People who have quit smoking have a lower chance of suffering a heart attack or stroke than current smokers, even if they put on a few extra kilos in the process, according to an international study.
The long-term cardiovascular benefits of kicking the smoking habit have been well-established, but researchers whose report appeared in the Journal of the American Medical Association said that it's been unclear how the weight gain that often accompanies quitting fits into the picture.
"Weight gain is a real concern for smokers who want to quit and this might not only be an aesthetic one," said Carole Clair, from the University of Lausanne in Switzerland and Massachusetts General Hospital in Boston.
"Overweight and obesity are risk factors for coronary heart disease, and it has been a concern that especially among people already at risk for (cardiovascular disease), weight gain following smoking cessation might cancel or at least decrease the benefits of smoking cessation," she added.
Smokers' heart rate and other body functions are revved up by nicotine, which may cause them to burn slightly more calories than nonsmoker - so when they quit, their metabolisms slow down. Recent quitters tend to compensate for nicotine withdrawal by snacking, according to Clair - hence the weight gain.
She and her colleagues analysed data from a long-term study of 3,251 people who took health surveys every four years between 1984 and 2011. At the onset, just under one-third of those participants were smokers.
Over an average of 25 years, 631 of all participants suffered a heart attack or stroke, or developed heart failure or another type of cardiovascular disease.
Both people who said they'd quit smoking since their last check-in, and longer-term quitters, were about half as likely to have heart problems as those who were still using cigarettes.
Quitters gained an average of 2.7 to 3.6 kilograms (6 to 8 lbs) after kicking the habit, consistent with past research. But quit-related weight gain had no clear effect on cardiovascular health, the team wrote.
"It's an understandable concern - might that weight gain offset the benefits that are known for quitting smoking?" said Michael Fiore from the University of Wisconsin School of Medicine and Public Health in Madison, who co-wrote a commentary published with the study.
"This is a good news story. You can be assured that if you quit smoking, even with a little bit of weight gain, you're going to achieve important health benefits."
He and colleague Timothy Baker pointed out in their commentary that the new study couldn't zero in on the small proportion of people who gain more than 9 kg (20 lbs) during a quit attempt. It's possible those former smokers might still be at risk for health problems tied to weight gain.
Even if adding a few kilos seems to be okay heart-wise, Fiore said there are steps quitters can take to try to keep off extra weight.
"We know that nicotine is an appetite suppressant, and when people quit smoking they often have an urge to eat more food,"he said. "What we need to do is ensure that the foods we're eating are low-fat, low-calories foods."
In addition, building a little more exercise into daily routines can also blunt weight gain, while nicotine gums or lozenges might also help keep weight gain under control.