Abstract
BACKGROUND: Dietary and physical activity behaviors can influence the development of breast cancer. This study aimed to evaluate the effectiveness of a web-app-based intervention in improving diet and physical activity among women aged 25-45 years residing in northern Spain. METHODS: A randomized experimental study was conducted with two groups: an intervention group (IG) and a control group (CG). The Motiva.Diaf questionnaire was used to evaluate the impact of a web-app-based intervention on dietary and physical activity behaviors (range: 0= lowest adherence, 12= highest adherence to healthy behaviors). Women in the IG participated in a 12-week intervention based on the Behavior Change Wheel Model. The web-app provided information on both behaviors. RESULTS: A total of 289 women completed the study (IG =101; CG =188). Considering the combined behaviors for IG (diet and physical activity), between PRE-intervention [8.12; standard deviation (SD) =2.51] and POST-intervention (8.46; SD =2.53), the score was significantly higher in POST [P=0.001; 95% confidence interval (CI): -0.546 to -0.140]. Similarly, significant improvements were observed in specific behavioral recommendations within the IG, with higher scores in dietary behaviors (P<0.001; 95% CI: -0.419 to -0.141), and in physical activity between IG and CG at POST (P=0.04; 95% CI: -0.531 to -0.014). Previous adherence to recommendations was a predictor of POST-intervention adherence to healthy behaviors (Standardized β =0.645; 95% CI: 0.773-0.886; R(2) =67%). CONCLUSIONS: The intervention has proven effective in improving adherence to healthy dietary and physical activity behaviors. Policymakers should prioritize the development of these digital interventions as they can play a crucial role in addressing challenges faced by healthcare systems and meeting societal demands. Therefore, healthcare professionals can implement them. TRIAL REGISTRATION: ClinicalTrials.gov NCT05267171.