Wednesday, April 20, 2011

Mediators of effective energy-balance interventions in youth

Obesity prevention in youth requires effective interventions targeting the so-called energy balance-related behaviours (that is, physical activity, sedentary and dietary behaviours). To improve (cost-)effectiveness of these interventions, we need to know the working mechanisms underlying behavioural change. Mediation analyses is a technique that helps to explore an analyse via what pathways interventions have their effects (...or not). Identifying such mediators of intervention effects can help professionals in developing new interventions or adapting existing interventions so that these are targetted at these succesful mediators as good as possible. Dr. Maartje van Stralen and colleagues just published a systematic review of studies on  identification of psychosocial and environmental mediators of  school-based interventions for youth, aiming to change physical activity, dietary and/or sedentary behaviours. The review paper was published in the International Journal of Obesity and was conducted as part of the ENERGY project, a cross-European and European Commission funded project to inform effective prevention of overweight and obesity in schoolchildren across Europe. Twenty-four studies were identified in the scientific literature. Based on the review of these 24 studies, strong evidence for self-efficacy and moderate evidence for intention as mediators of physical activity interventions was found, i.e. improvements in physical activity were brought about via positive changes in self-efficacy and intentions. Some evidence was found that attitudes, knowledge and habit strength were mediators of dietary behaviour interventions. Too few studies were avialbale on interventions aiming to reduce sedentary time to draw any conclusions regarding potential mediators.