Association of Smoke-Free Laws With Lower Percentages of New and Current Smokers Among Adolescents and Young Adults: An 11-Year Longitudinal Study.

IMPORTANCE Smoke-free laws are associated with a lower prevalence of smoking. OBJECTIVE To quantify the effect of 100% smoke-free laws on the smoking behavior of adolescents and young adults in a longitudinal analysis. DESIGN, SETTING, AND PARTICIPANTS Pooled logistic regression and zero-inflated negative binomial regression analysis of participants in the National Longitudinal Survey of Youth 1997 (data from 1997 to 2007), with complete data on initiation of smoking (n = 4098) and number of days respondents reported smoking in the past 30 days (n = 3913). EXPOSURES Laws for 100% smoke-free workplaces, laws for 100% smoke-free bars, and state cigarette taxes. MAIN OUTCOMES AND MEASURES Smoking initiation (first report of smoking cigarette), current (for 30 days) smoking, and number of days respondents reported smoking in the past 30 days among current smokers. RESULTS Laws for 100% smoke-free workplaces, but not bars, were associated with significantly lower odds of initiating smoking (odds ratio, 0.66 [95% CI, 0.44-0.99]). Laws for 100% smoke-free bars were associated with lower odds of being a current smoker (odds ratio, 0.80 [95% CI, 0.71-0.90]) and fewer days of smoking (incidence rate ratio, 0.85 [95% CI, 0.80-0.90]) among current smokers. Taxes were associated with a lower percentage of new smokers but not current smokers among adolescents and young adults. The effect of smoke-free workplace laws on smoking initiation is equivalent to a $1.57 (in 2007 dollars) tax increase. Smoke-free bar laws are associated with lower rates of current smoking, as well as a decrease in the number of days reported smoking among current smokers. CONCLUSIONS AND RELEVANCE Smoke-free laws are an important tobacco control tool. They not only protect bystanders from secondhand smoke but also contribute to less smoking among adolescents and young adults.