Reduced lung function is independently associated with increased risk of type 2 diabetes in Korean men

Background: Reduced lung function is associated with incident insulin resistance and diabetes. The aim of this study was to assess the relationship between lung function and incident type 2 diabetes in Korean men. Methods: This study included 9,220 men (mean age: 41.4 years) without type 2 diabetes at baseline who were followed for five years. Subjects were divided into four groups according to baseline forced vital capacity (FVC) (% predicted) and forced expiratory volume in one second (FEV1) (% predicted) quartiles. The incidence of type 2 diabetes at follow-up was compared according to FVC and FEV1 quartiles. Results: The overall incidence of type 2 diabetes was 2.2%. Reduced lung function was significantly associated with the incidence of type 2 diabetes after adjusting for age, BMI, education, smoking, exercise, alcohol, and HOMA-IR. Both FVC and FEV1 were negatively associated with type 2 diabetes (P<0.05). In non-obese subjects with BMI<25, the lowest quartile of FVC and FEV1 had a significantly higher odds ratio for type 2 diabetes compared with the highest quartile after adjusting for age and BMI (2.15 [95% CI 1.02-4.57] and 2.19 [95% CI 1.09-4.42]). Conclusions: Reduced lung function is independently associated with the incidence of type 2 diabetes in Korean men.