The ENDORSE study: Research into environmental determinants of obesity related behaviors in Rotterdam schoolchildren

BACKGROUND Children and adolescents are important target groups for prevention of overweight and obesity as overweight is often developed early in life and tracks into adulthood. Research into behaviors related to overweight (energy balance-related behaviors) and the personal and environmental determinants of these behaviors is fundamental to inform prevention interventions. In the Netherlands and in other countries systematic research into environmental determinants of energy balance related behaviors in younger adolescents is largely lacking. This protocol paper describes the design, the components and the methods of the ENDORSE study (Environmental Determinants of Obesity in Rotterdam SchoolchildrEn), that aims to identify important individual and environmental determinants of behaviors related to overweight and obesity and the interactions between these determinants among adolescents. METHODS The ENDORSE study is a longitudinal study with a two-year follow-up of a cohort of adolescents aged 12-15 years. Data will be collected at baseline (2005/2006) and at two years follow-up (2007/2008). Outcome measures are body mass index (BMI), waist circumference, time spent in physical activity and sedentary behaviors, and soft drink, snack and breakfast consumption. The ENDORSE study consists of two phases, first employing qualitative research methods to inform the development of a theoretical framework to examine important energy balance related behaviors and their determinants, and to inform questionnaire development. Subsequently, the hypothetical relationships between behavioral determinants, energy balance related behaviors and BMI will be tested in a quantitative study combining school-based surveys and measurements of anthropometrical characteristics at baseline and two-year follow-up. DISCUSSION The ENDORSE project is a comprehensive longitudinal study that enables investigation of specific environmental and individual determinants of overweight and obesity among younger adolescents. The project will result in specific recommendations for obesity prevention interventions among younger adolescents.