Maintaining healthy weight after quitting smoking can cut diabetes risk

New US research has found that those who gain weight after quitting smoking may have a temporarily increased risk of developing type 2 diabetes.

Gaining weight after quitting smoking can temporarily increase your risk of type 2 diabetes, but maintaining a healthy weight can cut this risk, say researchers. (AFP Relaxnews pic)

The study, by researchers at the Harvard T.H. Chan School of Public Health, looked at an average of nearly 19 years of data taken from 171,150 male and female participants.

Participants were asked to fill out questionnaires about their health and lifestyle every two years, enabling the researchers to assess who had quit smoking, and the impact of weight gain on the risk of developing type 2 diabetes as well as risk of death due to cardiovascular disease and other conditions.

The team found that compared to current smokers, those who had recently quit had, on average, a 22% higher risk of developing type 2 diabetes, with the risk peaking five to seven years after quitting, before gradually decreasing.

The more weight people gained after quitting smoking, the greater their risk of type 2 diabetes.

However, those who didn’t gain weight showed no increased risk, and in the long-term quitting smoking had a beneficial effect on diabetes risk. Among those who didn’t smoke for 30 years, the diabetes risk dropped to that of people who had never smoked.

“It’s been known that quitters may have an elevated risk of developing diabetes or worsening glucose tolerance in the first few years after quitting, and this may discourage smokers from quitting,” said Qi Sun, senior author of the study. “But our study shows that it is the weight change after quitting that determines diabetes risk — so as long as quitters minimize their weight gain, their diabetes risk will not increase and, over the long run, is reduced.”

Quitting smoking also comes with other significant benefits. The study found that even among those who gained more than 10 kg, the risk of early death due to cardiovascular disease as well as due to all other causes decreased, on average, by 67% and 50% respectively, after quitting smoking.

“Smokers shouldn’t be deterred by potential weight gain after quitting because the short-term and long-term reduction of cardiovascular disease risk is clear,” said co-lead author Yang Hu. “However, quitters may want to consider eating a healthful diet and engaging in physical activities to minimize weight gain to keep their diabetes risk at bay and to maximize the health benefits of quitting.”

The findings were published in the New England Journal of Medicine.