Physical activity level, determinants of physical activity, physical fitness, fatness and health in Norwegian children

INTRODUCTION: The obesity epidemic in the Western World is well known, and even if the prevalence of obesity in Norway is much lower than in countries such as USA and England body weight has increased in Norwegian children during the last decades. Althoug h weight gain is a consequence of higher energy intake than energy expenditure, most children can regulate their energy balance perfectly despite the fact that a positive balance storing of just a few grams of fat every day will result in overweight over time. Our hypothesis is that insulin resistance and high 24-h insulin levels are main factors in the development of the obesity epidemic, and physical inactivity may be one of the key factors starting the problem. However, in manifest obese individuals th e fat tissue may play a central role by producing cytokines. This hypothesis may be tested in children, who have not yet developed severe obesity. THE AIM OF THE STUDY: We aim to analyze the predictive value of the different cytokines and hormones for fut ure weight gain and the development of cardiovascular disease (CVD) risk factors related to the metabolic syndrome in a large cohort of 9- and 15-year old Norwegians METHODS: The study includes a randomly selected cohort of 1200 children (9 years) and 120 0 (15 years). We will analyze fasting blood samples, collect data on blood pressure, anthropometry and skinfold, measure physical activity by accelerometry, measure maximal oxygen uptake during a maximal test on a cycle ergometer, collect self-reported da ta on determinants of physical activity level. The cohort will be followed-up in 2011. A general report will be delivered to the Directorate for Health and Social Affairs and results will be published in international journals. The scientific sphere could have a potential interest of this study, and the knowledge from this project can be utilized in different strategies aiming to prevent obesity.