Follow-up associations between social support, physical activity and Mediterranean diet adherence in a digital intervention study: The CREDITS4HEALTH trial

Abstract

Background and aims Adopting and maintaining a healthy lifestyle—characterized by nutritious dietary patterns and regular physical activity—remains a persistent challenge for many individuals. Social support has been identified as a critical facilitator of successful lifestyle modification and long-term adherence. This study reports 6-month follow-up findings from 980 healthy adults (396 men, 584 women; median age: 43 years) residing in Italy, Spain, and Greece who participated in the Credits4Health (C4H) multicenter randomized controlled trial. We investigated whether social support and social integration moderated the efficacy of a digital health intervention designed to promote physical activity and Mediterranean diet adherence. Participants were randomized to either a dynamic platform (experimental arm: goal-setting, tailored recommendations, personalized pathways, and real-time feedback) or a static platform (control arm: general information and self-monitoring without personalization). Methods We employed mixed-effects ordinal and linear regression models to examine the effect of platform assignment (dynamic vs. static) on physical activity levels and Mediterranean Diet Adherence Screener (MEDAS) scores, stratified by social support and social integration subcategories. Likelihood ratio tests were conducted to assess potential interactions between social support/integration variables and platform assignment by comparing models with and without interaction terms. Results Analysis of data from 980 participants revealed no significant moderating effects of any social support or social integration subcategories on intervention efficacy for either physical activity promotion or Mediterranean diet adherence. Conclusion This study found no evidence that social support or social integration moderate the efficacy of digital interventions targeting physical activity and adherence to Mediterranean diet. These null findings may reflect the study’s 6-month duration or participation characteristics. Future investigations employing longer follow-up periods, enhanced participant engagement strategies, and more granular assessment of social support dimensions are warranted to better understand how social factors may influence the efficacy of digital health interventions, particularly as such technologies become increasingly prevalent in public health promotion.