Electronic Cigarettes Trigger an Inflammatory Response That May Set the Stage for Gum Disease

The oral microbiomes of 25 otherwise healthy participants who use e-cigarettes daily closely match those seen in patients with gum disease, a new study shows. The results suggest that e-cigarettes trigger a proinflammatory response, coating commensal bacteria in the mouth with a layer of slime that makes them unrecognizable to the body and prevents the sequential colonization of other bacteria that form a healthy community. Sukirth Ganesan and colleagues conclude that the glycerol/glycol vehicle in e-cigarettes appears to drive these changes. 

E-cigarettes have grown wildly popular among Americans, with six percent of the country's population - including 2.5 million high schoolers - puffing on the products nine years after their introduction to the United States. But while these e-cigarettes contain potentially toxic substances, including volatile organic compounds and metals, much remains unknown their long-term effects on human health. 

To gain insight into how e-cigarettes affect the oral microbiome, Ganesan et al. recruited 123 otherwise healthy individuals, including 25 smokers, 25 nonsmokers, 20 e-cigarette users, 25 former smokers currently using e-cigarettes, and 28 smokers who also use e-cigarettes. They created a catalog of bacterial genes in the microbial communities of e-cigarette users based on plaque samples collected from their teeth, finding that variations arose based on the duration of e-cigarette use, but were not tied to variations in the concentration of nicotine or the type of flavoring. 

The researchers also observed that while both smoking and e-cigarette use cause inflammation, they do so through different molecular pathways. 

"I am hoping this research will drive some level of policymaking about the harm we are seeing," said Purnima Kumar, a coauthor of the study, in an interview, challenging the popular perception that e-cigarettes provide a safer alternative to smoking. "If we can see changes in people who are otherwise healthy and have nothing wrong with them, then we should start seriously considering why would you put their lives and their wellbeing at risk."