New research from the University of California, San Francisco, provides the first long-term evidence that e-cigarette use alone raises the risk of chronic lung disease, and that combining vaping with traditional smoking dramatically amplifies that danger.
The study, published Monday in the American Journal of Preventive Medicine, analyzed data from the Population Assessment of Tobacco and Health (PATH), a national survey that tracked the tobacco habits of more than 32,000 American adults from 2013 to 2016. The UCSF team focused on participants who reported no lung disease at the start, then recorded any new diagnoses over the three-year period.
Results showed that exclusive vapers faced a roughly 33% higher chance of developing chronic lung disease compared to non-users. That risk was independent of smoking, according to researcher Stanton Glantz, who stated in a press release that “e-cigarettes are harmful on their own, and the effects are independent of smoking conventional tobacco.”
Smoking traditional cigarettes alone made a person 2.6 times more likely to develop lung disease—a higher relative risk than vaping. Some manufacturers have used such comparisons to argue that e-cigarettes are a safer alternative. But the study’s authors caution that this logic overlooks a critical pattern: most vapers do not quit smoking entirely.
Dual Use: A Compounding Danger
The study found that people who both vaped and smoked conventional cigarettes were more than three times as likely to develop lung disease than those who never used either product. That figure exceeds the risk from smoking alone, suggesting the two habits compound rather than replace each other.
Glantz noted that “switching from conventional cigarettes to e-cigarettes exclusively could reduce the risk of lung disease, but very few people do it.” He added, “For most smokers, they simply add e-cigarettes and become dual users, significantly increasing their risk of developing lung disease above just smoking.”
The PATH study’s large, nationally representative sample strengthens the credibility of these findings, which are among the first to assess long-term respiratory outcomes tied to vaping. Earlier research often relied on shorter follow-ups or smaller cohorts.
While the absolute risk increase for exclusive vapers was moderate, the public health implications are substantial given the rapid growth of e-cigarette use, particularly among younger adults. The study does not prove causation, but the association held even after accounting for factors like age, sex, and other tobacco use.
For policymakers and health officials, the results underscore the need to monitor dual use as a distinct risk pattern, rather than treating vaping as a simple substitute for smoking. The findings also add weight to ongoing regulatory debates about e-cigarette marketing and access.
As Glantz’s team points out, the data reflect a three-year window; longer-term effects remain unknown. But the evidence already suggests that the safest choice is to avoid both products entirely.
A first-of-its-kind long-term study from UC San Francisco finds that vaping alone raises the risk of chronic lung disease by about a third over three years, while dual use with cigarettes more than triples the risk. The findings challenge the notion that e-cigarettes are harmless, especially for those who continue smoking.
Leave a Comment