LOS ANGELES — A study led by researchers at the Keck School of Medicine of USC found that regular vaping alters activity in 3,124 genes across the genome compared with people who do not smoke or vape. The research, published in the journal Frontiers in Oncology, examined gene expression in oral cell samples from 83 healthy young adults—35 vapers, 24 smokers, and 24 non-users—using RNA sequencing to analyze biological activity.
The study showed that 66.6% of gene expression changes among vapers were linked to the type of e-cigarette flavors and devices used, while only 28.8% related to how often or how much participants vaped. Fruit flavors were associated with changes in 31% of the affected genes, and the use of multiple flavors correlated with alterations in 64.3% of those genes. In contrast, sweet flavors accounted for 2.9% of changes and mint/menthol flavors for 0.9%.
Higher-generation vaping devices, such as 'mods,' were tied to the strongest and most consistent shifts in gene regulation. These newer devices can deliver higher nicotine levels than earlier models and often contain additives designed to enhance smoothness and appeal. The study concluded that product characteristics—specifically flavor and device type—explained more variation in gene activity than usage frequency or intensity.
Among vapers, the gene expression changes were most strongly associated with cancer, followed by endocrine disorders, gastrointestinal diseases, and neurological diseases. Vapers also displayed more variable patterns of gene activity than smokers.
"The implication is that each flavor has unique attributes that produce different biological effects. This is something regulators should carefully consider when evaluating the health risks or potential benefits of each flavored e-cigarette product," said Ahmad Besaratinia, professor of research population and public health sciences at the Keck School of Medicine of USC and senior author of the study.
"One major question still remains: What is driving these changes? Is it the act of vaping itself—or is it the intensity and duration of vaping, the characteristics of the products used, or some combination of these?" he said. Besaratinia and his colleagues are now conducting a follow-up study to identify which specific chemicals in vaping liquids drive these genetic changes. The research was funded in part by the National Institutes of Health and supported by the National Institute of Dental and Craniofacial Research, the National Institute on Drug Abuse, and the University of California Tobacco-Related Disease Research Program.