A high risk for type 2 diabetes exists among both current smokers and those regularly exposed to second-hand smoke, according to a study published September 18 online ahead of print in The Lancet Diabetes & Endocrinology.

Researchers conducted a meta-analysis of 88 previous studies that investigated the association between smoking and type 2 diabetes risk. The study authors examined the health data of nearly 6 million participants and found that current smoking increased type 2 diabetes risk by 37%. Former smoking increased the risk by 14%, and passive smoking increased the risk by 22%. Those who quit smoking had an 11% increased risk more than 10 years after quitting. The investigators also noted that the degree of smoking affected the results. Increased type 2 diabetes risk was 21%, 34%, and 57% for light, moderate, and heavy smokers, respectively. 


It is estimated that nearly 27.8 million cases of diabetes worldwide can be attributed directly to active smoking. “Cigarette smoke should be considered as a key modifiable risk for diabetes,” said study co-author Frank Hu, MD, professor of nutrition and epidemiology at the Harvard School of Public Health. “Public health efforts to reduce smoking will have a substantial impact on the global burden of type 2 diabetes.”