Biomarker Levels and Illnesses Associated with Exposure to Noncombustible and Combustible Tobacco Products in Young Children

Up to one in six young adults in the U.S. currently use electronic cigarettes (ECs). Although these high EC use rates are fueled, in part, by adults who use ECs as tobacco cessation aids, the clinical effects of exposure on children who live with adult EC users remain unknown. What is known relates to adult EC use. Adult EC users have lower levels of biomarkers of exposure and harm compared to combustible cigarette (CC) smokers, but EC users may experience respiratory-related symptoms similar to symptoms in CC smokers. Further, EC and CC use is associated with epigenetic changes which may result in DNA methylation (DNAm) and epigenetic age acceleration (EAA), or faster DNAm-based age compared to chronological age. DNAm and EAA are biomarkers associated with an increased risk of morbidity including cancer in CC smokers and possibly EC users. Although Surgeon General’s reports warn that there is no safe level of exposure to CCs or ECs in children, some believe that EC exposure is safer than CC exposure. It is crucial to determine if this is true given the popularity of ECs. Our pilot research indicates that children with EC exposure have high tobacco exposure and oxidative stress biomarker levels, albeit at lower, but not negligible levels, compared to children exposed to CCs. No longitudinal studies have examined EC exposure patterns, biomarker levels, and respiratory health effects among children of exclusive EC users compared to children of exclusive CC smokers. To bridge this research gap, we will enroll a prospective cohort of 1-10-year-olds (N=300) who will comprise three equal groups at baseline (Month 0, M0): (1) EC Exposure Group - live with exclusive EC users, (2) CC Exposure Group - live with exclusive CC smokers, and (3) No-Tobacco Product Exposure Group - live with no tobacco product users. The objective of this project is to examine the characteristics, biomarker levels, and respiratory outcomes in children exposed to ECs vs. CCs. Biomarkers of EC and CC exposure, volatile organic compounds, propylene glycol, oxidative stress, and metals will be examined cross-sectionally at M0, at 6-months, and at 12-months (M12) in Aim 1, and then longitudinally in Aim 2. We will also examine respiratory symptoms and healthcare visits associated with EC Exposure, CC Exposure, or No Exposure over 12 months in Aim 2. In an Exploratory Aim, we will examine longer-term risk by comparing EAA and the pace of aging among exposure groups from M0 to M12. The central hypothesis is that compared to the No Exposure Group, The CC Group will have the highest biomarker levels, frequency of respiratory symptoms and healthcare utilization, and the fastest EAA, followed by the EC Exposure Group. This longitudinal project will bridge a gap that has failed to examine the pediatric effects of EC vs. CC exposure. We will study adult tobacco product use over 12 months with three waves of biomarkers and monthly respiratory outcomes, and we will explore children’s longer-term risk of cancer and age-related diseases via EAA. Results will inform recommendations for adults’ use of ECs around young children and the associated pediatric health effects. Project Number: 1R01CA303566-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Cancer Institute (NCI) | Principal Investigator: E. Melinda Mahabee-Gittens | Institution: CINCINNATI CHILDRENS HOSP MED CTR, CINCINNATI, OH | Award Amount: $694,182 | Activity Code: R01 | Study Section: Cardiovascular and Respiratory Diseases Study Section[CRD] View on NIH RePORTER: https://reporter.nih.gov/project-details/11367270