//BTH #6: Does vaping increase the risk of oral infections and inflammation?

Behind the Headlines is a regular feature taking a slightly deeper dive into a piece of recent media coverage of NGP research.

This edition’s story:

In late February a number of outlets, including The Telegraph, reported vapers were “more likely to have gum disease”.

The Daily Mail stated vape use “alters the mouth’s microbiome and raise[s] the risk of oral infections”. In addition, “vapers had higher levels of bacteria implicated in oral diseases, as well as biomarkers in their blood that indicate inflammation. In turn, [these] can damage all manner of tissues and raise risks for chronic diseases.”

The news articles were based on a scientific study published in the iScience journal by researchers at the New York University School of Dentistry. The results were interpreted by the Mail, who concluded vapers were at “1.5 times greater risk of gum disease or infection [compared to] non-smokers.”

Read all about it. Image by Jon S on Flickr.

But these findings conflict with various independent researchers who stated in a 2016 publication that: “in our role of highly experienced physicians in the field of oral medicine, we want to highlight how switching from combustible to e-cigarette[s] can represent a valid support toward a clear improvement in some specific oral health parameters.”

However, this study did not include controls for the effects of alcohol drinking – which can impact the makeup of mouth bacteria and oral health – or for dental hygiene or sugar intake, both of which are directly linked to oral infection.

How was the research conducted?

The research was conducted in two phases.

Phase 1: Firstly, researchers looked at how vape aerosol effected the human salivary microbiome − a community of bacteria and microorganisms which may impact an individual’s oral health − in 119 participants: 39 never smokers, 40 smokers and 40 vapers. The researchers defined vape use as using 0.5 to 1 vape per day over the past 6 months. However, they didn’t explain what sort of device or e-liquids the participants used.

Phase 2: Next, the authors looked at two groups of human cells in vitro to examine the influence of vape aerosols on the infection efficiency of oral pathogens.

What did the study find?

• 43% of vapers and 73% of smokers reportedly had what was described as “severe” gum disease, compared to 28% of never smokers.
• The researchers argued that vape use influences the oral microbiome and increases the “abundance of oral pathobionts” microorganisms, which have the potential to cause disease.
• In addition, they report that vape aerosol exposure “alters host response, promoting gum inflammation and making epithelial cells suitable to infection.”
• “For the first time”, the study concluded, it had found that vapers “were more prone to infection” in terms of their oral health.

Our take on the research and reporting…

The Daily Mail stated that vaping proponents “have touted [they are] less-harmful alternatives to traditional cigarettes, but no research exists to back these claims.”

Gum health is important. Image by Hans Erickson on Flickr.

• There are over 2000 pieces of vaping research conducted by both the industry and independent researchers. A significant number suggest that vapes are a potentially less harmful alternative for those adults who would otherwise have continued to smoke. This evidence has led government agencies, including Public Health England (PHE), to conclude vaping is: “likely to be 95% less harmful than smoking”. PHE has maintained this position since 2015 across a series of annual reviews.

The study behind the headlines also arguably suffered from several key design issues. For instance:

• There were significant discrepancies between the participant groups. For instance, there were more male participants in the cigarette and vape user groups (80% and 78% respectively), compared to just 56% in the never smoker cohort. There were also different ethnicity ratios across all the groups, as well as higher alcohol consumption across vapers. All of these factors may have impacted the study results. For example, as the Royal College of Surgeons has stated, “alcohol consumption can damage oral health”. Likewise, sugar consumption – also linked directly to oral health – was not controlled for.
• As the study is a single time point experiment it does not consider history of oral health. It’s therefore difficult to establish if it’s vaping which has affected the oral health of participants over time, compared to previous oral health conditions. Additionally, the inclusion criteria for the study was confirmation of mild-to-severe oral disease. Therefore, if a disease state was required to be included in the study, the results lack the context of oral disease in vapers/smokers as whole population – since the study authors are only sampling a subset i.e. those who already have disease.
• A microbiome is a complex community of organisms which is difficult to replicate within in vitro laboratory conditions, since they don’t accurately mimic human oral environments – where a complex microbiome can potentially provide protection against pathogens.
• In addition, the study’s infection scenario – where certain types of cell were incubated with bacteria for 2 hours – is not reflective of real-life. For example, in humans, saliva contributes significantly to the maintenance of good oral health as it contains several anti-microbial constituents. The presence or proliferation of bacteria in the mouth for two hours would not necessarily mean poorer dental outcomes if an individual practised good hygiene.
• The authors tended to report the findings in absolute terms. While the authors did use a cigarette comparator in phase 1, the in vitro tests in phase 2 did not. This method is not consistent. Phase 2 looked at absolute risk of EVP use rather than relative risk compared to smoking. Imperial Brands is clear: all NGPs are for adult former or current smokers. It’s unhelpful to consider vapes in terms of absolute risk when considering their intended use. To assess the harm reduction potential of all NGPs, we are firm in our belief that any research must use a cigarette comparator.

Is vaping safer than smoking when it comes to oral health? Interestingly, phase 1 of the study demonstrates it might be – with vapers showing a 30% reduction in gum disease compared to smokers. This is consistent with the findings of previous independent studies, and surely adds yet more weight to the credence of tobacco harm reduction.

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