Air pollution emerges as a growing concern in risk factors linked to lung cancer deaths

Even though lung and related cancer deaths decreased in the world’s 10 most populous countries from 1990 to 2019, these positive statistics do not address trends in mortality linked to tobacco use, air pollution and asbestos exposure. Those areas need ongoing policy measures and research to further reduce deaths, according to a new study from researchers at Sylvester Comprehensive Cancer Center, part of the University of Miami Miller School of Medicine, and collaborating organizations.

Their study, published in eClinicalMedicine, analyzed tracheal, bronchial and lung (TBL) cancer data from the open-source Global Burden of Disease database.

The results indicated an 8% overall decrease in TBL cancer deaths over the three-decade period. While tobacco-related deaths declined, they continue to represent the majority of cases. Meanwhile, mortality linked to particulate matter air pollution has risen globally, and asbestos exposure remains a critical concern, especially in the United States.

“This research allows us to better assess global trends and highlight areas where public health policies and further research are needed to tackle TBL cancers,” said Gilberto Lopes, M.D., senior author of the study, chief of the Division of Medical Oncology at Sylvester and its associate director.

Lung cancer is the No. 1 cause of cancer-related death worldwide, according to the World Health Organization. The study’s first author, Chinmay Jani, M.D., a clinical fellow in hematology and oncology at Sylvester and the Miller School, emphasized the importance of raising awareness about all TBL cancer risk factors on a global scale.

Tobacco risk persists

The study found that the percentage of TBL cancer deaths linked to tobacco use declined from 72% in 1990 to 66% in 2019, although certain countries, such as China and Indonesia, are still experiencing rising tobacco-related cancer mortality. Moreover, the global mortality rate among women increased by 2%, though men still account for about three-quarters of tobacco-linked deaths.

These trends indicate the need to continue public health measures to reduce tobacco use, Jani said. Even though we are making headway in reducing tobacco-related lung cancer deaths, the burden remains significant, he said.

“We are going on the right path, but I feel that the final end of the tunnel is far away,” Jani added.

Air pollution linked to cancer deaths

Air pollution now accounts for almost 20% of global TBL cancer mortality.

Overall deaths linked to air pollution decreased from 1990–2019, but deaths associated directly with ambient particulate matter (PM 2.5) increased by 11%. In China, the rate was twice the global average.

Research colleague Estelamari Rodriguez, M.D., M.P.H., co-lead of the Thoracic Site Disease Group at Sylvester, called for stronger global policies to address this rising threat.

“The association between lung cancer mortality and air pollution is still controversial, but there is an increasing body of evidence that there is a connection here that needs to be paid attention to,” she said. “This paper provides further evidence that this is not an issue limited to one country; it is a global phenomenon.”

Jani also stressed the need to increase awareness in regions like India, where burning solid waste is common and public awareness of air pollution‘s risk remains low.

“The government is trying to provide the resources and facilities so that solid waste is disposed of in other ways, but public awareness is not as strong among the general population,” he said.

Asbestos remains a concern

Jani presented an earlier phase of the study in April 2024 with MDRCollab, a clinician research group, shortly after the the U.S. Environmental Protection Agency finalized a ban on asbestos—one of the top occupational risk factors for TBL cancer.

This latest analysis included a comprehensive evaluation of asbestos exposure, making it the first study to focus on granular data related to these three critical risk factors.

Despite significant progress in banning asbestos, asbestos-related TBL cancer deaths in the U.S. remain nearly double the global average.

“Even though we have banned asbestos, we need to look more into the causes of exposure,” Jani said.

Further research and enhanced screening

A key takeaway from the study is the need for continued research to better understand the mechanisms driving TBL cancer, including how various risk factors contribute to molecular changes in cancer cells.

“Understanding all these risk factors and how they are impacting the molecular alterations of lung cancer is important, because then we can have targeted, precision medicine for lung cancer patients based on the risk factors that they had,” he said.

The findings also highlighted the need for revising current screening guidelines, which are primarily focused on tobacco exposure. Rodriguez noted an alarming increase in lung cancer diagnoses in younger people, especially women with low tobacco exposure, raising concerns about the adequacy of current screening practices.

“How can we change screening approaches to be able to diagnose younger patients when they can be cured?” she asked. “Currently, young patients with a cough are rarely considered at risk for lung cancer. Their symptoms are often overlooked, even though proper screening could have detected the condition earlier.”