One year results of a tailored behaviour change programme in highly educated adults: a randomised controlled trial

Abstract

Purpose: Little is known about the adequate intervention dose of interventions to change multiple risk behaviours for cardiovascular disease. The aims of our study were to examine the effects and the dose-response effects of a tailored behaviour change programme on diet and physical activity. Methods: 314 highly educated adults were allocated at random to intervention and usual care conditions. Both conditions involved medical interventions following the guidelines. The participants receiving the intervention had access to a website with tailored feedback, group sessions and individual coaching. For the latter, they could freely determine the dose(frequency and duration) and the delivery mode(e-mail, telephone, face-to-face). Repeated measures analysis of variances were used to examine the differences between the study groups. Linear modelling was used to examine the dose-response effects for diet and physical activity. Results: Of the participants, 236 completed the questionnaires at baseline and after one year. Both study groups had a lower fat intake(p<.05) and a higher level of physical activity(p<.001). No significant differences between the study groups were found. For diet, frequent telephone coaching should be combined with frequent face-to-face sessions to reduce the fat intake(p<.001). Intensive telephone coaching should be supplemented with frequent e-mails to increase physical activity(p<.05). Conclusions: No differences were found between the intervention and usual care conditions. However, significant dose-response effects were found for the intervention, independent of baseline motivation. These results emphasize the need to determine the adequate intervention dose and delivery mode to change behaviour.