October 1, 2010
Dear Mayo Clinic:
Does smoking have an effect on diabetes?
Yes. There is some evidence that cigarette smoking can raise the risk of developing diabetes. And for those who have diabetes, smoking can increase the number of complications from the disease, as well as the severity of those complications.
Someone who has diabetes has too much blood sugar (commonly called blood glucose), which can lead to serious health concerns, such as cardiovascular disease, nerve damage (neuropathy), kidney damage, problems with the eyes and feet, bone and joint disorders, and skin problems.
Smoking may increase the risk of diabetes because it can increase blood sugar levels. It also affects the body's ability to respond to its own insulin — a hormone whose main job is to keep the level of sugar in the bloodstream within a normal range. Eventually, smoking may lead to insulin resistance. Thus, the more a person smokes, the greater the risk of diabetes. Heavy smokers — more than 20 cigarettes a day — almost double their risk of developing diabetes, when compared with nonsmokers.
For those who have diabetes and smoke or use other tobacco products, the risk of various diabetes complications, including heart attack, stroke, nerve damage and kidney disease, is much higher than it would be for a nonsmoker. In fact, smokers who have diabetes are three times more likely to die of cardiovascular disease than are nonsmokers who have diabetes.
Smokers who have diabetes are sometimes concerned that if they quit smoking, they will gain weight, another risk factor for developing diabetes and its complications. Because nicotine in cigarettes acts as an appetite suppressant, smokers do commonly gain weight after quitting. Weight gain isn't inevitable, though, and can be counteracted. The health risks smokers expose themselves to far exceed the risks posed by any weight gain after quitting.
For someone who has diabetes, the benefits of quitting smoking are numerous. The risk of heart attack, stroke, nerve disease and kidney disease goes down. Also, cholesterol levels, blood pressure and blood circulation may improve.
The smoker who has diabetes and quits can also enjoy the benefits that people who don't have diabetes get when they quit smoking, such as a reduced risk of esophagus, larynx, throat, mouth and lung cancers and other lung diseases. Other pluses are that a smoker's skin should look better after quitting, breath doesn't smell like stale smoke, and the senses of taste and smell are enhanced.
Those who have diabetes and smoke or use other tobacco products should talk to their doctor about ways to quit. A variety of medications including nicotine replacement and other therapies are available to help make quitting easier. Although smoking can be a tough habit to break, the benefits are well worth the effort.
— Adrian Vella, M.D., Endocrinology, Mayo Clinic, Rochester, Minn.