A cohort study by Korean scientists has shown that it may take more than 25 years to reduce the residual risk of developing cardiovascular disease in people with an eight-pack-year smoking history. At the same time, for people with a shorter smoking history, this period was about ten years. The work was published in JAMA Network Open.
Smoking is the leading modifiable risk factor for cardiovascular disease, causing more than eight million deaths worldwide each year. With smoking cessation counseling, nicotine replacement therapy, drug treatment, and increased cultural and social awareness, the smoking rate among adults has declined from 32.7 percent in 2000 to 22.3 percent in 2020. However, the literature is poor in studies examining time-course changes in cardiovascular disease risk after smoking cessation.
A research team led by Jun Hwan Cho from Chung Ang University Hospital assessed the quantitative association between smoking cessation and subsequent cardiovascular disease risk depending on the duration of smoking and the time since quitting. To do this, the scientists analyzed a cohort of 5,391,231 participants. Overall, the incidence of cardiovascular disease was significantly higher among former and current smokers than among those who had never smoked.
In addition, compared with current smokers, former smokers with a smoking history of fewer than eight pack-years had a significantly reduced risk of developing cardiovascular disease in the 10 years after quitting. However, smokers with a smoking history of more than eight pack-years had a slower reduction in the risk of developing cardiovascular disease than quitters with a short smoking history. The researchers estimated that the residual risk decreased for 25 years after quitting.
Based on the results of this work, the researchers propose that former heavy smokers with a smoking history of more than eight pack-years be treated the same as current smokers in terms of cardiovascular risk assessment. Potentially, such patients require similar cardiovascular disease prevention and treatment methods as current smokers.
We previously reported that quitting smoking after being diagnosed with coronary heart disease almost halved the risk of developing a heart attack.