The risk of type 2 diabetes decreases over the long-term following cessation of smoking, new evidence suggests.
Chinese researchers from Huazhong University of Science and Technology analysed data on roughly six million people in 88 previous studies that had examined the connection between smoking, second-hand exposure to smoke and diabetes.
295 446 incident cases of type 2 diabetes were identified, and active and passing smoking were associated with significantly increased risks of type 2 diabetes.
The researchers estimated that around 11.7 per cent of type 2 diabetes cases in men and 2.4 per cent in women across the world were attributable to active smoking.
In one particular study, the relative risk of type 2 diabetes from smoking was examined in over one million participants, with people who had quit smoking compared to never-smokers. Those who had recently quit smoking had a heightened relative risk, but this decreased substantially among long-term quitters.
Lead study author An Pa, University of Science and Technology, said: “The diabetes risk remains high in the recent quitters. However, the diabetes risk is reduced substantially after five years. The long-term benefits – including benefits for other diseases like cancer and heart disease – clearly outweigh the short-term higher risk.”
A causal link between smoking has not yet been confirmed, but further findings showed that occasional smokers were 21 per cent more likely to have diabetes, while this risk increased 57 per cent for heavy smokers. People exposed to second-hand smoke were 22 per cent more likely to develop type 2 diabetes.
According to Dr. Abbas Dehgha, of Erasmus University Medical Centre in Rotterdam, The Netherlands, it is the inflammation caused from smoking which could boost the risk of type 2 diabetes.
“The more one smokes, the more chronic inflammation there will be, and the higher the risk of diabetes will be,” Dehghan told Reuters.
The study was published in The Lancet Diabetes and Endocrinology.

Get our free newsletters

Stay up to date with the latest news, research and breakthroughs.