Effects of a multicomponent workplace intervention programme with environmental changes on physical activity among Japanese white collar employees: a protocol for a cluster randomised controlled trial

INTRODUCTION: Physical activity is one of the most important health behaviours as a determinant of physical and mental health. Although intervention strategies for promoting physical activity among workers are needed, evidence for the effectiveness of multilevel workplace interventions with environmental changes on the promotion of physical activity are still limited due to lack of cluster randomised controlled trials (RCTs). The aim of this study is to investigate effects of a 3-month workplace intervention programme with environmental changes on the improvement in physical activity among Japanese white collar employees. METHODS AND ANALYSIS: This study will be a two-arm and parallel-group cluster (worksite) RCT. Japanese worksites and employees who are employed by the worksites will be recruited through health insurance associations and chambers of commerce. Worksites that meet the inclusion criteria will be randomly allocated to intervention or control groups. The intervention worksites will be offered the original intervention programme that consists of 13 contents with environmental changes. The control worksites will be able to get three times feedback of the assessment of the amount of physical activity and basic occupational health service in each worksite. The primary outcome will be the total amount of physical activity measured by the Global Physical Activity Questionnaire at baseline, 3 months and 6 months. Multilevel latent growth modelling will be conducted to examine the effectiveness of the intervention programme. ETHICS AND DISSEMINATION: This study was ethically approved by the research ethics committee of the Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, Japan (No. 11230). Results will be submitted and published in a scientific peer-reviewed journal. TRIAL REGISTRATION NUMBER: UMIN000024069; Pre-results.