This well-conducted review concluded that evidence on weight management interventions for prevention of obesity in under-fives was scarce and disparate (no evidence on treatment). There was some evidence of positive trends in weight measures, but except for one subgroup this was not statistically significant. Further randomised controlled trials were required. This conclusion is likely to be reliable.

To assess the effectiveness and cost-effectiveness of weight management schemes for the under fives.

Twelve databases including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL) and PsycINFO were searched from 1990 to February 2009 for studies reported in English. Three clinical trials registers were also searched. The full search strategy was reported to be available from the authors.

Systematic reviews, randomised controlled trials (RCTs) and non-randomised controlled studies were eligible if they assessed weight management schemes delivered in any setting designed to maintain appropriate weight and/or achieve weight loss and/or manage weight gain. Normal practice or attention control interventions were eligible comparators. Both universal and targeted prevention or management schemes and treatment for children already overweight or obese were included. Interventions targeting children with underlying causal morbidity such as Prader-Willi syndrome were excluded. Included studies had to report on outcomes such as body mass index (BMI), weight or a related measure. Other outcomes considered were related to health and quality of life.

Only RCTs were included in this publication, included systematic reviews were considered in the full report (see other publications of related interest). All the included trials were of preventative interventions. Three of the four trials included physical activity components. Two were conducted in the USA, one in the UK and one in Thailand. Low income or ethnic minority populations were involved in the UK and USA trials. Comparators were usual care, general health education, a home-based parenting skills course and a one hour physical education session. The mean age of the children was over four years in all studies, except one where it was 22 months.

Three reviewers independently assessed the papers for inclusion at both abstract and full text stage; disagreements were resolved through discussion.

Studies were assessed for validity using the criteria of the Centre for Reviews and Dissemination.

From the full report it appeared that validity was assessed by one reviewer and the assessment checked by two others.

Data were extracted on population and intervention characteristics and on weight, health and quality of life outcomes to permit the calculation of mean differences. The full report stated that the data were extracted using standardised forms by one reviewer and checked by two others.

The studies were combined in a narrative synthesis.

Four RCTs were included in the review (the full report also included 16 systematic reviews). The quality of the trials varied; none reported the method of randomisation and only one reported adequate allocation concealment. Two had blinded outcome assessment, two had baseline comparability but the other two reported imbalances. All trials reported withdrawals and an appropriate analysis. Follow-up ranged from 16 weeks to five years.

BMI and related outcomes: One trial showed a statistically significant difference between groups with significantly smaller increases in BMI in children in the intervention arm (0.48 versus 1.14; p=0.008); this difference was apparent only in study sites that enrolled African American children but remained significant after adjustment for demographic factors. A second trial found decreases in adiposity in both groups but no significant difference. Two trials found no differences between groups.

None of the trials reported any statistically significant differences in weight or physical activity.

Evidence from controlled trials on the efficacy of weight management interventions for prevention of obesity was scarce and disparate; there was some evidence of positive trends in weight measures but with the exception of one subgroup this was not statistically significant. There was no evidence on treatment interventions. Further RCTs were required.

The review question and inclusion criteria were clear. The search was comprehensive, but the restriction to studies published in English may potentially have introduced language bias and led to the omission of some relevant studies. The full report indicated that methods designed to reduce reviewer bias and error were used throughout the review process.

he validity assessment used appropriate criteria and the decision to employ a narrative synthesis was also correct. There were clinically relevant differences between the groups at the beginning of two of the studies, including the only one to show a statistically significant difference between the intervention and control groups.

The authors' cautious conclusions reflect the results of the review and appear likely to be reliable.

Practice: The authors hypothesised that important features to include in future interventions may be: cultural sensitivity; sustained moderate-to-vigorous exercise; active engagement of parents both in the programme and as role models; and active engagement of children in nutrition education.

Research: The authors stated that further well-designed RCTs were urgently required to assess weight management schemes aimed at both the prevention and/or treatment of obesity in the under-fives. These studies should be combined with cost-effectiveness assessments and should have at least 12 months follow-up with assessment of objective outcomes. A qualitative component was also recommended (along with smaller observational studies) to investigate barriers to and facilitators of successful interventions.

National Institute for Health Research through the Health technology Assessment programme.

Bond M, Wyatt K, Welch K, Taylor R. Systematic review of the effectiveness and cost-effectiveness of weight management schemes for the under-fives: a short report. Health Technology Assessment 2009; Vol 13: No 61.

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.