, gender and sexuality, accessibility, disability, Covid-19, affordability, ethnicity, and proximity of social networks. A need emerged for safe spaces in which young people can come together, within the local community and choose to be active. CONCLUSIONS: The overarching concept of 'physical activity insecurity' emerged as a significant concern for the young people in this study. We posit that PA insecurity in this context can be described as a limited or restricted ability to be active, reinforced by worries and lived experiences of feeling uncomfortable, insecure, or unsafe.

Co-design and content validity of the movement measurement in the early years (MoveMEY) tool for assessing movement behaviour of pre-school aged children.

BACKGROUND: Movement behaviours (physical activity, sedentary behaviour, and sleep) are important for pre-school children's health and development. Currently, no tools with appropriate content validity exist that concurrently capture these movement behaviours in young children. The aim of this study was to co-design and assess the content validity of a novel tool to concurrently measure movement behaviours in pre-school aged children (aged 3-4 years). METHODS: We followed four distinct steps to develop and assess the content validity of Movement Measurement in the Early Years (MoveMEY): (1) We conducted an extensive literature search, to identify pre-existing proxy measurement tools (questionnaires and diaries) to inform the design of a novel tool, which aimed to effectively capture movement behaviour guidelines of pre-school aged children. (2) We facilitated focus group discussions with parents and carers of pre-school aged children (n = 11) and (3) a qualitative survey with free text responses was completed by topic relevant researchers (n = 6), to co-design the measurement tool. (4) We assessed the content validity of the developed tool, MoveMEY, through interviews with parents of pre-school aged children (n = 12) following piloting of the tool. RESULTS: We developed an initial version of MoveMEY based on the format of an existing questionnaire and by mapping the content of questions to the guidelines. Co-design of MoveMEY resulted in changes to the format (e.g. short questionnaire to a seven-day diary) and content (e.g. inclusion of 'general information' questions on illness, disabilities and sleep disturbances; question on screen time before bed). Content validity assessment demonstrated that the items of MoveMEY were relevant and comprehensive for the assessment of children's movement behaviours. MoveMEY was felt to be comprehensible, however, parental suggestions were implemented to finalise and improve MoveMEY (e.g. adding examples to questions aiming to detect moderate to vigorous physical activity). CONCLUSION: MoveMEY is the first co-designed measurement tool that has relevance for assessing the movement behaviour guidelines of pre-school aged children. Parent/carer and topic relevant researcher involvement throughout the development process resulted in a seven-day daily reported activity diary that is comprehensive of children's movement behaviours and comprehensible to parents and carers.

Characterizing restrictions on commercial advertising and sponsorship of harmful commodities in local government policies: a nationwide study in England.

BACKGROUND: Commercial advertising and sponsorship drive the consumption of harmful commodities. Local authorities (LAs) have considerable powers to reduce such exposures. This study aimed to characterize local commercial policies across all English LAs. METHODS: We conducted a census of all English LAs (n = 333) to identify local commercial policies concerning advertising and sponsorship of tobacco, alcohol, less healthy foods and gambling, through online searches and Freedom of Information requests. We explored policy presence, commodity frequency and type, and associations with LA characteristics (region, urban/rural and deprivation). RESULTS: Only a third (106) of LAs in England had a relevant policy (32%). These included restrictions on tobacco (91%), gambling (79%), alcohol (74%) and/or less healthy foods (24%). Policy prevalence was lowest in the East of England (22%), North East (25%) and North West (27%), higher in urban areas (36%) than rural areas (28%) and lower in the least (27%) compared with the most (38%) deprived areas. Definitions in policies varied, particularly for alcohol and less healthy foods. CONCLUSIONS: English LAs currently underutilize their levers to reduce the negative impacts of harmful commodity industry marketing, particularly concerning less healthy foods. Standardized guidance, including clarity on definitions and application, could inform local policy development.

A qualitative exploration of food portion size practices and awareness of food portion size guidance in first-time parents of one- to two-year-olds living in the UK.

BACKGROUND: Food portion size guidance resources aimed at parents of young children in the UK are freely available from a number of credible sources. However, little is known about whether parents are aware of, and use, any of these resources to guide their food portioning practices. OBJECTIVES: We aimed to explore the food portion size practices used by first-time parents living in the UK when feeding their one- to two-year-old child, and their awareness of and views on six food portion size guidance resources. METHODS: Participants were recruited via parent Facebook groups and online parent forums. Online 1-1 semi-structured interviews were conducted, during which parents were shown images of six food portion size guidance resources to facilitate discussion. Data was analysed in NVivo 11 using a Reflexive Thematic Analysis approach. RESULTS: Of the 27 participants, most were women (n = 25), white (n = 18), and educated to first degree level or higher (n = 24). First-time parents mostly relied on their own judgement and "instinct" to portion foods, based on their learned experience of how much their child ate on a day-to-day basis. This experience was used alongside physical indicators of food portion size, such as the size of children's dishware and food packaging. Most participants were unaware of any of the six food portion size guidance resources we showed them; only four had read any of the resources. Parents suggested they had previously sought advice about weaning from a range of sources (e.g. online, friends, community groups) but would be unlikely to seek out specific food portion size guidance. Parents suggested recommendations on food portion size should acknowledge and highlight parents' perception that "every child is different". CONCLUSIONS: Existing food portion size guidance resources for parents of young children in the UK are ineffective as they have poor reach and impact. We suggest parents should be involved in developing novel strategies to promote age-appropriate consumption and healthy weight gain in young children.

This needs to be a journey that we're actually on together'-the introduction of integrated care systems for children and young people in England: a qualitative study of the views of local system stakeholders during winter 2021/22.

BACKGROUND: Integrated care has become a central feature of health system reform worldwide. In England, Integrated Care Systems (ICS) are intended to improve integration across public health, the National Health Service (NHS), education and social care. By April 2021, England had been divided into 42 geographical areas, each tasked with developing local ICS provision. However, it was not clear how ICSs would address the specific needs of children and young people (CYP). This study elicited the views of senior professional stakeholders in the first year of the ICS national roll out, to learn how integrated care for CYP was being implemented within the ICSs and future plans for service provision. METHODS: A qualitative analysis of in-depth interviews with stakeholders, including healthcare professionals, NHS managers and local authority leaders (n = 25) selected from a diverse sample of ICSs (n = 7) across England, conducted during winter 2021/22. Reflexive thematic analysis involving a collaborative coding approach was used to analyse interview transcripts. RESULTS: Four themes were identified, indicating challenges and opportunities for ICSs in relation to the health of CYP: 1) Best start in life (a more holistic approach to health afforded by integrated care); 2) Local and national contexts (tensions between local and national settings and priorities); 3) Funding and planning (instituting innovative, long-term plans using limited existing CYP funding streams); 4) Organisational complexities (integrating the work of diverse organisations). CONCLUSIONS: The views of stakeholders, provided at the beginning of the journey towards developing local ICS CYP provision, revealed a common aspiration to change focus from provision of acute, largely adult-orientated services towards one with a broader, population health remit, including prevention and early intervention. This would be delivered by integration of a range of local services, including health, education, housing and social care, to set CYP on a life-long path towards improved health and wellbeing. Yet there was an awareness that change would take place over time within existing national policy and funding frameworks, and would require overcoming organisational barriers through further developing local collaborations and partnerships. As ICSs mature, the experiences of stakeholders should continue to be canvassed to identify practical lessons for successful CYP integrated care.

An analysis of English national policy approaches to health inequalities: 'transforming children and young people's mental health provision' and its consultation process.

BACKGROUND: A national policy for England, published in 2017, entitled 'Transforming Children and Young People's Mental Health Provision' aimed to address the increasing prevalence mental health problems in children and tackle inequalities. In the context of this policy's implementation as ongoing and the effects of the Covid-19 pandemic, the need for appropriate, timely and ongoing national government commitment is vital. METHODS: A narrative review using a problem representation evaluation [1], we critiqued the policy and related consultation documents using a social determinants of health perspective. We also reviewed wider policy discourses through engaging with stakeholder responses, providing an innovative methodological contribution to scholarship on public health policy and health inequalities. RESULTS: We found absences and oversights in relation to inequalities (most notably the lack of acknowledgement that mental health can cause inequalities), access, workforce capacity, and the impacts of cuts and austerity on service provision. We suggest these inadequacies may have been avoided if stakeholder responses to the consultation process had been more meaningfully addressed. We illustrate how 'problems' are discursively created through the process of policy development, justified using specific types of evidence, and that this process is politically motivated. Local policy makers have a critical role in translating and adapting national policy for their communities but are constrained by absences and oversights in relation to health inequalities. CONCLUSIONS: This narrative review illustrates how policy discourse frames and produces 'problems', and how the evidence used is selected and justified politically. This review contributes to the existing transdisciplinary field of knowledge about how using methods from political and social science disciplines can reveal new insights when critiquing and influencing policy approaches to health inequalities.

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.

A systematic review of the validity, reliability, and feasibility of measurement tools used to assess the physical activity and sedentary behaviour of pre-school aged children.

Physical activity (PA) and sedentary behaviour (SB) of pre-school aged children are associated with important health and developmental outcomes. Accurate measurement of these behaviours in young children is critical for research and practice in this area. The aim of this review was to examine the validity, reliability, and feasibility of measurement tools used to assess PA and SB of pre-school aged children.Searches of electronic databases, and manual searching, were conducted to identify articles that examined the measurement properties (validity, reliability or feasibility) of measurement tools used to examine PA and/or SB of pre-school aged children (3-7 years old). Following screening, data were extracted and risk of bias assessment completed on all included articles.A total of 69 articles, describing 75 individual studies were included. Studies assessed measurement tools for PA (n = 27), SB (n = 5), and both PA and SB (n = 43). Outcome measures of PA and SB differed between studies (e.g. moderate to vigorous activity, step count, posture allocation). Most studies examined the measurement properties of one measurement tool only (n = 65). Measurement tools examined included: calorimetry, direct observation, combined heart rate and accelerometry, heart rate monitors, accelerometers, pedometers, and proxy report (parent, carer or teacher reported) measures (questionnaires or diaries). Studies most frequently assessed the validity (criterion and convergent) (n = 65), face and content validity (n = 2), test-retest reliability (n = 10) and intra-instrument reliability (n = 1) of the measurement tools. Feasibility data was abstracted from 41 studies.Multiple measurement tools used to measure PA and SB in pre-school aged children showed some degree of validity, reliability and feasibility, but often for different purposes. Accelerometers, including the Actigraph (in particular GT3X versions), Actical, ActivPAL and Fitbit (Flex and Zip), and proxy reported measurement tools used in combination may be useful for a range of outcome measures, to measure intensity alongside contextual information.

Where and when are portion sizes larger in young children? An analysis of eating occasion size among 1·5-5-year-olds in the UK National Diet and Nutrition Survey (2008-2017).

OBJECTIVE: To identify eating occasion-level and individual-level factors associated with the consumption of larger portions in young children and estimate their relative importance. DESIGN: Cross-sectional. SETTING: Data from parent-reported 4-d food diaries in the UK National Diet and Nutrition Survey (2008-2017) were analysed. Multilevel models explored variation in eating occasion size (kJ) within (n 48 419 occasions) and between children (n 1962) for all eating occasions. Eating contexts: location, eating companion, watching TV, and sitting at a table and individual characteristics: age, gender, ethnicity and parental socio-economic status were explored as potential correlates of eating occasion size. PARTICIPANTS: Children aged 1·5-5 years. RESULTS: Median eating occasion size was 657 kJ (IQR 356, 1117). Eating occasion size variation was primarily attributed (90 %) to differences between eating occasions. Most (73 %) eating occasions were consumed at home. In adjusted models, eating occasions in eateries were 377 kJ larger than at home. Eating occasions sitting at a table, v. not, were 197 kJ larger. Eating in childcare, with additional family members and friends, and whilst watching TV were other eating contexts associated with slightly larger eating occasion sizes. CONCLUSIONS: Eating contexts that vary from one eating occasion to another are more important than demographic characteristics that vary between children in explaining variation in consumed portion sizes in young children. Strategies to promote consumption of age-appropriate portion sizes in young children should be developed, especially in the home environment, in eating contexts such as sitting at the table, eating with others and watching TV.

Exploring the local policy context for reducing health inequalities in children and young people: an in depth qualitative case study of one local authority in the North of England, UK.

BACKGROUND: Improving children and young people's (CYP) health and addressing health inequalities are international priorities. Reducing inequalities is particularly pertinent in light of the Covid-19 outbreak which has exacerbated already widening inequalities in health. This study aimed to explore understandings of inequality, the anticipated pathways for reducing inequalities among CYP and key factors affecting the development and implementation of policy to reduce inequalities among CYP at a local level. METHODS: We carried out a qualitative case study of one local government region in the North of England (UK), comprising semi structured interviews (n = 16) with service providers with a responsibility for child health, non-participant observations of key meetings (n = 6 with 43 participants) where decisions around child health are made, and a local policy documentation review (n = 11). We employed a novel theoretical framework, drawing together different approaches to understanding policy, to guide our design and analysis. RESULTS: Participants in our study understood inequalities in CYP health almost exclusively as socioeconomically patterned inequalities in health practices and outcomes. Strategies which participants perceived to reduce inequalities included: preventive support and early intervention, an early years/whole family focus, targeted working in local areas of high deprivation, organisational integration and whole system/place-based approaches. Despite demonstrating a commitment to a social determinants of health approach, efforts to reduce inequalities were described as thwarted by the prevalence of poverty and budget cuts which hindered the ability of local organisations to work together. Participants critiqued national policy which aimed to reduce inequalities in CYP health for failing to recognise local economic disparities and the interrelated nature of the determinants of health. CONCLUSIONS: Despite increased calls for a 'whole systems' approach to reducing inequalities in health, significant barriers to implementation remain. National governments need to work towards more joined up policy making, which takes into consideration regional disparities, allows for flexibility in interpretation and addresses the different and interrelated social determinants of health. Our findings have particular significance in light of Covid-19 and indicate the need for systems level policy responses and a health in all policies approach.

A critique of the English national policy from a social determinants of health perspective using a realist and problem representation approach: the 'Childhood Obesity: a plan for action' (2016, 2018, 2019).

BACKGROUND: The UK government released Chapter 1 of the 'Childhood Obesity: a plan for action' (2016), followed by Chapter 2 (2018) and preliminary Chapter 3 was published for consultation in 2019 (hereon collectively 'The Policy'). The stated policy aims were to reduce the prevalence of childhood obesity in England, addressing disparities in health by reducing the gap (approximately two-fold) in childhood obesity between those from the most and least deprived areas. METHODS: Combining a realist approach with an analysis of policy discourses, we analysed the policies using a social determinants of health (SDH) perspective (focusing on socio-economic inequalities). This novel approach reveals how the framing of policy 'problems' leads to particular approaches and interventions. RESULTS: While recognising a social gradient in relation to obesity measures, we critique obesity problem narratives. The Policy included some upstream, structural approaches (e.g. restrictions in food advertising and the soft-drinks industry levy). However, the focus on downstream individual-level behavioural approaches to reduce calorie intake and increase physical activity does not account for the SDH and the complexity and contestedness of 'obesity' and pays insufficient attention to how proposals will help to reduce inequalities. Our findings illustrate that individualising of responsibility to respond to what wider evidence shows is structural inequalities, can perpetuate damaging narratives and lead to ineffective interventions, providing caution to academics, practitioners and policy makers (local and national), of the power of problem representation. Our findings also show that the problem framing in The Policy risks reducing important public health aims to encourage healthy diets and increase opportunities for physical activity (and the physical and mental health benefits of both) for children to weight management with a focus on particular children. CONCLUSIONS: We propose an alternative conceptualisation of the policy 'problem', that obesity rates are illustrative of inequality, arguing there needs to be policy focus on the structural and factors that maintain health inequalities, including poverty and food insecurity. We hope that our findings can be used to challenge and strengthen future policy development, leading to more effective action against health inequalities and intervention-generated inequalities in health.

Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease.

BACKGROUND: Omega-3 polyunsaturated fatty acids from oily fish (long-chain omega-3 (LCn3)), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), as well as from plants (alpha-linolenic acid (ALA)) may benefit cardiovascular health. Guidelines recommend increasing omega-3-rich foods, and sometimes supplementation, but recent trials have not confirmed this. OBJECTIVES: To assess the effects of increased intake of fish- and plant-based omega-3 fats for all-cause mortality, cardiovascular events, adiposity and lipids. SEARCH METHODS: We searched CENTRAL, MEDLINE and Embase to February 2019, plus ClinicalTrials.gov and World Health Organization International Clinical Trials Registry to August 2019, with no language restrictions. We handsearched systematic review references and bibliographies and contacted trial authors. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that lasted at least 12 months and compared supplementation or advice to increase LCn3 or ALA intake, or both, versus usual or lower intake. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trials for inclusion, extracted data and assessed validity. We performed separate random-effects meta-analysis for ALA and LCn3 interventions, and assessed dose-response relationships through meta-regression. MAIN RESULTS: We included 86 RCTs (162,796 participants) in this review update and found that 28 were at low summary risk of bias. Trials were of 12 to 88 months' duration and included adults at varying cardiovascular risk, mainly in high-income countries. Most trials assessed LCn3 supplementation with capsules, but some used LCn3- or ALA-rich or enriched foods or dietary advice compared to placebo or usual diet. LCn3 doses ranged from 0.5 g a day to more than 5 g a day (19 RCTs gave at least 3 g LCn3 daily). Meta-analysis and sensitivity analyses suggested little or no effect of increasing LCn3 on all-cause mortality (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.93 to 1.01; 143,693 participants; 11,297 deaths in 45 RCTs; high-certainty evidence), cardiovascular mortality (RR 0.92, 95% CI 0.86 to 0.99; 117,837 participants; 5658 deaths in 29 RCTs; moderate-certainty evidence), cardiovascular events (RR 0.96, 95% CI 0.92 to 1.01; 140,482 participants; 17,619 people experienced events in 43 RCTs; high-certainty evidence), stroke (RR 1.02, 95% CI 0.94 to 1.12; 138,888 participants; 2850 strokes in 31 RCTs; moderate-certainty evidence) or arrhythmia (RR 0.99, 95% CI 0.92 to 1.06; 77,990 participants; 4586 people experienced arrhythmia in 30 RCTs; low-certainty evidence). Increasing LCn3 may slightly reduce coronary heart disease mortality (number needed to treat for an additional beneficial outcome (NNTB) 334, RR 0.90, 95% CI 0.81 to 1.00; 127,378 participants; 3598 coronary heart disease deaths in 24 RCTs, low-certainty evidence) and coronary heart disease events (NNTB 167, RR 0.91, 95% CI 0.85 to 0.97; 134,116 participants; 8791 people experienced coronary heart disease events in 32 RCTs, low-certainty evidence). Overall, effects did not differ by trial duration or LCn3 dose in pre-planned subgrouping or meta-regression. There is little evidence of effects of eating fish. Increasing ALA intake probably makes little or no difference to all-cause mortality (RR 1.01, 95% CI 0.84 to 1.20; 19,327 participants; 459 deaths in 5 RCTs, moderate-certainty evidence),cardiovascular mortality (RR 0.96, 95% CI 0.74 to 1.25; 18,619 participants; 219 cardiovascular deaths in 4 RCTs; moderate-certainty evidence), coronary heart disease mortality (RR 0.95, 95% CI 0.72 to 1.26; 18,353 participants; 193 coronary heart disease deaths in 3 RCTs; moderate-certainty evidence) and coronary heart disease events (RR 1.00, 95% CI 0.82 to 1.22; 19,061 participants; 397 coronary heart disease events in 4 RCTs; low-certainty evidence). However, increased ALA may slightly reduce risk of cardiovascular disease events (NNTB 500, RR 0.95, 95% CI 0.83 to 1.07; but RR 0.91, 95% CI 0.79 to 1.04 in RCTs at low summary risk of bias; 19,327 participants; 884 cardiovascular disease events in 5 RCTs; low-certainty evidence), and probably slightly reduces risk of arrhythmia (NNTB 91, RR 0.73, 95% CI 0.55 to 0.97; 4912 participants; 173 events in 2 RCTs; moderate-certainty evidence). Effects on stroke are unclear. Increasing LCn3 and ALA had little or no effect on serious adverse events, adiposity, lipids and blood pressure, except increasing LCn3 reduced triglycerides by ˜15% in a dose-dependent way (high-certainty evidence). AUTHORS' CONCLUSIONS: This is the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date. Moderate- and low-certainty evidence suggests that increasing LCn3 slightly reduces risk of coronary heart disease mortality and events, and reduces serum triglycerides (evidence mainly from supplement trials). Increasing ALA slightly reduces risk of cardiovascular events and arrhythmia.

Stakeholders' perceptions and experiences of the National Health Service diabetes prevention programme in England: qualitative study with service users, intervention providers and deliverers, commissioners and referrers.

BACKGROUND: The National Health Service diabetes prevention programme in England, (NHS DPP) aims to identify people at high risk of type 2 diabetes (T2D) and offer them a face-to-face, group-based, behaviour change intervention for at least 9 months. The NHS DPP was rolled out in phases. We aimed to elicit stakeholders' perceptions and experiences of the factors influencing implementation of, and participation in, the programme during the development phase. METHODS: Individual, semi-structured telephone interviews were conducted with 50 purposively sampled stakeholders: service users (n = 20); programme commissioners (n = 7); referrers (n = 8); and intervention deliverers (n = 15). Topic guides were structured using a pragmatic, theory-informed approach. Analysis employed the framework method. RESULTS: We identified factors that influenced participation: Risk communication at referral - stakeholders identified point of referral as a window of opportunity to offer brief advice, to provide an understanding of T2D risk and information about the programme; Perceived impact of the NHS DPP - service users highlighted the positive perceived impact on their behaviour change, the peer support provided by participating in the programme, the option to involve a relative, and the 'knock on' effect on others. Service users also voiced disappointment when blood test results still identified them at high risk after the programme; and Behavioural maintenance - participants highlighted the challenges linked to behavioural maintenance (e.g. discontinuation of active support). Factors influencing implementations were also identified: Case finding - stakeholders suggested that using community involvement to identify service users could increase reach and ensure that the workload was not solely on GP practices; Adaptability: intervention deliverers acknowledged the need to tailor advice to service users' preferences and needs; Accountability - the need to acknowledge who was responsible for what at different stages of the NHS DPP pathway; and Fidelity - stakeholders described procedures involved in monitoring service users' satisfaction, outcome data collection and quality assurance assessments. CONCLUSIONS: The NHS DPP offers an evidence-informed behavioural intervention for T2D prevention. Better risk communication specification could ensure consistency at the referral stage and improve participation in the NHS DPP intervention. Cultural adaptations and outreach strategies could ensure the NHS DPP contributes to reducing health inequalities.

Assessing the acceptability of an adapted preschool obesity prevention programme: ToyBox-Scotland.

BACKGROUND: Childhood obesity is a global public health issue. Interventions to prevent the onset of obesity in the early years are often implemented in preschool settings. The ToyBox intervention was delivered across Europe and targeted energy balance-related behaviours in preschools and children's homes through teacher-led activities and parental education materials and was adapted for use in Scotland. This study assessed the acceptability of the 18-week adapted intervention to both parents and teachers. METHODS: Mixed methods were employed to collect both qualitative and quantitative data. Preschool staff and children's parents/caregivers completed post-intervention feedback surveys, from which acceptability scores were calculated and presented as proportions. Focus groups were conducted with preschool staff, whereas parents/caregivers participated in semi-structured interviews. A thematic analysis was applied to qualitative data following the development of a coding framework. Quantitative and qualitative data were analysed using SPSS and NVivo 10, respectively. RESULTS: Preschool staff rated the intervention as highly acceptable based on post-intervention feedback surveys (80%; mean score 8.8/11). Lower acceptability scores were observed for parents/caregivers (49%; 3.9/8). Nine preschool practitioners participated in focus groups (n = 3). User-friendliness of the intervention materials, integration of the intervention with the curriculum, and flexibility of the intervention were identified as facilitators to delivery. Barriers to delivery were time, insufficient space, and conflicting policies within preschools with regard to changing classroom layouts. Parental interviews (n = 4) revealed a lack of time to be a major barrier, which prevented parents from participating in home-based activities. Parents perceived the materials to be simple to understand and visually appealing. CONCLUSIONS: This study identified a number of barriers and facilitators to the delivery and evaluation of the ToyBox Scotland preschool obesity prevention programme, which should be considered before any further scale-up of the intervention.

Correlates of English local government use of the planning system to regulate hot food takeaway outlets: a cross-sectional analysis.

BACKGROUND: Greater neighbourhood takeaway food outlet access has been associated with increased takeaway food consumption and higher body weight. National planning guidelines in England suggest that urban planning could promote healthier food environments through takeaway food outlet regulation, for example by restricting the proliferation of outlets near schools. It is unknown how geographically widespread this approach is, or local characteristics associated with its use. We aimed to address these knowledge gaps. METHODS: We used data from a complete review of planning policy documents adopted by local government areas in England (n = 325), which contained policies for the purpose of takeaway food outlet regulation. This review classified local government area planning policies as having a health (diet or obesity) or non-health focus. We explored geographical clustering of similar planning policies using spatial statistics. We used multinomial logistic regression models to investigate whether the odds of planning policy adoption varied according to local characteristics, for example the proportion of children with excess weight or the current number of takeaway food outlets. RESULTS: We observed clusters of local government areas with similar adopted planning policies in the North East, North West, and Greater London regions of England. In unadjusted logistic regression models, compared to local government areas with the lowest, those with highest proportion of 10-11 year olds with excess weight (OR: 25.31; 95% CI: 6.74, 94.96), and takeaway food outlet number (OR: 54.00; 95% CI: 6.17, 472.41), were more likely to have a health-focused planning policy, than none. In models adjusted for deprivation, relationships for excess weight metrics were attenuated. Compared to local government areas with the lowest, those with the highest takeaway food outlet number remained more likely to have a health-focused planning policy, than none (OR: 16.98; 95% CI: 1.44, 199.04). When local government areas were under Labour political control, predominantly urban, and when they had more geographically proximal and statistically similar areas in the same planning policy status category, they were also more likely to have health-focused planning policies. CONCLUSIONS: Planning policies for the purpose of takeaway food outlet regulation with a health focus were more likely in areas with greater numbers of takeaway food outlets and higher proportions of children with excess weight. Other characteristics including Labour political control, greater deprivation and urbanisation, were associated with planning policy adoption, as were the actions of similar and nearby local government areas. Further research should engage with local policymakers to explore the drivers underpinning use of this approach.

WITHDRAWN: Interventions for treating obesity in children.

BACKGROUND: Child and adolescent obesity is increasingly prevalent, and can be associated with significant short- and long-term health consequences. OBJECTIVES: To assess the efficacy of lifestyle, drug and surgical interventions for treating obesity in childhood. SEARCH METHODS: We searched CENTRAL on The Cochrane Library Issue 2 2008, MEDLINE, EMBASE, CINAHL, PsycINFO, ISI Web of Science, DARE and NHS EED. Searches were undertaken from 1985 to May 2008. References were checked. No language restrictions were applied. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) of lifestyle (i.e. dietary, physical activity and/or behavioural therapy), drug and surgical interventions for treating obesity in children (mean age under 18 years) with or without the support of family members, with a minimum of six months follow up (three months for actual drug therapy). Interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity were excluded. DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial quality and extracted data following the Cochrane Handbook. Where necessary authors were contacted for additional information. MAIN RESULTS: We included 64 RCTs (5230 participants). Lifestyle interventions focused on physical activity and sedentary behaviour in 12 studies, diet in 6 studies, and 36 concentrated on behaviorally orientated treatment programs. Three types of drug interventions (metformin, orlistat and sibutramine) were found in 10 studies. No surgical intervention was eligible for inclusion. The studies included varied greatly in intervention design, outcome measurements and methodological quality.Meta-analyses indicated a reduction in overweight at 6 and 12 months follow up in: i) lifestyle interventions involving children; and ii) lifestyle interventions in adolescents with or without the addition of orlistat or sibutramine. A range of adverse effects was noted in drug RCTs. AUTHORS' CONCLUSIONS: While there is limited quality data to recommend one treatment program to be favoured over another, this review shows that combined behavioural lifestyle interventions compared to standard care or self-help can produce a significant and clinically meaningful reduction in overweight in children and adolescents. In obese adolescents, consideration should be given to the use of either orlistat or sibutramine, as an adjunct to lifestyle interventions, although this approach needs to be carefully weighed up against the potential for adverse effects. Furthermore, high quality research that considers psychosocial determinants for behaviour change, strategies to improve clinician-family interaction, and cost-effective programs for primary and community care is required.

Community pharmacy interventions for health promotion: effects on professional practice and health outcomes.

BACKGROUND: Community pharmacies are an easily accessible and cost-effective platform for delivering health care worldwide, and the range of services provided has undergone rapid expansion in recent years. Thus, in addition to dispensing medication, pharmacy workers within community pharmacies now give advice on a range of health-promoting behaviours that aim to improve health and to optimise the management of long-term conditions. However, it remains uncertain whether these health-promotion interventions can change the professional practice of pharmacy workers, improve health behaviours and outcomes for pharmacy users and have the potential to address health inequalities. OBJECTIVES: To assess the effectiveness and safety of health-promotion interventions to change community pharmacy workers' professional practice and improve outcomes for users of community pharmacies. SEARCH METHODS: We searched MEDLINE, Embase, CENTRAL, six other databases and two trials registers to 6 February 2018. We also conducted reference checking, citation searches and contacted study authors to identify any additional studies. SELECTION CRITERIA: We included randomised trials of health-promotion interventions in community pharmacies targeted at, or delivered by, pharmacy workers that aimed to improve the health-related behaviour of people attending the pharmacy compared to no treatment, or usual treatment received in the community pharmacy. We excluded interventions where there was no interaction between pharmacy workers and pharmacy users, and those that focused on medication use only. DATA COLLECTION AND ANALYSIS: We used standard procedures recommended by Cochrane and the Effective Practice and Organisation of Care review group for both data collection and analysis. We compared intervention to no intervention or to usual treatment using standardised mean differences (SMD) and 95% confidence intervals (95% CI) (higher scores represent better outcomes for pharmacy user health-related behaviour and quality of life, and lower scores represent better outcomes for clinical outcomes, costs and adverse events). Interpretation of effect sizes (SMD) was in line with Cochrane recommendations. MAIN RESULTS: We included 57 randomised trials with 16,220 participants, described in 83 reports. Forty-nine studies were conducted in high-income countries, and eight in middle-income countries. We found no studies that had been conducted in low-income countries. Most interventions were educational, or incorporated skills training. Interventions were directed at pharmacy workers (n = 8), pharmacy users (n = 13), or both (n = 36). The clinical areas most frequently studied were diabetes, hypertension, asthma, and modification of cardiovascular risk. Duration of follow-up of interventions was often unclear. Only five studies gave details about the theoretical basis for the intervention, and studies did not provide sufficient data to comment on health inequalities. The most common sources of bias were lack of protection against contamination - mainly in individually randomised studies - and inadequate blinding of participants. The certainty of the evidence for all outcomes was moderate. We downgraded the certainty because of the heterogeneity across studies and evidence of potential publication bias. Professional practice outcomes We conducted a narrative analysis for pharmacy worker behaviour due to high heterogeneity in the results. Health-promotion interventions probably improve pharmacy workers' behaviour (2944 participants; 9 studies; moderate-certainty evidence) when compared to no intervention. These studies typically assessed behaviour using a simulated patient (mystery shopper) methodology. Pharmacy user outcomes Health-promotion interventions probably lead to a slight improvement in health-related behaviours of pharmacy users when compared to usual treatment (SMD 0.43, 95% CI 0.14 to 0.72; I2 = 89%; 10 trials; 2138 participants; moderate-certainty evidence). These interventions probably also lead to a slight improvement in intermediate clinical outcomes, such as levels of cholesterol or glycated haemoglobin, for pharmacy users (SMD -0.43, 95% CI -0.65 to -0.21; I2 = 90%; 20 trials; 3971 participants; moderate-certainty evidence). We identified no studies that evaluated the impact of health-promotion interventions on event-based clinical outcomes, such as stroke or myocardial infarction, or the psychological well-being of pharmacy users. Health-promotion interventions probably lead to a slight improvement in quality of life for pharmacy users (SMD 0.29, 95% CI 0.08 to 0.50; I2= 82%; 10 trials, 2687 participants; moderate-certainty evidence). Adverse events No studies reported adverse events for either pharmacy workers or pharmacy users. Costs We found that health-promotion interventions are likely to be cost-effective, based on moderate-certainty evidence from five of seven studies that reported an economic evaluation. AUTHORS' CONCLUSIONS: Health-promotion interventions in the community pharmacy context probably improve pharmacy workers' behaviour and probably have a slight beneficial effect on health-related behaviour, intermediate clinical outcomes, and quality of life for pharmacy users. Such interventions are likely to be cost-effective and the effects are seen across a range of clinical conditions and health-related behaviours. Nevertheless the magnitude of the effects varies between conditions, and more effective interventions might be developed if greater consideration were given to the theoretical basis of the intervention and mechanisms for effecting behaviour change.

Interventions for preventing obesity in children.

BACKGROUND: Prevention of childhood obesity is an international public health priority given the significant impact of obesity on acute and chronic diseases, general health, development and well-being. The international evidence base for strategies to prevent obesity is very large and is accumulating rapidly. This is an update of a previous review. OBJECTIVES: To determine the effectiveness of a range of interventions that include diet or physical activity components, or both, designed to prevent obesity in children. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, PsychINFO and CINAHL in June 2015. We re-ran the search from June 2015 to January 2018 and included a search of trial registers. SELECTION CRITERIA: Randomised controlled trials (RCTs) of diet or physical activity interventions, or combined diet and physical activity interventions, for preventing overweight or obesity in children (0-17 years) that reported outcomes at a minimum of 12 weeks from baseline. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data, assessed risk-of-bias and evaluated overall certainty of the evidence using GRADE. We extracted data on adiposity outcomes, sociodemographic characteristics, adverse events, intervention process and costs. We meta-analysed data as guided by the Cochrane Handbook for Systematic Reviews of Interventions and presented separate meta-analyses by age group for child 0 to 5 years, 6 to 12 years, and 13 to 18 years for zBMI and BMI. MAIN RESULTS: We included 153 RCTs, mostly from the USA or Europe. Thirteen studies were based in upper-middle-income countries (UMIC: Brazil, Ecuador, Lebanon, Mexico, Thailand, Turkey, US-Mexico border), and one was based in a lower middle-income country (LMIC: Egypt). The majority (85) targeted children aged 6 to 12 years.Children aged 0-5 years: There is moderate-certainty evidence from 16 RCTs (n = 6261) that diet combined with physical activity interventions, compared with control, reduced BMI (mean difference (MD) -0.07 kg/m2, 95% confidence interval (CI) -0.14 to -0.01), and had a similar effect (11 RCTs, n = 5536) on zBMI (MD -0.11, 95% CI -0.21 to 0.01). Neither diet (moderate-certainty evidence) nor physical activity interventions alone (high-certainty evidence) compared with control reduced BMI (physical activity alone: MD -0.22 kg/m2, 95% CI -0.44 to 0.01) or zBMI (diet alone: MD -0.14, 95% CI -0.32 to 0.04; physical activity alone: MD 0.01, 95% CI -0.10 to 0.13) in children aged 0-5 years.Children aged 6 to 12 years: There is moderate-certainty evidence from 14 RCTs (n = 16,410) that physical activity interventions, compared with control, reduced BMI (MD -0.10 kg/m2, 95% CI -0.14 to -0.05). However, there is moderate-certainty evidence that they had little or no effect on zBMI (MD -0.02, 95% CI -0.06 to 0.02). There is low-certainty evidence from 20 RCTs (n = 24,043) that diet combined with physical activity interventions, compared with control, reduced zBMI (MD -0.05 kg/m2, 95% CI -0.10 to -0.01). There is high-certainty evidence that diet interventions, compared with control, had little impact on zBMI (MD -0.03, 95% CI -0.06 to 0.01) or BMI (-0.02 kg/m2, 95% CI -0.11 to 0.06).Children aged 13 to 18 years: There is very low-certainty evidence that physical activity interventions, compared with control reduced BMI (MD -1.53 kg/m2, 95% CI -2.67 to -0.39; 4 RCTs; n = 720); and low-certainty evidence for a reduction in zBMI (MD -0.2, 95% CI -0.3 to -0.1; 1 RCT; n = 100). There is low-certainty evidence from eight RCTs (n = 16,583) that diet combined with physical activity interventions, compared with control, had no effect on BMI (MD -0.02 kg/m2, 95% CI -0.10 to 0.05); or zBMI (MD 0.01, 95% CI -0.05 to 0.07; 6 RCTs; n = 16,543). Evidence from two RCTs (low-certainty evidence; n = 294) found no effect of diet interventions on BMI.Direct comparisons of interventions: Two RCTs reported data directly comparing diet with either physical activity or diet combined with physical activity interventions for children aged 6 to 12 years and reported no differences.Heterogeneity was apparent in the results from all three age groups, which could not be entirely explained by setting or duration of the interventions. Where reported, interventions did not appear to result in adverse effects (16 RCTs) or increase health inequalities (gender: 30 RCTs; socioeconomic status: 18 RCTs), although relatively few studies examined these factors.Re-running the searches in January 2018 identified 315 records with potential relevance to this review, which will be synthesised in the next update. AUTHORS' CONCLUSIONS: Interventions that include diet combined with physical activity interventions can reduce the risk of obesity (zBMI and BMI) in young children aged 0 to 5 years. There is weaker evidence from a single study that dietary interventions may be beneficial.However, interventions that focus only on physical activity do not appear to be effective in children of this age. In contrast, interventions that only focus on physical activity can reduce the risk of obesity (BMI) in children aged 6 to 12 years, and adolescents aged 13 to 18 years. In these age groups, there is no evidence that interventions that only focus on diet are effective, and some evidence that diet combined with physical activity interventions may be effective. Importantly, this updated review also suggests that interventions to prevent childhood obesity do not appear to result in adverse effects or health inequalities.The review will not be updated in its current form. To manage the growth in RCTs of child obesity prevention interventions, in future, this review will be split into three separate reviews based on child age.