Vaping after quitting cigarettes tied to higher lung cancer risk
A South Korean study of more than 4.5 million people found higher lung cancer risk among former smokers who used e-cigarettes.
By Priya Raghavan · Science Reporter
3 min read
Former smokers who used e-cigarettes after quitting had higher rates of lung cancer and death from the disease than those who stopped using cigarettes without vaping, according to a study published in Nature Medicine. The findings matter because e-cigarettes are often treated as a safer substitute for cigarettes, including by people trying to leave tobacco behind.
Researchers led by Yeon Wook Kim analyzed health data from 4,524,895 people in South Korea, using records from the country’s National Health Screening Program. The program includes health screenings for employees aged 20 and older and for other citizens aged 40 and older, according to the study as reported by Medical Xpress.
The researchers compared lung cancer outcomes across smoking and e-cigarette use groups. They looked at current smokers, people who had quit cigarettes for less than five years, and people who had quit for five years or more. They also examined a higher-risk group of adults aged 50 to 80.
Compared with people who quit smoking and did not vape, former smokers who used e-cigarettes had a 56% higher risk of developing lung cancer and were twice as likely to die from it, according to the Nature Medicine study. The researchers also found that people who switched to e-cigarettes fared better than those who continued smoking regular cigarettes.
The study found that lung cancer risk declined the longer people stayed off cigarettes. But that reduction was weaker among former smokers who used e-cigarettes. Long-term quitters who vaped had a higher lung cancer risk than long-term quitters who did not vape, according to the researchers.
Among short-term quitters, e-cigarette use was also linked with less reduction in risk than quitting without vaping. In the higher-risk group of adults aged 50 to 80, switching to e-cigarettes was associated with a 91% higher risk of lung cancer and a 92% higher chance of death from the disease compared with quitting completely, the study found.
The researchers said the study does not prove that vaping directly causes lung cancer. It shows an association between e-cigarette use after smoking cessation and worse lung cancer outcomes among former smokers.
The long timeline of lung cancer has made it difficult to measure the long-term effects of vaping, Medical Xpress reported. Earlier studies have often focused on shorter-term symptoms, such as cough or throat irritation, rather than cancer outcomes that can take years to appear.
The authors also noted that e-cigarettes are not chemically harmless. Vapes can contain cancer-causing substances including formaldehyde and toxic metals such as lead, nickel and chromium, according to the researchers.
Lung cancer remains a leading cause of cancer cases and deaths worldwide. Medical Xpress reported that there were an estimated 2.5 million new lung cancer cases globally in 2022 and 1.8 million deaths from the disease that year.
The study adds evidence for clinicians and public health officials weighing how to discuss e-cigarettes with smokers who want to quit. Its central finding is narrow but significant: quitting cigarettes remains beneficial, but replacing them with e-cigarettes may reduce some of the lung cancer benefit seen in people who stop smoking without vaping.
This story draws on original reporting from Medical Xpress.