Korean study finds former smokers who use e-cigarettes or vapes have higher risk for lung cancer than ex-smokers who don't

Photo by Steve Helber, The Associated Press

Kentucky Health News

Former cigarette smokers who use electronic cigarettes or vaping devices may be at higher risk for lung cancer than former smokers who don’t vape, according to new research in South Korea.

“This is the first large population-based study to demonstrate the increased risk of lung cancer in e-cigarette users after smoking cessation,” said Dr. Yeon Wook Kim of Seoul National University, corresponding author of the study published at the 2024 international conference of the American Thoracic Society (ATS).

E-cigarettes are promoted as an aid to smoking cessation, but "There is little knowledge about the long-term consequences of vaping, and epidemiological evidence for the association between e-cigarette use and lung cancer is lacking," said an ATS news release.

"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 (such as formaldehyde, acetaldehyde, acrolein and diacetyl) and toxic metals (such as chromium, nickel and lead), which are known to be carcinogenic. These toxins are also present in conventional cigarettes."

Kim said, “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.”

To determine the risk to former smokers, the researchers looked at the records of more than 4.3 million Koreans with a history of conventional smoking who participated in the Republic of Korea’s National Health Screening Program in 2012-14 and 2018. They conducted follow-up in December 2021.

"They found that 53,354 individuals had developed lung cancer," or 1.24%, and 6,351 died from it, or 0.147%, the release says. "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."

The researchers also looked at people aged 50 to 80 with a smoking history of 20 or more pack-years , because in the U.S. they would be likely be referred for lung cancer screening under American 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," the release says. "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, “Clinicians must highlight the potential harmful effects of alternative e-cigarettes use when integrating smoking-cessation interventions, to reduce lung-cancer risk.”