Effects of a blended face-to-face and eHealth lifestyle intervention on physical activity, diet, and health outcomes in Hong Kong community-dwelling older adults: a randomized controlled trial

Background: The effectiveness of a blended approach integrating face-to-face and eHealth interventions for promoting positive lifestyle behaviours in older adults has not been systematically tested. This study aimed to assess the feasibility and effectiveness of such interventions in improving health behaviours and outcomes among older adults in Hong Kong. Methods: A 10-week, single-blind, randomized controlled trial recruited 132 eligible older adults. Participants were assigned to three groups: (1) a blended intervention group: two sessions per week for ten weeks with one for physical activity and one for diet (fruit and vegetable intake; meat, fish, egg and alternatives intake) and two web-based sessions; (2) a face-to-face intervention group: same content and intensity like the blended group but as face-to-face sessions; and (3) a control group receiving biweekly telephone calls. Data on lifestyle behaviours and health outcomes (physical fitness, depression, loneliness, health-related quality of life) were collected at baseline (T1), 10 weeks post-test (T2), and a 3-month follow-up (T3). All data were analyzed using IBM SPSS 29.0. Descriptive statistics were used to describe the feasibility. The generalized linear mixed models were used to evaluate the effects of the intervention. Results: The study demonstrated high feasibility with > 90% adherence, > 88% session attendance, and an acceptability score of 4.7/5. The blended intervention outperformed the face-to-face and control conditions for both diet behaviours at T2 and T3, with a Cohen’s d effect size ranging from 0.77 to 1.18 (p < 0.05). It also showed a significant effect on physical activity compared to controls at T3 (Cohen’s d = 0.21, p < 0.05). Both intervention groups improved in lower body strength, agility and dynamic balance, and health-related quality of life compared to control at T3 (p < 0.05). Conclusions: This study provides empirical evidence for the feasibility and superiority of blended interventions to promote dietary habits among Hong Kong older adults. Future research applying rigorous study design, identifying effective strategies promoting physical activity, and exploring psychological mechanisms of health behaviour changes is warranted to enhance the efficacy of lifestyle interventions among older adults. Trial registration: This study was retrospectively registered on the ISRCTN (ISRCTN32329348).