Impact of smoking reduction scenarios on the burden of myocardial infarction in the French population by 2035

Myocardial infarction is a major burden for public health in France: it is one of the main cardiovascular diseases that together represent the second leading cause of death in France. Myocardial infarction is responsible for more than 70,000 hospitalisations per year in France. Tobacco is one of the main risk factors for this disease, and the quality that sets apart the cardiovascular impact in smokers is that it is immediate, while cancers may take several years of exposure to develop. In addition, cardiovascular risk is reduced as soon as the individual stops smoking. These two factors make myocardial infarction a good model for studying the impact of smoking reduction scenarios in France.

In this work, we modelled four smoking reduction scenarios based on the proportion of smokers aged 18–75 in the French population between 2024 and 2035. The first scenario, known as the standard scenario, uses the current trend of smoking reduction in France, which is that the proportion of smokers falls by 1% per year. The second scenario simulates double the current reduction in smokers, i.e. 2% per year. The third scenario applies one of the preliminary objectives of the National Tobacco Control Plan (PNLT), which targets 22% of the population being smokers by 2027, equating to a 10% reduction per year. Finally, the fourth scenario simulates a total cessation of tobacco consumption from 2024, i.e. the proportion of smokers being 0% from that year. The data supporting these different scenarios are taken from the French National Health Data System (SNDS), the 2021 Santé publique France Health Barometer and INSEE.

The implementation of scenario 3 would mean that 45,000 myocardial infarctions could be prevented by 2035, of which more than 60% in the under-65 age group, as well as 4,500 deaths due to myocardial infarction and 265,000 deaths from all causes. The second scenario, which is less ambitious in terms of reducing the prevalence of smoking, would enable a significant gain compared to maintaining the current trend, but the impact would be smaller than in scenario 3: 6,800 fewer myocardial infarctions, 640 fewer myocardial infarction deaths and 40,000 deaths from all causes avoided.

Finally, a theoretical scenario of complete cessation of smoking in France in 2024, used to estimate the maximum gain, would mean that 103,000 myocardial infarctions, 12,800 deaths from myocardial infarction and 653,000 deaths from all causes could be prevented in 2035. Beyond the impact on the number of cases and deaths, a reduction in the prevalence of smoking in the population would result in the average age of disease onset being delayed by between 2.8 and 4.1 years in men and between 1.1 and 2.0 years in women. These results confirm the relevance of ambitious quantitative targets for reducing smoking.

Our work has shown that without any prevention scenario the prevalence of myocardial infarction in France will increase significantly by 2035. This projected increase is linked to several factors that are both demographic, with the inevitable ageing of the population, and epidemiological, with the prevalence of cardiovascular risk factors remaining high in France.

It is estimated that nearly half of the increase in the prevalence of myocardial infarction by 2035 is linked to population ageing alone. INSEE data show that in 2050 in France, people aged 60 and over will account for one third of the population, against one fifth in 2005.

Prevention takes on a major importance in this context, as it also does for chronic diseases more broadly. The risk factors with the highest share of cardiovascular events attributable to them are smoking, cholesterol, diabetes and hypertension. These four risk factors can be modified through behaviour changes. While smoking is currently the target of active and regular prevention campaigns which have been demonstrated to be effective, the other three risk factors remain at a very high level in the population (30% of adults have hypertension, 7.4% of adults have diabetes and 23.3% of adults have LDL hypercholesterolaemia), and a significant proportion of people have not been screened (45% for hypertension, 23% for diabetes and 43% for high LDL cholesterol) (3-5). Improving screening for hypertension, diabetes and hypercholesterolaemia, as well as running nutrition campaigns, are of greater priority than ever if we are to reverse these trends.

The multiple-state model used for myocardial infarction can be applied to other cardiovascular or chronic diseases as long as appropriate hypotheses are formulated for each disease targeted.

Applying the model to all tobacco-related diseases would quantify the overall gain that could be expected from smoking prevention.

It is also possible to consider using these models for other risk factors or combining several risk factors. However, we need to bear in mind that these models are complex and many hypotheses need to be formulated for them to work. They are also very costly in terms of calculation time.

As well as simulating prevention scenarios, the advantage of these models is that they show the major impact of ageing on the prevalence of cardiovascular diseases by considering the population age structure projections provided by INSEE in the modelling. Given the significance of the influence of demographics on the projected prevalence trend, our results highlight the need to adapt the healthcare system to anticipate treating rising patient numbers. These adaptations would be required not only during the acute hospital admission phase, but also in the management of the chronic phase. This means cardiac rehabilitation followed by the delivery of secondary and tertiary prevention and therapeutic patient education on the return home.

Beyond cardiovascular diseases, population ageing has an impact on all age-related chronic diseases. Our findings about the need for more active prevention and adaptation of the care system apply to all chronic diseases.