The review concluded there was some evidence that weight-related health interventions that required parent participation more effectively reduced body mass indexes of children and adolescents. Longer interventions that included parent participation appeared to have greater success. The reliability of the authors conclusions is uncertain due to the lack of quality assessment and limitations in the review process.

To evaluate the effectiveness of child and adolescent weight-related health interventions with a focus on levels of parental participation.

More than 13 databases (including MEDLINE, PsycINFO, and CINAHL Plus) were searched for peer-reviewed articles in English from January 2004 to December 2010. Search terms were reported.

Randomised controlled trials of interventions that targeted weight-related health and health behaviours of children or adolescents (aged two to 19 years) were eligible for inclusion. Control groups had to include participants of unrelated activities or those who received a pamphlet but no instructional manual for weight reduction. Interventions had to actively target behavioural habits such as dietary, physical activity or sedentary activity habits. The outcome of interest was change in body mass index. Eligible studies had to include enough data to enable analysis. Studies that evaluated medical practices or included participants with eating disorders or those confined in institutions or camps away from home were excluded.

Interventions included education on nutrition or physical activity, physical activity sessions, behaviour education or behaviour therapy, or a combination of these. Twenty-five studies were aimed at treatment for overweight or obese children or adolescents. Seventeen studies were preventive interventions. Some studies targeted specific racial or ethnic populations. Half of the interventions required parent participation; some provided the option for parental participation or did not include parents. Most studies included male and female participants; some included either only male or only female participants. Intervention durations ranged from nine weeks to four years.

The authors did not state how many reviewers selected the studies.

The authors did not state that they assessed quality.

Data were extracted to calculate the mean difference in body mass index from pre- to post-intervention for intervention and control groups. These were used to calculate an effect size (Cohen's d) weighted by the sample size of the intervention groups. Where studies reported on multiple interventions, each intervention was reviewed separately.

The authors did not state how many reviewers extracted data.

Differences in effect sizes between intervention and control groups were examined. Subgroup analyses were used to compare interventions with different levels of parental participation by testing for heterogeneity between the groups using Levene's test and then comparing the groups with t-tests of analysis of variance (where no heterogeneity detected) or Brown-Forsythe and Welch tests (where heterogeneity detected). Further subgroup analyses were performed to explore intervention types and participation age. A linear regression model was used to look at the combined effect of intervention characteristics upon outcomes.

Thirty-six studies (7,455 participants, range six to 1,029) with 42 interventions were included in the review.

Interventions that required parental participation (24 interventions) had greater success than interventions with no parent participation (11 studies) (p=0.027). No significant differences in success rates were found between interventions with different age groups, prevention compared to treatment and single compared to multiple activity interventions.

In further analyses that focused on prevention studies only, parent participation (p=0.01) and intervention duration (p=0.006) were significant positive predictors of intervention effectiveness.

The evidence suggested that weight-related health interventions that required parent participation more effectively reduced body mass indexes of child and adolescent participants. Longer interventions that included parent participation appeared to have greater success.

The review question was clear with defined inclusion criteria. Several relevant sources were searched. Only papers in English were eligible so language and publication biases were possible. Study quality was not assessed so it was difficult to determine the reliability of the results. The authors did not report whether they used methods to reduce reviewer error and bias.

Data for individual studies were reported but only limited data were provided for the combined studies. The aim of this review was to compare patient and intervention characteristics rather than evaluate the effectiveness of the weight interventions. The authors noted that due to sample sizes in the studies most data related to prevention rather than treatment interventions. There were variations in participant ages and body mass indexes.

The reliability of the authors conclusions is uncertain due to the lack of quality assessment and limitations in the review process.

Practice: The authors did not state any implications for practice.

Research: The authors stated that future research was required to investigate parental involvement in intervention activities and the effect on their children's weight-related behaviour. Studies were also needed to explore optimal intervention duration and intensity, evaluate specific age groups and include parents and children in intervention design. Comparisons were needed between preventive and treatment interventions. Reviews that measured long-lasting intervention effects were needed.

Not stated.

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.