Last month, after years of strictly prohibiting candy, fruit and dessert flavors, the FDA updated its e-cigarette guidance to include mango and blueberry flavors. The authorization has drawn sharp criticism from groups like the American Academy of Pediatrics and the Campaign for Tobacco-Free Kids, who fear the return of fruit flavors will spark a resurgence in underage vaping.
In fact, a new study out of the University of Southern California (USC) shows fruit flavors specifically may be the most harmful.
While “vaping” is still relatively new and without sufficient long-term data to inform health risks, previous literature has shown that it—similar to smoking—is linked to changes in gene expression involved in the development of cancer, as well as certain heart and lung diseases.
“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?” said senior author of the study Ahmad Besaratinia, professor of research population and public health sciences at the Keck School of Medicine of USC.
Fruit from a spoiled tree
In the new study, published in Frontiers in Oncology, Besaratinia and team collected oral cell samples from all study participants—35 vapers, 24 smokers and 24 non-users, all healthy young adults.
Using RNA sequencing, the researchers examined activity across thousands of genes at the same time. Compared with people who did not smoke or vape, vapers had altered expression in 3,124 genes.
Vapers also showed more variable patterns of gene activity than smokers. Analysis showed that different vape flavors produced different changes in gene regulation. Sweet flavors were linked to changes in 2.9% of affected genes; mint/menthol flavors to changes in 0.9% of affected genes; fruit flavors to changes in 31% of affected genes; and multiple flavors to changes in 64.3% of affected genes. In addition, higher-generation devices, such as mods, were associated with the strongest and most consistent changes in gene regulation.
“The implication is that each flavor has unique attributes that produce different biological effects,” said Besaratinia. “This is something regulators should carefully consider when evaluating the health risks or potential benefits of each flavored e-cigarette product.”
The researchers also conducted a bioinformatics analysis to identify the molecular processes, biological pathways and diseases linked to the gene expression changes observed. Among vapers, cancer was linked to the highest number of gene expression changes, followed by endocrine disorders, gastrointestinal diseases and neurological diseases.
Policy shifts
The new findings have particular relevance as the regulatory landscape continues to shift. The researchers recommend regulators evaluate products in a more granular way, with greater attention to flavors and device characteristics.
Besaratinia and colleagues are now conducting a follow-up study of the chemicals used in vaping liquid to determine which compounds are linked to changes in gene expression.
“Once we identify these chemicals, policymakers could instruct manufacturers to either eliminate these chemicals or reduce their level in e-cigarette products to minimize potential harm,” said Besaratinia.