Using a variety Z-VAD-FMK of smoking status definitions (typically nondaily or 1�C5 CPD), existing longitudinal studies suggest that the lightest smokers are more likely than heavier smokers to either increase or decrease consumption (Hassmiller, Warner, Mendez, Levy, & Romano, 2003; Hennrikus, Jeffery, & Lando, 1996; Hyland, Rezaishiraz, Bauer, Giovino, & Cummings, 2005; Lindstrom & Isacsson, 2002; McDermott, Dobson, & Owen, 2007; Stanton, Papandonatos, Lloyd-Richardson, & Niaura, 2007; Wetter et al., 2004; Zhu, Sun, Hawkins, Pierce, & Cummins, 2003). However, these studies are of limited utility for identifying factors associated with transitions in smoking status in the U.S. context. They focus on non-U.S. populations (Lindstrom & Isacsson, 2002; McDermott et al., 2007) or narrowly defined U.S.

populations (e.g., adolescents, college students, or employees; Hennrikus et al., 1996; Stanton et al., 2007; Wetter et al., 2004), lack a prospective design (e.g., using recall of prior year’s smoking; Hassmiller et al., 2003), or do not focus on determinants of increased or decreased cigarette consumption (Hyland et al., 2005; Zhu et al., 2003). We addressed these research gaps by analyzing survey data from a recent large population-based cohort of adult smokers in Massachusetts who were interviewed three times over a 4-year follow-up period. We disaggregated smokers into four groups by consumption (CPD) and frequency (daily vs. nondaily smoking), examined changes in smoking status over time in each of these groups, and identified factors associated with progression to heavier smoking and to quitting or reduction for different groups of light smokers (defined in this study as smoking ��10 CPD).

Methods Sample A probability-sample random-digit�Cdialed survey was administered to residents of Massachusetts in 2001�C2002 to study smoking practices, attitudes, and support for tobacco control policies in the state. The survey oversampled smokers, young adults, and recent quitters to ensure adequate power to study those subpopulations. Professional interviewers from the University of Massachusetts�CBoston Center for Survey Research attempted to interview one systematically selected adult aged at least 18 years in each eligible household identified through an initial screening interview with an adult household resident.

They successfully screened 66% of sampled households and interviewed 70% of selected adults for a final sample size at baseline of 6,739. All 3,083 respondents who indicated at baseline that they had smoked at least 100 cigarettes in their lives and currently smoked every day or some days were contacted again 2 and 4 years later. Of the Drug_discovery baseline smokers, 1,726 (56.0%) completed follow-up interviews in 2003�C2004 and 1,319 (42.8%) completed interviews in 2005�C2006.