We sought to explore whether reduced pulmonary function is an independent risk factor for incident diabetes in Koreans.

We conducted a prospective cohort study of pulmonary function as a risk factor for incident diabetes using 10-year follow-up data from 3,864 middle-aged adults from the Ansung cohort study in Korea. The incidence of diabetes was assessed using both oral glucose tolerance tests and glycosylated hemoglobin levels.

During 37,118 person-years of follow-up, 583 participants developed diabetes (incidence rate: 15.7 per 1,000 person-years). The mean follow-up period was 8.0±3.7 years. Forced vital capacity (FVC; % predicted) and forced expiratory volume in 1 second (FEV1; % predicted) were significantly correlated with incident diabetes in a graded manner after adjustment for sex, age, smoking, exercise, and metabolic parameters. The adjusted hazard ratio (HR) and confidence interval (CI) for diabetes were 1.408 (1.106 to 1.792) and 1.469 (1.137 to 1.897) in the first quartiles of FVC and FEV1, respectively, when compared with the highest quartile. Furthermore, the FVC of the lowest first and second quartiles showed a significantly higher 10-year panel homeostasis model assessment of insulin resistance index, with differences of 0.095 (95% CI, 0.010 to 0.018; P=0.028) and 0.127 (95% CI, 0.044 to 0.210; P=0.003), respectively, when compared to the highest quartiles.

FVC and FEV1 are independent risk factors for developing diabetes in Koreans. Pulmonary factors are possible risk factors for insulin resistance and diabetes.