Association between glycemic state and pulmonary function and effect of walking as a protective factor in subjects with diabetes mellitus

Background: Several population-based studies have shown that individuals with type 2 diabetes mellitus (T2DM) have decreased pulmonary function. Moreover, impaired pulmonary function is associated with all-cause mortality in T2DM. We investigated the association between glycemic state and pulmonary function and evaluated the role of walking as protective factor in subjects with diabetes using a nationwide, population-based, cross-sectional survey. Methods: The study included 17,542 subjects: 2,195 with diabetes, 4,042 with prediabetes, and 11,305 with normal glucose tolerance. Furthermore, 1,770 subjects with available data on walking exercise were divided into three groups according to weekly exercise time: <150, 150-300, and >= 300 min/week. Results: The diabetes group had reduced pulmonary function, particularly forced vital capacity (FVC) (P<0.001), and a decrease in pulmonary function was observed in the subjects with prediabetes (P<0.001). The walking exercise analysis revealed that the percentage of predicted FVC (P=0.001) and percentage of predicted forced expiratory volume in 1 s (P=0.021) were highest in the subjects with diabetes who walked >= 300 min/week after adjustment for age, sex, body mass index, and waist circumference (WC) measurements. Conclusions: Pulmonary function was significantly associated with walking exercise in diabetic patients, and walking >= 300 min/week may have a preventive effect against pulmonary dysfunction in subjects with diabetes.