633 Journal of Physical Activity and Health, 2010, 7, 633-640 © 2010 Human Kinetics, Inc. Antonogeorgos, Papadimitriou, and Nikolaidou are with the 3rd Dept of Pediatrics, University of Athens, Haidari, Greece. Panagiotakos is with the Dept of Nutrition Science-Dietetics, Harokopio University of Athens, Greece. Priftis is with the Allergy Dept, Penteli Children’s Hospital, P. Penteli, Greece. Physical Activity Patterns and Obesity Status Among 10- to 12-Year-Old Adolescents Living in Athens, Greece George Antonogeorgos, Anastasios Papadimitriou, Demosthenes B. Panagiotakos, Kostas N. Priftis, and Polyxeni Nikolaidou Background: Childhood obesity has become a modern epidemic with escalating rates. The aim of our study was to identify physical activity patterns among Greek schoolchildren and to examine their relationship with obesity. Methods: 700 adolescents age 10 to 12 years were evaluated through a standardized questionnaire. Several demographic, socioeconomic, and physical activity characteristics were recorded. Physical activ- ity was assessed and adolescents were characterized as active and nonactive. Body height and weight were measured and body mass index was calculated in order to to classify subjects as overweight or obese (IOTF classiication). Multiple logistic regression and multivariate techniques (principal components analysis) were performed. Results: Eight physical activity patterns were identiied, including increased physical activity in weekdays and weekends, sports physical activity, vigorous, moderate, and low physical activity. Increased physical activity on weekends and vigorous physical activity in boys were negatively associated with being overweight or obese (OR: 0.65; 95% CI: 0.48–0.90 and OR: 0.66; 95% CI: 0.49–0.88, correspondingly) and moderate physical activity was marginally positively associated in girls (OR: 1.28; 95% CI: 0.97–1.69), after adjusting for several confounders. Conclusions: Our indings demonstrate the important role of vigorous physical activity in the maintenance of normal weight of adolescents Keywords: vigorous, weight, maintenance, exercise, moderate Background Childhood obesity has become a major public health concern in the last 4 decades, affecting both developed and developing countries globally. It is estimated that worldwide, approximately 1 out of 10 children are over- weight (a total of 155 million) and among them 35 to 45 million children of school age and 22 million children under 5 years are obese. 1 Most alarming is the fact that the prevalence of childhood obesity is rising rapidly. The prevalence of overweight and obese children in United States age 2 to 5 years and adolescents age 12 to 19 years has doubled during the past 3 decades and has tripled for the age group of 6 to 11 years. 2 In Europe, about 400,000 children every year are affected by the obesity epidemic and approximately 14 million children are overweight or obese. 3 Moreover, it has been suggested that childhood obesity is one of the main risk factors for adulthood obe- sity. 4 It has been associated with increased risk of devel- oping cardiovascular diseases, 5–7 hypercholesterolemia, hypertension, 6 and increased prevalence of early onset of type 2 diabetes mellitus. 8,9 Most important are the psychological consequences of childhood obesity, which includes low self-esteem, depression, and body dissatis- faction. 10,11 One of the most important factors implicated in the multifactorial etiology of childhood obesity is physical activity. Obesity is the result of an imbalance of energy intake and expenditure. As a key determinant of energy expenditure, physical activity (PA) is essential to energy balance and weight control. Obese children tend to follow lifestyles with decreased levels of physical activ- ity and tend to spend more time in sedentary activities like television viewing or video game playing than their nonobese counterparts. 12,13 In Greece, the prevalence of childhood obesity is high and follows a secular trend, comparable to that reported for most European countries. 14,15 Limited data exist about the association of physical activity and obesity in Greek adolescents. In a study by Lagiou et al, time spent watching television or operating the com- puter per day was positively associated with overweight among primary school students. 16 Moreover, Krassas et al reported that overweight in 2495 Greek children age 6 to 17 years that participated in a cross-sectional study in North Greece’s region surrounding Thessaloniki was also positively inluenced by hours of daily television viewing. 17