Association between dual smoking and dyslipidemia in South Korean adults

Objectives: Dyslipidemia increases the risk of serious cardiovascular disease; and conventional cigarette smoking is widely recognized as a risk factor. Thus, as electronic cigarettes were introduced, many smokers utilized them for smoking cessation. However, due to the lack of researches scrutinized the relationship between dual smoking and dyslipidemia, a lot of those who failed in cessation end up utilizing both types of cigarettes (dual smoking). Therefore, this study aimed to examine the effect of dual smoking on dyslipidemia in South Korean adults. Methods: Data were included from the 2013, 2014, 2015, 2016, and 2019 Korean National Health and Nutrition Examination Survey of 8,398 Korean men. The KNHANES is conducted by a national institution based on random cluster sampling, and therefore, the data gained from it is statistically reliable and representative in comparison to surveys performed by private institutions. Cigarette use status was the main independent variable. Cigarette use status was categorized as one of the four status: dual smoker, single smoker, non-smoker, and ex-smoker. The dependent variable, presence of dyslipidemia, was defined according to the National Cholesterol Education Program as displaying one or more of the following criteria: total cholesterol: ≥240 ㎎/dL, LDL cholesterol: ≥160 ㎎/dL, triglyceride: ≥200 ㎎/dL, or HDL cholesterol: ≤40 ㎎/dL. Multiple logistic regression analysis was performed to examine target association. Results: Current and former users of either electronic or conventional cigarettes presented with a higher odd ratio of dyslipidemia compared to non-smokers. (ex-smoker: OR = 1.60, 95% CI = 1.41–1.83; single smoker: OR = 1.21, 95% CI = 1.06–1.38). More importantly, those who smoke both conventional and electronic cigarettes were also, at high risk of dyslipidemia (dual smoker: OR = 1.66, 95% CI = 1.26–2.20). Along with smoking status, those who did not exercise had a higher risk of dyslipidemia than those who exercised regularly and higher self-reported health status was also related to a lower risk of dyslipidemia. Conclusion: This study suggests that along with conventional cigarettes, dual smoking negatively impacts dyslipidemia, and smoking cessation of evert types is necessary for a healthy life.