Although childhood overweight and obesity prevalence has increased substantially worldwide in the past three decades, scarce evidence exists for effective preventive strategies. We aimed to establish whether a school-based intervention for children aged 9–10 years would prevent excessive weight gain after 24 months. This pragmatic cluster randomised controlled trial of the Healthy Lifestyles Programme (HeLP), a school-based obesity prevention intervention, was done in 32 schools in southwest England. All state-run primary and junior schools in Devon and Plymouth (UK) with enough pupils for at least one year-5 class were eligible. Schools were assigned (1:1) using a computer-generated sequence to either intervention or control, stratified by the number of year-5 classes (one vs more than one) and the proportion of children eligible for free school meals (<19% [the national average] vs ≥19%). HeLP was delivered to year-5 children (ages 9–10 years) over 1 year, and included dynamic and interactive activities such as physical activity workshops, education sessions delivered by teachers with short homework tasks, drama sessions, and setting goals to modify behaviour (with parental support and one-to-one discussions with HeLP coordinators). The primary outcome was change in body-mass index (BMI) standard deviation score (SDS) between baseline and 24 months, analysed in children with BMI data available for both timepoints. This study is registered with the International Standard Randomised Controlled Trial register, number ISRCTN15811706, and the trial status is complete. Between March 21, 2012, and Sept 30, 2013, 32 eligible schools with 1324 children were recruited, of which 16 schools (676 children) were randomly assigned to the HeLP intervention and 16 schools (648 children) to control. All schools that began the trial completed the intervention, and 1244 children (628 in intervention group and 616 in control group) had BMI data at both baseline and 24 months for the primary outcome analysis. Mean BMI SDS was 0·32 (SD 1·16) at baseline and 0·35 (1·25) at 24 months in the intervention group, and 0·18 (1·14) at baseline and 0·22 (1·22) at 24 months in the control group. With adjustment for school-level clustering, baseline BMI scores, sex, cohort, and number of year-5 classes and socioeconomic status of each school, the mean difference in BMI SDS score (intervention–control) at 24 months was −0·02 (95% CI −0·09 to 0·05), p=0·57. One parent reported an adverse event related to their child's eating and activity behaviours, but agreed for the child to continue trial participation after discussion with the chief investigator. Despite a theoretically informed and extensively piloted intervention that achieved high levels of engagement, follow-up, and fidelity of delivery, we found no effect of the intervention on preventing overweight or obesity. Although schools are an ideal setting in which to deliver population-based interventions, school-based interventions might not be sufficiently intense to affect both the school and the family environment, and hence the weight status of children. Future research should focus on more upstream determinants of obesity and use whole-systems approaches. UK National Institute for Health Research, Public Health Research Programme.

To examine the effectiveness of interventions using the World Health Organization Health Promoting Schools (HPSs) framework approach in increasing physical activity (PA) and improving the diet of 11-18-year-olds. A systematic review guided by the National Health Services Centre for Reviews and Dissemination framework and reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses. Nine databases and trial registries were searched from 2013 to 2018 for cluster randomised controlled trials involving adolescents' aged 11-18 years. We also included relevant studies from a 2014 Cochrane Review of HPS approach on health behaviours. Data were extracted from included studies and assessed for quality. Twelve eligible studies were identified from seven countries. The studies varied in outcome measures, sample size, quality and duration of intervention and follow-up. Only four of the included studies were of high to moderate quality. We found some evidence of effectiveness for physical activity only interventions and limited evidence of effectiveness for nutrition only and combined PA and nutrition interventions. There were no discernible patterns across the studies to suggest effective mechanisms for the HPS approach. The family/community component was poorly developed and superficially reported in all studies. Future research should seek to understand how best to work in partnership with secondary schools, to foster and sustain a healthy eating and physical activity culture, which aligns with their core aims. More attention should be paid to the restriction of unhealthy foods in the school environment.

Objective To search for, review and synthesise studies of the effectiveness and cost-effectiveness of weight management schemes for the under fives. Data sources MEDLINE [Ovid], MEDLINE In-Process [Ovid], EMBASE [Ovid], CAB [Ovid], Health Management Information Consortium [Ovid], The Cochrane Database of Systematic Reviews, Cochrane Register of Controlled Trials, Science Citation Index Expanded [Web of Science], Conference Proceedings Citation Index [The Web of Science], Database of Abstract Reviews [CRD; Centre for Reviews and Dissemination], HTA [CRD], PsycINFO [Ebsco], NHS CRD. These databases were searched from 1990 to February 2009. Supplementary internet searches were additionally conducted. Review methods Relevant clinical effectiveness studies were identified in two stages. Titles and abstracts returned by the search strategy were examined independently by three researchers and screened for possible inclusion. Disagreements were resolved by discussion. Full texts of the identified studies were obtained. Three researchers examined these independently for inclusion or exclusion, and disagreements were again resolved by discussion. Results One of the randomised controlled trials (RCTs) was from the UK. It measured the effects of a physical activity intervention for children in nurseries combined with home-based health education for their parents; this was compared to usual care. The main outcome measure was body mass index (BMI); secondary measures were weight and physical activity. At the 12-month follow-up, no statistically significant differences were found between the groups on any measure. However, a trend, favouring the intervention, was found for BMI and weight. The other two RCTs were from the USA. The larger trial investigated the effects of a combined preschool and home intervention in African American and Latino communities. Nutrition education and physical activity programmes were aimed at under fives in preschool. The home component consisted of related health education and homework for the parents, who received a small financial reward on completion. The 1- and 2-year results for the African American sites showed a significantly slower rate of increase in BMI than for results at baseline, for the intervention group than for the control group. However, in the Latino communities no such differences were found. The second US trial was a much smaller home-based parental education programme in Native American communities in the USA and Canada. The intervention consisted of a parental skills course for parents to improve their children’s diet and physical activity. This was compared with a course providing skills to improve child behaviour. Follow-up was at 16 weeks and showed no significant differences between groups in BMI. Conclusions No controlled trials addressing the issue of treating obesity or evidence of cost-effectiveness studies in the under fives’ population were found. From the three prevention studies, apart from the larger US trial, the interventions showed no statistically significant differences in BMI and weight between the intervention and control groups (although there was some evidence of positive trends for BMI and weight). It should also be noted that these conclusions are based on only three dissimilar studies, thereby making the drawing of firm conclusions difficult. Further research is urgently needed in well-designed UK-based RCTs of weight management schemes aimed at the prevention of obesity, that combine with cost-effectiveness studies targeted at preschool children with long-term follow-up.

There can be a tendency for investigators to disregard or explain away null or negative results in prevention science trials. Examples include not publicizing findings, conducting spurious subgroup analyses, or attributing the outcome post hoc to real or perceived weaknesses in trial design or intervention implementation. This is unhelpful for several reasons, not least that it skews the evidence base, contributes to research “waste”, undermines respect for science, and stifles creativity in intervention development. In this paper, we identify possible policy and practice responses when interventions have null (ineffective) or negative (harmful) results, and argue that these are influenced by: theinterventionitself (e.g., stage of gestation, perceived importance);trial design,conduct,and results(e.g., pattern of null/negative effects, internal and external validity);context(e.g., wider evidence base, state of policy); andindividual perspectives and interests(e.g., stake in the intervention). We advance several strategies to promote more informative null or negative effect trials and enable learning from such results, focusing on changes to culture, process, intervention design, trial design, and environment.

Background: Parent carers of children with special educational needs or disability are at higher risk of poor mental and physical health. The need for a tailored, peer-led group programme was raised by parent carers, who co-developed the Healthy Parent Carers programme with researchers. This study aimed to test the feasibility of programme delivery in community settings, and the feasibility and acceptability of a randomised controlled trial design. Methods: Participants were individually randomised with concealed allocation to a structured group programme and access to online resources (intervention), or access to the online resources only (control). Measures of wellbeing and secondary and economic outcomes were collected before randomisation, immediately post-intervention, and 6 months post-intervention. Descriptive statistics on recruitment and attrition, demographics, attendance, and fidelity of intervention delivery were analysed with feedback on the acceptability of the trial design. Results: One hundred and ninety-three parent carers expressed an interest in taking part. Ninety-two participants recruited from across six sites were randomised (47 intervention, 45 control). Lead and assistant facilitators were trained and delivered the group sessions. Sixteen (34%) participants in the intervention arm did not attend any sessions, and attendance varied across sites and sessions. One participant withdrew post-randomisation, and 83 (90%) participants completed outcome measures at the six-month follow-up. Conclusions: The study demonstrated that it was feasible to deliver the programme in community settings. The number of parent carers who expressed interest signifies the need for such a programme and the feasibility of recruiting to a definitive trial. Loss to follow-up was low. Further research is needed to explore ways to reduce barriers to participation in person and assess the feasibility and acceptability of programme content and delivery for more ethnically diverse groups, and potentially using interpreters. Given the Covid-19 pandemic and delivery format feedback, there is also a need to investigate remote or blended delivery strategies. Although the results indicate that a definitive trial is feasible, programme impact would be strengthened through exploration of these uncertainties. Trial registration: ISRCTN, ISRCTN15144652, registered on 25 October 2018, ClinicalTrials.gov, NCT03705221, registered on 15 October 2018.