Same CVD Risk When Former Smokers Gain Weight
Weight gained after someone quits smoking has no effect on the cardiovascular benefits of butting out, at least among people without diabetes, researchers reported.
In a prospective community-based cohort with more than 20 years of data, former smokers had about half the risk of developing cardiovascular disease as smokers, according to Carole Clair, MD, of the University of Lausanne in Lausanne, Switzerland, and colleagues.
But adjusting those estimates for weight gained after stopping smoking had no significant effect, Clair and colleagues reported in the March 13 issue of the Journal of the American Medical Association.
The results, strictly speaking, apply only to participants without diabetes, Clair and colleagues reported, but estimates were similar among those with diabetes, although they did not reach statistical significance.
They concluded that the findings support “a net cardiovascular benefit of smoking cessation, despite subsequent weight gain.”
Indeed, “overall, the study supports the belief that smoking cessation is beneficial for smokers,” commented Michael Fiore, MD, and Timothy Baker, PhD, both of the University of Wisconsin School of Medicine and Public Health in Madison.
And importantly, they argued in an accompanying editorial, “no subpopulation has yet been identified that shows significantly reduced benefit from quitting, let alone harm.”
Clinicians, they concluded, can use the study to reassure smokers that any weight gain won’t take away the cardiovascular benefits of quitting tobacco. Although the knowledge may not assuage concerns about appearance, Fiore and Baker argued, it still might help tip the balance.
The researchers noted that cigarette smoking is the leading cause of preventable mortality in the U.S. and a major risk factor for cardiovascular disease. Quitting cuts the risk of cardiovascular disease, but it has not been clear what effect subsequent weight gain might have, since obesity is also a risk factor.
To try to clarify the issue, Clair and colleagues used data from the long-running Framingham Offspring Study, collected from 1984 through 2011 and involving 3,251 participants who were free of cardiovascular disease at the beginning of the analysis.
Participants had a physical examination every 4 years, and at each exam investigators categorized their self-reported smoking status as smoker, recent quitter (within the previous 4 years), long-term quitter (off tobacco for more than 4 years), and nonsmoker.
Clair and colleagues estimated the association between quitting smoking and incident cardiovascular disease, as well as testing whether post-quitting change in weight had any effect on that association.
As expected, quitting smoking led to weight gains, they found.
Among participants without diabetes, recent quitters gained a median of 5.9 lbs., significantly more than long-term quitters (at 1.9 lbs.), smokers (also at 1.9 lbs.), and nonsmokers (at 3.0 lbs.).
Among patients with diabetes, recent quitters also gained significantly more weight – a median of 7.9 lbs. — than smokers, long-term quitters, and nonsmokers, whose median gains were 1.9, 0, and 1.1 lbs., respectively.
After an average follow-up of 25 years, there were 631 cardiovascular disease events, Clair and colleagues reported.
Among participants without diabetes, the incidence rate – adjusted for age and sex — was 5.9 events per 100 person-examinations among smokers, compared with 3.2 in recent quitters, 3.1 in long-term quitters, and 2.4 in nonsmokers.
After the researchers adjusted for cardiovascular risk factors, recent quitters had a hazard ratio for cardiovascular disease (compared with smokers) of 0.47 (95% CI 0.23 to 0.94). For long-term quitters, the hazard ratio was 0.46 (95% CI 0.34 to 0.63).
The associations underwent “only a minimal change” after they were adjusted for changes in weight, Clair and colleagues reported.
The researchers cautioned that they did not use biochemical measures to verify smoking status. In addition, the participants were mostly white, so it’s not clear how widely the findings apply.