Testing mediator variables in a physical activity intervention for women with Type 2 Diabetes

Abstract

Abstract Objectives A limited understanding of the mechanisms of behavior change has hindered the development of more effective interventions. The aim of this study was to identify potential mediators of objectively measured physical activity (PA) behavior change in women with type 2 diabetes (T2DM). Design Mediation test of a randomized controlled trial. Method Women with T2DM (n = 93) from the control group (standard PA materials, n = 44) and the full intervention group (control + stage-matched printed material and telephone counseling, n = 49) of a larger PA intervention trial were included. PA outcomes were minutes of MET weighted moderate and vigorous PA/week (self-report) and steps/3-days (objective) recorded at baseline and 12-months. Social-cognitive constructs were measured and tested in a mediating variable framework. Results Perceived behavioral control and barrier self-efficacy mediated intervention effects on objective PA (proportion of intervention effect mediated = 18% and 24% respectively). Intention was a mediator of objective PA (23%). Conclusion Perceived behavior control, barrier self-efficacy, and intention are effective mechanisms of PA behavior change in women with T2DM.