Smoking cessation reduces the risks of cardiovascular disease (CVD), but weight gain that follows quitting smoking may weaken the CVD benefit of quitting.
To test the hypothesis that weight gain following smoking cessation does not attenuate the benefits of smoking cessation among people with and without diabetes.
Design, Setting, and Participants
Prospective community-based cohort study using data from the Framingham Offspring Study collected from 1984 to 2011. At each 4-year exam, self-reported smoking status was assessed and categorized as smoker, recent quitter (≤ 4 years), long-term quitter (> 4 years), and non-smoker. Pooled Cox proportional hazards models were used to estimate the association between quitting smoking and 6-year CVD events and to test whether 4-year change in weight following smoking cessation modified the association between smoking cessation and CVD events.
Main outcome measure
Incidence over 6 years of total CVD events, comprising coronary heart disease, cerebrovascular events, peripheral artery disease, and congestive heart failure.
After a mean follow-up of 25 years (SD, 9.6), 631 CVD events occurred among 3251 participants. Median 4-year weight gain was greater for recent quitters without diabetes (2.7 kg, Interquartile range [IQR] −0.5-6.4) and with diabetes (3.6 kg, IQR −1.4-8.2) than for long term quitters (0.9 kg, IQR −1.4-3.2 and 0.0 kg, IQR −3.2-3.2, respectively, p<0.001). Among people without diabetes, age and sex-adjusted incidence rate of CVD was 5.9/ 100 person-exams (95% confidence interval [CI] 4.9-7.1) in smokers, 3.2/ 100 person-exams (95% CI 2.1-4.5) in recent quitters, 3.1 /100 person-exams (95% CI 2.6-3.7) in long-term quitters, and 2.4 /100 person-exams (95% CI 2.0-3.0) in non-smokers. After adjustment for CVD risk factors, compared with smokers, recent quitters had a hazard ratio (HR) for CVD of 0.47 (95% CI, 0.23-0.94) and long-term quitters had an HR of 0.46 (95% CI, 0.34-0.63); these associations had only a minimal change after further adjustment for weight change. Among people with diabetes, there were similar point estimates that did not reach statistical significance.
Conclusions and Relevance
In this community based cohort, smoking cessation was associated with a lower risk of CVD events among participants without diabetes, and weight gain that occurred following smoking cessation did not modify this association. This supports a net cardiovascular benefit of smoking cessation despite subsequent weight gain.