Weight gain after quitting smoking linked to diabetes: NEJM

A new study published in The New England Journal of Medicine finds that substantial weight gain after smoking cessation is associated with an increased risk for type 2 diabetes (T2D) in the first six years after quitting. But it did not mitigate the benefits of quitting smoking on reducing cardiovascular and all-cause mortality.

Qi Sun, associate professor, the Harvard T.H. Chan School of Public Health in Boston, and colleagues conducted the study to determine whether weight gain after smoking cessation attenuates the health benefits of quitting is unclear.

For the study, the investigators identified men and women in the U.S. who had reported quitting smoking and then prospectively assessed changes in smoking status and body weight. Risks of T2D, death from cardiovascular disease, and death from any cause among those who had reported quitting smoking was then estimated according to weight changes after smoking cessation.

Also Read: Smoking linked with higher risk of type 2 diabetes

Key Findings:

• The risk of type 2 diabetes was higher among recent quitters (2 to 6 years since smoking cessation) than among current smokers.


• The risk peaked 5 to 7 years after quitting and then gradually decreased.


• The temporary increase in the risk of type 2 diabetes was directly proportional to weight gain, and the risk was not increased among quitters without weight gain.


• In contrast, quitters did not have a temporary increase in mortality, regardless of weight change after quitting.


• As compared with current smokers, the hazard ratios for death from cardiovascular disease were 0.69 (95% CI, 0.54 to 0.88) among recent quitters without weight gain, 0.47 (95% CI, 0.35 to 0.63) among those with weight gain of 0.1 to 5.0 kg, 0.25 (95% CI, 0.15 to 0.42) among those with weight gain of 5.1 to 10.0 kg, 0.33 (95% CI, 0.18 to 0.60) among those with weight gain of more than 10.0 kg, and 0.50 (95% CI, 0.46 to 0.55) among longer-term quitters (>6 years since smoking cessation).


• Similar associations were observed for death from any cause.

"Smoking cessation that was accompanied by substantial weight gain was associated with an increased short-term risk of type 2 diabetes but did not mitigate the benefits of quitting smoking on reducing cardiovascular and all-cause mortality," concluded the authors.