Estimated impact of a tobacco-elimination strategy on lung-cancer mortality in 185 countries: a population-based birth-cohort simulation study.

Background: The tobacco-free generation aims to prevent the sale of tobacco to people born after a specific year. We aimed to estimate the impact of eliminating tobacco smoking on lung-cancer mortality in people born during 2006-10 in 185 countries.

Methods: For this population-based birth-cohort simulation study, we proposed a scenario in which tobacco sales were banned for people born between Jan 1, 2006, and Dec 31, 2010, and in which this intervention was perfectly enforced, quantified until Dec 31, 2095. To predict future lung-cancer mortality rates, we extracted lung-cancer mortality data by sex, 5-year age group, and 5-year calendar period for countries with at least 15 years of data from the WHO Mortality Database. For countries for which mortality data were not available, we extracted data on lung-cancer incidence from the Cancer Incidence in Five Continents. To establish the number of lung-cancer deaths that could be prevented in the birth cohort if tobacco smoking was eliminated, we subtracted reported age-specific rate of deaths in people who had never smoked tobacco (hereafter referred to as never smokers) from a previous study from the expected rate of lung-cancer deaths in our birth cohort and applied this difference to the size of the population. We computed population impact fractions (PIFs), the percentage of lung-cancer deaths that could be prevented, by dividing the number of preventable lung-cancer deaths by the expected lung-cancer deaths in the birth cohort. We also aggregated expected and prevented deaths into the four World Bank income groups (ie, high-income, upper-middle-income, lower-middle-income, and low-income). The primary outcome was the impact on lung-cancer mortality of implementing a tobacco-free generation.

Findings: Our birth cohort included a total population of 650 525 800 people. Globally, we predicted that 2 951 400 lung-cancer deaths could occur in the population born during 2006-10 if lung-cancer rates continue to follow trends observed during the past 15 years. Of these deaths, 1 842 900 (62·4%) were predicted to occur in male individuals and 1 108 500 (37·6%) were expected to occur in female individuals. We estimated that 1 186 500 (40·2%) of 2 951 400 lung-cancer deaths in people born during 2006-10 could be prevented if tobacco elimination (ie, a tobacco-free generation) was achieved. We estimated that more lung-cancer deaths could be prevented in male individuals (844 200 [45·8%] of 1 842 900 deaths) than in female individuals (342 400 [30·9%] of 1 108 500 deaths). In male individuals, central and eastern Europe had the highest PIF (48 900 [74·3%] of 65 800 deaths) whereas in female individuals, western Europe had the highest PIF (56 200 [77·7%] of 72 300 deaths). Middle Africa was the region with the lowest PIF in both male individuals (180 [2·1%] of 8600 deaths) and female individuals (60 [0·9%] of 6400 deaths). In both sexes combined, PIF was 17 400 (13·5%) of 128 900 deaths in low-income countries, 104 900 (15·8%) of 662 800 deaths in lower-middle-income countries, 650 100 (43·9%) of 1 482 200 deaths in upper-middle-income countries, and 414 100 (61·1%) of 677 600 deaths in high-income countries.

Interpretation: The implementation of a tobacco-free generation could substantially reduce global lung-cancer mortality. However, data from low-income countries were scarce and our estimates should be interpreted with caution.

Funding: Spanish Society of Pneumology and Thoracic Surgery.