New US research has found that individuals who use e-cigarettes could be at risk of developing oral diseases in the future, which could range from gum disease to cancer. Carried out by researchers at The Ohio State University, the new study looked at a group of 123 people with no signs of oral disease. The group included 25 smokers, 25 non-smokers, 20 e-cigarette users, 25 former tobacco smokers who used e-cigarettes and 28 people who smoked both tobacco cigarettes and e-cigarettes. The team collected plaque samples taken from under the gums of the participants to analyze the bacteria in this part of the mouth; bacteria here is the last line of defense against disease as it is the least likely to be disrupted by environmental changes in the mouth, such as food, toothpaste and tobacco. The researchers then carried out DNA deep sequencing of the bacteria’s genomes to identify what types of microbes were living in participants’ mouths and what their functions were. The findings, published in the journal Science Advances, showed that although the e-cigarette users didn’t have signs of active disease, their oral bacteria composition was similar to that of people with severe periodontitis, a severe gum infection that can lead to health problems such as tooth loss, and, if left untreated, is a risk factor for serious conditions such as heart and lung disease. The effect of e-cigarette smoking was also seen with or without nicotine, which the researchers say suggests that it is the heated and pressurized liquids in e-cigarette cartridges that are making vapers’ mouths a welcoming environment for a dangerous combination of microbes. Even long-term current and former cigarette smokers had worse oral profiles linked to using e-cigarettes after just three to 12 months of vaping. “Vaping is such a big assault on the oral environment, and the change happens dramatically and over a short period of time,” said Purnima Kumar, senior author of the study. “If you stop smoking and start vaping instead, you don’t move back toward a healthy bacterial profile but shift up to the vaping profile,” Kumar explains. “Knowing the vaping profile is pathogen-rich, you’re not doing yourself any favors by using vaping to quit smoking.” The researchers say this is the first human study on the effects of e-cigarette exposure in the mouth, and like previous research into e-cigarettes, also questions their safety.