Effects of smoking cessation on the risk of cardiovascular disease: a nationwide population-based study

Abstract

Abstract Introduction Cardiovascular disease (CVD) is the global leading cause of death, and the economic and social burden of CVD is still increasing, Smoking is one of the top three leading risk factors for the disease and one of the well-established and important modifiable risk factors for CVD. However, the time course of CVD risk after smoking cessation is unclear. Purpose We assess the association between smoking and CVD and the incidence of CVD with years quitting smoking. Methods This study used the Korean National Health Insurance Service (NHIS) database. Self-reported smoking habit data were used to classify participants as current, former or never smokers and to investigate the duration and intensity of smoking. Smoking records of participants were updated every 2 years, and all participants whose smoking records were changed or unclear were excluded. The primary outcome was the development of CVD, including myocardial infarction, stroke, heart failure, and cardiovascular death. Results Total 5,391,231 participants (953,756 subjects were current smokers, 104,604 subjects were former smokers, 4,432,871 subjects never smoker) were followed-up for an average of 4.2 years. The mean age was 45.8 years, 39.9% were male. Cumulative pack-year (PY) were 14 in current smoker, 10.5 in former smokers at baseline. The median years of quitting smoking for former smoker was 4. Regardless of whether smoking continues or not, a dose-dependent relationship exists between smoking and CVD (Fig. 1). For those smoked less than 8PY, smoking cessation significantly lowered the CVD risk within 10 years compared to current smokers, and the CVD risk was not significantly different from never smokers (Fig. 2A). However, in the case of smokers over 8PY, although smoking cessation affects the reduction of CVD, the CVD risk decreases slowly over decades, and it takes more than 20 years for the effect of smoking on the CVD risk to disappear (Fig. 2B). Conclusion Smoking and CVD have a dose-dependent relationship, and mild smokers with less than 8PY had a similar CVD risk to never smokers when quitting smoking. However, for heavy smokers over 8PY, it takes a long time for the CVD risk from smoking to disappear Funding Acknowledgement Type of funding sources: None.