The aim of the study was to determine the association between smoking and the risk of type 2 diabetes mellitus.
Material and methods: A case-control study included 234 cases with newly confirmed diagnose of type 2 diabetes mellitus and 468 controls who were free of the disease in 2001. Cases and controls were matched by gender and age (+/-5 years). Information on age, gender, body mass index, family history on diabetes, education level, years of total education, occupation status, nutrition habits, alcohol consumption, cigarette smoking, physical activity, and stress was collected using questionnaire. Conditional logistic regression was used to compute the odds ratios (OR), 95% confidence intervals (CI), and p for trend. The ORs were adjusted for potential confounders such as family history on diabetes, body mass index, speed of eating, portion of food, using of salty and fatty food, physical activity early in life, exercise, years of total education, and stress that were related to type 2 diabetes mellitus in univariate regression model, and alcohol drinking that was associated with the disease.
Results: After adjustment for possible confounders, increased risk of type 2 diabetes mellitus was determined for current smokers (OR=2.25; 95% CI 1.03-4.92), who have smoked for 20-39 years (OR=2.43; 95% CI 1.14-5.20), as compared with never-smokers. There were no statistically significant associations between risk of type 2 diabetes mellitus and number of cigarettes smoked a day, number of pack-years, and time after quitting smoking.
Conclusions: Our data suggest that smoking is a significant risk factor of type 2 diabetes mellitus.