Poor-quality evidence for lifestyle interventions in overweight children
medwireNews: Cochrane reviewers have assessed the effectiveness of behavior-changing interventions in overweight and obese children, finding an indication of benefit but based on mostly low-quality evidence.
The two just-published reviews cover children aged 6–11 and 12–17 years. The reviewers identified 70 trials with over 8000 participants for the younger age group and 44 trials with nearly 5000 participants for the adolescents. But although these were randomized, controlled trials, the evidence quality according to the GRADE instrument for the outcomes of interest was low or very low in the younger age group and low or moderate in the adolescents.
In both reviews, the included studies were highly heterogeneous. The interventions included dietary and physical activity interventions, group education, motivational interviewing, and cognitive behavioral therapy, with many trials delivering a multicomponent intervention. And there were also marked differences between the tools used to assess diet and physical activity, study designs, and outcomes.
The length of the interventions ranged from 10 days to 2 years. Post-intervention follow-up, where stated, ranged from 1 month to 2 years and overall follow-up from 6 months to 3 years.
“The evidence highlights a focus in paediatric obesity on initial weight reduction interventions rather than longer term maintenance interventions,” write Louisa Ells (Teesside University, Middlesbrough, UK) and colleagues, the authors of the pre-teen children review.
They note that the studies they reviewed mostly showed a positive effect at the end of the intervention and up to 6 months later.
“[T]he fact that these intervention effects might not persist is not a failure of the initial intervention, but due to a lack of maintenance interventions,” they write in The Cochrane Library.
The team found that the average reductions achieved by the interventions versus control conditions were 0.53 kg/m2 for body mass index (BMI), 0.06 units for BMI z score, and 1.45 kg for weight. For adolescents, Karen Rees (University of Warwick, Coventry, UK) and colleagues report corresponding reductions of 1.18 kg/m2, 0.13 units, and 3.67 kg.
But they say that “the results of this review should be interpreted with caution as most of the evidence was rated as low quality due to inconsistency, indirectness or risk of bias for many of the outcomes measured.”
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