For the study, which was published Monday in the American Journal of Preventive Medicine, researchers from the University of California-San Francisco analyzed data from 32,000 adults who responded to CDC's Population Assessment of Tobacco and Health (PATH). The survey tracked respondents' e-cigarette use and tobacco smoking, along with new lung disease diagnoses between 2013 and 2016. None of the participants had lung disease at the beginning of the study.
The researchers found that by 2016, when compared with adults who never smoked or vaped, adults who used e-cigarettes had a 30% increased chance—or 1.3 times higher odds—of developing a chronic lung disease including asthma, bronchitis, chronic obstructive pulmonary disease, or emphysema.
The researchers also found that the risk of chronic lung disease was 2.6 times higher among adults who smoked traditional cigarettes compared with those who never smoked, and it was 3.3 times higher for those who both smoked traditional cigarettes and used e-cigarettes.
According to Reuters, the study is one of the first to demonstrate the potential long-term health effects of e-cigarettes, which are frequently promoted as a safer option than traditional smoking and as a way to help quit smoking.
Robert Tarran, a physiologist at the University of North Carolina School of Medicine, explained that while previous research has focused on a representative sample of the population at a given point in time, the new study is more robust because it assesses lung health over a period of time.
Separately, Stanton Glantz, lead author of the study and professor of medicine and director of UCSF's Center for Tobacco Control Research and Education, said, "Everybody, including me, used to think e-cigarettes are like cigarettes but not as bad." However, the study shows that "e-cigarettes are harmful on their own, and the effects are independent of smoking conventional tobacco," he said.
Glantz acknowledged that the findings indicate using either conventional tobacco products or e-cigarettes alone is likely less dangerous than using both products—and that, in fact, if someone was going to choose between either product, "in terms of these respiratory effects, [he or she is] probably better off with an e-cigarette."
However, Glantz pointed out that the study's three-year time period is a relatively short amount of time to assess the negative health effects of vaping. "Based on what we know about the biological effects of e-cigarettes, my guess is that if we followed these people for 20 years, the e-cigarette effect would be similar (to the risks associated with smoking)," he explained.
According to USA Today, the study is yet "another blow" to e-cigarette companies following a sudden increase in cases of EVALI, a vaping-associated lung disease which has caused 52 deaths and more than 2,4000 hospitalizations as of Dec. 10, 2019 (Steenhuysen, Reuters, 12/16; Ortiz, USA Today, 12/17; Aubrey, "Shots," NPR, 12/16; Ducharme, TIME, 12/16).