Accelerating tobacco decline could boost global life expectancy

The LancetOct 3 2024

Accelerating the decline in tobacco smoking globally, by decreasing smoking prevalence from current levels to 5% everywhere, could increase life expectancy and prevent millions of premature deaths by 2050, according to a study from the Global Burden of Disease, Injuries and Risk Factors (GBD) Tobacco Forecasting Collaborators published in The Lancet Public Health journal.

The analysis suggests speeding up progress toward ending smoking could deliver substantial population health benefits over the next three decades. 

Findings from the study suggest that, based on current trends, global life expectancy will likely rise to 78.3 years by 2050 – up from 73.6 years in 2022. However, if tobacco smoking were to gradually decline from current levels to a rate of 5% in 2050, this would result in one year of additional life expectancy in males and 0.2 years in females. In a scenario where tobacco smoking was eliminated from 2023 onwards, this could result in up to 1.5 additional years of life expectancy among males and 0.4 years among females in 2050. In both scenarios, millions of premature deaths would also be avoided. 

Smoking is a leading risk factor for preventable death and ill health globally, accounting for more than one in ten deaths in 2021. While rates of smoking have fallen substantially over the past three decades, the pace of decline varies and has slowed in many countries. Cancers, ischemic heart disease, and chronic obstructive pulmonary disease (COPD) are-;and will continue to be-;the leading causes of premature deaths from smoking. Together, these conditions account for 85% of potentially avoidable years of life lost (YLLs)-;a measure of premature deaths.

Several countries have set ambitious goals to reduce smoking rates to below 5% in the coming years. However, there is still significant opportunity to expand and strengthen proven policies and interventions to achieve these targets.

We must not lose momentum in efforts to reduce, and ultimately eliminate, smoking around the world. Our findings highlight that millions of premature deaths could be avoided by bringing an end to smoking."

Professor Stein Emil Vollset, senior author, Institute for Health Metrics and Evaluation (IHME)

The authors produced estimates using IHME's Future Health Scenarios platform, which uses data from the GBD study. The new analysis provides in-depth forecasts of the health burden for 204 countries, broken down by age and sex, from 2022 until 2050. It is the first study to comprehensively forecast the health impacts due to smoking for all countries and all causes, as well as on 365 diseases and injuries. The main measure studied was YLLs, a measure of premature deaths, counting each death by the remaining life expectancy at the age of death. For example, if the ideal life expectancy is 91 years, and someone dies at age 50, that would result in 41 YLLs. This is because they lost 41 years that they could have potentially lived.

Life expectancy at birth and YLLs were evaluated under three future scenarios. As well as modeling a most likely future scenario based on current trends, the authors estimated the impact of two alternative scenarios: one assumed countries steadily reduce smoking levels among their populations to 5%; the other modeled future health impacts had smoking been eliminated globally in 2023. Taking the difference between the reference and the Tobacco Smoking Elimination as of 2023 scenario allowed researchers to measure the total future health burden that could be theoretically avoided with intervention. 

The platform enabled researchers to forecast unique populations for each scenario, allowing them to account for changing population dynamics across the scenarios.

Between 1990 and 2022, age-standardized smoking rates among males aged 10 years and older fell from 40.8% to 28.5%. In the same period, smoking in females aged 10 years and older declined from 9.94% to 5.96%. 

Based on current trends, the estimates indicate smoking rates will continue to decline, albeit at a slower pace than over the past three decades. In 2050, it is estimated that, after adjusting for age, 21.1% of males and 4.18% of females will smoke, with considerable regional variation – for males, ranging from 3.18% in Brazil to 63.2% in Micronesia, and for females ranging from 0.5% in Nigeria to 38.5% in Serbia.

However, the findings indicate that accelerating efforts to eliminate smoking could result in fewer premature deaths. 

In the scenario in which countries reduce smoking rates to 5% by 2050, there would be 876 million fewer YLLs compared to the most likely future scenario. Life expectancy in 2050 would be 77.1 years in males and 80.8 years in females. The greatest gains in life expectancy among males would be in East Asia, Central Asia, and Southeast Asia, with between 1.2 and 1.8 extra years of life gained. Among females, life expectancy would increase the most in East Asia, High-income North America and Oceania, with between 0.3 and 0.5 additional years gained. 

For the scenario in which smoking ended globally in 2023, the estimates indicate a maximum of 2.04 billion YLLs could be avoided by 2050 compared to the most likely future scenario, and life expectancy in 2050 would be higher still, at 77.6 years for male and 81 years for female. 

The authors acknowledge some limitations to their study. Only the direct effects of reductions in tobacco smoking on health were estimated, meaning overall health benefits may be underestimated as the impact of associated reductions in second-hand smoke exposure was not analyzed. The analysis did not account for the possible health effects of e-cigarettes. The estimates also could not account for potential future accelerations in healthcare improvements, such as in improved lung cancer detection or treatment.