Heavy cigarette smokers with at least a 20 pack-year smoking history can reduce their risk of cardiovascular disease (CVD) by 39% within five years if they quit. However, it takes at least five to 10 years, and perhaps up to 25 years after quitting to lower a smoker’s CVD risk level to that of a non-smoker, according to a study published in the Journal of the American Medical Association.
Previous studies have found an association between quitting and reduced CVD risk, but the current Atherosclerotic CVD Risk Calculator, which is routinely used in clinical practice, considers former smokers’ risk after years of cessation to be similar to those who have never smoked, which is not consistent with the current findings.
The researchers used the Framingham Heart Study, a longitudinal study of men and women from Framingham, MA, which began enrollment in 1948 and now includes their children and grandchildren, as well as multiethnic cohorts.
The prospective data included 8,770 participants from 1954 through 2014. This participant group consisted of 3,805 individuals from the Original cohort and 4,965 from the Offspring cohort. Researchers aimed to determine the effect of lifetime smoking and smoking cessation on the risk of CVD, which includes myocardial infarction, stroke, CVD death and heart failure.
The Framingham Heart Study provided robust data on lifetime smoking history as well as a unique opportunity to document CVD risk after quitting smoking compared with the risk of those who have never smoked. They found that former heavy smokers’ risk of cardiovascular disease was significantly lower within five years of smoking cessation relative to current smokers. However, the risk remained significantly elevated for up to 10 years and possibly for 25 years after cessation relative to those who never smoked.
Cigarette smoking is responsible for 20% of CVD deaths in the United States, according to the report. The study authors urge smokers to act on these study results by putting out their cigarettes.