Evaluation of a nutrition intervention in adolescents of an urban area in Greece: short- and long-term effects of the VYRONAS study

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.

A systematic review of educational nutrition interventions based on behavioral theories in school adolescents

The purpose of this study was to summarize the evidence from studies conducted on adolescents, evaluating educational nutrition interventions for the modification of food consumption through controlled trials based on behavior change theories or models and implemented in school settings. A systematic search was carried out through PubMed and ERIC databases between November and December 2020, and updated in February 2023; English-language keywords were used, and no publication date limits were applied. Two authors independently performed the search, data extraction, data synthesis and risk of bias assessment. Twelve studies meeting the inclusion criteria were included. The interventions were based on different theories; the most used was the Social Cognitive Theory. Eleven of the twelve studies showed favorable modifications in the consumption of at least two of the food groups. Most studies were at low risk of bias, and only one was classified as high risk. It is concluded that educational nutrition interventions based on behavior change theories/models and implemented in the school setting influence positive changes in adolescents eating behavior.

Re-Licious: Co-Design with Adolescents to Turn Leftovers into Delicious and Healthy Meals-A School-Based Pilot Intervention

One-third of the food produced globally is lost or wasted, and one cause is consumer leftovers. Re-licious was an eight-week pilot intervention aiming to increase awareness of food waste and healthy eating by building adolescents' ability to prepare and cook leftovers. Re-licious used a co-design approach and was piloted in a secondary school, half of which was during a COVID-19 lockdown period. Students watched videos on food waste and healthy eating during class. They identified leftover ingredients at home and repurposed ingredients to create recipes. Students co-created recipe criteria to ensure the personal relevance of the recipes. They completed pre- and post-intervention questionnaires (n = 40) about food waste and motivation and interest in healthy eating. Four group interviews were conducted. The factors identified as important in the co-creation sessions were preparation time, cost, healthiness, and sustainability. Participants with low motivation and interest in healthy eating decreased, and participants with high interest increased (p < 0.001). The intention to reduce food waste increased (p = 0.007), as did resourcefulness (p < 0.001) and personal norms (p = 0.048). Interviews highlighted the students' increased awareness of food waste and enjoyment of the intervention. With improvements based on this pilot, Re-licious could be adapted and re-trialled in a face-to-face format to educate young people about food waste.

Interventions to prevent obesity in school-aged children 6-18 years: An update of a Cochrane systematic review and meta-analysis including studies from 2015-2021

BACKGROUND

Childhood obesity remains a global public health priority due to the enormous burden it generates. Recent surveillance data suggests there has been a sharp increase in the prevalence of childhood obesity during the COVID-19 pandemic. The Cochrane review of childhood obesity prevention interventions (0-18 years) updated to 2015 is the most rigorous and comprehensive review of randomised controlled trials (RCTs) on this topic. A burgeoning number of high quality studies have been published since that are yet to be synthesised.

METHODS

An update of the Cochrane systematic review was conducted to include RCT studies in school-aged children (6-18 years) published to 30 June 2021 that assessed effectiveness on child weight (PROSPERO registration: CRD42020218928). Available cost-effectiveness and adverse effect data were extracted. Intervention effects on body mass index (BMI) were synthesised in random effects meta-analyses by setting (school, after-school program, community, home), and meta-regression examined the association of study characteristics with intervention effect.

FINDINGS

Meta-analysis of 140 of 195 included studies (183,063 participants) found a very small positive effect on body mass index for school-based studies (SMD -0·03, 95%CI -0·06,-0·01; trials = 93; participants = 131,443; moderate certainty evidence) but not after-school programs, community or home-based studies. Subgroup analysis by age (6-12 years; 13-18 years) found no differential effects in any setting. Meta-regression found no associations between study characteristics (including setting, income level) and intervention effect. Ten of 53 studies assessing adverse effects reported presence of an adverse event. Insufficient data was available to draw conclusions on cost-effectiveness.

INTERPRETATION

This updated synthesis of obesity prevention interventions for children aged 6-18 years, found a small beneficial impact on child BMI for school-based obesity prevention interventions. A more comprehensive assessment of interventions is required to identify mechanisms of effective interventions to inform future obesity prevention public health policy, which may be particularly salient in for COVID-19 recovery planning.

FUNDING

This research was funded by the National Health and Medical Research Council (NHMRC), Australia (Application No APP1153479).

Effect of School-Based Food and Nutrition Education Interventions on the Food Consumption of Adolescents: A Systematic Review and Meta-Analysis

The school is a favorable environment for the development of interventions to prevent obesity. The objective of this systematic review is to evaluate the effects of school-based food and nutrition education interventions on adolescent food consumption. The literature search was conducted on databases: MEDLINE/PubMed, Embase, Scopus, ERIC, Science Direct, Web of Science, Cochrane, LILACS, and ADOLEC. The following research strategies were focused on: population (adolescents), intervention (food and nutrition education), outcome (food consumption), and study design (clinical trial). The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement guidelines were followed and all stages of this review were performed by two researchers and, when necessary, a third researcher resolved discrepancies. Included studies are randomized clinical trials (RCT). A total of 24 articles were included for review and 11 articles in meta-analysis. In the evaluation of the general effects, there was a significant effect (mean difference (MD) for fruit consumption (MD = 0.09, CI 0.05, 0.14) in serving/day; and for vegetables (MD = 0.59, IC 0.15, 1.03) at times/week. In the consumption of FV (fruits and vegetables), there was no significant effect (standardized mean difference (SMD) of interventions in their consumption (SMD = 0.00, 95% C1 -0.11, 0.11). The evidence available in this review and meta-analysis concludes that food and nutrition education interventions in schools presented favorable results in the food consumption of adolescents. Registered on the PROSPERO database (CRD42019116520).

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

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

Themes in Train-the-Trainer Nutrition Education Interventions Targeting Middle School Students: A Systematic Review

Context-appropriate nutrition education interventions targeting middle school students have the potential to promote healthy dietary patters that may help prevent unnecessary weight gain at a point in childhood development when youth experience increasing agency over their food choices. The aim of this review was to identify and synthesize themes in train-the-trainer approaches, intervention content and delivery, and youth receptivity across teacher, mentor, and peer-led nutrition education interventions that targeted middle school-age youth in urban, primarily low-income settings. A systematic, electronic literature search was conducted in seven electronic databases, PubMed/Medline, CINAHL, ERIC, PsycINFO, Scopus, SPORTDiscus, and Cochrane CENTRAL, using fixed inclusion and exclusion criteria. A total of 53 papers representing 39 unique interventions were selected for data extraction and quality assessment. A framework synthesis approach was used to organize the interventions into six categories and identify themes according to whether the intervention was classroom-based or out-of-school-based and whether adults, cross-age peers or same-age peers delivered the intervention. Ten of the interventions contained multiple components such that they were included in two of the categories. The review findings indicated that trainings should be interactive, include opportunities to role-play intervention scenarios and provide follow-up support throughout intervention delivery. Interventions targeting middle school youth should include positive messaging and empower youth to make healthy choices within their specific food environment context.

The impact of, and views on, school food intervention and policy in young people aged 11-18 years in Europe: A mixed methods systematic review

Understanding the social and environmental influencers of eating behaviours has the potential to improve health outcomes for young people. This review aims to explore the effectiveness of school nutrition interventions and the perceptions of young people experiencing a nutrition focused intervention or change in school food policy. A comprehensive systematic search identified studies published between 1 December 2007 to 20 February 2020. Twenty-seven studies were included: 22 quantitative studies of nutrition related outcomes and five qualitative studies reporting views and perceptions of young people (combined sample of 22,138 participants, mean ages 12-18 years). The primary outcome was nutrition knowledge/dietary behaviours, with secondary outcomes exploring body mass index (BMI) and wellbeing. Due to the heterogeneity of studies, a narrative results description is presented. The findings demonstrate that school nutrition programmes can be effective in reducing sugar, sugar sweetened beverages (SSB) and saturated fat and increasing fruit and vegetable (FV) intake. The lived experiences of young people in a school context provide valuable insights that should be considered in the development of effective school food policy and interventions. This review affirms the significant role that schools can play in supporting good nutrition in all young people and provides opportunities to inform the school food agenda.

Nutrition knowledge and its relation with dietary behaviour in children and adolescents: a systematic review

OBJECTIVES

This review explored the relationship between knowledge among children and adolescents and their dietary behaviour.

CONTENT

Potentially eligible original research articles were identified through a systematic search in PubMed, SCOPUS, Web of Science and WHO Virtual Health Library from 2000 to 2018. From the initial search, a total of 7,258 research articles were obtained. Duplicate studies were identified and removed. Observational studies on children and adolescents (5-19 years) of any gender, ethnicity and country were included in which the outcome measured was either a scoring of/ association between nutrition knowledge and practices. After screening using the inclusion criteria, 13 studies were selected for this paper.

SUMMARY AND OUTLOOK

Four studies reported non-significant association between overall nutrition knowledge and practices. Only two studies found a significant association, out of which one showed a weak association highlighting that nutrition knowledge is not sufficient to result in healthy eating. Other factors which showed significant but weak associations with knowledge/practices included age, gender, nutritional status and lifestyle, peer influence, parents'/guardians' knowledge, education and occupation level. The causal relationship couldn't be examined in the present review due to the cross-sectional nature of the studies. Besides imparting knowledge through nutrition education interventions, there is a need for holistic behaviour change strategies including supporting food skills like menu planning, food shopping and cooking to encourage healthy eating habits among children. These interventions should target children from an early age, involving family/parents, teachers and peers to facilitate improvement in the food environment for sustainable change.

A systematic review and meta-analysis of school-based interventions with health education to reduce body mass index in adolescents aged 10 to 19 years

BACKGROUND

Adolescents are increasingly susceptible to obesity, and thus at risk of later non-communicable diseases, due to changes in food choices, physical activity levels and exposure to an obesogenic environment. This review aimed to synthesize the literature investigating the effectiveness of health education interventions delivered in school settings to prevent overweight and obesity and/ or reduce BMI in adolescents, and to explore the key features of effectiveness.

METHODS

A systematic search of electronic databases including MEDLINE, CINAHL, PsychINFO and ERIC for papers published from Jan 2006 was carried out in 2020, following PRISMA guidelines. Studies that evaluated health education interventions in 10-19-year-olds delivered in schools in high-income countries, with a control group and reported BMI/BMI z-score were selected. Three researchers screened titles and abstracts, conducted data extraction and assessed quality of the full text publications. A third of the papers from each set were cross-checked by another reviewer. A meta-analysis of a sub-set of studies was conducted for BMI z-score.

RESULTS

Thirty-three interventions based on 39 publications were included in the review. Most studies evaluated multi-component interventions using health education to improve behaviours related to diet, physical activity and body composition measures. Fourteen interventions were associated with reduced BMI/BMI z-score. Most interventions (n = 22) were delivered by teachers in classroom settings, 19 of which trained teachers before the intervention. The multi-component interventions (n = 26) included strategies such as environment modifications (n = 10), digital interventions (n = 15) and parent involvement (n = 16). Fourteen studies had a low risk of bias, followed by 10 with medium and nine with a high risk of bias. Fourteen studies were included in a random-effects meta-analysis for BMI z-score. The pooled estimate of this meta-analysis showed a small difference between intervention and control in change in BMI z-score (- 0.06 [95% CI -0.10, - 0.03]). A funnel plot indicated that some degree of publication bias was operating, and hence the effect size might be inflated.

CONCLUSIONS

Findings from our review suggest that school-based health education interventions have the public health potential to lower BMI towards a healthier range in adolescents. Multi-component interventions involving key stakeholders such as teachers and parents and digital components are a promising strategy.

Effectiveness of Lifestyle Interventions for Prevention of Harmful Weight Gain among Adolescents from Ethnic Minorities: A Systematic Review

The escalating obesity among adolescents is of major concern, especially among those from an ethnic minority background. The adolescent period offers a key opportunity for the implementation of positive lifestyle behaviours as children transition to adulthood. The objective of this review was to examine the effectiveness of lifestyle interventions for adolescents and their impact in ethnic and racial minorities for the prevention of overweight and obesity. Seven electronic databases were searched from 2005 until March 2019 for randomized controlled trials of lifestyle programs conducted in this population. The main outcome was change in Body Mass Index (BMI) z-score (kg/m2) or change in BMI and secondary outcomes were changes in physical activity and diet. Thirty studies met the inclusion criteria. Seven studies reported and/or conducted subgroup analysis to determine if ethnic/racial group affected weight change. None demonstrated an overall decrease in BMI z-score. However, six of the seven demonstrated changes in secondary measures such as fruit and vegetable intake and screen time. Results did not differ by ethnic/racial group for primary and secondary outcomes. Overweight and obesity prevention among adolescents from ethnic minorities is an area that needs further research. There is a lack of interventions that include analyses of effectiveness in ethnic minorities.

A developmental cascade perspective of paediatric obesity: A systematic review of preventive interventions from infancy through late adolescence

The goals of this systematic review were to identify and describe paediatric obesity prevention interventions from infancy to late adolescence and to provide recommendations for future intervention research in light of a recently proposed developmental cascade (DC) model of paediatric obesity. We conducted an electronic search of randomized controlled trials with a minimum 6-month postintervention follow-up published between 1995 and 2019. We included 74 interventions: prenatal/infancy (n = 4), early childhood (n = 11), childhood (n = 38), early to mid-adolescence (n = 18), and late adolescence (n = 3). Infancy and early childhood trials targeted early feeding and positive parenting skills. Half of the childhood and adolescence trials were school based and used universal prevention strategies; those classified as selective or indicated prevention tended to involve the family for more intensive lifestyle modification. Less than 10% of studies followed participants over long periods of time (greater than or equal to 5 years), and only 16% and 31% of studies assessed intervention mediators and moderators, respectively. We recommend that future interventions focus on early prevention, assess long-term intervention effects, use a standardized taxonomy for defining intervention behavioural strategies, assess underlying mechanisms of action and intervention moderators, target parent and family management strategies across development, and increase scientific equity. We also provide specific recommendations regarding intervention targets for each developmental stage.

Schoolteachers' Nutrition Knowledge, Beliefs, and Attitudes Before and After an E-Learning Program

OBJECTIVE

Το explore teachers' nutrition knowledge, beliefs, and attitudes and to examine the effectiveness of an electronic learning (e-learning) program in teachers' nutrition knowledge.

DESIGN

Cross-sectional and experimental design.

SETTING

The study took place in Greece, while schoolteachers were invited by e-mail.

PARTICIPANTS

Teachers of primary and secondary education, with no exclusion criteria, were enrolled in the study between March, 2015 and 2016.

MAIN OUTCOME MEASURES

Schoolteachers' nutrition knowledge, beliefs, and attitudes.

INTERVENTION

Teachers completed a 36-item nutrition questionnaire and then a subgroup participated in an e-learning program. After the intervention, teachers completed the same questionnaire.

ANALYSIS

Principal component analysis and multivariate logistic regression were used for data analysis.

RESULTS

A total of 1,094 teachers completed the questionnaire; 619 participated in the e-learning program. Teachers showed moderate nutrition knowledge scores (ie, 65% correct answers) before the intervention, whereas their attitudes regarding acting as role models and their belief in the importance of the role of nutrition were associated with 74% (odds ratio, 1.28; 95% confidence interval, 1.13-1.45) and 79% (odds ratio, 1.21; 95% confidence interval, 1.07-1.37) increased possibility of having good nutrition knowledge, respectively. The e-learning program was effective in strengthening teachers' nutrition knowledge (P < .001) and improving their beliefs and attitudes (P < .05).

CONCLUSIONS AND IMPLICATIONS

Future research is needed to validate the current results, which can be used to design and implement similar educational programs to teachers as a means of creating health-promoting schools.

Interventions for preventing obesity in children

EDITORIAL NOTE

This Cochrane review is now out of date and should not be used for reference. It has been split into four age groups and updated. Please refer to the 5‐11 and 12‐18 age group Cochrane reviews which were published in May 2024: https://doi.org/10.1002/14651858.CD015328.pub2 https://doi.org/10.1002/14651858.CD015330.pub2 The 2‐4 age group Cochrane review is planned for publication in September 2024.

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.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects and associations of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective cohort studies if they related baseline total fat intake to weight or body fatness at least 12 months later.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted body weight and blood lipid levels outcomes at six months, six to 12 months, one to two years, two to five years and more than five years for RCTs; and for cohort studies, at baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three studies were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous to combine.Effects of dietary counselling to reduce total fat intake from RCTsTwo studies recruited children aged between 4 and 11 years and a third recruited children aged 12 to 13 years. Interventions were combinations of individual and group counselling, and education sessions in clinics, schools and homes, delivered by dieticians, nutritionists, behaviourists or trained, supervised teachers. Concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability.One study of dietary counselling to lower total fat intake found that the intervention may make little or no difference to weight compared with usual diet at 12 months (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; n = 620; low-quality evidence) and at three years (MD -0.60 kg, 95% CI -2.39 to 1.19; n = 612; low-quality evidence). Education delivered as a classroom curriculum probably decreased BMI in children at 17 months (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence). The effects were smaller at longer term follow-up (five years: MD 0 kg/m2, 95% CI -0.63 to 0.63; n = 541; seven years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; n = 576; low-quality evidence).Dietary counselling probably slightly reduced total cholesterol at 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Dietary counselling probably slightly decreased low-density lipoprotein (LDL) cholesterol at 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and at five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. Dietary counselling probably made little or no difference to HDL-C at 12 months (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), and at five years (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, counselling probably made little or no difference to triglycerides in children at 12 months (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height at seven years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Associations between total fat intake, weight and body fatness from cohort studiesOver half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to dietary counselling or education to lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls. There were no consistent effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Most studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings to look at both possible benefits and harms.

Effects of total fat intake on bodyweight in children

BACKGROUND

As part of efforts to prevent childhood overweight and obesity, we need to understand the relationship between total fat intake and body fatness in generally healthy children.

OBJECTIVES

To assess the effects of total fat intake on measures of weight and body fatness in children and young people not aiming to lose weight.

SEARCH METHODS

For this update we revised the previous search strategy and ran it over all years in the Cochrane Library, MEDLINE (Ovid), MEDLINE (PubMed), and Embase (Ovid) (current to 23 May 2017). No language and publication status limits were applied. We searched the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing and unpublished studies (5 June 2017).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children aged 24 months to 18 years, with or without risk factors for cardiovascular disease, randomised to a lower fat (30% or less of total energy (TE)) versus usual or moderate-fat diet (greater than 30%TE), without the intention to reduce weight, and assessed a measure of weight or body fatness after at least six months. We included prospective analytical cohort studies in these children if they related baseline total fat intake to weight or body fatness at least 12 months later. We duplicated inclusion decisions and resolved disagreement by discussion with other authors.

DATA COLLECTION AND ANALYSIS

We extracted data on participants, interventions or exposures, controls and outcomes, and trial or cohort quality characteristics, as well as data on potential effect modifiers, and assessed risk of bias for all included studies. We extracted outcome data using the following time point ranges, when available: RCTs: baseline to six months, six to 12 months, one to two years, two to five years and more than five years; cohort studies: baseline to one year, one to two years, two to five years, five to 10 years and more than 10 years. We planned to perform random-effects meta-analyses with relevant subgrouping, and sensitivity and funnel plot analyses where data allowed.

MAIN RESULTS

We included 24 studies comprising three parallel-group RCTs (n = 1054 randomised) and 21 prospective analytical cohort studies (about 25,059 children completed). Twenty-three were conducted in high-income countries. No meta-analyses were possible, since only one RCT reported the same outcome at each time point range for all outcomes, and cohort studies were too heterogeneous.For the RCTs, concerns about imprecision and poor reporting limited our confidence in our findings. In addition, the inclusion of hypercholesteraemic children in two trials raised concerns about applicability. Lower versus usual or modified total fat intake may have made little or no difference to weight over a six- to twelve month period (mean difference (MD) -0.50 kg, 95% confidence interval (CI) -1.78 to 0.78; 1 RCT; n = 620; low-quality evidence), nor a two- to five-year period (MD -0.60 kg, 95% CI -2.39 to 1.19; 1 RCT; n = 612; low-quality evidence). Compared to controls, lower total fat intake (30% or less TE) probably decreased BMI in children over a one- to two-year period (MD -1.5 kg/m2, 95% CI -2.45 to -0.55; 1 RCT; n = 191; moderate-quality evidence), with no other differences evident across the other time points (two to five years: MD 0.00 kg/m2, 95% CI -0.63 to 0.63; 1 RCT; n = 541; greater than five years; MD -0.10 kg/m2, 95% CI -0.75 to 0.55; 1 RCT; n = 576; low-quality evidence). Lower fat intake probably slightly reduced total cholesterol over six to 12 months compared to controls (MD -0.15 mmol/L, 95% CI -0.24 to -0.06; 1 RCT; n = 618; moderate-quality evidence), but may make little or no difference over longer time periods. Lower fat intake probably slightly decreased low-density lipoprotein (LDL) cholesterol over six to 12 months (MD -0.12 mmol/L, 95% CI -0.20 to -0.04; 1 RCT; n = 618, moderate-quality evidence) and over two to five years (MD -0.09, 95% CI -0.17 to -0.01; 1 RCT; n = 623; moderate-quality evidence), compared to controls. However, lower total fat intake probably made little or no difference to HDL-C over a six- to 12-month period (MD -0.03 mmol/L, 95% CI -0.08 to 0.02; 1 RCT; n = 618; moderate-quality evidence), nor a two- to five-year period (MD -0.01 mmol/L, 95% CI -0.06 to 0.04; 1 RCT; n = 522; moderate-quality evidence). Likewise, lower total fat intake probably made little or no difference to triglycerides in children over a six- to 12-month period (MD -0.01 mmol/L, 95% CI -0.08 to 0.06; 1 RCT; n = 618; moderate-quality evidence). Lower versus usual or modified fat intake may make little or no difference to height over more than five years (MD -0.60 cm, 95% CI -2.06 to 0.86; 1 RCT; n = 577; low-quality evidence).Over half the cohort analyses that reported on primary outcomes suggested that as total fat intake increases, body fatness measures may move in the same direction. However, heterogeneous methods and reporting across cohort studies, and predominantly very low-quality evidence, made it difficult to draw firm conclusions and true relationships may be substantially different.

AUTHORS' CONCLUSIONS

We were unable to reach firm conclusions. Limited evidence from three trials that randomised children to a lower total fat intake (30% or less TE) versus usual or modified fat intake, but with no intention to reduce weight, showed small reductions in body mass index, total- and LDL-cholesterol at some time points with lower fat intake compared to controls, and no consistent differences in effects on weight, high-density lipoprotein (HDL) cholesterol or height. Associations in cohort studies that related total fat intake to later measures of body fatness in children were inconsistent and the quality of this evidence was mostly very low. Twenty-three out of 24 included studies were conducted in high-income countries, and may not be applicable in low- and middle-income settings. High-quality, longer-term studies are needed, that include low- and middle-income settings and look at both possible benefits and risks.

Systematic review on evidence-based adolescent nutrition interventions

Adolescence is a critical stage in the life cycle, and adequate nutrition is necessary for the proper growth and development of individuals and their offspring. Here, we comprehensively review all published systematic reviews (through October 2016) on adolescents (10-19 years) and women of reproductive age, including pregnant women, which targeted interventions related to nutrition. For interventions where there was no existing systematic review on adolescents, we reviewed primary studies/trials. We included interventions on micronutrient supplementation (iron, folic acid, iron-folic acid (IFA), calcium, vitamin D, vitamin A, zinc, iodine, and multiple micronutrients), food/protein energy supplementation, nutrition education for pregnant adolescents, obesity prevention and management, and management of gestational diabetes. We identified a total of 35 systematic reviews, of which only five were conducted on adolescents, and 107 primary studies on adolescents. Our review suggests that iron alone, IFA, zinc, and multiple micronutrient supplementation in adolescents can significantly improve serum hemoglobin concentration. While zinc supplementation in pregnant adolescents showed improvements in preterm birth and low birth weight, we found a paucity of trials on calcium, vitamin D, vitamin A, and iodine supplementation. We found limited evidence on food/protein energy supplementation in adolescents. Interventions to prevent and manage obesity showed a nonsignificant impact on reducing body mass index. This review underscores the importance of adolescent nutrition interventions. It is imperative that countries design nutritional interventions, particularly for adolescents.

Mediterranean diet decreases adolescent waist circumference

BACKGROUND

To explore the effects of a multicomponent-multilevel school-based educational intervention on the nutritional habits and abdominal obesity indices of a representative adolescent sample.

MATERIALS AND METHODS

A representative sample of 1610 adolescents aged 12-17 years in 23 public high schools of three municipalities in the Attica region in Greece participated in a programme funded by the European Union (August 2013-August 2014). Participants underwent dietary assessment with the use of the Mediterranean Diet Quality Index in children and adolescents (KIDMED), blood pressure (BP) assessment and screening for general and abdominal obesity by measuring body mass index, waist circumference (WC) and waist-to-height ratio (WHtR), at baseline and following a 6-month school-based intervention. The intervention involved nutritional education, physical activity and body image awareness using a multilevel approach to the adolescent participants, their parents, school teachers and health staff.

RESULTS

Analysis included 1032 adolescents (mean age ± SD 14·1 ± 1·6 years). Following intervention, mean KIDMED score ± SD increased significantly from 5·6 ± 2·4 to 5·8 ± 2·4 (P = 0·004). Higher percentage of boys (P = 0·028) and younger adolescents (P < 0·001) had optimal KIDMED scores ≥ 8. Significant decreases were observed in overweight and obesity (P = 0·033), mean systolic (P = 0·049) and diastolic (P < 0·001) BP, WC (P < 0·001) and WHtR (P < 0·001). WC decreased as the KIDMED score increased (P = 0·020). Living with both parents (P = 0·036), higher maternal (P = 0·039) and paternal (P = 0·004) education and having a younger father (P = 0·034) were associated with better adherence to Mediterranean diet, post-intervention.

CONCLUSIONS

Increased adherence to MD was associated with decreased WC, indicating a potential of multicomponent-multilevel school-based interventions to combat adolescent abdominal obesity.

A Systematic Review of the Impact of Multi-Strategy Nutrition Education Programs on Health and Nutrition of Adolescents

OBJECTIVE

To update evidence on the impact of multi-strategy nutrition education interventions on adolescents' health and nutrition outcomes and behaviors.

DESIGN

Systematic review of randomized controlled studies of multi-strategy interventions encompassing nutrition education published from 2000 to 2014 guided by the Preferred Reported Items for Systematic Reviews and Meta-analyses statement.

SETTING

Secondary schools in developed countries.

PARTICIPANTS

Adolescents aged 10-18 years.

MAIN OUTCOME MEASURES

Anthropometric and dietary intake.

ANALYSIS

Systematic search of 7,009 unduplicated articles and review of 11 studies (13 articles) meeting inclusion criteria using qualitative comparison.

RESULTS

Four studies reported significant changes in anthropometric measures and 9 showed significant changes in dietary intake. Type of nutrition education varied. Components of the interventions that showed statistically significant changes in anthropometric and dietary intake included facilitation of the programs by school staff and teachers, parental involvement, and using theoretical models to guide the intervention's development. Changes in canteens, food supply, and vending machines were associated with significant changes in dietary intake.

CONCLUSIONS AND IMPLICATIONS

Multi-strategy interventions can have significant impacts on nutrition of adolescents when the nutrition education is theoretically based and facilitated by school staff in conjunction with parents and families, and includes changes to the school food environment.

A systematic review of children's dietary interventions with parents as change agents: Application of the RE-AIM framework

INTRODUCTION

Interventions targeting children's dietary behavior often include strategies that target parents as implementation agents of change, though parent involvement on intervention effectiveness is unclear. The present study systematically assessed (1) reporting of reach, effectiveness, adoption, implementation and maintenance (RE-AIM) of child dietary intervention studies with parents as change agents and (2) evaluated within these studies the comparative effectiveness of interventions with and without a parent component.

METHODS

The search was conducted in PubMed, PsycINFO, and Cochrane Library. Eligible studies were required to include a condition with a parental component, a comparison/control group, and target a child dietary behavior outcome. Forty-nine articles met criteria. Raters extracted RE-AIM and parent implementation information for each study.

RESULTS

Effectiveness (72.5%) was the highest reported RE-AIM element, followed by reach (27.5%), adoption (12.5%), implementation (10%), and maintenance (2.5%). Median reporting of parent implementation was highest for adoption and enactment (20%), followed by receipt (7.5%), and maintenance (2.5%). Six studies tested comparative effectiveness of parental involvement on child dietary outcomes.

CONCLUSION

Current RE-AIM reporting among children's dietary interventions is inchoate. The contribution of parental involvement on intervention effectiveness remains unclear. Increased focus should be placed on reporting of external validity information, to enable better translation of research to practical applications.

Systematic Review of School-Based Interventions to Modify Dietary Behavior: Does Intervention Intensity Impact Effectiveness?

BACKGROUND

Owing to the associations between diet and health, it is important that effective health promotion strategies establish healthful eating behaviors from an early age. We reviewed the intensity of school-based interventions aimed to modify dietary behavior in preadolescent and adolescents and related intervention characteristics to effectiveness.

METHODS

Our systematic literature search of 8 databases sought to identify interventions measuring dietary intake in school settings to students aged 9 to 18. We evaluated these studies for effectiveness, intensity, intervention category, and follow-up measures.

RESULTS

Of the 105 interventions 81 were found to be effective immediately postintervention, irrespective of intensity. Studies that were 6 weeks to 5 months in duration, targeted students' environment or group (alone or in combination), and reached students only in schools were more effective. Only one-fifth of interventions conducted a follow-up measure, and a majority showed a loss of effectiveness from postintervention to follow-up.

CONCLUSIONS

We identified characteristics of effective interventions. These findings may inform the development of future interventions targeting dietary behavior in preadolescents and adolescents in the school-based setting.

Effectiveness of social marketing strategies to reduce youth obesity in European school-based interventions: a systematic review and meta-analysis

CONTEXT

The use of social marketing to modify lifestyle choices could be helpful in reducing youth obesity. Some or all of the 8 domains of the National Social Marketing Centre's social marketing benchmark criteria (SMBC) are often used but not always defined in intervention studies.

OBJECTIVE

The aim of this review is to assess the effectiveness of European school-based interventions to prevent obesity relative to the inclusion of SMBC domains in the intervention.

DATA SOURCES

The PubMed, Cochrane, and ERIC databases were used.

STUDY SELECTION

Nonrandomized and randomized controlled trials conducted from 1990 to April 2014 in participants aged 5 to 17 years were included.

DATA EXTRACTION

After the study selection, the 8 domains of the SMBC were assessed in each included study.

RESULTS

Thirty-eight publications were included in the systematic review. For the meta-analysis, randomized controlled trials (RCTs) reporting body mass index or prevalence of overweight and obesity were considered. Eighteen RCTs with a total of 8681 participants included at least 5 SMBC. The meta-analysis showed a small standardized mean difference in body mass index of -0.25 (95%CI, -0.45 to -0.04) and a prevalence of overweight and obesity odds ratio of 0.72 (95%CI, 0.5-0.97).

CONCLUSION

Current evidence indicates that the inclusion of at least 5 SMBC domains in school-based interventions could benefit efforts to prevent obesity in young people. PROSPERO registration number: CRD42014007297.

Effects of total fat intake on body weight

BACKGROUND

In order to prevent overweight and obesity in the general population we need to understand the relationship between the proportion of energy from fat and resulting weight and body fatness in the general population.

OBJECTIVES

To assess the effects of proportion of energy intake from fat on measures of weight and body fatness (including obesity, waist circumference and body mass index) in people not aiming to lose weight, using all appropriate randomised controlled trials (RCTs) and cohort studies in adults, children and young people

SEARCH METHODS

We searched CENTRAL to March 2014 and MEDLINE, EMBASE and CINAHL to November 2014. We did not limit the search by language. We also checked the references of relevant reviews.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomised intervention trial, 2) included children (aged ≥ 24 months), young people or adults, 3) randomised to a lower fat versus usual or moderate fat diet, without the intention to reduce weight in any participants, 4) not multifactorial and 5) assessed a measure of weight or body fatness after at least six months. We also included cohort studies in children, young people and adults that assessed the proportion of energy from fat at baseline and assessed the relationship with body weight or fatness after at least one year. We duplicated inclusion decisions and resolved disagreement by discussion or referral to a third party.

DATA COLLECTION AND ANALYSIS

We extracted data on the population, intervention, control and outcome measures in duplicate. We extracted measures of weight and body fatness independently in duplicate at all available time points. We performed random-effects meta-analyses, meta-regression, subgrouping, sensitivity and funnel plot analyses.

MAIN RESULTS

We included 32 RCTs (approximately 54,000 participants) and 30 sets of analyses of 25 cohorts. There is consistent evidence from RCTs in adults of a small weight-reducing effect of eating a smaller proportion of energy from fat; this was seen in almost all included studies and was highly resistant to sensitivity analyses. The effect of eating less fat (compared with usual diet) is a mean weight reduction of 1.5 kg (95% confidence interval (CI) -2.0 to -1.1 kg), but greater weight loss results from greater fat reductions. The size of the effect on weight does not alter over time and is mirrored by reductions in body mass index (BMI) (-0.5 kg/m(2), 95% CI -0.7 to -0.3) and waist circumference (-0.3 cm, 95% CI -0.6 to -0.02). Included cohort studies in children and adults most often do not suggest any relationship between total fat intake and later measures of weight, body fatness or change in body fatness. However, there was a suggestion that lower fat intake was associated with smaller increases in weight in middle-aged but not elderly adults, and in change in BMI in the highest validity child cohort.

AUTHORS' CONCLUSIONS

Trials where participants were randomised to a lower fat intake versus usual or moderate fat intake, but with no intention to reduce weight, showed a consistent, stable but small effect of low fat intake on body fatness: slightly lower weight, BMI and waist circumference compared with controls. Greater fat reduction and lower baseline fat intake were both associated with greater reductions in weight. This effect of reducing total fat was not consistently reflected in cohort studies assessing the relationship between total fat intake and later measures of body fatness or change in body fatness in studies of children, young people or adults.

What childhood obesity prevention programmes work? A systematic review and meta-analysis

Previous reviews of childhood obesity prevention have focused largely on schools and findings have been inconsistent. Funded by the US Agency for Healthcare Research and Quality (AHRQ) and the National Institutes of Health, we systematically evaluated the effectiveness of childhood obesity prevention programmes conducted in high-income countries and implemented in various settings. We searched MEDLINE®, Embase, PsycINFO, CINAHL®, ClinicalTrials.gov and the Cochrane Library from inception through 22 April 2013 for relevant studies, including randomized controlled trials, quasi-experimental studies and natural experiments, targeting diet, physical activity or both, and conducted in children aged 2-18 in high-income countries. Two reviewers independently abstracted the data. The strength of evidence (SOE) supporting interventions was graded for each study setting (e.g. home, school). Meta-analyses were performed on studies judged sufficiently similar and appropriate to pool using random effect models. This paper reported our findings on various adiposity-related outcomes. We identified 147 articles (139 intervention studies) of which 115 studies were primarily school based, although other settings could have been involved. Most were conducted in the United States and within the past decade. SOE was high for physical activity-only interventions delivered in schools with home involvement or combined diet-physical activity interventions delivered in schools with both home and community components. SOE was moderate for school-based interventions targeting either diet or physical activity, combined interventions delivered in schools with home or community components or combined interventions delivered in the community with a school component. SOE was low for combined interventions in childcare or home settings. Evidence was insufficient for other interventions. In conclusion, at least moderately strong evidence supports the effectiveness of school-based interventions for preventing childhood obesity. More research is needed to evaluate programmes in other settings or of other design types, especially environmental, policy and consumer health informatics-oriented interventions.

Prevention of overweight and obesity in children and youth: a systematic review and meta-analysis

BACKGROUND

One-third of Canadian children are overweight or obese. This problem carries considerable concern for negative impacts on current and future health. Promoting healthy growth and development is critical. This review synthesized evidence on the effectiveness of behavioural interventions for preventing overweight and obesity in children and adolescents.

METHODS

We updated the search of a previous Cochrane review. Five databases were searched up to August 2013. Randomized trials of primary care-relevant behavioural (diet, exercise and lifestyle) interventions for preventing overweight and obesity in healthy normal- or mixed-weight children or youth aged 0-18 years were included if 12-week postbaseline data were provided for body mass index (BMI), BMI z-score, or prevalence of overweight or obesity. Any study reporting harms was included. Meta-analyses were performed if possible. Features of interventions showing significant benefits were examined.

RESULTS

Ninety studies were included, all with mixed-weight populations. Compared with controls, interventions showed a small but significant effect on BMI and BMI z-score (standardized mean difference -0.07, 95% confidence interval [CI] -0.10 to -0.03, I (2) = 74%), a reduction in BMI (mean difference -0.09 kg/m(2), 95% CI -0.16 to -0.03, I (2) = 76%) and a reduced prevalence of overweight and obesity (risk ratio [RR]; RRintervention - RRcontrol 0.94, 95% CI 0.89 to 0.99, I (2) = 0%; number needed to treat 51, 95% CI 29 to 289). Little evidence was available on harms. There was variability across efficacious interventions, although many of the interventions were short-term, involved school-aged children and were delivered in educational settings.

INTERPRETATION

Behavioural prevention interventions are associated with small improvements in weight outcomes in mixed-weight populations of children and adolescents. No intervention strategy consistently produced benefits.

REGISTRATION

PROSPERO no. CRD42012002754.

The Dutch Obesity Intervention in Teenagers (DOiT) cluster controlled implementation trial: intervention effects and mediators and moderators of adiposity and energy balance-related behaviours

Background

The Dutch Obesity Intervention in Teenagers (DOiT) programme is an evidence-based obesity prevention programme tailored to adolescents attending the first two years of prevocational education in the Netherlands. The initial programme showed promising results during an effectiveness trial. The programme was adapted and prepared for nationwide dissemination. To gain more insight into the process of translating evidence-based approaches into ‘real world’ (i.e., ‘natural’) conditions, our research aims were to evaluate the impact of the DOiT-implementation programme on adolescents’ adiposity and energy balance-related behaviours during natural dissemination and to explore the mediating and moderating factors underlying the DOiT intervention effects.

Methods

We conducted a cluster-controlled implementation trial with 20 voluntary intervention schools (n=1002 adolescents) and 9 comparable control schools (n = 484 adolescents). We measured adolescents’ body height and weight, skinfold thicknesses, and waist circumference. We assessed adolescents’ dietary and physical activity behaviours by means of self-report. Data were collected at baseline and at 20-months follow-up. We used multivariable multilevel linear or logistic regression analyses to evaluate the intervention effects and to test the hypothesised behavioural mediating factors. We checked for potential effect modification by gender, ethnicity and education level.

Results

We found no significant intervention effects on any of the adiposity measures or behavioural outcomes. Furthermore, we found no mediating effects by any of the hypothesised behavioural mediators. Stratified analyses for gender showed that the intervention was effective in reducing sugar-containing beverage consumption in girls (B = -188.2 ml/day; 95% CI = -344.0; -32.3). In boys, we found a significant positive intervention effect on breakfast frequency (B = 0.29 days/week; 95% CI = 0.01; 0.58). Stratified analyses for education level showed an adverse intervention effect (B = 0.09; 95% CI = 0.02; 0.16) on BMI z-scores for adolescents attending the vocational education track.

Conclusions

Although not successful in changing adolescents’ adiposity, the DOiT-implementation programme had some beneficial effects on specific obesity-related behaviours in subgroups. This study underlines the difficulty of translating intervention effectiveness in controlled settings to real world contexts. Adaptations to the implementation strategy are needed in order to promote implementation as intended by the teachers.

Trial registration

Current Controlled Trials ISRCTN92755979.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-014-0158-0) contains supplementary material, which is available to authorized users.

Sustainability of a Curriculum-based Intervention on Dietary Behaviours and Physical Activity among Primary School Children in Trinidad and Tobago

OBJECTIVES

Childhood obesity and poor lifestyle practices are emerging as major public health challenges in the Caribbean. Given the fact that a significant part of childhood is spent at school, curriculum-based interventions aimed at improving good dietary and physical activity patterns may provide a useful vehicle for mass inculcation of long-term healthy lifestyle practices. In this study, we evaluated the long-term impact of a brief curriculum based intervention on dietary behaviour, physical activity and knowledge level of primary schoolchildren.

METHODS

The study was a randomized, controlled, school-based nutrition education and physical activity intervention. One hundred students each were then randomly assigned to the intervention (IVG) and non-intervention (NIVG) groups and followed-up for 18 months. Participants in the IVG group were exposed to a curriculum consisting of six one-hour modules followed by school-based activities geared at fostering healthy behaviours. Students in the non-intervention group did not receive any modules and were subject to the information available at school on a regular basis.

RESULTS

In multivariate regression equations controlling for age, gender, body mass index (BMI) and baseline values, intervention was associated with lower intake of fried foods and sodas (p < 0.05) and higher knowledge scores (p < 0.01) 18 months later but not significantly associated with improved physical activity or lower BMI.

CONCLUSIONS

In this study, participants in the intervention group reported significantly lower intakes of fried foods and sodas and higher knowledge scores than participants in the control group some 18 months post-intervention independent of age, gender, BMI, ethnicity and the intakes at baseline.

School-based obesity prevention programs: a meta-analysis of randomized controlled trials

OBJECTIVE

Attempts have been made to reduce childhood obesity through school-based programs. Systematic reviews of studies until 2006 reported a lack of consistency about effectiveness of such programs. Presented is an updated systematic review and meta-analysis.

DESIGN AND METHODS

Replication of methodology used in previous comprehensive systematic review and meta-analysis of randomized controlled trials of school-based obesity prevention programs covering studies until 2006 to review studies thru January 2012.

RESULTS

Based on 32 studies (n = 52,109), programs were mildly effective in reducing BMI relative to controls not receiving intervention. Studies of children had significant intervention effects, those of teenagers did not, though the difference between the two groups was not statistically significant. Meta-regression showed a significant linear hierarchy of studies with the largest effects for comprehensive programs more than 1 year long that aimed to provide information on nutrition and physical activity, change attitudes, monitor behavior, modify environment, involve parents, increase physical activity and improve diet, particularly among children.

CONCLUSIONS

Unlike earlier studies, more recent studies showed convincing evidence that school-based prevention interventions are at least mildly effective in reducing BMI in children, possibly because these newer studies tended to be longer, more comprehensive and included parental support.

Relation between eating habits and a high body mass index among freshman students: a cross-sectional study

OBJECTIVES

This study aimed to examine the relation between eating habits and a high body mass index (BMI) in first-year freshman university students and included 2525 freshman university students 18 to 22 years old from a Turkish population.

METHODS

İn this study, 48% of the students were men. They were asked to complete a questionnaire on their dietary habits including the frequency of their consumption of individual food items, demographic data, and smoking habit.

RESULTS

The effects of eating habits on increased BMI (≥25) were analyzed. Of 2259 subjects included in the analyses, 322 were overweight or obese and 1937 had normal and thin BMI (<25). Multivariate analyses identified male gender, recent weight change, and high number of meals as independent predictors of obesity/overweight. Frequent consumptions of beer, alcoholic drinks other than beer and wine (e.g., spirits including whisky, gin, raki, vodka), coffee, tea, coke, red meat, variety meat, and eggs were associated with a significantly higher risk of obesity/overweight, whereas frequent consumption of snacks was associated with a low risk.

CONCLUSIONS

Findings of further studies, possibly taking into consideration the absolute quantities of consumption along with cultural and local issues, would guide the adoption of healthier feeding behaviors in this particular age group.

Effect of reducing total fat intake on body weight: systematic review and meta-analysis of randomised controlled trials and cohort studies

OBJECTIVE

To investigate the relation between total fat intake and body weight in adults and children.

DESIGN

Systematic review and meta-analysis of randomised controlled trials and cohort studies.

DATA SOURCES

Medline, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials to June 2010.

INCLUSION CRITERIA

Randomised controlled trials and cohort studies of adults or children that compared lower versus usual total fat intake and assessed the effects on measures of body fatness (body weight, body mass index, or waist circumference) after at least six months (randomised controlled trials) or one year (in cohorts). Randomised controlled trials with any intention to reduce weight in participants or confounded by additional medical or lifestyle interventions were excluded.

DATA EXTRACTION

Data were extracted and validity was assessed independently and in duplicate. Random effects meta-analyses, subgroups, sensitivity analyses, and metaregression were done.

RESULTS

33 randomised controlled trials (73,589 participants) and 10 cohort studies were included, all from developed countries. Meta-analysis of data from the trials suggested that diets lower in total fat were associated with lower relative body weight (by 1.6 kg, 95% confidence interval -2.0 to -1.2 kg, I(2)=75%, 57,735 participants). Lower weight gain in the low fat arm compared with the control arm was consistent across trials, but the size of the effect varied. Metaregression suggested that greater reduction in total fat intake and lower baseline fat intake were associated with greater relative weight loss, explaining most of the heterogeneity. The significant effect of a low fat diet on weight was not lost in sensitivity analyses (including removing trials that expended greater time and attention on low fat groups). Lower total fat intake also led to lower body mass index (-0.51 kg/m(2), 95% confidence interval -0.76 to -0.26, nine trials, I(2)=77%) and waist circumference (by 0.3 cm, 95% confidence interval -0.58 to -0.02, 15,671 women, one trial). There was no suggestion of negative effects on other cardiovascular risk factors (lipid levels or blood pressure). GRADE assessment suggested high quality evidence for the relation between total fat intake and body weight in adults. Only one randomised controlled trial and three cohort studies were found in children and young people, but these confirmed a positive relation between total fat intake and weight gain.

CONCLUSIONS

There is high quality, consistent evidence that reduction of total fat intake has been achieved in large numbers of both healthy and at risk trial participants over many years. Lower total fat intake leads to small but statistically significant and clinically meaningful, sustained reductions in body weight in adults in studies with baseline fat intakes of 28-43% of energy intake and durations from six months to over eight years. Evidence supports a similar effect in children and young people.

Community-based interventions for enhancing access to or consumption of fruit and vegetables among five to 18-year olds: a scoping review

BACKGROUND

Low fruit and vegetable ( FV) consumption is a key risk factor for morbidity and mortality. Consumption of FV is limited by a lack of access to FV. Enhanced understanding of interventions and their impact on both access to and consumption of FV can provide guidance to public health decision-makers. The purpose of this scoping review is to identify and map literature that has evaluated effects of community-based interventions designed to increase FV access or consumption among five to 18-year olds.

METHODS

The search included 21 electronic bibliographic databases, grey literature, targeted organization websites, and 15 key journals for relevant studies published up to May 2011. Retrieved citations were screened in duplicate for relevance. Data extracted from included studies covered: year, country, study design, target audience, intervention setting, intervention strategies, interventionists, and reported outcomes.

RESULTS

The search located 19,607 unique citations. Full text relevance screening was conducted on 1,908 studies. The final 289 unique studies included 30 knowledge syntheses, 27 randomized controlled trials, 55 quasi-experimental studies, 113 cluster controlled studies, 60 before-after studies, one mixed method study, and three controlled time series studies. Of these studies, 46 included access outcomes and 278 included consumption outcomes. In terms of target population, 110 studies focused on five to seven year olds, 175 targeted eight to 10 year olds, 192 targeted 11 to 14 year olds, 73 targeted 15 to 18 year olds, 55 targeted parents, and 30 targeted teachers, other service providers, or the general public. The most common intervention locations included schools, communities or community centres, and homes. Most studies implemented multi-faceted intervention strategies to increase FV access or consumption.

CONCLUSIONS

While consumption measures were commonly reported, this review identified a small yet important subset of literature examining access to FV. This is a critically important issue since consumption is contingent upon access. Future research should examine the impact of interventions on direct outcome measures of FV access and a focused systematic review that examines these interventions is also needed. In addition, research on interventions in low- and middle-income countries is warranted based on a limited existing knowledge base.

Efeito de intervenções sobre o índice de massa corporal em escolares

OBJETIVO: Avaliar o efeito dos programas de intervenções com a atividade física e/ou a educação nutricional na redução do índice de massa corporal em escolares. MÉTODOS: Revisão sistemática com metanálise de estudos controlados randomizados disponíveis nas seguintes bases de dados eletrônicas entre o ano de 1998 a 2010: PubMed, Lilacs, Embase, Scopus, Web of Science e Cochrane Library, com os descritores: estudo controlado randomizado, sobrepeso, obesidade, índice de massa corporal, criança, adolescente, atividade física, educação nutricional e escolas. Medida de sumário baseada na diferença das médias padronizadas foi usada com intervalo de 95% de confiança. O teste de inconsistência foi utilizado para avaliar a heterogeneidade dos estudos. RESULTADOS: Foram identificados 995 estudos, dos quais 23 foram incluídos e realizadas três metanálises. Intervenções isoladas com atividade física não apresentaram efeito significativo na redução do índice de massa corporal, com diferença das médias padronizadas: -0,02 (IC95% -0,08;0,04). Resultado semelhante (n = 3.524) foi observado nas intervenções isoladas com educação nutricional, com diferença das médias padronizadas: -0,03 (IC95% -0,10;0,04). Quando combinadas as intervenções com atividade física e educação nutricional, o resultado da metanálise (n = 9.997) apresentou efeito estatisticamente significativo na redução do índice de massa corporal em escolares, com diferença das médias padronizadas: - 0,37 (IC95% -0,63;-0,12). CONCLUSÕES: As intervenções combinadas de atividade física e educação nutricional tiveram mais efeitos positivos na redução do índice de massa corporal em escolares do que quando aplicadas isoladamente.

Healthier food choices as a result of the revised healthy diet programme Krachtvoer for students of prevocational schools

BACKGROUND

Krachtvoer is a Dutch healthy diet programme for prevocational schools, developed in 2001 and revised for a broader target group in 2007, based on the findings of an evaluation of the first version. The goal of this study was to report on the short- and longer-term total and subgroup effects of the revised programme on students' fruit, fruit juice, breakfast, and snack consumption.

METHODS

Schools were randomized to the experimental condition, teaching the Krachtvoer programme, or to the control condition teaching the regular nutrition lessons. Self-reported consumption of fruit, fruit juice, breakfast and snacks was measured at baseline directly before programme implementation, one to four weeks after finishing programme implementation, and after six months. Mixed linear and logistic regression analyses were conducted.

RESULTS

In total 1117 students of 13 experimental schools and 758 students of 11 control schools participated in the study. Short- and longer-term favourable intervention effects were found on fruit consumption (mean difference between experimental and control group 0.15 servings at both posttests). Regarding fruit juice consumption, only short-term favourable effects were revealed (mean difference between experimental and control group 0.05 glasses). Intervention effects on breakfast intakes were limited. No changes in snack frequency were reported, but students made healthier snack choices as a result of the programme. Some favourable as well as unfavourable effects occurred in subgroups of students.

CONCLUSIONS

The effects on fruit consumption and snack choices justify the current nationwide dissemination of the programme. Achieving changes in breakfast consumption may, however, require other strategies.

Universal childhood and adolescent obesity prevention programs: review and critical analysis

Authors reviewed randomly controlled studies of universal prevention of childhood obesity, identifying 29 studies that met review criteria. Review suggested that outcomes are generally modest across all age groups and there were few replications of any program; thus, at this time no universal prevention program for childhood obesity meets criteria for a well-established intervention of the American Psychological Association. A wide variety of intervention targets have been investigated (knowledge and attitudes, family involvement, physical activity, television watching, water consumption, vegetable consumption, breast feeding, etc.) in a wide number of countries. Effects seem to be stronger for girls than for boys, for unknown reasons. Many studies fail to achieve sufficient statistical power and/or a sophisticated measurement strategy, neglecting key variables such as cost, treatment fidelity, longer-term follow up data, and process variables. Questions as to the theories of change associated with the interventions are also raised and suggestions for future research in this area are provided.

Nutrition transition among adolescents of a south-Mediterranean country: dietary patterns, association with socio-economic factors, overweight and blood pressure. A cross-sectional study in Tunisia

BACKGROUND

The increase in the burden of chronic diseases linked to the nutrition transition and associated dietary and lifestyle changes is of growing concern in south and east Mediterranean countries and adolescents are at the forefront of these changes. This study assessed dietary intake and association with socio-economic factors and health outcomes among adolescents in Tunisia.

METHODS

Cross-sectional survey (year 2005); 1019 subjects 15-19 y. from a clustered random sample. Dietary intake was assessed by a validated semi-quantitative frequency questionnaire (134 items) as was physical activity; the Diet Quality Index International measured diet quality; dietary patterns were derived by multiple correspondence analysis from intakes of 43 food groups. Body Mass Index (BMI) ≥ 85th and 95th percentile defined overweight and obesity. Waist Circumference (WC) assessed abdominal fat. High blood pressure was systolic (SBP) or diastolic blood pressure (DBP) ≥ 90th of the international reference for 15-17 y., and SBP/DBP ≥ 120/80 mm Hg for 18-19 y.

RESULTS

Energy intake levels were quite high, especially for females. The macro-nutrient structure was close to recommendations but only 38% had a satisfactory diet quality. A main traditional to modern dietary gradient, linked to urbanisation and increased economic level, featured an increasing consumption of white bread, dairy products, sugars, added fats and fruits and decreasing consumption of oils, grains, legumes and vegetables; regarding nutrients this modern diet score featured a decreasing relationship with total fat and an increase of calcium intake, but with an increase of energy, sugars and saturated fat, while vitamin C, potassium and fibre decreased. Adjusted for age, energy and physical activity, this modern pattern was associated with increased overweight in males (2nd vs. 1st tertile: Prevalence Odds-Ratio (POR) = 4.0[1.7-9.3], 3rd vs. 1st: POR = 3.3[1.3-8.7]) and a higher WC. Adjusting also for BMI and WC, among females, it was associated with decreased prevalence of high blood pressure (2nd vs. 1st tertile: POR = 0.5[0.3-0.8], 3rd vs. 1st tertile: POR = 0.4[0.2-0.8]).

CONCLUSION

The dietary intake contrasts among Tunisian adolescents, linked to socio-economic differentials are characteristic of a nutrition transition situation. The observed gradient of modernisation of dietary intake features associations with several nutrients involving a higher risk of chronic diseases but might have not only negative characteristics regarding health outcomes.