Trends in Combustible Cigarette Smoking, Electronic Cigarette Use, and Related Behaviors among Korean Adults: An 11-Year Analysis of Data from the Korea National Health and Nutrition Examination Survey (2013–2023)

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Tuberc Respir Dis. 2026;89(2):245-256

Publication date (electronic) : 2026 February 19

doi : https://doi.org/10.4046/trd.2025.0201

Won Jin Yang

Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea

Address for correspondence Won Jin Yang Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Korea University Anam Hospital, Korea University College of Medicine, 73 Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea Phone 82-2-920-5439 Fax 82-2-920-5439 E-mail octa821@kumc.or.kr

Received 2025 December 12; Revised 2026 January 4; Accepted 2026 February 9.

Abstract

Introduction

Smoking causes approximately 8 million deaths worldwide annually, of which 1.3 million are attributable to second-hand smoke [1]. Smoking is a risk factor for major chronic diseases such as lung cancer, chronic obstructive pulmonary disease, and cardiovascular disease, with younger age at initiation and longer duration of exposure exacerbating disease risk [2]. Following implementation of the World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC), policies such as tax increases, expansion of smokefree areas, and warning labels have reduced traditional cigarette smoking rates [3]. However, the rapid spread of e-cigarettes and heated tobacco products (HTPs) threatens tobacco control achievements, raising concerns about dual use and youth smoking initiation [4,5].

E-cigarettes are promoted as a less harmful smoking cessation aid compared with combustible cigarettes because they vaporize nicotine-containing liquids rather than burning tobacco [6,7]. However, cohort studies indicate that while some smokers succeed in quitting, dual use may maintain or worsen nicotine dependence and cardiopulmonary health risks [8]. HTPs reduce some carcinogens by heating rather than burning tobacco but still emit volatile organic compounds and fine particles, with long-term safety remaining uncertain [9]. In Korea, HTP use surged in 2017, and they are being used by adolescents over relatively short periods [10,11].

Korea has historically recorded high male smoking rates (71.7% in 1992), but FCTC-based policies reduced this rate by approximately 30% (39.7% in 2016) [12]. However, increasing e-cigarette use and risks of youth smoking initiation emerge as public health challenges [13,14]. The coronavirus disease 2019 (COVID-19) pandemic reduced second-hand smoke exposure but may have lowered intention to quit owing to increased home e-cigarette use and economic stress [15]. Motivations for e-cigarette use (odorless nature, social acceptability, perceived harm reduction) are similar to global trends, but further investigation within Korea’s cultural context is needed [16,17]. Quitting intentions are generally low in Asia and vary with policy implementation and pharmacotherapy accessibility [18,19].

The outbreak of e-cigarette or vaping product use-associated lung injury (EVALI; approximately 2,800 cases) reported in the United States during 2019–2020 demonstrates the potential for aerosols to cause bronchiolitis and pneumonia [20]. The global trend for age at smoking initiation is 16 to 18 years, but early initiation among females has been observed in Korea [21,22]. Second-hand smoke remains a public health threat, and smoke-free policies have reduced exposure by 30%– 50%, although low-income areas remain vulnerable [23,24]. This study utilized Korea National Health and Nutrition Examination Survey (KNHANES IX-2) to analyze trends in traditional smoking, e-cigarette use, dual use, intention to quit, and second-hand smoke exposure from 2013 to 2023, investigating demographic differences to provide baseline data for strengthening Korea’s tobacco control and smoking cessation policies.

Materials and Methods

Results

This study utilized KNHANES IX-2 data to analyze smoking patterns among Korean adults from 2013 to 2023. The analysis showed an overall downward trend in smoking prevalence, with some recent rebound and an increasing pattern in e-cigarette use. Distinct differences were confirmed by sex, age, and income level, with meaningful changes in dual use, intention to quit, and second-hand smoke exposure. Below, results are presented focusing on detailed trends and periods of change by major indicators.

1. Current smoking prevalence

Current smoking prevalence decreased from 23.2% in 2013 to 18.5% in 2023 (–4.7%), reflecting a steady decline but with a rebound (1.6%) in 2023 after reaching its lowest point in 2022 (16.9%). The decline in current smoking rate was larger in males (41.4% to 32.1%; –9.3%), whereas females remained in the 5% range (5.7% to 5.1%) but showed a slight increase (0.6%) from 2022 (4.5%) to 2023. By age, the largest decrease was in the 30–39 years age group (30.7% to 18.3%; –12.4%), with decreases also observed in 19–29-year group (24.1% to 20.8%) and 40–49-year group (26.9% to 23.6%), but a slight increase was observed in the 50–59-year group (22.0% to 22.7%). By income level, the low-income group (27.6% to 24.8%) showed a clear rebound (4.9%) in 2023 after reaching its lowest level in 2022 (19.9%), whereas the middle-income (23.3% to 16.8%; –6.5%) and high-income groups (19.1% to 13.1%; –6.0%) showed sustained declines.

Periods of change included males in 2014–2015 (–4.0%), 2019–2022 (–5.3%), and 2022–2023 (2.7%); 30–39-year group in 2013–2023 (–12.4%) and 2016– 2017 (–4.9%); and by income level: low-income group in 2019–2020 (–4.4%) and 2022–2023 (4.9%) (Figure 1A and Supplementary Table S2).

Fig. 1.

Comprehensive trends in tobacco products use among Korean adults, 2013–2023. (A) Current smoking prevalence among Korean adults, 2013–2023. (B) Current prevalence of liquid-type e-cigarettes use among Korean adults, 2013–2023. (C) Current prevalence of heated tobacco product use among Korean adults, 2019–2023.

3. Multiple use

From 2019 to 2023, total tobacco product use (combined) decreased from 22.2% to 21.9%, but compared with the simple sum of individual use rates (2019: 27.9%; 2023: 26.6%), a difference of 4.7%–6.2% was confirmed, suggesting dual use. For example, in 2019, the simple sum was 27.9%, but actual combined use was 22.2% (–5.7%). The difference was large among young males aged 19–29 years (2019: –12.0%) and the low-income group (2019: –6.7%). Dual use was prominent among males aged 19–29 and 30–39 years (Figure 2 and Supplementary Table S5).

Fig. 2.

Comparison between the current use rate of tobacco products and sum of individual product use rates among Korean adults, 2019–2023. ‘A’: Current tobacco product use prevalence (accounting for dual use); ‘B’: Sum of current smoking prevalence, liquid-type e-cigarettes use prevalence, and heated tobacco products (HTPs) use prevalence (not accumulating for dual use). The difference between ‘B’ and ‘A’ indicates the extent of dual or multiple product use.

4. Age of smoking initiation

The average age at initiation remained largely unchanged at 19.8 years overall (2015–2023, –0.1 years). Males showed no major change and remained stable (19.3 years), whereas females showed a decrease from 24.2 to 22.7 years (–1.5 years), with large fluctuation among females 40–49 years (–4.3 years). By age, decreases were observed in the 60–69-year group (–0.9 years) and the ≥70-year group (–1.0 years), and by income level, a decrease was observed in the lower-middle-income group (–0.8 years).

Periods of high variability among females were overall 2016–2017 (–2.3 years), females aged 50–59 years in 2016–2017 (–3.8 years), and females aged 60–69 years in 2017–2018 (4.1 years) (Figure 3A and Supplementary Tables S6, S7).

Fig. 3.

Behavioral and motivational characteristics of tobacco use among Korean adults, 2013–2023. (A) Mean age at smoking initiation among ever smokers by sex and demographic characteristics. (B) Prevalence of intention to quit smoking within 1 month among current tobacco users, 2019–2023.

6. Motivations of HTP use

Odorless nature (no cigarette smell) was the most frequently cited motivation (43.9%), followed by perceived reduced harm (seems less harmful than combustible cigarettes, 18.4%), and perceived assistance with smoking cessation (helps quit smoking, 12.8%). Both males and females cited odorless nature as the highest motivation (males: 43.8%; females: 44.6%), with males reporting high rates of perceived reduced harm (20.7%) and females reporting high rates of curiosity (11.3%) and perceived assistance with cessation (13.7%). By age, curiosity was prominent in the 19–29-year group (14.4%), and perceived reduced harm was prominent in the 60–69-year group (46.8%); by income level, odorless nature was particularly prominent in the middle-in-come group (50.1%) (Figure 4 and Supplementary Table S10).

Fig. 4.

Motivations for heated tobacco product use among current users, 2019–2023. ‘A’: Perceived reduced harm compared with combustible cigarettes; ‘B’: Perceived assistance with smoking cessation; ‘C’: Ability to use indoors; ‘D’: Absence of cigarette odor; ‘E’: Perceived reduced second-hand smoke exposure to others; ‘F’: Ability to conceal smoking behavior; ‘G’: Absence of cigarette ash; ‘H’: Curiosity; and ‘I’: Other reasons.

7. Second-hand smoke exposure

Non-users’ workplace exposure decreased from 14.2% in 2019 to 7.6% in 2023 (–6.6%), public place exposure decreased from 16.8% to 7.4% (–9.4%). During the 2019–2021 COVID-19 period, public place second-hand smoke rate exposure in the 19–29-year group decreased by 14.8% overall (males: –19.2%; females: –11.5%), but a rebound (3.0%) was confirmed in 2022– 2023. By sex, prominent decreases were observed in male workplace exposure (–7.0%), and female public place exposure (–8.6%); by age in the 19–29-year group’s public place exposure (–14.6%); and by income level in lower-middle-income group’s public place exposure (–10.5%).

Periods of change included public place exposure in the 19–29-year group in 2019–2020 (–10.5%) and 2022–2023 (3.0%) and workplace exposure in the 50–59-year group in 2022–2023 (4.3%) (Figure 5A and Supplementary Tables S11-S14).

Fig. 5.

Second-hand smoke exposure in non-users of tobacco products across multiple indoor environments, 2019–2023. (A) Prevalence of second-hand smoke exposure in indoor workplace and public places among current tobacco product non-users, 2019–2023. (B) Prevalence of second-hand smoke exposure in indoor home settings among current tobacco product non-users, 2019–2023.

Non-smokers’ home second-hand smoke exposure rate decreased from 4.3% in 2019 to 2.6% in 2023 (–1.7%), with higher exposure among females (5.8% to 3.4%) than males (2.2% to 1.4%). By age, the highest exposure was in the 19–29-year group (7.8% to 5.6%), and the lowest in the ≥70-year group (2.7% to 1.1%). By income level, exposure was relatively high in low- and lower-middle-income groups, but all levels recorded their lowest rates in 2022 followed by slight rebound in 2023. Overall, home second-hand smoke rates decreased during COVID-19 period (2020–2021), with some increases in certain age groups and income levels in 2023 alongside the resumption of social activities (Figure 5B and Supplementary Tables S15, S16).

Discussion

This study analyzed smoking patterns among Korean adults from 2013 to 2023 based on KNHANES IX-2 data, confirming trends such as decreased smoking rates, increased e-cigarette use, weakened intention to quit, and reduced second-hand smoke exposure. Smoking rates decreased from 23.2% to 18.5% (–4.7%), reflecting the effects of WHO FCTC-based policies such as tax increases, expansion of smoke-free areas, and advertising regulations [1]. For example, the large decreases among males (–9.3%) and in the 30–39-year age group (–12.4%) can be attributed to workplace smoking cessation programs targeting working-age groups and tax increases, consistent with studies reporting smoking rate decreases following Korea’s 2015 cigarette price increase [25]. However, the 2022–2023 rebound (1.6%) can be explained by resumption of social activities post-COVID-19, economic stress, and relaxed policy enforcement, similar to post-pandemic smoking rebounds observed in US Centers for Disease Control and Prevention reports [26]. The low-income group’s rebound (4.9%) emphasizes health inequalities, consistent with studies on income disparities that highlight lack of policy accessibility in low-income groups [27].

Liquid-type e-cigarette use increased from 1.1% to 3.3% (2.2%), predominantly in young males aged 30–39 years (11.1%) [4]. This suggests substitution effects attributable to e-cigarettes’ appeal (odorless nature, 43.9%;harm reduction, 18.4%), but dual use (4.7%–6.2%) may slow overall smoking reduction [5]. HTP use stabilized at 4.8%, but increased among females aged 19–29 years (3.4%), and curiosity as a motivation (11.3%) raises concerns about risks of youth smoking initiation. The decrease in female age at smoking initiation (–1.5 years) may result in increased burden of lung cancer and cardiovascular diseases, consistent with Australian studies linking declines in female smoking initiation age to increased cancer incidence [28].

The decrease in intention to quit (–4.1%) is likely attributable to e-cigarette motivations such as odorless (43.9%) and perceived harm reduction (18.4%), suggesting that e-cigarettes may delay smoking cessation [8]. Fluctuations in quit intentions among young females aged 19–29 years (+21.4%/–29.5%) can be attributed to social pressures and marketing influences, similar to UK and Australian studies reporting that social factors (60%–70%) affect quit intentions [29]. The decline in second-hand smoke exposure from 2019 to 2023 (workplace, –6.6%; public places, –9.4%) demonstrates the success of smoke-free policies, but the rebound in 2023 in public places (3.0%) may be due to weakened policy enforcement or resumption of activities, consistent with Japanese studies on post-COVID smoking environment changes [30]. High second-hand smoke exposure in low-income groups raises health inequality issues, consistent with United States studies emphasizing income-based smoking exposure disparities [31].

Overall, despite smoking reductions, increased e-cigarette use and weakened intentions of quitting present new public health challenges. Future research should focus on long-term health impacts of e-cigarettes and development of tailored policies by target population, emphasizing the need for KNHANES IX-2-based longterm tracking studies [32].

This study has some limitations. First, the KNHANES IX-2 survey employs a cross-sectional design, making it difficult to identify causal relationships between smoking, e-cigarette use, and health outcomes. Second, key variables such as smoking, intention to quit, and e-cigarette use are collected via self-reported, potentially leading to underreported smoking rates. Among females in particular, there may be a high risk of underreporting smoking status due to social desirability bias. Third, although questionnaire items on liquid-type e-cigarette use have been included in the KNHANES since 2011, the present study focused on the period from 2013 to 2023 to describe recent long-term trends in smoking behaviors. In contrast, items related to HTPs were introduced only in 2019, which limits the assessment of long-term trends for HTP use. Additionally, KNHANES IX-2 is designed to survey general household residents, excluding some groups such as hospital inpatients, military personnel, and correctional facility residents, which may limit the generalizability of findings regarding smoking behaviors in these vulnerable populations. Finally, owing to personal information protection policies, analysis at the regional (city/county/district) level was impossible, preventing evaluation of differences in smoking environments and second-hand smoke exposure.

In conclusion, Korea’s traditional cigarette smoking rate decreased from 23.2% to 18.5% during 2013–2023, representing meaningful progress in tobacco control. However, increases in e-cigarette use (3.3%) and dual use (4.7%–6.2%) represent emerging public health challenges that require attention. Our findings reveal distinct patterns by demographic characteristics, with particularly notable increases in e-cigarette use among younger males and concerning trends in low-income populations. These patterns highlight the need for targeted youth education and smoking cessation support programs tailored to younger generations and low-income groups. The observed post-pandemic rebound in smoking rates and weakened quitting intentions further emphasize the importance of sustained policy enforcement and adaptive interventions. Continuous monitoring through nationally representative surveys and implementation of demographic-specific interventions will be essential to enhance our understanding of evolving tobacco use behaviors and inform the development of effective tobacco control policies suited to population characteristics.

Supplementary Material

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