Changes in smoking behaviours from late childhood to adolescence: 4 years later. 
The purpose of this short report is to estimate trajectories documenting changes in the frequency of cigarette smoking between 10-11 and 20-21 years of age for 3959 participants to the Canadian National Longitudinal Survey of Children and Youth.  This study is a follow up to Maggi, Hertzman, and Vaillancourt [Maggi, S., Hertzman, C., Vaillancourt, T., 2007.  Changes in smoking behaviours from late childhood to adolescence: insights from the Canadian National Longitudinal Survey of Children and Youth.  Health Psychol.  26, 232-240] who found that there are five distinct trajectories of acquisition of smoking from 10-11 to 16-17 years of age.  While findings from this study replicate those reported in Maggi, Hertzman, and Vaillancourt [Maggi, S., Hertzman, C., Vaillancourt, T., 2007.  Changes in smoking behaviours from late childhood to adolescence: insights from the Canadian National Longitudinal Survey of Children and Youth.  Health Psychol.  26, 232-240], they provide a more accurate representation of the possible outcomes of the smoking acquisition process by indicating what specific trajectories of experimentation may lead to daily smoking, occasional smoking or non-smoking.