Social Network Interventions for Improving Dietary Adherence Among Adults With Type 2 Diabetes: A Systematic Review

CONTEXT: Adhering to recommended diets is essential for managing glycemic concentrations in type 2 diabetes (T2D). However, there is limited evidence on the effectiveness of interventions that leverage social networks to improve dietary adherence. OBJECTIVE: Given the influence of social networks on health behavior, this review was conducted to assess the effectiveness of social network interventions involving families, friends, and peers in enhancing dietary adherence among people with T2D. DATA SOURCES: We searched for social network interventions in randomized controlled trials (RCTs) and controlled before-and-after studies aimed at improving dietary adherence and glycemic control across 7 databases and 2 trial registries up to October 2024. DATA EXTRACTION: Data extraction was conducted independently by 2 reviewers. Study quality was assessed using the Cochrane Revised Risk of Bias tool for randomized trials and the Risk of Bias in Nonrandomized Studies of Interventions tool for nonrandomized studies. RESULTS: Ten studies were conducted from 2014 to 2023, including 9 RCTs and 1 quasi-RCT. Most involved family networks (n = 7), 2 centered on peer support, and 3 on significant others. Half of the studies reported improved dietary adherence, and 6 showed reduced hemoglobin A1C concentrations. Increased physical activity ranged from 18.6% to 23.6%, with 3 studies noting weight or BMI reductions. Two studies reported systolic (3.89 to 12.4 mm Hg) and diastolic (3.12 to 4.1 mm Hg) blood pressure decreases. One study reported a 0.52-point decrease in diabetes-related stress, and another noted a 27.6% improvement in quality of life. However, 6 studies had a high risk of bias and 2 had unclear risks, mainly due to detection and attrition bias. CONCLUSIONS: The findings of review suggest social network interventions can enhance and sustain dietary adherence. However, the evidence is limited due to a lack of high-quality studies and considerable variability in intervention components. More rigorous research using standardized metrics and cost-effectiveness data is necessary to support evidence-based health service recommendations. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration No. CRD42023441223.