The habits that lead to the three leading causes of preventable death in the United States -- smoking, obesity, and alcohol abuse -- are already in place by early adulthood, according to a new analysis of the most comprehensive survey of adolescent health behavior undertaken to date that appears in the January 2006 Archives of Pediatrics and Adolescent Medicine and was conducted by researchers at the Carolina Population Center and the University of North Carolina at Chapel Hill. "When they were young teenagers, most of the participants had fairly healthy behaviors," said Christine Bachrach, Ph.D., Chief of NICHD's Demographic and Behavioral Sciences Branch and project officer for the study. "What's really alarming is how rapidly healthy practices declined by the time the participants reached young adulthood."