Associations between tobacco 21 and state flavour restrictions with young adult tobacco use.

Background: States have recently enacted tobacco-related age and flavour restrictions in addition to federal T21 laws. Little is known about the independent effects of these policies on young adult tobacco use.

Methods: Linking 2011-2022 Behavioural Risk Factor Surveillance System data on 2 696 870, 18-59 years from 50 states and DC with policy data, we conducted probit regression models to evaluate the associations between state and federal T21 laws and state flavour restrictions with cigarettes, electronic nicotine delivery system (ENDS) and smokeless tobacco use. Models were adjusted for sociodemographics, additional tobacco policies, COVID-19-related factors, year and state. We tested two-way and three-way interactions between age, state T21 and federal T21 laws.

Results: Although we did not find evidence that state T21 laws were associated with cigarette, smokeless tobacco or ENDS use overall, the federal T21 law was associated with lower use of all three tobacco products by 0.39-0.92 percentage points. State flavour restrictions were associated with lower use of cigarettes by 0.68 (-1.27 to -0.09) and ENDS by 0.56 (-1.11 to -0.00) percentage points, but not with smokeless tobacco. A three-way interaction revealed that state and federal T21 laws together were associated with a lower prevalence of ENDS use among 18-20 years, but there were no differences in cigarette use from both policies combined versus either alone.

Conclusion: State and federal T21 laws are broadly effective at reducing adult tobacco use, while state flavour restrictions specifically lower use of cigarettes and ENDS.