Smokers who quit cigarettes often turn to vaping as a safer alternative to smoking. However, a study found that ex-smokers who vape still face a high risk of lung cancer compared to those who quit nicotine completely.

The latest study presented at the annual meeting of the American Thoracic Society in San Diego suggests that among smokers who switched to vaping, the risk of lung cancer is particularly high in those already considered high-risk and recommended for screening.

"This is the first large population-based study to demonstrate the increased risk of lung cancer in e-cigarette users after smoking cessation," corresponding author Dr. Yeon Wook Kim said in a news release.

"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," Dr. Kim said.

In a nationwide population-based study involving more than 4.3 million people in South Korea, researchers evaluated the link between switching from conventional cigarettes to e-cigarettes and the risk of developing lung cancer.

All the participants had a conventional smoking history. Based on the habit change to e-cigarette use, the participants were categorized as:

1. Ex-smokers with more than 5 years since quitting:

  • Without e-cigarette use
  • With e-cigarette use

2. Ex-smokers with less than 5 years since quitting:

  • Without e-cigarette use
  • With e-cigarette use

3. Current smokers:

  • Without e-cigarette use
  • With e-cigarette use

More than 53,000 individuals developed lung cancer during the follow-up and 6,351 people died from lung cancer.

The risk of lung cancer death was higher in ex-cigarette smokers who had quit five years or more and switched to e-cigarettes than in ex-smokers who quit five years or more but did not use e-cigarettes.

Among smokers who had quit less than five years and switched to e-cigarettes, both the risk of lung cancer and death from lung cancer was high.

The researchers also noted that the link was particularly high in ex-smokers of the age group 50 to 80 with a smoking history of 20 or more pack years.

"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," the news release stated.