People who gain weight after quitting smoking have a temporary increase in type 2 diabetes risk, but this is offset by long-lasting reductions in mortality, a New England Journal of Medicine study finds.
Researchers examined rates of diabetes and mortality after smoking cessation in three large cohorts of U.S. health professionals. During roughly 20 years’ follow-up, participants who recently quit smoking were 22% more likely than current smokers to develop diabetes, with the risk peaking 5–7 years after quitting and then decreasing thereafter. The increased risk, however, was limited to those who gained over 5 kg after quitting.
In terms of mortality, quitting smoking showed a consistent benefit, regardless of weight gain. Even quitters who gained over 10 kg had a 67% reduction in cardiovascular mortality and a 50% reduction in overall mortality, relative to current smokers.
The researchers emphasize that even though quitters who gained weight saw a net benefit, “preventing excessive weight gain may maximize the health benefits of smoking cessation through reducing the short-term risk of diabetes and further lowering the long-term risk of death.”