Quitting Smoking Raises The Risk of Developing Diabetes


quit_smokingAccording to new study, People who quit smoking are at high risk of developing type 2 diabetes. Experts caution, however, that the benefits of quitting smoking—including a lower risk of heart attack and lung cancer—far outweigh the risk of developing diabetes, which can be treated with diet, exercise, and medication.

The study followed nearly 11,000 middle-aged people without diabetes—45% of whom were smokers—over a nine-year period. Compared to those who had never smoked, the people who quit smoking during the study had a 73% increased risk of developing type 2 diabetes three years after quitting.

The increased risk was even more dramatic in the years immediately after quitting. “Based on our analysis, [it’s] probably 80% or even 90%,” says the study’s lead author, Hsin-Chieh (Jessica) Yeh, PhD, an assistant professor of internal medicine and epidemiology at the Johns Hopkins University School of Medicine.

By contrast, the smokers who continued to light up were only 31% more likely than non-smokers to have developed diabetes at the three-year mark. Previous research has shown that smokers are at higher risk of developing diabetes.

There was some good news in the study: The increased risk of diabetes does not appear to last over the long term. After 12 years without cigarettes, the ex-smokers were at no greater risk for diabetes than the people who had never smoked, the study showed.

In all, 1,254 participants in the study developed type 2 diabetes, a chronic disease in which the body fails to adequately convert blood sugar (glucose) into energy.

The spike in diabetes risk that the researchers observed is most likely due to the extra pounds that many ex-smokers pack on after giving up cigarettes, Yeh and her colleagues note. Weight gain is a major risk factor for type 2 diabetes, and it’s also one of the most common side effects of smoking cessation.

The people in the study who quit smoking gained an average of 8.4 pounds, which is in the normal range (most ex-smokers gain about 4 to 10 pounds), and those who gained the most weight showed the greatest risk for developing diabetes. The waistlines of the ex-smokers in the study also grew by an average of 1.25 inches; abdominal fat is another risk factor for diabetes.

“Quitting smoking is good,” says Yeh. “[But] after quitting you should pay additional attention to weight control.”