Smoking raises risk for diabetes, researchers say

WASHINGTON (Reuters) - Here’s another reason to throw away the cigarettes: Smoking, already known to cause lung cancer, heart disease and stroke, also raises one’s risk for the most common form of diabetes, researchers said on Tuesday.

Smokers faced a 44 percent increased risk of developing type 2 diabetes when compared to nonsmokers, the Swiss researchers found.

Dr. Carole Willi of the University of Lausanne in Switzerland and colleagues analyzed 25 studies exploring the connection between smoking and diabetes published between 1992 and 2006, with a total of 1.2 million participants tracked for up to 30 years.

They found risk was even higher for heavy smokers. Those who puffed on at least 20 cigarettes a day had a 61 percent higher risk for diabetes than nonsmokers.

Quitting smoking cut the risk, with former smokers seeing a 23 percent higher risk than nonsmokers, far lower than the risk for current smokers, they reported in the Journal of the American Medical Association.

“On a public health level, this is very important because diabetes incidence is dramatically increasing. The avoidance of diabetes would then be another good reason for smokers to quit or for nonsmokers not to begin,” Willi said by e-mail.

Type 2 diabetes, the form of the disease often associated with excess body weight, poor diet and a sedentary lifestyle, is becoming increasingly common in many countries.


Cigarette smoking is the leading preventable cause of death globally, killing about 4 million people a year or about 9 percent of deaths worldwide, the researchers noted.

In addition to causing most lung cancer cases as well as other types of cancer, it also can lead to heart attack, stroke, chronic lung disease and other illnesses.

“The consequences of this finding are also important because both diabetes and cigarette smoking are major cardiovascular risk factors,” Willi said.

Willi noted that the research was not designed in a way that could conclude that smoking actually caused diabetes in the people in the 25 studies who developed it.

But Willi said the fact that more smoking led to a higher diabetes risk suggested that smoking was causing the disease. In addition, smoking preceded the development of diabetes in the participants in all the studies, Willi said.

Smoking can lead to insulin resistance, the researchers said -- meaning that it can interfere with how well the body uses insulin. Insulin resistance usually precedes type 2 diabetes.

In an editorial accompanying the research, Eric Ding and Dr. Frank Hu of the Harvard School of Public Health in Boston said public health recommendations for preventing type 2 diabetes should include an anti-smoking message.

“Major population prevention of type 2 diabetes is achievable via avoidance of smoking and modification of lifestyle factors through a combination of healthy weight control, regular physical activity, moderate alcohol intake and proper diet,” they wrote.

Editing by Maggie Fox and Cynthia Osterman