RATIONALE: Adolescent obesity is a global public health problem with multiple causes. The mainstay approach for managing obesity includes interventions targeting changes in health-related behaviours (diet, physical activity, and behaviour). However, previous research highlighted uncertainty about the sustainability and long-term results of these approaches.
OBJECTIVES: To assess the effects of multimodal health behaviour-changing interventions for adolescents aged 10 to 19 living with obesity.
SEARCH METHODS: We used CENTRAL, MEDLINE, three other databases, and two trial registers, together with reference checking and contact with study authors, to identify studies included in the review. The latest search date was 28 February 2024.
ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) in adolescents aged 10 to 19 living with obesity that compared interventions involving a minimum of two health-related behaviour components (modifications in diet, physical activity, or behavioural change) to control (including no treatment, usual care, or waiting-list control) with a minimum of one year of follow-up.
OUTCOMES: Critical outcomes included physical well-being, mental well-being, physical activity, health-related quality of life (HRQoL), obesity-associated disability, adverse events, and anthropometry (body mass index (BMI) z-score).
RISK OF BIAS: We used the original version of the Cochrane Collaboration's tool for assessing risk of bias (RoB 1).
SYNTHESIS METHODS: We synthesised results for each outcome using meta-analysis, where possible, with a random-effects model. Where this was not possible, we described the results narratively. We used GRADE to assess the certainty of evidence for critical outcomes included in two key summary of findings tables. For continuous outcomes, we calculated mean differences (MDs) or standardised mean differences (SMD).
INCLUDED STUDIES: We included 33 RCTs with 5949 participants aged 10 to 19, primarily from high-income countries. We included 13 community-based interventions in schools, churches, and community centres, and 20 healthcare-based interventions implemented in primary care and hospitals. Intervention components included sessions on dietary modification, physical activity, and behavioural change. Of the 33 included studies, one targeted parents only, one involved only adolescents, and the remainder used family-based approaches, primarily through individual or group sessions.
SYNTHESIS OF RESULTS: Healthcare-based multimodal interventions versus control Healthcare-based multimodal interventions may result in little to no difference in physical well-being at 12 months of follow-up (multiple scales: SMD 0.13, 95% CI -0.13 to 0.39; I² = 67%; 4 studies, 1006 participants; low-certainty evidence). They may result in little to no difference in mental well-being at 12 to 18 months of follow-up (multiple scales: SMD 0.09, 95% CI -0.07 to 0.24; I² = 0%; 4 studies, 693 participants; low-certainty evidence). The evidence is very uncertain about the effect of these interventions on self-reported physical activity (final score) at 12 months (multiple scales: SMD 0.51, 95% CI -0.07 to 1.10; I² = 93%; 4 studies, 964 participants; very low-certainty evidence), and when measured as a change-from-baseline score, these interventions may result in little to no difference in self-reported physical activity (multiple scales: SMD 0.02, 95% CI -0.29 to 0.34; I² = 0%; 2 studies, 156 participants; low-certainty evidence). These interventions may slightly improve HRQoL at 12 months (multiple scales: SMD 0.13, 95% CI 0.02 to 0.24; I² = 4%; 7 studies, 1454 participants; low-certainty evidence). The evidence is very uncertain about the effect of healthcare-based multimodal interventions on adverse events (0 events; 1 study, 46 participants; very low-certainty evidence). These interventions may result in little to no difference in BMI z-score at 12 to 18 months (MD -0.11, 95% CI -0.19 to -0.02; I² = 78%; 17 studies, 2666 participants; low-certainty evidence) and 24 months (MD 0.50, 95% CI -0.35 to 1.35; I² not applicable; 1 study, 33 participants; low-certainty evidence). None of the included studies reported obesity-associated disability. Community-based multimodal interventions versus control Community-based multimodal interventions may improve physical well-being at 12 months of follow-up (Youth Quality of Life instrument - Weight module: MD 13.50, 95% CI 4.99 to 22.01; I² not applicable; 1 study, 136 participants; low-certainty evidence). These interventions may result in little to no difference in mental well-being at 12 months (Strengths and Difficulties Questionnaire: MD 1.20, 95% CI -0.46 to 2.86; I² not applicable; 1 study, 208 participants; low-certainty evidence). These interventions may result in little to no difference in self-reported physical activity at 24 months (Global Physical Activity Questionnaire: ß coefficient = -0.04, 95% CI -0.3 to 0.2; P = 0.76; low-certainty evidence). Community-based multimodal interventions likely result in little to no difference in HRQoL at 12 months (multiple scales: SMD 0.06, 95% CI -0.11 to 0.24; I² = 19%; 4 studies, 666 participants; moderate-certainty evidence) and may result in little to no difference in HRQoL at 24 months (Pediatric Quality of Life Inventory: SMD -0.03, 95% CI -0.33 to 0.27; I² not applicable; 1 study, 188 participants; low-certainty evidence). These interventions may result in little to no difference in BMI z-score at 12 months (MD -0.07, 95% CI -0.21 to 0.08; I² = 85%; 5 studies, 585 participants; low-certainty evidence), and may reduce BMI z-score slightly at 24 months of follow-up (MD -0.47, 95% CI -0.96 to 0.02; I² = 98%; 3 studies, 430 participants; low-certainty evidence). None of the included studies reported data on obesity-associated disability or adverse events.
AUTHORS' CONCLUSIONS: Multimodal health behaviour-changing interventions may result in a small improvement in physical well-being at 12 months and BMI z-score at 12 months when delivered in the community, and in HRQoL at 12 months when delivered in healthcare settings. They may have little to no effect on other pre-defined critical outcomes, including mental well-being and physical activity. Future research should consider innovative approaches to the care of adolescents living with obesity and involve diverse populations, as we found limited research conducted in disadvantaged and culturally/ethnically diverse populations and other low-resource settings.
FUNDING: World Health Organization (WHO) REGISTRATION: Protocol (2024): PROSPERO CRD42023468867.
