Pulmonary function in children with type 1 diabetes mellitus

AIM: To assess lung function in children and adolescents with type 1 diabetes mellitus (T1DM). PATIENTS AND METHODS: We conducted a case-control study of 100 patients with T1DM [median age 13 (10.6-14.7), 44% men, 23% prepubertal, and all nonsmokers] and 77 controls. None had evidence of lung disease or any other comorbidity. We performed pulmonary function tests, including spirometry [forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), and FEV₁/FVC ratio], plethysmography [total lung capacity (TLC), residual volume (RV), RV/TLC ratio, and airway resistance (Raw)], and diffusing capacity of carbon monoxide in the lung (TLCO), alveolar volume (AV), and TLCO/AV ratio. The duration of diabetes, degree of metabolic control, insulin dose, and presence of diabetic complications were registered. The χ²-test and analysis of variance were used to compare categorical and quantitative variables, respectively. RESULTS: The duration of diabetes was 6.2±3.8 years with a median HbA₁c of 7.08±0.4%. FEV₁/FVC ratio was found to be significantly higher in patients with TIDM than in controls. Patients with diabetes also had a nonsignificant trend towards lower FVC, FEV₁, Raw, and TLCO, and higher RV, TLC, and RV/TLC than controls. There were no differences in pulmonary function based on duration of disease or metabolic control. We found differences in pulmonary evaluation when pubertal stage was analyzed. CONCLUSIONS: The lung is functionally involved in children with T1DM. Pubertal development stage influences the evaluation of lung function.