Purdue researchers investigate the effects of vaping on oral and lung health
Written By: Rebecca Hoffa, rhoffa@purdue.edu

As data from the Centers for Disease Control and Prevention reports declining combustible cigarette use, vaping and e-cigarette sales have continued to soar, increasing by more than 46% from January 2020 to December 2022, according to the Truth Initiative. While combustible cigarettes have a proven risk of cancers and other diseases, less is known about the health effects of vaping and e-cigarette use.
Two Purdue University College of Health and Human Sciences researchers, Thivanka Muthumalage and Jonathan Shannahan, are investigating these vaping and e-cigarette technologies to explore the health effects in both the lungs and the mouth. Their goal is to not only educate the public but also work toward therapies that can help reduce the harmful effects of vaping and e-cigarette use.
“With all the information that we know, smoking and vaping are still a health concern, so education, outreach and reporting scientific data that the Food and Drug Administration can use for implementing appropriate regulations are important, as well as investigating molecular targets in lung disease mechanisms for potential therapies,” Muthumalage said.
The hazards of inhaling

Thivanka Muthumalage(Photo provided)
Muthumalage, an assistant professor in the School of Health Sciences who joined the school in fall 2023, focuses his work on how the components of vaping and e-cigarette products damage the lungs. Because these products are made up of a mixture of chemicals and follow different recipes across brands, he noted it can be difficult to identify the toxicity of vapes and e-cigarettes. As a result, Muthumalage is taking multiple approaches, using both cell culture models and preclinical mouse models to understand the hazard categorization of the different components of the emitted aerosol. He uses state-of-the-art exposure systems — similar to “smoking robots” — in his lab to mimic human inhalation.
“I want to see what the long-term effects exposure to electronic cigarettes and also the effects of switching from tobacco smoke to electronic cigarettes,” Muthumalage said. “We’re asking people to quit smoking, and they may start vaping. They may go from menthol-flavored cigarettes to menthol-flavored electronic cigarettes. Is there a difference? Is it getting better, or is there a modified risk that we don’t know about? These are chemicals — we don’t know really what is going to happen with chronic exposure to these chemicals in the lungs. Though there are certain common chemicals giving a specific aroma and flavor, it’s very different when you look at the chemical compositions from brand to brand that impart a specific flavor.”
Muthumalage and his collaborators recently published a narrative review to help standardize the lab measurements used to assess inhalable tobacco toxicity — a step that’s beneficial to contributing toward FDA regulations.
“Reporting recommended experimental parameters will give us an idea of the comparability of my work to somebody else’s work,” Muthumalage said. “Obviously it’s not going to be perfect, but we want to give certain parameters in publications for better standardization of data between research labs. The more information we give in the methods, it’s better for reproducibility of the data, and will be useful to the FDA for implementing guidelines and policies.”
For Muthumalage, the work is a balancing act between e-cigarette regulation to avoid younger people, such as middle and high school students, picking up the habit while also moving adults away from smoking combustible cigarettes.
“Of course we want to educate,” Muthumalage said. “We want to regulate electronic cigarettes by removing bad constituents from them that are known to cause detrimental lung diseases, but at the same time, we don’t want to encourage people to go back to smoking.”
While individuals may think picking up a vape and inhaling a few times won’t make a difference on their lung health, Muthumalage’s research has indicated otherwise.
“The fact that even a short exposure made such a remarkable outcome (on lung health) was very interesting to me because I don’t think very many people realize that there are consequences that come from it,” Muthumalage said. “It’s very interesting to me how we like to put things in our lungs without even knowing the damage it can cause.”
Oral outcomes of vaping

Jonathan Shannahan(Photo provided)
Complementing Muthumalage’s work, Shannahan, an associate professor of health sciences, is focused on the effects of vaping and e-cigarette use abit higher in the respiratory system: the oral cavity — an often-overlooked area in inhalation toxicology research.
“It’s an area that actually can have substantial health effects and be detrimental to overall quality of life,” Shannahan said. “When you have any kind of disease in your oral cavity, it’s pretty impactful. Our research primarily looks at the periodontal health effects associated with the use of vaping products.”
Shannahan is interested in focusing on subpopulations that are more likely to be affected by exposures like inhaling chemicals found in vapes and e-cigarettes. In doing so, he has investigated a wide range of groups, from looking at specific racial minorities to individuals with underlying conditions, such as metabolic disease.
“I really think we should be focusing on these sensitive subpopulations and that by understanding the risks associated with the environmental and other exposures in these most susceptible subpopulations, we can better set regulations and standards that positively impact all people,” Shannahan said. “That’s really at the heart of why we started this type of research — it’s an emerging exposure; it’s a very dynamic field where you have legislation, changes in products and usage patterns that are always arising; and then you have the susceptibility factor that no one has actually looked at.”
Shannahan works with a variety of collaborators as he investigates the health effects of vaping and e-cigarettes on the oral cavity through the Underwriters Laboratory Chemical Insights Research Institute based in Atlanta, Georgia. The multi-PI team consists of exposure assessment experts, oral hygienists, clinicians, oral microbiome experts, experts in omics approaches and more.
“Instead of looking at distinct components of the disease, we’re looking at the entire oral cavity to get more of an idea of the complex biological processes that are underway,” Shannahan said. “The diseases are very complex with multiple things changing at one time, so it takes a lot of people with a lot of different expertise working together to kind of understand the breadth of the issue and the scope of it.”
While the research is ongoing, Shannahan said he hopes the work will eventually lead to making a difference through education and messaging, and he sees collaborations both within Purdue and beyond continuing to expand.
“How can we best take our data and utilize it to educate the general population in the most impactful way possible?” Shannahan said. “Are there ways to modify both people’s behaviors and maybe the device itself to enhance safety? Are there certain at-risk populations that we could identify and make concentrated efforts in communicating these findings through targeted messaging?”
Discover more from News | College of Health and Human Sciences
Subscribe to get the latest posts sent to your email.