Effect of a cardiovascular prevention program on health behavior and BMI in highly educated adults: A randomized controlled trial

To examine the effects and dose-response effects of an intervention on health behavior (fat intake, physical activity, and smoking) and Body Mass Index (BMI) in a sample of highly educated adults.Participants were randomized to a 'usual care' condition (=medical assessment) (n=106) and an intervention condition (=cardiovascular prevention program) that additionally included a website and one-on-one coaching (by e-mail, telephone, and/or face-to-face) (n=208). The participants could select their own intervention dose and delivery mode.Participants completed questionnaires at baseline (n=93; n=194) and 6 months post-baseline (n=84; n=168). The intervention was not more effective than 'usual care' but a higher intervention dose led to better outcomes for fat intake and physical activity, independent of baseline motivation. Furthermore, the effect of combining different delivery modes was dependent on the behavioral context.A higher intervention dose led to better results but allowing people to select their own intervention dose probably undermined the potential intervention effect.The present study highlights the importance of intervention dose and delivery mode for the development, evaluation, and optimization of health promotion programs.