Impact of UK Tobacco Control Policies on Inequalities in Youth Smoking Uptake: A Natural Experiment Study.

UK countries implemented smoke-free public places legislation and increased the legal age for tobacco purchase from 16 to 18 years between 2006 and 2008. We evaluated the immediate and long-term impacts of these UK policy changes on youth smoking uptake and inequalities therein.We studied 74 960 person-years of longitudinal data from 14 992 youths (aged 11-15 years) in annual UK household surveys between 1994 and 2016. Discrete-time event history analyses examined whether changes in rates of youth smoking transitions (initiation, experimentation, and escalation to daily smoking or quitting) or their inequalities (by parental education) were associated with policy implementation. Parallel analyses examined smoke-free legislation and the change in legal age. We interpret the results as a combined effect of the two pieces of legislation as their implementation dates were too close to identify separate effects. Models were adjusted for sex, age, UK country, historical year, tobacco taxation, and e-cigarette prevalence, with multiple imputation for missing data.For both policies, smoking initiation reduced following implementation (change in legal age odds ratio [OR]: 0.67; 95% confidence interval [CI]: 0.55 to 0.81; smoke-free legislation OR: 0.68; 95% CI: 0.56 to 0.82), while inequalities in initiation narrowed over subsequent years. The legal age change was associated with annual increases in progression from initiation to occasional smoking (OR: 1.26; 95% CI: 1.07 to 1.50) and a reduction in quitting following implementation (OR: 0.57; 95% CI: 0.35 to 0.94). Similar effects were observed for smoke-free legislation but CIs overlapped the null.Policies such as these may be highly effective in preventing and reducing socioeconomic inequalities in youth smoking initiation.UK implementation of smoke-free legislation and an increase in the legal age for tobacco purchase from 16 to 18 years were associated with an immediate reduction in smoking initiation and a narrowing of inequalities in initiation over subsequent years. While the policies were associated with reductions in the initiation, progression to occasional smoking increased and quitting decreased following the legislation.