摘要:The prevalence of obesity has become a primary risk factor for adolescents’ health, which is an essential factor in poverty reduction and sustainable development. Physical activity can help adolescents reduce obesity risk and keep a healthy body mass index (BMI). We analyze the 2010 National Youth Physical Activity and Nutrition Survey (NYPANS) for U.S. school students from 9th to 12th grades (aging from 12 to 18). A latent variable analysis explored the relationship between adolescents’ BMI, physical activity, and physical and social environment. We found that Hispanic adolescents have higher BMI because they participate in fewer physical activities. We found that active commuting to school does not provide sufficient physical activity to keep a healthy BMI. The neighborhood environment for physical activity, such as public exercise and recreational center facilities, can reduce BMI but cannot help underweight adolescents increase BMI. Finally, spending too much leisure time on electronic entertainment, such as video games, is a dominating contributor to unhealthy BMI. These research outcomes suggest that providing a physical activity-friendly environment for adolescents, such as the facilities for physical activity in the neighborhood, is critical to a healthy BMI. Interventions that encourage physical activity and reduce leisure time on electronic entertainment to meet physical activity guidelines are also necessary.