Smoking and Diabetes

Karim Farah, M.D.
Pulmonary & Critical Care Medicine

Cigarette smoking is the leading preventable cause for all mortality. The risks of cigarette smoking on cardiac diseases and vascular problems are well known to both the medical profession and the public. Currently, an estimated 21% of men and 17% of women in the United States smoke. Smoking rates are higher among men and women with lower educational and income levels. The majority of smokers start smoking before the age of 18, with the most common age being 14 to 15 years. In Lebanon, the percentage of smokers is much higher, reaching 45.5% among men and 39.6% among women.

Is smoking a risk factor for diabetes?

There is rising proof that smoking is by itself a risk factor for developing type II diabetes. This happens through several mechanisms. First, smoking was found to be associated with insulin resistance; which is the decreased sensitivity of our cells to the effect of insulin, a hormone secreted by the pancreas to decrease the level of sugar in our blood. Second, smoking was also found to be associated with decreased sugar metabolism. Having both insulin resistance and less sugar metabolism predispose patients to develop type 2 diabetes. Moreover, smoking was found to be linked to increased obesity, which by itself is a risk factor for diabetes.

A recent study showed that current smokers have a 37% increased risk for developing diabetes when compared to non-smokers. As for former smokers, the chance is still 14% higher than non-smokers, and decreases with every 5 years from smoking cessation, reaching around 10% after 10 years.

Second hand smokers or passive smokers are also at risk for developing type II diabetes, with a 22% increased risk compared to non-exposed individuals. So when you smoke, not only do you increase your risk for developing diabetes but you also increase the risk of your surroundings, including your family and friends.

Not to forget that if you are a diabetic, whether type I or type II and you smoke, smoking makes you unable to control your diabetes with medication, by the same mechanisms.

Smoking & diabetes and their complications

Both smoking and diabetes increase the risk of cardiovascular events. They affect the blood vessels supplying different organs and might cause complications, such as heart attacks, kidney failure, and strokes. They can also decrease blood flow in the legs and feet, which can lead to infections, ulcers, and possible amputations. Moreover, smoking in patients with diabetes may result in eye diseases and blindness, and may damage nerves in arms and legs causing numbness, pain and weakness.

Quitting smoking decreases the risk of developing diabetes and decreases the risk of associated complications. Smokers may be worried about the weight gain associated with smoking cessation, which might put them at higher risk for diabetes. However this is not true, and might be prevented by exercise, which decreases the risk of smoking dependence and stress. Smokers who fail to stop smoking should seek the help of professionals who can assist them in their struggle and help them decrease the risk of diabetes, the risk of cancer and the risk of cardiovascular complications.

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