The improvement in cardiovascular health that results from quitting smoking far outweighs the limited risks to cardiovascular health from the modest amount of weight gained after quitting, reports a National Institutes of Health-funded community study.
The study found that former smokers without diabetes had about half as much risk of developing cardiovascular disease as current smokers, and this risk level did not change when post-cessation weight gain was accounted for in the analysis.
This study is the first epidemiological effort to directly address the health impact of the weight gain that many people experience following smoking cessation. The findings will be published in the March 13 Journal of the American Medical Association.
"Our findings suggest that a modest weight gain, around 5-10 pounds, has a negligible effect on the net benefit of quitting smoking," says study co-author Caroline Fox, MD, MPH, senior investigator in the Laboratory for Metabolic and Population Health at the NIH's National Heart, Lung, and Blood Institute (NHLBI). "Being able to quantify to some degree the relationship between the benefits and side effects of smoking cessation can help in counseling those who have quit or are thinking about quitting."
Fox adds that the analysis could not definitively conclude the role of modest weight gain in former smokers with diabetes, though the numbers suggested a similar trend. She noted that follow-up studies to confirm this negligible effect of weight gain in people with diabetes would be important, as weight control is a key factor in managing diabetes and preventing diabetes-related heart problems.
The study team analyzed data collected between 1984 and 2011 from 3,251 participants enrolled in the NHLBI's Framingham Heart Study. During this time, participants received periodic medical exams so that researchers could calculate changes in weight and smoking status. Participants were divided whether they had diabetes or not, then further divided into four smoking categories: smokers, non-smokers, recent quitters (quit for four years or less), and long-term quitters (quit for more than four years). The researchers then examined the occurrence of cardiovascular problems such as coronary heart disease, stroke or heart failure in each group.
The initial analysis, which did not account for any changes in weight, found that former smokers without diabetes had about half as much risk of cardiovascular problems as smokers (0.47 times the risk for recent quitters and 0.46 for long-term quitters). By comparison, non-smokers had about one-third as much risk (0.32).
The researchers then made statistical adjustments to account for the fact that recent quitters gained more weight on average than other groups (about 6.5 pounds). The researchers found that even accounting for weight, the lowered risk remained nearly the same for recent quitters (going from 0.47 to 0.49 times the risk). The lowered risk for long-term quitters and non-smokers remained constant when adjusting for weight gain.