Association of Smoking and E-Cigarette in Chronic Liver Disease: An NHANES Study.

Background: There is an increased trend of e-cigarette but the toxic effects of e-cigarette metabolites are not widely studied especially in liver disease. Hence, we aimed to evaluate the prevalence and patterns of recent e-cigarette use in a nationally representative sample of US adults and adolescents and its association amongst respondents with liver disease.

Methods: We conducted a retrospective cross-sectional study using National Health and Nutrition Examination Survey (NHANES) database from 2015 to 2018. The self-reported NHANES questionnaire was used to assess liver disease (MCQ160L, MCQ170L and MCQ 510 (a-e)), e-cigarette use (SMQ900) and traditional smoking status (SMQ020 or SMQ040). We conducted univariate analysis and multivariable logistic regression models to predict the association of e-cigarette use, traditional smoking and dual smoking amongst the population with liver disease.

Results: Out of total 178,300 respondents, 7,756 (4.35%) were e-cigarette users, 48,625 (27.27%) traditional smoking, 23,444 (13.15%) dual smoking and 98,475 (55.23%) non-smokers. Females had a higher frequency of e-cigarette use (49.3%) compared to dual (43%) and traditional smoking (40.8%) (P < 0.0001). Respondents with a past history of any liver disease have lower frequency of e-cigarette use compared to dual and traditional smoking, respectively (2.4% vs. 6.4% vs. 7.2%; P < 0.0001). In multivariate logistic regression models, we found that e-cigarette users (odds ratio (OR): 1.06; 95% confidence interval (CI): 1.05 - 1.06; P < 0.0001) and dual smoking (OR: 1.50; 95% CI: 1.50 - 1.51; P < 0.0001) were associated with higher odds of having history of liver disease compared to non-smokers.

Conclusion: Our study found that despite the low frequency of e-cigarette use in respondents with liver disease, there was higher odds of e-cigarette use amongst patients with liver disease. This warrants the need for more future prospective studies to evaluate the long-term effects and precise mechanisms of e-cigarette toxicants on the liver.