Previous studies reported that the COVID-19 pandemic affected trends in the prevalence of smoking; however, the results are inconclusive owing to small sample sizes, inadequate study designs, non-representative enrolled samples, short-term follow-up periods including only the early pandemic (2020), and non-comprehensive smoking type (i.e., only traditional smoking usage).[1, 2]
The hypothesis of our study was that the COVID-19 pandemic will affect cigarette smoking and e-cigarette usage, compared to before the pandemic. In the past, we published preliminary research findings; however, we have since elaborated on additional papers through a more comprehensive analysis. Consequently, our objective was to conduct a thorough examination of the enduring prevalence of cigarette smoking and e-cigarette usage both prior to (2014 to 2019) and during the COVID-19 pandemic (2020 to 2021) within the Korean adult population.
We aimed to investigate the long-term prevalence of cigarette and e-cigarette smoking before (2014 to 2019) and during the COVID-19 pandemic (2020 to 2021) among Korean adults. Data were obtained from the Community Health Survey (CHS) between 2014 and 2021 (nationwide long-term serial study). The data utilized in this study were derived from the Community Health Survey (CHS), conducted by the Korea Disease Control and Prevention Agency (KDCA).[3, 4] Korean adults (age ≥19 years) were enrolled and their baseline information, body measurements, and health-related outcomes were obtained (n=1,539,982). The protocol used in the study was approved by the Korea Disease Control and Prevention Agency (KDCA). Every participant provided written informed consent at the time of their enrollment into the study. In our previous study, we provided a demographic description of the population distribution.
Smoking was considered as having smoked a cigarette or an e-cigarette within the last year. Current smokers were divided into two groups: traditional smokers (cigarettes) and e-cigarette smokers.
We included age (19 to 39, 40 to 59, and ≥60 years), sex, residence region (urban areas [Seoul, Gyeonggi, Incheon, Daejeon, Sejong, Gwangju, Ulsan, Daegu, and Busan] and rural areas [Gangwon, Chungbuk, Chungnam, Jeonbuk, Jeonnam, Gyeongbuk, Gyeongnam, and Jeju]),[5, 6] basic livelihood security recipient, household income (low, middle-low, middle-high, and high), education background (less than elementary school, middle school, high school, and above than college), occupational group (white-collar, blue-collar, soldier, and unemployed), marital status, subjective health level (good, normal, and bad), walking activities (≤1, 2 to 4, and ≥5 times/week), body mass index (BMI, kg/m2; underweight [<18.5], normal [18.5 to 23], overweight [23 to 25], and obese [≥25]), and depressive experience within one year.
A post-hoc secondary analysis was performed separately by age group (19 to 39, 40 to 59, and ≥60 years), sex (male and female), residence region (urban and rural), basic livelihood security recipient, income (low, middle-low, middle-high, and high), education background (elementary school or less, middle school, high school, and college or more), occupational group (white-collar, blue-collar, soldier, and unemployed), marital status (married or single), subjective health level (good, normal, and bad), walking practice days (≤1, 2–4, and ≥5 times/week), BMI group (underweight, normal, overweight, and obese), and depressive experience. Statistical analyses were performed using the SAS software (version 9.4; SAS Institute, Cary, NC, USA). A two-sided p value <0.05 was considered statistically significant.
The study sample consisted of adults (aged ≥19 years) living in South Korea between 2014 and 2021 (Table 1). Smoking was considered as having smoked a cigarette (traditional smoker) or an e-cigarette (e-cigarette smoker) within the previous year (Fig. 1). 1,282,599 adults were included from 2014 to 2021, and the prevalence of total, traditional, and e-cigarette smokers were 22.4% (22.3 to 22.5; 95% CI), 20.8% (20.8 to 20.9; 95% CI), and 1.5% (1.5 to 1.6; 95% CI), respectively. The prevalence of total and traditional smokers decreased before the pandemic (β -0.047 [95% CI, -0.051 to -0.044] and β -0.074 [95% CI, -0.078 to -0.070]); however, they decreased less than expected during the pandemic (β -0.023 [95% CI, -0.026 to -0.020] and β -0.001 [95% CI, -0.005 to 0.002]). E-cigarette smokers increased before the COVID-19 pandemic (β 0.247 [95% CI, 0.235 to 0.259]); however, they decreased during the pandemic (β -0.203 [95% CI, -0.212 to -0.193]).
4. Plausible mechanism
Our study shows that traditional, total, and e-cigarette smokers tended to decrease less after the pandemic. During the COVID-19 pandemic, increased working from home, time spent alone, prevalence of unemployment, social isolation, and a lack of social contact due to social distancing may lead to loneliness and feeling stressful.[8-11] This plausible mechanism may support our main findings that the prevalence of smokers who were unemployed, and obese increased during the pandemic. In addition, along with growing evidence that e-cigarettes are no longer harmless alternatives to traditional cigarette, preference for e-cigarettes has declined. Also, wearing masks has been legally mandated in South Korea during the COVID-19 pandemic. Therefore, the inconvenience of smoking e-cigarettes indoors has increased, which would have led to a decrease in the e-cigarette smoking status as the result of our study.
5. Policy implication
Smoking is associated with an increased risk of respiratory diseases related to COVID-19,[14, 15] and it is necessary to determine the risk of cigarette and e-cigarette use during the COVID-19 pandemic. In particular, the prevalence of smokers who were unemployed and obese have increased during the pandemic. This supports the hypothesis that smokers may have vulnerable factors due to employment instability and economic stress across society due to the influence of the pandemic. Especially, smokers with obesity have an increased risk of heart disease when they have severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection; thus, such individuals as well as physicians should be more careful. A more active and precise strategy to prevent and quit smoking campaign (MPOWER, monitor tobacco use, protect from smoking, offer help to quit smoking, warn about the dangers of smoking, enforce bans on smoking sponsorship, and raise taxes) is needed during and after the pandemic.[18-20]
Through a post-hoc secondary analysis from a nationwide, long-term serial, and representative study of 1.2 million individuals, the prevalence of traditional smoking decreased less than expected during the pandemic; however, that of e-cigarette smoking decreased. Our results provide an improved epidemiological understanding of smoking status before and during the COVID-19 pandemic, and suggest that more individualized and precise strategies to prevent and quit smoking are needed to improve public and global health during the pandemic.