0 
0 
Research presented at the ATS 2024 International Conference shows that former smokers who switch to e-cigarettes may face a higher lung cancer risk than those who don’t vape. The study, involving over four million individuals, found increased risks of lung cancer and related deaths among e-cigarette users, particularly among those who had quit smoking five or more years prior.
A significant study finds that ex-smokers using e-cigarettes have a higher risk of lung cancer and mortality compared to non-users, emphasizing the dangers of vaping as a smoking cessation tool.
Research published at the ATS 2024 International Conference has found that former cigarette smokers who use e-cigarettes or vaping devices may be at higher risk for lung cancer than those who don’t vape.
“This is the first large population-based study to demonstrate the increased risk of lung cancer in e-cigarette users after smoking cessation,” said corresponding author Yeon Wook Kim, MD, assistant professor, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
E-cigarettes have become increasingly popular worldwide as a substitute for traditional cigarette smoking, with many smokers using them as an aid to quit smoking. Despite this trend, the long-term effects of vaping remain poorly understood, and there is a lack of epidemiological evidence linking e-cigarette use to lung cancer.
Former cigarette smokers who use e-cigarettes or vaping devices may be at higher risk for lung cancer than those who don’t vape. Credit: ATS
Evidence of Harm from E-Cigarettes
Biological studies suggest the possible dangers of e-cigarettes, including pulmonary toxicity and lung cancer. E-cigarettes and heating elements have been shown to contain carbonyl compounds (e.g., formaldehyde, acetaldehyde, acrolein, and diacetyl) and toxic metals (e.g., chromium, nickel, and lead), which are known to be carcinogenic. These toxins are also present in conventional cigarettes.
“Our results indicate that when integrating smoking cessation interventions to reduce lung cancer risk, the potential harms of using e-cigarettes as an alternative to smoking must be considered,” said Dr. Kim.
Research Methodology and Findings
To determine these individuals’ risk, the researchers evaluated 4,329,288 individuals with a history of conventional smoking who participated in the Republic of Korea’s National Health Screening Program at two time points: 2012-2014 and 2018. They conducted a follow-up in December 2021.
The research team categorized participants into six groups according to their smoking history and habit change. They used statistical analyses to assess each group’s risk of developing lung cancer and of dying from it.
During follow-up, they found that 53,354 individuals had developed lung cancer and 6,351 died from lung cancer. Ex-cigarette smokers who had quit five years or more and used e-cigarettes were at greater risk of lung cancer-related death than ex-smokers who had quit five years or more and hadn’t used e-cigarettes. For smokers who had quit less than five years, those who used e-cigarettes were found to have both a higher risk of both lung cancer and lung cancer mortality than non-e-cigarette users.
Dr. Kim and colleagues also conducted a stratified analysis in which they looked at individuals ages 50-80 with a smoking history of 20 or more pack-years, because these individuals would be likely to be referred for lung cancer screening according to the 2021 US Preventive Services Task Force (USPSTF) and the 2023 American Cancer Society (ACS) guidelines. Ex-smokers in this group who had quit smoking for five years or more and used e-cigarettes reported a higher risk of both lung cancer and lung cancer-related death than those who didn’t use e-cigarettes. In addition, ex-smokers who used e-cigarettes and had quit smoking less than five years before had a higher comparative risk of lung cancer.
The authors conclude that, “Clinicians must highlight the potential harmful effects of alternative e-cigarettes use when integrating smoking cessation interventions to reduce lung cancer risk.”
