A period of increased susceptibility to cigarette smoking among high school students.

Cross-sectional surveys of randomly selected high school students were conducted in October 1999 and in May 2000 to measure awareness of youth-led tobacco prevention efforts. A secondary goal of the surveys was to learn about tobacco use and attitudes. Respondents who never smoked cigarettes were asked if they had made a firm commitment to not smoke, and respondents who had not made such a commitment were considered susceptible. Among ninth graders, susceptibility increased from 31% in October to 47% in May, while susceptibility decreased from October to May for students in more advanced grades (p = 0.03, interaction of linear trends). Susceptibility was more common among students who felt smoking produced social benefits (OR 1.59, 95% CI 1.22-2.08) or who were tolerant of tobacco company behavior (OR 1.65, 95% CI 1.23-2.21), and less common among students who felt short-term adverse effects of cigarette smoking on health or hygiene were important to them (OR 0.74, 95% CI 0.56-0.97). Further studies should confirm the increase in susceptibility and its underlying mechanisms. Whether associated with ninth grade or with the first year in a new school, this previously unrecognized period of heightened susceptibility might represent an important opportunity for prevention.