SMOKING, already known to cause lung cancer, heart disease and stroke, also raises the risk for the most common form of diabetes.
Smokers faced a 44 per cent increased risk of developing type 2 diabetes when compared with non-smokers, the Swiss researchers found.
Switzerland's University of Lausanne's Dr Carole Willi and her colleagues analysed 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 per cent higher risk for diabetes than non-smokers.
Quitting smoking cut the risk, with former smokers seeing a 23 per cent higher risk than non-smokers, 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 non-smokers not to begin," Dr Willi said.
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 four million people a year or about 9 per cent of deaths worldwide, the researchers said.
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 important because both diabetes and cigarette smoking are major cardiovascular risk factors," Dr Willi said.
She 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 the disease.
However, Dr 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, she 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, the highly respected US Harvard School of Public Health's Eric Ding and Dr Frank Hu 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," the pair wrote.