Smoking ups risk for type 2 diabetes

It’s well known that smoking causes heart disease and several types of cancer. Researchers now say that the habit also boosts the risk of developing type 2 diabetes, by as much as 61 percent.

That’s for people who smoke at least a pack a day. Lighter smokers face a 29 percent increased risk for diabetes, compared with people who never smoke, while former smokers have a 23 percent increased risk, according to an analysis in the Dec. 12 Journal of the American Medical Association.

The authors reached their conclusions after reviewing 25 studies that included 1.2 million people. Carole Willi of the University of Lausanne in Switzerland led the research.

While the types of observational studies included in the report cannot conclusively prove that smoking causes diabetes, the authors say that there is strong evidence that it does. First, smoking always preceded diabetes in the studies. Second, more smoking led to a higher risk. And third, other research has found plausible biological reasons for the connection: Smoking causes insulin resistance and damages insulin-producing beta cells in the pancreas, a two-pronged diabetic impact.