Association Between Combustible Tobacco Cigarette Smoking, Liquid Electronic Cigarette Use and Inadequate Sleep Duration Among Adults in South Korea: KNHANES 2016–2020

Objective: Nicotine use is associated with inadequate sleep. However, there is limited research on the relationship between smoking and inadequate sleep duration in the Korean population. This study assessed the effect of combustible tobacco cigarette use, liquid electronic cigarette use, and dual use on inadequate sleep duration.Methods: This study included 32,005 Korean adults in the final analysis, using data from the Korean National Health and Nutrition Examination Survey (2016–2020). Smoking patterns were classified into four groups: non-users, exclusive combustible cigarette users, exclusive liquid e-cigarette users, and dual users. Inadequate sleep duration was defined as less than 7 hours of sleep per day, according to the National Sleep Foundation’s age-specific recommendations. Logistic regression analysis was performed to evaluate the incidence of inadequate sleep, according to smoking patterns.Results: After adjusting for covariates, logistic regression analysis showed that both exclusive combustible cigarette users and dual users had significantly higher odds of inadequate sleep duration compared to non-users (adjusted odds ratio [AOR]=1.11, 95% confidence interval [CI]: 1.02–1.20; p=0.010 and AOR=1.25, 95% CI: 1.01–1.55; p=0.043, respectively). Although the trend between exclusive e-cigarette use and inadequate sleep was consistent, it was not statistically significant (AOR=1.34, 95% CI: 0.90–1.99; p=0.153).Conclusion: Smoking only combustible tobacco cigarettes, as well as the dual use of e-cigarettes and combustible cigarettes, is linked to inadequate sleep duration among Korean adults. Encouraging smoking cessation, particularly for dual users and combustible cigarette smokers, can help improve sleep health.