Time since initiation on current vaping among adolescents and associations with adverse health outcomes.

Background: Electronic cigarettes (e-cigarettes) are the most commonly used tobacco products among U.S. youth. This study examined time since initiation among current adolescent e-cigarette users.

Methods: Data were drawn from the 2019-2022 National Youth Tobacco Survey, and the study sample included adolescents who reported ≥ 1 day of e-cigarette use in the past 30 days (n = 9,424). Time since initiation was calculated by subtracting the age of first e-cigarette use from the current age, then classified as < 1 year, 1 year, 2 years, and ≥ 3 years. Logistics regressions were performed to examine the change in time since initiation (≥3 years vs. < 3 years) from 2019 to 2022 and associations of time since initiation with tobacco use and adverse health outcomes.

Results: The proportion of current e-cigarette users with time since initiation < 1 year decreased from 29.6 % in 2019 to 13.2 % in 2022, while the proportion of those with time since initiation ≥ 3 years increased from 16.5 % to 46.0 % (p < 0.0001). The increases in time since initiation ≥ 3 years were observed across demographic groups. Longer time since initiation (≥3 years vs. < 3 years) was associated with lower odds of vaping quit intention (AOR=0.6[0.4-0.8],p = 0.0003) and higher odds of frequent e-cigarette use (AOR=3.0[2.3-4.0],p < 0.0001), dual use of e-cigarettes and other tobacco products (AOR=1.7[1.3-2.3],p = 0.0005), tobacco craving (AOR=2.2[1.5-3.1],p < 0.0001), tobacco dependence (AOR=1.9[1.2-3.0],p = 0.004) and the presence of cognitive impairment (AOR=1.3[1.04-1.73],p = 0.03) CONCLUSIONS: The findings of this study underscore the need for comprehensive public health initiatives, accessible cessation programs, and effective tobacco control policies to curb prolonged e-cigarette use in early life.