Background Smoking prevalence has declined considerably in recent decades. However, it still accounts for approximately 17% of deaths and over 450,000 hospital admissions annually in England. In addition, inequalities in smoking persist. Recognising the need for stricter tobacco policies, an All-Party Parliament Group recently recommended increasing the Minimum Age to Legal Access tobacco to 21(MALA21) in England. Enforced in the United States, this policy has seen a 30% reduction of smoking prevalence in the 18–21 year age group since 2019. In this research, we quantified the potential health, economic and equity impact of the tobacco MALA21 policy on the English population.

Methods We modelled two scenarios over a 50-year time horizon: a) Baseline (maintaining current policy levels and trends); and b) Enforcement of tobacco MALA21.

We used the IMPACT _HINT dynamic stochastic microsimulation. This implementation of the validated, open-source IMPACT _NCD framework was created using R v4.04 to estimate changes in smoking prevalence, tobacco-related disease burden, equity and economic impacts.

We extracted data from the Health Survey for England and high-quality meta-analysis. MALA21 effectiveness was also drawn from experience with increasing the age of sales from 16 to 18 in England.

We quantified uncertainty using a second-order Monte Carlo approach. We used probabilistic sensitivity analysis to estimate 95% uncertainty intervals and discounted net costs by 3.5% annually.

Results Compared to the baseline scenario preliminary results suggest the MALA21 policy might reduce smoking prevalence by approximately 5.1% (5.0%-5.3%) over the 50-year time horizon. The MALA21 policy could thus decrease the number of cases of cardiometabolic disease, common cancers, and chronic obstructive pulmonary disease by approximately 780,000 (480,000–990,000) case-years, with some 66,000 (58,000–78,000) fewer deaths. The biggest reductions would likely occur in the most deprived fifth (5.6% smoking prevalence reduction versus 4.2% in the most affluent fifth; 21,000 (16,000–26,000) deaths prevented versus 7,100 (4,300–10,000) in the most affluent fifth).

The MALA21 policy could thus generate healthcare and social care savings of approximately £300m (£36m-£510m), with most occurring some three decades after policy implementation.

Conclusion Our research used an innovative dynamic stochastic microsimulation specially designed for tobacco policy analysis. Our results indicate that raising the minimum age of legal tobacco access from 18 to 21 in England would likely generate significant health and economic gains and reduce smoking inequalities, especially over the mid-term. This move would also enhance/extend the near-term benefits of other tobacco policies.