Cigarettes kill nearly six million people a year worldwide, from cancer, cardiovascular and pulmonary diseases. But new research, published in The Lancet Diabetes & Endocrinology journal, has found Type 2 diabetes can be added to the list of smoking-related conditions.

The study — by researchers with the Harvard T.H. Chan School of Public Health and Huazhong University of Science and Technology in China — was prompted by the U.S. Surgeon General's Report last year mentioning tobacco as a possible cause of Type 2 diabetes, Medical News Today reports.

The researchers, who analyzed 88 studies involving nearly 6 million participants, found smoking increased the risk of Type 2 diabetes by 37 percent, secondhand smoke boosted the risk by 22 percent, and former smokers were 14 percent more likely to develop the metabolic disorder than individuals who had never used tobacco.

The results suggest nearly 12 percent of global diabetes cases in men and 2.4 percent in women — approximately 27.8 million cases in total — are attributable to active cigarette smoking.