A population study of low-rate smokers: quitting history and instability over time.

This study used 1 longitudinal and 2 cross-seconal population surveys to compare stability of low-rate daily smokers (less than 5 cigarettes per day) with other daily smokers and occasional smokers. Few low-rate smokers maintained consumption level; 36% retained smoking status after 20 months, compared with 82% and 44% for regular daily and occasional smokers, respectively. In a dynamic process, established smokers quit smoking and/or modified (decreased or increased) consumption. Low-rate and occasional smokers quit at higher rates than regular daily smokers (odds ratios 3:1) but were replenished by new members, many converted from regular daily smoker. The overall trend is an increasing proportion of low-consumption smokers while smoking prevalence declines. The dynamic process has implications for tobacco control efforts and for addiction theory.