Associations of nicotine concentration levels in e-cigarettes and tobacco dependence among US adults

Abstract Introduction Nicotine concentration level, a key characteristic of modern e-cigarettes, may affect dependence risk. This study examined whether e-cigarette nicotine concentration is associated with dependence on e-cigarettes and/or combustible tobacco. Methods We conducted a cross-sectional analysis using data from adult Wave 7 (2022-2023) of the Population Assessment of Tobacco and Health study, which surveys individuals aged 18+ in the United States. Self-reported nicotine concentration was grouped as high (5.0%+), moderate (1.8%–4.9%), low (0.1%–1.7%), 0%, and “I don’t know.” Separate regressions tested associations between nicotine levels and symptoms of dependence on e-cigarettes (e-cigarette nicotine dependence [ETD], range 0–32) derived from Wisconsin Inventory of Smoking Dependence Motives, Nicotine Dependence Syndrome Scale, and Diagnostic and Statistical Manual criteria, for individuals reporting exclusive e-cigarette use or dual (e-cigarette+cigarette) use, and symptoms of dependence on combustible tobacco (tobacco dependence, range 0–32) for dual use. Results Among 2246 respondents with exclusive e-cigarette use and 896 with dual use, 24.4% reported using e-cigarettes with high nicotine levels, 11.1% moderate, 36.4% low, 4.3% with 0%, and 23.8% responded “I don’t know.” For exclusive e-cigarette use, individuals with 0% nicotine had the lowest average ETD (8.5), while 5.0+% had the highest (17.0). For dual use, ETD was likewise highest with 5.0+% nicotine (14.2) and lowest with 0% nicotine (4.5); tobacco dependence was highest with 0.1%–1.7% nicotine (16.7) and lowest with 5.0+% (10.2), though not statistically significant after adjusting for covariates. Conclusions E-cigarette nicotine concentration was associated with nicotine dependence, suggesting that product nicotine levels may play an important role in addiction risk. Implications E-cigarette dependence increased with increased nicotine concentration among individuals using exclusive e-cigarettes and dual cigarettes+e-cigarettes, suggesting that product nicotine levels may play an important role in addiction risk. Policies are needed to regulate nicotine concentration in e-cigarettes. Clear and full disclosures and warnings about the nicotine concentration in e-cigarettes are needed.