摘要：Objectives. We studied the effect of home smoking bans on transitions in smoking behavior during emerging adulthood. Methods. We used latent transition analysis to examine movement between stages of smoking from late adolescence (ages 16–18 years) to young adulthood (ages 18–20 years) and the effect of a home smoking ban on these transitions. We used data from the Minnesota Adolescent Community Cohort study collected in 2004 to 2006. Results. Overall, we identified 4 stages of smoking: (1) never smokers, (2) experimental smokers, (3) light smokers, and (4) daily smokers. Transition probabilities varied by stage. Young adults with a home ban during late adolescence were less likely to be smokers and less likely to progress to higher use later. Furthermore, the protective effect of a home smoking ban on the prevalence of smoking behavior was evident even in the presence of parental smoking. However, this effect was less clear on transitions over time. Conclusions. In addition to protecting family members from exposure to secondhand smoke, home smoking bans appear to have the additional benefit of reducing initiation and escalation of smoking behavior among young adults. Cigarette smoking, particularly among young people, continues to be a major public health concern. Although initiation rates have declined for adolescents, initiation rates among young adults have risen. 1 Also, of all age groups, young adults have the highest prevalence of current cigarette smoking. 2 Therefore, developing effective interventions for this population is a public health priority. Young or emerging adulthood is typically defined as 18 to 25 years of age and is marked by important transitions such as increased autonomy in decision-making and fewer social constraints than during adolescence. 3 It also represents a time for increased vulnerability for both the initiation of smoking and nicotine addiction. 4 This period of emerging adulthood may be an important, yet often overlooked, age for formation of long-term health behaviors such as smoking. Relatively little research has examined transitions and trajectories of smoking behaviors among young adults. 5 Most researchers have used person-centered techniques such as growth curve and growth mixture modeling to explicitly model the heterogeneity in developmental processes and, in the process, have identified several distinct patterns of smoking trajectories from adolescence to young adulthood. 6–9 These approaches assume progression to be continuous instead of incremental (i.e., stage sequential); therefore, smoking must be modeled as a continuous function of time. Growth curves and growth mixture modeling are not as appropriate in situations characterized by a high degree of movement into and out of stages over time, which may be especially relevant to the onset and progression of smoking during emerging adulthood. 10 An alternative approach is to take a person-centered approach such as Markov models 10,11 and latent transition analysis 2 to examine person-specific patterns of developmental stages. This approach has been applied to the study of smoking behavior 2,11 but not extensively to the study of smoking behaviors in emerging adulthood. Multiple social, psychological, and environmental factors have been found to influence smoking progression and have been extensively studied as antecedents or correlates of trajectories of smoking. 6,8 Among these, home smoking bans have emerged as an important yet understudied protective factor. Although the primary goal of a home ban is to protect children and adult nonsmokers from secondhand smoke, 12 recent evidence suggests that home smoking restrictions promote antismoking attitudes and reduce initiation and progression of smoking behavior among adolescents by changing norms about the prevalence and social acceptability of smoking. 13–15 Additionally, adult smokers with a home ban are more likely to quit and remain nonsmokers. 16 As noted by Albers et al., 17 youths with a smoking ban in their parental homes are more likely to prefer smoke-free housing as independently living young adults. In essence, establishing a home ban has a long-term and even intergenerational effect on promoting nonsmoking attitudes and norms among young adults. 17 Individuals with home bans also are more likely to support clean indoor air laws, crucial to tobacco prevention efforts. 18 A recent literature review on the association between home bans and youth smoking reported reduced smoking among adolescents with a home ban. 19 As noted by Emory et al., 19 a few studies also investigated the moderating effect of parental smoking, and most studies found either an association or a stronger association between home smoking restrictions and reduced smoking in homes without parental smoking or an adult smoker. However, 2 studies found that home bans significantly lowered smoking rates, regardless of parental smoking, underscoring the salience of a home ban. 14,20 All but 2 of the studies in this review were cross-sectional, and more important, none of the studies examined the effect of a home ban on stage-sequential transitions or the effect on smoking behaviors in emerging adulthood. Therefore, despite previous important findings, relatively little is known about the prospective effect of home smoking restrictions on smoking behavior during emerging adulthood, especially in the presence of parental smoking. 19 The main goals of this study were to (1) identify distinct stages of smoking behavior and examine within-individual transitions in smoking from late adolescence (ages 16–18 years) to young adulthood (ages 18–20 years) in a population-based cohort sample and (2) evaluate whether a home smoking ban during late adolescence influences the prevalence of smoking and transitions into and out of smoking stages in young adulthood and whether the effect of a home ban differs by parental smoking status.
