Are occasional smokers a heterogeneous group? An exploratory study.

Background: Occasional smokers represent an important segment of all smokers and have been described to be a heterogeneous group in terms of past experience and likelihood of maintaining nondaily smoking behavior.

Methods: In the prospective Ontario Tobacco Survey, 408 occasional smokers were followed for a year. Characteristics of subgroups of occasional smokers, as suggested by previous literature, were studied for personal and smoking behavior group differences. Agglomerative hierarchical clustering was also used to empirically identify subgroups of occasional smokers using average linkage. Smoking status at 1-year follow-up was examined overall and by the identified subgroups to determine if any were useful predictors of persistent status as nondaily smoking and likelihood of smoking cessation.

Results: Significant differences were seen among the subgroups of occasional smokers suggested in previous studies including the number of quit attempts, setting a firm quit date, and whether or not participants cared others knew they smoked in descriptive analyses. Exploratory cluster analysis suggested 4 clusters of occasional smokers based on differences in age, perceived addiction, and history of daily smoking. Subgroups based on participants' history of smoking, self-reported addiction level, and empirically identified cluster subgroups resulted in significant differences of smoking status at 1-year follow-up.

Conclusions: This study suggests that occasional smokers may be a heterogeneous group with different subgroups characterized by age, accumulated smoking experience and smoking pattern, as well as factors associated with the likelihood of quitting altogether, over time, and perceived addiction.