Study protocol

Vitalum study design: RCT evaluating the efficacy of tailored print communication and telephone motivational interviewing on multiple health behaviors

Hilde M van Keulen¹ , Ilse Mesters¹ , Johannes Brug² , Marlein Ausems¹ , Marci Campbell³ , Ken Resnicow⁴ , Paul J Zwietering⁵ , Gerard van Breukelen⁶ , Willem van Mechelen⁷ , Johan L Severens⁸ and Hein de Vries¹

¹  Department of Health Education and Health Promotion, School for Public Health and Primary Care (Caphri), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands

²  EMGO Institute, VU University Medical Centre, Van der Boechortstraat 7, 1081 BT Amsterdam, The Netherlands

³  Department of Nutrition, University of North Carolina at Chapel Hill, School of Public Health, 4102 McGravan-Greenberg Hall, Chapel Hill, NC 27599-7461, USA

⁴  Faculty of Health Behavior and Health Education, University of Michigan, School of Public Health, 109 South Observatory, Ann Arbor, MI 48109-2029, USA

⁵  Department of General Practice, School for Public Health and Primary Care (Caphri), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands

⁶  Department of Methodology and Statistics, School for Public Health and Primary Care (Caphri), Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands

⁷  Department of Public and Occupational Health, EMGO Institute, VU University Medical Centre, Van der Boechortstraat 7, 1081 BT Amsterdam, The Netherlands

⁸  Department of Health Organization, Policy, and Economics and Department of Clinical Epidemiology and Medical Technology Assessment, School for Public Health and Primary Care (Caphri), University Hospital Maastricht and Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands

author email corresponding author email

BMC Public Health 2008, 8:216doi:10.1186/1471-2458-8-216

Published:	19 June 2008

Abstract

Background

A large proportion of adults fail to meet public health guidelines for physical activity as well as fruit, vegetable and fat intake. Interventions are needed to improve these health behaviors. Both computer tailoring and motivational interviewing have shown themselves to be promising techniques for health behavior change. The Vitalum project aims to compare the efficacy of these techniques in improving the health behaviors of adults aged 45–70. This paper describes the design of the Vitalum study.

Methods/Design

Dutch general medical practices (N = 23) were recruited via a registration network or by personal invitation. The participants were then enrolled through these general practices using an invitational letter. They (n = 2,881) received a written baseline questionnaire to assess health behaviors, and potential psychosocial and socio-demographic behavioral determinants. A power analysis indicated that 1,600 participants who were failing to meet the guidelines for physical activity and either fruit or vegetable consumption were needed. Eligible participants were stratified based on hypertension status and randomized into one of four intervention groups: tailored print communication, telephone motivational interviewing, combined, and control. The first two groups either received four letters or took part in four interviews, whereas the combined group received two letters and took part in two interviews in turns at 5, 13, 30 and 43 weeks after returning the baseline questionnaire. Each letter and interview focused on physical activity or nutrition behavior. The participants also took part in a telephone survey 25 weeks after baseline to gather new information for tailoring. There were two follow-up questionnaires, at 47 and 73 weeks after baseline, to measure short- and long-term effects. The control group received a tailored letter after the last posttest. The process, efficacy and cost-effectiveness of the interventions will be examined by means of multilevel mixed regression, cost-effectiveness analyses and process evaluation.

Discussion

The Vitalum study simultaneously evaluates the efficacy of tailored print communication and telephone motivational interviewing, and their combined use for multiple behaviors and people with different motivational stages and education levels. The results can be used by policymakers to contribute to evidence-based prevention of chronic diseases.

Trial Registration

Dutch Trial Register NTR1068