The Global, Regional, and National Burden of Tracheal, Bronchus, and Lung Cancer Caused by Smoking: An Analysis Based on the Global Burden of Disease Study 2021

Introduction

Tracheal, bronchus, and lung (TBL) cancer represent a significant global public health challenge. In 2022, lung cancer accounted for 12.4% of all global cancer cases and 18.7% of cancer‑related deaths, ranking first in both categories [1]. Clinically, the majority of patients are diagnosed with lung cancer at an advanced stage, with an overall 5‑year survival rate of only about 20% [2]. In 2017, the financial burden of lung cancer in China was estimated at 25.069 billion US dollars (USD), and it is projected that by 2030, this economic burden will rise to 53.4 billion USD, requiring greater social resources [3]. Smoking is the primary risk factor for lung cancer, and the variation in lung cancer incidence largely reflects differences in smoking patterns. In some countries, tobacco control policies have effectively reduced lung cancer incidence [4, 5]. Cohort studies have shown that the risk of lung cancer incidence and mortality is significantly lower in non‑smokers compared with smokers [6]. Therefore, systematically understanding the epidemiological trends of smoking‑induced TBL cancer can help policymakers develop targeted strategies. While previous studies have analyzed lung cancer attributable to ambient fine particulate matter pollution and historical global epidemiological patterns of TBL cancer [7–9], there remains a lack of updated global data on smoking‑related TBL cancer.

The Global Burden of Disease (GBD) Study 2021 includes data on the incidence, mortality, and disability‑adjusted life‑years (DALYs) for 371 diseases and injuries across 204 countries and 811 regions from 1990 to 2021, along with 88 associated risk factors [10, 11]. In 2021, the risk factors for TBL cancer included environmental, behavioral, and metabolic factors, with smoking accounting for 58.89% of age‑standardized lung cancer mortality, surpassing the combined contribution of other risk factors (Supplementary Figure 1). This study, based on GBD 2021 data, analyzes the burden of smoking‑induced TBL cancer by gender, age, region, country, and sociodemographic index (SDI), aiming to provide insights for developing effective prevention and control strategies.

Methods

Results

Regional deaths and DALYs

At the regional level, in 2021, the top three regions with the highest number of smoking‑attributable TBL cancer deaths were East Asia (529,329.30), Western Europe (148,841.48), and high‑income North America (116,171.00). The region with the highest ASMR was East Asia (24.15/100,000). From 1990 to 2021, only two regions, East Asia (EAPC: 0.39) and Western Sub‑Saharan Africa (EAPC: 0.17), experienced a positive EAPC in ASMR, indicating an overall increasing trend in smoking‑related TBL cancer mortality rates, with the largest increase in East Asia. In contrast, the other 19 GBD regions showed a negative EAPC for ASMR, reflecting an overall decreasing trend. Central Latin America had the steepest decline in ASMR, with an EAPC of −3.08, followed by high‑income North America and Australasia. Additionally, in 2021, the ASMR for smoking‑related TBL cancer in men was significantly higher than in women across all regions, with the highest ASMR in men observed in East Asia and the highest in women in high‑income North America (Supplementary Table 1, Figures 1A and 2A).

Figure 1

Figure 2

Similarly, in 2021, the highest DALYs attributable to smoking‑related TBL cancer were observed in East Asia (12,198,631.52). Central Europe had the highest ASDR (608.12/100,000), followed by East Asia (538.21/100,000) and high‑income North America (390.40/100,000). From 1990 to 2021, East Asia showed the largest increase in ASDR (EAPC: 0.07). Except for East Asia and Western Sub‑Saharan Africa, all other regions exhibited a declining trend in ASDR. The largest decline occurred in Central Latin America (EAPC: −3.19). Notably, in 2021, the ASDR for smoking‑related TBL cancer in men was significantly higher than in women across all regions, with the highest male ASDR in Central Europe and the highest female ASDR in high‑income North America (Supplementary Table 1, Figures 1B and 2B).

National deaths and DALYs

At the national level, in 2021, the countries with the highest number of smoking‑attributable TBL cancer deaths were China (518,796.30), followed by the United States of America (103,752.30) and Japan (49,851.35). The countries with the highest ASMRs were Greenland (43.76/100,000), Monaco (39.42/100,000), and Montenegro (34.29/100,000). Between 1990 and 2021, 46 countries experienced an overall increase in smoking‑related TBL cancer ASMR, while 157 countries saw a decrease. The largest increase in ASMR was observed in Egypt (EAPC: 4.15), Lesotho (EAPC: 2.97), and Georgia (EAPC: 1.49). Conversely, the countries with the largest decreases in ASMR were Mexico (EAPC: −4.27), Kazakhstan (EAPC: −3.49), and Singapore (EAPC: −3.35). Notably, the ASMR for smoking‑related TBL cancer in the Democratic People’s Republic of Korea remained stable, with no significant upward or downward trend (Supplementary Table 2, Figure 3A).

Figure 3

In 2021, the countries with the highest smoking‑related TBL cancer DALYs were China (11,942,343.33), the United States of America (2,274,968.50), and the Russian Federation (931,684.96). Similar to ASMR, the countries with the highest ASDRs were Greenland (1,066.51/100,000), Monaco (972.73/100,000), and Montenegro (889.64/100,000). Between 1990 and 2021, ASDRs increased in 36 countries and decreased in 166. Egypt had the largest increase in ASDR (EAPC: 3.65), followed by Lesotho (EAPC: 3.25) and Guinea‑Bissau (EAPC: 1.33). In contrast, the largest decreases in ASDR were in Mexico (EAPC: −4.39), Kazakhstan (EAPC: −3.85), and Singapore (EAPC: −3.70). It is noteworthy that the ASDR for smoking‑related TBL cancer in the Democratic People’s Republic of Korea and Timor‑Leste remained stable, showing no significant change (Supplementary Table 2, Figure 3B).

Burden of smoking‑induced TBL cancer based on SDI

At the SDI regional level, in 2021, the High‑middle SDI region recorded the highest smoking‑induced TBL cancer deaths (414,797.64) and DALYs (9,802,635.50). This was followed by the middle SDI and high SDI regions. Similarly, the high‑middle SDI region also had the highest ASMR (20.56/100,000) and ASDR (486.63/100,000). Additionally, from 1990 to 2021, ASMR and ASDR of smoking‑induced TBL cancer in all five SDI regions showed varying degrees of decline, with the high SDI region exhibiting the most significant decrease. The EAPC for ASMR and ASDR in this region was −1.73 and −2.05, respectively. Notably, the ASMR and ASDR for females in the high SDI region consistently remained higher than in the other four SDI regions, while males in the high‑middle SDI region also had higher ASMR and ASDR compared with other SDI regions. Furthermore, between 1990 and 2021, the decline in ASMR and ASDR for males in both the high‑middle and high SDI regions was significantly greater than that for females (Supplementary Table 1, Supplementary Figure 2).

Between 1990 and 2021, a negative correlation was observed between ASMR and ASDR of smoking‑induced TBL cancer and SDI levels, except in East Asia, in regions with medium and high SDI levels. In regions with low SDI levels, changes in SDI did not significantly impact ASMR and ASDR. At the national level, in 2021, there was a positive correlation between smoking‑induced TBL cancer ASMR and SDI. ASDR exhibited a positive correlation with SDI at low and medium SDI levels, while in regions with high SDI levels, it gradually decreased with increasing SDI. Moreover, the ASMR and ASDR in low SDI regions were generally lower than in high SDI regions. From 1990 to 2021, there was a negative correlation between EAPC of ASMR and ASDR and SDI, a relationship that became more pronounced when SDI exceeded 0.5, with EAPC increasingly tending toward negative values as SDI increased (Figures 4, 5, 6).

Figure 4

Figure 5

Figure 6

Burden of smoking‑induced TBL cancer based on age and sex

In 2021, the highest number of smoking‑induced TBL cancer deaths occurred in both men and women aged 70–74. Before age 74, the number of deaths increased with age for both sexes, but after 74, the number of deaths decreased as age increased. There was a positive correlation between age‑specific mortality rate and age in women, while for men, the age‑specific mortality rate peaked at 85–89 years and then gradually declined. The majority of DALYs due to smoking‑induced TBL cancer were observed in the 65–69 age group. The age‑specific DALY rate for both men and women increased with age until 74, after which it showed a negative correlation with age. Additionally, the age‑specific DALY rate in women showed little variation after age 80. It is noteworthy that at all age groups, the age‑specific mortality rate and age‑specific DALY rate for men were higher than those for women, and no smoking‑induced TBL cancer deaths or DALYs were observed in individuals under 30 (Figure 7).

Figure 7

Discussion

This study, utilizing the latest GBD 2021 data, analyzed the epidemiological trends of smoking‑induced TBL cancer at global, regional, and national levels, revealing significant changes in the disease burden compared to 1990. In 2021, 58.89% of TBL cancer deaths were attributable to smoking, far surpassing the contribution of other risk factors such as particulate matter pollution, occupational carcinogens, and high fasting plasma glucose. From 1990 to 2021, global deaths and DALYs attributable to smoking‑induced TBL cancer increased significantly, which may be associated with global population growth and the intensification of population aging [21]. The expansion of the global population tends to increase the absolute number of cancer cases and deaths, adding pressure on healthcare systems [22]. The growing elderly population is more prone to immune decline, further increasing the risk of cancer [23]. However, ASMR and ASDR have shown a declining trend, possibly owing to advancements in medical technology and the implementation of more robust tobacco control policies. Additionally, the signing of the WHO Framework Convention on Tobacco Control in 2003, along with the increased public media campaigns highlighting the harms of smoking, have contributed to reducing tobacco use and alleviating the global burden of smoking‑related TBL cancer [24, 25]. Smoking cessation after TBL cancer diagnosis also plays a crucial role in improving both overall and progression‑free survival. Recent studies have shown that smoking cessation at any stage of lung cancer can significantly reduce treatment complications, improve immune responses, and enhance the efficacy of chemotherapeutic and immunotherapeutic agents [26]. This underscores the critical role of cessation programs in the overall management of smoking‑induced TBL cancer.

The burden of smoking‑induced TBL cancer varies significantly across different regions and countries. From 1990 to 2021, ASMR and ASDR increased only in East Asia and Western Sub‑Saharan Africa, while declining in 19 other regions. This disparity may be attributed to differences in tobacco control measures and the timeline of smoking prevalence across regions. In contrast to regions like Europe and North America, East Asia’s early tobacco control efforts were insufficient, and many countries only implemented stringent policies in the last decade. Additionally, rapid economic development in the region has led to lifestyle changes, with smoking often regarded as a symbol of social status, contributing to the rise in smoking rates [27]. In Western Sub‑Saharan Africa, economic development over the past 30 years has expanded the tobacco market, with tobacco companies targeting low‑income populations with affordable products [28]. Public health policies remain relatively weak, and there is insufficient awareness of the dangers of smoking [29]. Combined with limited healthcare resources, where the focus is predominantly on maternal health and infectious diseases, cancer prevention and management are often neglected, leading to increasing ASMR and ASDR in this region [30]. Moreover, in some low‑income regions, cultural norms and economic dependence on tobacco farming complicate the implementation of comprehensive anti‑smoking campaigns, further exacerbating the public health challenge.

In contrast, regions such as Western Europe, North America, and Australia implemented effective tobacco control measures early on, imposed heavy taxes on tobacco, and benefited from abundant healthcare resources, resulting in a decline in ASMR and ASDR. Australia’s plain packaging legislation and strict tobacco advertising restrictions have significantly reduced smoking prevalence, serving as a global model for tobacco control policies [31]. Similarly, North America’s integration of public health initiatives with educational programs has strengthened the effectiveness of anti‑smoking campaigns [32].

In 2021, among the top 10 countries with the highest ASMR for smoking‑induced TBL cancer, China ranked 9th, while 8 of the top 10 were European countries, most of which were located in Eastern Europe or the Balkans. These European countries have a deep‑rooted smoking culture, where smoking remains socially acceptable, especially in social interactions [33]. Although tobacco control measures, such as restrictions on smoking advertisements and enhanced public smoking bans, have been implemented in recent years, these policies were introduced later and with less intensity compared to countries in North America and Western Europe [22, 34]. Furthermore, these countries face significant gaps in early cancer screening and diagnosis [35]. Tobacco taxes in these nations are relatively low, making smoking economically feasible. In China, despite strengthened tobacco control measures in recent years, enforcement remains relatively weak compared with other countries, particularly in rural areas, and there is an imbalance in the distribution of healthcare resources between urban and rural regions [36]. The large number of smokers over the past decades is now entering the high‑risk age for TBL cancer [37]. This highlights the urgent need for expanding healthcare infrastructure and ensuring equitable access to smoking cessation services and cancer screening programs in rural regions.

Most cancers exhibit significant sociodemographic disparities [38]. In 2021, the high‑middle SDI region had the highest ASMR and ASDR for smoking‑induced TBL cancer. A possible explanation is the historically high smoking rates in high‑middle SDI regions (such as parts of South America, Eastern Europe, and East Asia) during the mid to late 20th century, combined with the long latency period of smoking‑induced TBL cancer, which could have led to the current peak in ASMR and ASDR. Additionally, these regions often face significant wealth disparities, where lower‑income populations have greater access to tobacco and limited access to early disease screening and quality healthcare services [22, 39]. From 1990 to 2021, the high SDI region showed the most significant decline in ASMR and ASDR, attributed to the widespread establishment of smoking cessation services in many developed countries, offering counseling, pharmacotherapy, and online support [40]. There is also a focus on youth through school education and strict regulations on tobacco purchasing age and sales channels, limiting the influx of new smokers [41]. Furthermore, comprehensive cancer screening, prevention programs, and advancements in cancer treatment have further reduced the burden of smoking‑induced TBL cancer in these regions [42].

In 2021, deaths and DALYs from smoking‑induced TBL cancer were predominantly concentrated among middle‑aged and elderly populations. This is likely due to the cumulative nature of lung mutations and DNA damage caused by smoking, which reach their peak in middle to older age. Additionally, the immune system and repair mechanisms in older individuals tend to weaken, often accompanied by other chronic conditions [43]. Many patients do not undergo health screenings until they retire in middle or old age, by which point the disease has often progressed to a late stage, with more rapid malignant development [44]. Furthermore, the ASMR and ASDR for smoking‑induced TBL cancer have consistently been higher in men than in women, which could be attributed to the historically higher smoking rates among men. Smoking among men is more socially accepted, while women face more societal restrictions regarding smoking [45]. However, in certain regions, rising smoking rates among women and young adults necessitate targeted prevention strategies, particularly through culturally sensitive public health campaigns.

The implementation of lung cancer screening programs, particularly those utilizing low‑dose computed tomography (LDCT), has shown promise in reducing mortality rates by facilitating early detection [46]. For instance, the United States of America initiated the National Lung Screening Trial (NLST), which demonstrated a 20% reduction in lung cancer mortality among high‑risk populations undergoing LDCT screening compared with chest radiography. Similarly, European countries have launched pilot programs to assess the feasibility and effectiveness of LDCT screening [47]. However, the adoption of such programs varies globally, with low‑ and middle‑income countries facing challenges related to resource allocation, infrastructure, and accessibility.

This study provides an updated global and regional burden analysis of smoking‑induced TBL cancer. It examines epidemiological trends based on age, gender, geography, and SDI levels. The findings offer valuable insights for governments and public health organizations to implement more targeted policies and interventions, such as strengthening anti‑smoking legislation (e.g., higher tobacco taxes and stricter advertising restrictions), increasing public awareness campaigns about the dangers of smoking, and expanding access to smoking cessation programs [48]. In addition, prioritizing equitable access to healthcare services, particularly in low‑ and middle‑income countries, and fostering international collaborations to share successful tobacco control models could further alleviate the burden of smoking‑induced TBL cancer globally. These measures can help optimize the allocation of healthcare resources, promote regional collaboration and assistance, and ultimately minimize the future burden of smoking‑related TBL cancer.

This study has certain limitations. First, it relies on public health data collected by GBD 2021 from various countries, and in some regions, the data collection may be incomplete or inaccurate due to inadequacies in healthcare systems, potentially introducing bias in the burden analysis. Second, GBD data does not cover all regions and racial groups globally, summarizing only specific areas. Third, changes in smoking exposure will have a delayed effect on TBL cancer incidence, and therefore, there will be a lag before any recently introduced interventions, such as tobacco control legislation, affect outcomes. The medium‑ to long‑term success of these policies may not yet be reflected in the current burden data. Finally, smoking‑related data often come from subjective patient reports, which may lead to an underestimation or overestimation of the disease burden.

Conclusions

Despite the decline in the burden of smoking‑induced TBL cancer over the past 30 years, it remains a significant global health risk and challenge. Therefore, it is essential to implement more targeted tobacco control policies and public health interventions based on the geographical, age, and population distribution of the disease. Efforts should focus on enhancing public health education campaigns, raising awareness of early cancer screening, and strengthening early detection practices among the population to mitigate the future societal impact of smoking‑induced TBL cancer.

Author Contributions

Conceived and designed the analysis: PH Zeng, HY Jian, and SQ Chen; collected the data: JT Zhang and JC Tang; contributed data or analysis tools: RY Yang; wrote the paper: JT Zhang and JC Tang. The authors read and approved the final manuscript.

Data Availability Statement

The validation dataset was available on request. Further information can be directed to the corresponding author. The data used for these analyses are all publicly available at https://ghdx.healthdata.org/gbd-2021.

Funding

This study was supported by the National Natural Science Foundation of China (82074425), the Natural Foundation of Hunan Province (2023JJ30364 and 2023JJ30361), Hunan Provincial Key R&D Program (2023SK2057), the Key Project of Hunan Provincial Administration of Traditional Chinese Medicine (A2023042), Hunan Provincial Graduate Research and Innovation Project (CX20230835), Health Research Projects in Hunan Province (20232605), Major Scientific Research Special Project for High-level Talents in Hunan Province Health and Wellness (R2023081), Clinical Research Center for Integrating Chinese and Western Medicine to Prevent and Control Tumors (Letter of Hunan Traditional Chinese Medicine (2022) No. 93), the Hunan Provincial Health Commission Traditional Chinese Medicine Shennong Leading Talent Project, and the Hunan Province Science and Technology Top Leading Talent Project.

Ethics Approval Statement

The GBD study data followed the guidelines for Accurate and Transparent Health Estimation Reporting for Population Health Research (GATHER). This is an observational study. No ethical approval is required.

Competing Interests

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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