Cigarette smoking is a well-known risk factor for type 2 diabetes, but new research from Johns Hopkins suggests that quitting the habit may raise diabetes risk in the short term.
The researchers suspect the elevated diabetes risk is related to the extra pounds people typically put on after renouncing cigarettes and caution that no one should use the study’s results as an excuse to keep smoking, which is also a risk factor for lung disease, heart disease, strokes and many types of cancer.
“The message is: Don’t even start to smoke,” study leader Hsin-Chieh “Jessica” Yeh, PhD, an assistant professor of general internal medicine and epidemiology at the Johns Hopkins University School of Medicine, said in a news release. “If you smoke, give it up. That’s the right thing to do. But people have to also watch their weight.”
In the study, published in the Annals of Internal Medicine, researchers found that people who quit smoking have a 70% increased risk of developing type 2 diabetes in the first 6 years without cigarettes as compared to people who never smoked. The risks were highest in the first 3 years after quitting and returned to normal after 10 years. Among those who continued smoking over that period, the risk was lower, but the chance of developing diabetes was still 30% higher compared with those who never smoked.
The study enrolled 10,892 middle-aged adults who did not yet have diabetes from 1987 to 1989. The patients were followed for up to 17 years and data about diabetes status, glucose levels and weight were collected at regular intervals.
According to the study, those who smoked the most and those who gained the most weight had the highest likelihood for developing diabetes after they quit. On average, over the first 3 years of the study, quitters gained about 8.4 pounds and saw their waist circumferences grow by approximately 1.25 inches.