Abstract LB086: Measuring oral DNA damage to evaluate electronic cigarette use as a tobacco harmreduction strategy
Authors: Ganapathy Vengatesh , Chinnaiyan Mayilvanan , Brobst Daniel , Sadhasivam Balaji , Nshimiyimana Jean D. , Zhao Yan , Wagener Theodore , Queimado Lurdes 
Published: April 2024

Abstract
Background: Smokers increase their risk of numerous types of diseases, including lung and oral cancer. Despite this knowledge, approximately 18.7% of U.S. adults are smokers, and millions of smokers across the U.S. struggle to quit tobacco every day. Although difficult due to nicotine addiction, you can increase your chances of quitting with the tools available, and help is an important part of any quitting plan. The prevalence of electronic cigarette (e-cigarette) use has increased as users perceive them to be safer than traditional tobacco smoke. Studies have shown that e-cigarettes contain fewer chemicals than tobacco smoke. Therefore, addressing the effectiveness of e-cigarette use in reducing tobacco harm is essential and is currently a priority for the FDA.
Aim: To determine whether combustible tobacco users who are provided with free e-cigarettes and free e-liquids reduce the levels of DNA damage in their oral epithelial cells.
Methods: Adult smokers who smoked at least 5 cigarettes per day over the past year and did not plan to quit smoking in the next 3 months were enrolled in a randomized 3-arm clinical trial (NCT03113136): “Usual Brand Cigarettes” (UBC), Low Wattage e-cigarettes (LWe), and High Wattage e-cigarettes (HWe). Free combustible cigarettes or e-cigarettes plus e-liquid were provided during the first 12 weeks according to assigned group. Tobacco product use details, CO level, and oral mucosa samples were collected at 0, 4, and 12 weeks. DNA was extracted from oral cells and damage was quantified by q-PADDA, at three time points (Week 0, 4, 12). Data analysis was performed using ANOVA model.
Results: Participants who provided samples at all time points were included in this DNA damage study. 201 complete data sets (UBC=77, LWe=61 and HWe=66) were available for DNA damage quantification at the time of this report. At enrolment (week 0), there were no significant differences in age, sex or tobacco product use across groups. At 12 weeks, combustible tobacco use was significantly reduced in smokers also using LWe or HWe (dual users). At 4 and 12 weeks, the CO levels were reduced in dual users of combustible tobacco and e-cigarettes (LWe or HWe), compared to exclusive combustible tobacco users. Compared to combustible tobacco users, dual users of combustible tobacco and LWe or HWe showed a significant reduction in the levels of oral mucosa DNA damage at 4 and 12 weeks (3 to 5 fold).
Conclusion: Our study shows that when provided with free e-cigarette devices and e-liquids, smokers who were dual users or completely switched to LWe or HWe significantly reduced the levels of DNA damage in their oral mucosa compared with exclusive combustible tobacco users. These data suggest that LW and HW e-cigarette devices are an effective harm reduction tool and might help to reduce tobacco-associated health effects.
Funding: NIH/NCI (R01CA204891, Wagener; R01CA242168, Queimado).
Citation Format: Vengatesh Ganapathy, Mayilvanan Chinnaiyan, Daniel Brobst, Balaji Sadhasivam, Jean D. Nshimiyimana, Yan Zhao, Theodore Wagener, Lurdes Queimado. Measuring oral DNA damage to evaluate electronic cigarette use as a tobacco harmreduction strategy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB086.