Atherosclerotic disease risk persists decades after smoking cessation

Adults who quit smoking reduced their risk for peripheral artery disease in the short term, but remained at increased risk for up to 30 years, compared with never-smokers, based on data from more than 13,000 adults in a community-based study.

^{Courtesy Journal of the American College of Cardiology}

Most reports on the impact of smoking cessation on cardiovascular disease have focused on coronary heart disease (CHD), and stroke, while data on the effects of smoking cessation on peripheral artery disease (PAD) are limited, wrote Ning Ding, MBBS, SCM, of the Johns Hopkins Bloomberg School of Public Health, Baltimore, Md., and colleagues.

To compare the impact of smoking on PAD, CHD, and stroke, the researchers used data from the Atherosclerosis Risk in Communities (ARIC) study, which included 15,792 adults aged 45-64 years in four communities. The findings were published in the Journal of the American College of Cardiology.

The study population of 13,355 individuals had no baseline history of PAD, CHD, or stroke. Over a median 26 years of follow-up, the researchers identified 492 cases of PAD, 1,798 cases of CHD, and 1,106 cases of stroke.

The risk of all three conditions began to decline within 5 years of smoking cessation, which could be encouraging to smokers who wish to quit, the researchers noted. In addition, the longer the duration of smoking cessation, the lower the risk for all three conditions (See central illustration).

However, a significantly elevated risk remained for PAD for up to 30 years after smoking cessation and for CHD for up to 20 years after smoking cessation, compared with never-smokers.

The researchers also found a roughly fourfold increased risk for PAD for smokers who smoked for 40 or more pack-years, compared with never-smokers, which was greater than the 2.1 hazard ratio for CHD and 1.8 HR for stroke. In addition, current smokers of at least one pack per day had a significantly greater risk of PAD, compared with never-smokers (HR, 5.36) that was higher than the risk for CHD or stroke (HR, 2.38 and HR, 1.88, respectively).

The study findings were limited by several factors including the reliance on self-reports, potential misclassification of data, and the potential exclusion of mild PAD cases that did not require hospitalization, the researchers noted. However, the results support the value of encouraging smokers to quit and support the need to include PAD risk in public health information, they said. “Although public statements about smoking and [cardiovascular disease] have been focusing on CHD and stroke, our results indicate the need to take account of PAD as well for comprehensively acknowledging the effect of smoking on overall cardiovascular health,” they added.

The ARIC study was funded by the National Heart, Lung, and Blood Institute, National Institutes of Health. Lead author Dr. Ding had no financial conflicts to disclose; coauthors disclosed relationships with Bristol-Myers Squibb and Fukuda Denshi.

SOURCE: Ding N et al. J Am Coll Cardiol. 2019 Jul 22;74:498-507. doi: 10.1016/j.jacc.2019.06.003.