Researchers reveal that while stricter air quality policies are cutting pollution-related cancer deaths in the U.S., Japan, and South Korea, China’s persistently high rates and global aging trends mean the worldwide burden is projected to climb.
Study: PM2.5-Related Burden of Tracheal, Bronchial, and Lung Cancer in China, the United States, Japan, and South Korea (1990–2021). Image credit: oneinchpunch/Shutterstock.com
A recent study in the International Journal of Public Health evaluated the tracheal, bronchial, and lung (TBL) cancer burden associated with fine particulate matter (PM2.5) pollution in many countries.
Air pollution and its impact on public health
Rapid global industrialization has significantly impacted the economy and substantially increased air pollution, primarily driven by industrial activities, such as fossil fuel combustion in transportation, agricultural production, and construction. This increase in air pollution has significantly impacted public health worldwide.
According to previous research, air pollution is linked with approximately seven million premature deaths annually. It also contributes to over 3% of the global disability-adjusted life years (DALYs) lost.
PM comprises naturally occurring or human-made components like dust, ash, and soot. PM can induce systemic inflammation and trigger epigenetic alterations, increasing the risk of various diseases.
Due to its small size, PM2.5 can remain in the air for a prolonged period and penetrate deep into the lungs. PM2.5 includes ambient particulate matter pollution (APM) from vehicle exhaust, industrial emissions, and construction activities. It may also emerge from the incomplete combustion of solid fuels used in households. Previous studies have associated PM2.5 exposure with the development and progression of TBL cancers.
The United States, China, Japan, and South Korea are four major global economies with distinct environmental policies, urbanization patterns, and industrialization trends. A previous study highlighted a connection between the economic development of these countries and a significant increase in disease burdens attributable to PM2.5 exposure, including those related to TBL. Therefore, it is essential to understand the disease burden incurred by PM2.5.
About the study
The current study assessed the DALY and mortality burdens of TBL cancers associated with PM2.5 exposure from 1990 to 2021 using the Global Burden of Disease (GBD) 2021 study data. GBD provides detailed epidemiological estimates for 371 diseases and injuries across 204 countries and territories, stratified by age and sex. DisMod-MR 2.1, a Bayesian meta-regression tool, was used to evaluate the risk of bias for each data source.
The trends in mortality and DALY burdens of TBL cancers linked to APM pollution between 1990 and 2021 were assessed using joinpoint regression analysis. The effect of age, period, and cohort on health outcomes was predicted using the Age-period-cohort model.
Study findings
In comparison to Japan, South Korea, and the United States, China demonstrated a significantly higher age-standardized mortality rate (ASMR) of TBL cancer between 1990 and 2021, which has been linked with PM2.5 exposure. A declining global trend in the ASMR of TBL cancer attributable to PM2.5 exposure was found with the AAPC of −1.2811. Similar downward trends were also seen in the age-standardized DALY rate (ASDR), reflecting reductions not only in deaths, but also in years of healthy life lost.
In line with the global trend, China, Japan, South Korea, and the US also indicated downward trajectories in the ASMR of TBL cancer linked to PM2.5 exposure. No significant difference in the effect of PM2.5 exposure was observed between males and females.
A steady trend was observed in the global ASMR of TBL cancer attributable to exposure to household air pollution from solid fuels (HAP). However, the ASMR for females increased with an AAPC of 1.1691, while males revealed a decreasing trend with an AAPC of −0.3264.
A considerable variation in the ASMR of TBL cancer attributable to HAP exposure was observed. In China, an increase in the ASMR of TBL cancer attributable to HAP was estimated between 1990 and 2015, followed by a decrease from 2016 to 2020, which again rose after 2020 with an overall AAPC of 3.3234. In contrast, South Korea, Japan, and the United States exhibited a consistent decline in HAP-related mortality rates.
Globally, the ASMR of TBL cancer attributable to APM exposure showed a generally declining or stable trend. In China, the ASMR was consistently higher than the global average but followed a downward trajectory rather than an increase. Similarly, the ASMR of TBL cancer attributable to PM2.5 exposure in China was significantly higher than the global average. There was no significant difference in these trends between males and females.
A decreasing trend in the mortality burden of TBL cancer attributable to PM2.5 was observed across all age groups in China and the United States. In Japan and South Korea, the mortality burden of TBL cancer attributable to HAP exposure decreased among younger age groups but increased among older age groups. In contrast, TBL cancer linked to APM exposure exhibited a decrease across all age groups in China, the United States, Japan, and South Korea.
A Bayesian age-period-cohort (BAPC) analysis projected an increasing trend in the global ASMR of TBL cancer attributable to PM2.5 and HAP exposure over the next 29 years. However, the study noted that while the global average is expected to rise, China, South Korea, and the United States are projected to experience significant decreases, and Japan’s trend is anticipated to remain relatively stable.
Download your PDF copy now!
Conclusions
The findings indicate the importance of controlling air pollution to reduce the disease burden of TBL cancers attributable to PM2.5 exposure. Although some countries exhibited a decreasing trend in mortality rates due to TBL cancers from PM2.5 exposure, recent findings have also predicted a global increase in mortality rates over the next 29 years.
The authors further emphasized the influence of factors such as population aging, rural-urban differences in energy use, and the interaction between PM2.5 exposure and smoking in shaping future disease burdens.
Considering these predictions, stronger international collaboration, targeted interventions, and enhanced governance strategies are imperative to reduce global mortality rates. Policymakers must adapt policies to strengthen health systems and protect vulnerable populations.
Lung tumors rewire immune cells in the bone marrow before they reach cancer sites