摘要：Objectives. We examined the mutual effects of smoking bans and taxes on smoking among a longitudinal cohort of young adults. Methods. We combined a repository of US tobacco policies at the state and local level with the nationally representative geocoded National Longitudinal Survey of Youth 1997 (2004–2011) from ages 19 to 31 years and Census data, to examine the impact of tobacco policies on any current and daily pack smoking. The analytic sample amounts to 19 668 observations among 4341 individuals within 487 cities. Results. For current smoking, we found significant effects for comprehensive smoking bans, but not excise taxes. We also found an interaction effect, with bans being most effective in locales with no or low taxes. For daily pack smoking, we found significant effects for taxes, but limited support for bans. Conclusions. Social smoking among young adults is primarily inhibited by smoking bans, but excise taxes only deter such smoking in the absence of a ban. Heavy smokers are primarily deterred by taxes. Although both policies have an impact on young adult smoking behaviors, their dual presence does not intensify each policy’s efficacy. The denormalization of tobacco use in Western nations has led to declines in both smoking and its public acceptability. 1 Even with overall reductions in smoking, tobacco use remains the leading cause of preventable illness and death in the United States, 2 making assessment of the efficacy of particular policies on actual smoking behavior an imperative. Tobacco-control policies have been described as intensifying the process of denormalization of smoking among young people. 3 The focus on young people is much deserved, as those who begin smoking at younger ages are at higher risk for smoking, particularly heavy smoking, as adults. 4,5 The identification of policies that affect smoking behavior among young people can have long-term implications for public health as those individuals age into later life. Estimates suggest that tobacco-control policies have likely had an impact on tobacco consumption in the aggregate. 6 A wide array of research has suggested that excise taxes and clean air policies are efficacious tobacco-control policy tools, but these studies have come with several limitations that prohibit linking policy with actual individual-level behavior. For clean air policies, studies have inferred the effects of such prohibitions through cohort effects, 7 have relied on cross-sectional data, 8–10 have not considered city-level policy, 9–13 or have used data within a single locality. 14,15 Studies have also found robust effects of excise taxes on tobacco use. 10,12,13,16–29 We note, however, that most studies of excise taxes used either aggregate time-series or repeated cross-sectional data, and often at the state or national level. Thus, for both bans and taxes, the literature has yet to link policy contexts at the local level to a longitudinal data set of the same individuals over time as well as account for potential interactive effects of these policies. Even studies using the same data sets used herein have not considered the interaction between smoking bans and excise taxes. 12 The local level is critically important, yet often is overlooked in studies of both clean air policies and excise taxes. Cities led the way in enacting smoking bans in the United States, such that the diffusion of clean air regulations began at the local level and spread vertically up to the state in an unusual example of “bottom-up federalism.” 30 Chahine et al. suggested that contextual covariates play a larger role more locally, for example at the level of towns or neighborhoods. This may especially be the case for indoor smoking restrictions, which are highly variable within states.9(p757) They later suggested that future research should consider contextual variables at the local level to “fully characterize social determinants of smoking variability across populations and places.”9(p758) Furthermore, although prohibited in some states, cities in several states may levy taxes on tobacco products in addition to those imposed by the state, creating similar variability on the issue of taxation. Thus, without accounting for the city level, the policies to which an individual is subjected may be mischaracterized. In our study, we overcame the limitations of past studies by, first, combining a repository of all tobacco ordinances in the United States with a nationally representative annual survey of a single cohort of youths, allowing us to directly link a multilevel policy context to individual-level behavior over time in a manner not possible through aggregate or repeated cross-sectional data. Second, we considered the critical but underexplored policy context of the city level. Third, no studies have considered the independent and interactive effects of taxes and bans simultaneously. This is important as interaction analyses may lead to the identification of potential synergistic effects of tobacco policies. Thus, we used multilevel statistical modeling to identify the impact of these 2 important tobacco-control policies on smoking behaviors over time in a nationally representative sample of US youths.
