Weight Gain After Smoking Cessation: No Link With Increased CVD Risk in Young People

Fear of gaining weight can be a significant obstacle to quitting smoking, but a new study of people under age 40 provides reassurance that any weight gained is unlikely to increase the risk of cardiovascular disease and may even be protective.

“Although weight gain is associated with an increase in CVD risk, our analyses showed that weight gain attributable to smoking cessation does not adversely affect the overall cardiovascular health benefits of successfully quitting smoking in young adults,” Kyuwoong Kim, BSc (Seoul National University, Republic of Korea), and colleagues write in the July 2, 2019, issue of the Journal of the American College of Cardiology.

The researchers used a Korean database to evaluate over 2 million people between the ages of 20 and 39 years. Participants were categorized as never smokers, quitters, or continual smokers and their health was tracked for approximately 10 years.

Compared with continual smokers, those who quit gained approximately two additional pounds over the study period, but their risk of cardiovascular events was lower (HR 0.82; 95% CI 0.78-0.87). Somewhat surprisingly, the data also appear to suggest that the benefit of quitting on event rates was actually greater with more weighed gained after smoking cessation: 0.71 (95% CI 0.62- 0.83) among those who gained more than 5.0 kg, 0.71 (95% CI 0.64-0.79) among those who gained 2.1 kg to 5.0 kg, 0.79 (95% CI 0.70-0.88) among those with weight gain of 0.1 kg to 2.0 kg, and 0.90 (95% CI: 0.83 to 0.98) for those with no weight gain after quitting.

Ongoing Questions About Weight Gain’s Impact

Kim and colleagues note that “risk estimates for quitters with weight gain showed a protective association” but do not directly address why or how the weight gain could offset future cardiovascular events.

“I don’t know of any reason why that should be protective,” said Nancy Rigotti, MD (Massachusetts General Hospital, Boston), who commented on the results in an email to TCTMD.

She said the study adds to prior research from the same group, but extends the findings to younger people and women. As with their prior study, Kim and colleagues relied on self-reported questionnaires for assessing change in smoking behavior, which Rigotti, as well as the authors themselves, acknowledge is a limitation. Another issue is that in the Korean smoking cessation studies, the amount of weight gained after quitting was relatively small overall and may not be consistent with what would be seen among smokers in different countries. According to Rigotti, it is unclear if the benefits would be different if quitters gained more weight than those in the Korean study populations did.

“The results of our study imply the need for promoting smoking cessation in young adults for CVD prevention, despite concern over weight gain,” Kim and colleagues conclude. “However, clinical intervention for those who gain substantial body weight after smoking cessation might be necessary to sustain cardiovascular health benefit of smoking cessation.”