The use of e-cigarette among Korean adolescents is spreading with alarming rapidity, but it has not been studied along with the severity level of GAD-7. This study aims to identify adolescents' e-cigarette use and its associated factors among four different anxiety groups using the problem behavioral theory (PBT).

A cross-sectional secondary dataset was retrieved from the 2020 Korea Youth Risk Behavior Survey. Of the total sample of 54,948, four anxiety groups were formed: minimal (score 0–4; n = 36,711), mild (score 5–9; n = 12,138), moderate (score 10–14; n = 4143), and severe (score above 15; n = 1965). A total of 11 variables were selected based on the PBT domains. Descriptive analysis, Chi-square, ANOVA, univariate analysis, and multiple linear regression analysis were performed.

E-cigarette use was the highest in the order of severe, mild, moderate, and minimal. While cigarette use was associated with vaping in all anxiety groups, adolescents with minimal or mild anxiety levels were more likely to be influenced by tobacco accessibility and other behavior system factors such as sexual intercourse, alcohol use, and smartphone addiction. Meanwhile, secondhand smoke exposure in public areas was only associated with those with severe anxiety levels, and secondhand smoke exposure at school was a significant factor in all anxiety groups except for those with moderate anxiety levels.

Due to the nature of cross-sectional dataset, the study could not draw causal links between vaping and other identified factors, include all the necessary PBT components.

These findings underscore the need to consider different levels of anxiety when addressing the problems related to vaping among Korean adolescents.