Vaping Alters Mouth Microbes

By Jane Farrell

The use of electronic cigarettes—also called vaping—has been on the rise. In 2019, almost 5% of adults in the U.S reported using e-cigarettes, according to the National Institutes of Health (NIH). Overall, e-cigarettes are thought to produce fewer toxic compounds than conventional cigarettes, but they can still contain many harmful substances, including nicotine and heavy metals like lead.

Smoking conventional cigarettes is a known risk factor for the development of gum disease, or periodontitis. Part of this risk is driven by changes in the bacterial communities that normally live in the mouth, called the oral microbiome. But whether e-cigarettes induce similar changes hasn’t been well understood.

According to an NIH news release written by Sharon Reynolds, a team led by Drs. Deepak Saxena and Xin Li from New York University examined 84 volunteers over a six-month period: 27 people who smoked conventional cigarettes, 28 who used only e-cigarettes, and 29 nonsmokers. All participants had at least mild gum disease at the start of the study. To reduce other factors that could affect the oral microbiome, the release says, none had their teeth cleaned during the study period.

At the beginning and end of the study, Reynolds writes, the team compared the types of bacteria found where the gums meet the teeth at the beginning and end of the six-month study. They also compared markers of inflammation and immune cell activity.

The study was funded in part by NIH’s National Institute of Dental and Craniofacial Research (NIDCR). Results appeared on February 22, 2022, in mBio.

The number of unique bacterial species—a measure called alpha diversity—living in and around the gums increased for all participants during the study. This can be a sign of gum disease getting worse.

The specific types of microbes found in the oral microbiomes differed substantially between the three groups. There was a core set of species common among the groups, the NIH says, but each also had unique features. They were so distinct that a machine-learning program could use the oral microbiome to predict which group people were in with 74% accuracy.

However, the program was least accurate at picking out e-cigarette users. The patterns of their oral microbes shared characteristics with both smokers and nonsmokers, with slightly more similarities to smokers. Unique traits among e-cigarette users included enrichment with Fusobacterium and Bacteroidales species. Both of these are linked with gum disease.

Several markers of inflammation and immune response were also higher in smokers and e-cigarette users than in nonsmokers. But again, these patterns differed between smokers and e-cigarette users.

“We are now beginning to understand how e-cigarettes and the chemicals they contain are changing the oral microbiome and disrupting the balance of bacteria,” Saxena says.

More work will be needed to better understand how e-cigarette use alters the oral microbiome and potentially affects gum health and disease.