"Cigarette smoking is the leading cause of preventable mortality in the United States and a major risk factor for cardiovascular disease (CVD). Smoking cessation substantially reduces the risks of CVD; however, quitting smoking is associated with a small number of adverse health consequences, weight gain being one of smokers' major concerns," according to background information in the article. The average postcessation weight gain varies between 6.6 lbs. and 13.2 lbs. in North America, happens within 6 months after smoking cessation, and persists over time. Obesity is also a risk factor for CVD.
Weight gain following smoking cessation therefore might lessen the benefits of quitting smoking on CVD outcomes. In addition, among people with type 2 diabetes, weight gain following smoking cessation has potential to be of greater concern because it is a risk factor for poor diabetes control and increased risk of illness and death. "The effect on CVD of potential weight gain following smoking cessation is not well understood," the authors write.
Carole Clair, M.D., M.Sc., of the University of Lausanne, Switzerland, and colleagues conducted a study to assess the association between 4-year weight gain following smoking cessation and CVD event rate among adults with and without diabetes. The study included data from the Framingham Offspring Study collected from 1984 through 2011. At each 4-year examination, self-reported smoking status was assessed and categorized as smoker, recent quitter (≤ 4 years), long-term quitter (>4 years), and nonsmoker. 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. The primary outcome measure was the incidence over 6 years of total CVD events, comprising coronary heart disease, cerebrovascular events, peripheral artery disease, and congestive heart failure.
Weight gain occurred over 4 years in participants without and with diabetes. Among participants without diabetes, recent quitters gained significantly more weight (median [midpoint], 5.9 lbs.) than long-term quitters (1.9 lbs.), smokers (1.9 lbs.), and nonsmokers (3 lbs.). Among patients with diabetes, recent quitters also gained significantly more weight (7.9 lbs.) than smokers (1.9 lbs.), long-term quitters (0.0 lbs., and nonsmokers (1.1 lbs.).
After an average follow-up of 25 years, 631 CVD events occurred among 3,251 participants. The researchers found that among participants without diabetes, the age- and sex-adjusted CVD incidence rates were lower for nonsmokers, recent quitters, and long-term quitters, compared with smokers.
After adjustment for CVD risk factors, compared with smokers, recent quitters had a 53 percent lower risk for CVD and long-term quitters had a 54 percent lower risk for CVD; these associations had only a minimal change after further adjustment for weight change. "Among participants with diabetes, there were similar point estimates that did not reach statistical significance," the authors write.
The researchers observed similar benefits associated with smoking cessation for total CVD and for fatal and non-fatal coronary heart disease, with the cessation benefits not offset by weight gain.
"In conclusion, among adults without diabetes, quitting smoking was associated with a lower risk of CVD compared with continuing smoking. There were qualitatively similar lower risks among participants with diabetes that did not reach statistical significance, possibly because of limited study power. Weight gain that occurred following smoking cessation was not associated with a reduction in the benefits of quitting smoking on CVD risk among adults without diabetes. This supports a net cardiovascular benefit of smoking cessation, despite subsequent weight gain," the authors write.(JAMA