"In the United States, nearly two-thirds of all deaths among young people aged 10--14 years result from only five causes: motor-vehicle crashes (23.4%), other unintentional injuries (15.7%), cancer (12.5%), suicide (7.2%), and homicide (5.2%). Substantial morbidity and social problems also result from the approximately 20,000 pregnancies and 7,000 live births that occur annually among girls younger than aged 15 years and the approximately 500,000 new cases of sexually transmitted diseases (STDs) reported among youth aged 10--19. Among adults aged 25 or older, 58% of all deaths in the United States result from cardiovascular diseases (34%) and cancer (24%). […] To monitor priority health-risk behaviors among adolescents and young adults in each of these six categories, the Centers for Disease Control and Prevention (CDC) established the Youth Risk Behavior Surveillance System (YRBSS). The YRBSS includes national, state, and local school-based surveys of high school students in grades 9--12. In addition, some states and cities conduct a school-based Youth Risk Behavior Survey (YRBS) among middle school students. In 2005, 10 states and 11 cities conducted a middle school YRBS. This report summarizes results from five state and eight local middle school surveys with weighted data in 2005. With the exception of one local survey (San Francisco) conducted during fall 2004, all weighted surveys were conducted during spring 2005. Data from the five state and two local school-based surveys with unweighted data are not included in this report."
Center for Disease Control and Prevention: http://www.cdc.gov/