Association between smoking status and death from COVID-19 in South Korea: A nationwide cohort study

INTRODUCTION This study examined the association between smoking status andMETHODS This study used nationwide cohort data collected from the Korean National Health Insurance Service, linking to information on all individuals who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The smoking status of subjects who participated twice in national health screenings between 2015 and 2018 was measured. This study investigated death from COVID-19 among those who tested positive from 1 January to 30 May 2020.RESULTS This study included 4259 patients who tested positive for SARS-CoV-2 in Korea. After adjusting for all potential confounding factors, current smokers (adjusted odds ratio, AOR=3.75; 95% CI: 1.23-11.36) and recent quitters (AOR=3.74; 95% CI: 1.12-12.53) were associated with an increased risk of death from COVID-19 compared to never smokers. Compared with current smokers, long-term quitters (AOR=0.33; 95% CI: 0.11-0.95) and never smokers (AOR=0.27; 95% CI: 0.09-0.81) were associated with a reduced risk of death from COVID-19.CONCLUSIONS Smoking was associated with an increased risk of death among patients with COVID-19. Given the lower possibility of death in long-term quitters with COVID-19, continuous smoking cessation among smokers or recent quitters is needed.