Predictors of smoking onset over two years.

The objective of this analysis was to identify variables that predict the initiation of smoking among adolescents, and the development of susceptibility to smoking, over a 2-year period. We assessed variables that might predict later smoking among nonsmoking students in grades 7 and 9 and assessed their smoking status 2 years later, when they were in grades 9 and 11, thus receiving data from 4,130 students at two time points. Initiation of weekly smoking over the 2 years was associated with having a parent, sibling, or close friend who smokes; low school grades; higher levels of deviant behavior; susceptibility to smoking; use of smokeless tobacco; and for 7th graders, perception of higher levels of normative smoking. Susceptibility, defined as not being able to rule out the idea of smoking a year after the survey, was identified as a strong predictor of smoking and a valuable intermediary measure. We also assessed factors associated with the prediction of susceptibility 2 years post-test. Susceptibility to smoking was associated with deviant behavior, low grades, lower parental monitoring, relaxed parental attitude toward youth smoking, ease of access to tobacco, and lower exposure to anti-tobacco messages. This study provides support for the idea that susceptibility to smoking could be a useful outcome variable for tobacco research, as an intermediary to the initiation of smoking. In addition, evidence indicates that theoretically manipulable variables, including access to tobacco and exposure to anti-tobacco information, have the potential to influence susceptibility to smoking over a time.