Interventions to prevent obesity in children aged 12 to 18 years old

Abstract

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 wit...