DIABETES AND BRONCHIAL REACTIVITY

The data of the literature concerning bronchial reactivity in diabetic patients are controversial. Therefore, we studied the influence of th e presence of a diabetic cardiac autonomic neuropathy (CAN) on the ven tilatory parameters measured during a methacholine-induced bronchocons triction test. Ten insulin-dependent diabetic patients without CAN, te n insulin-dependent diabetic patients with CAN and ten healthy volunte ers, all non-smokers and free of respiratory symptoms, have undergone a functional respiratory check-up before the methacholine test. The pr esence of CAN was classically studied by the decrease in heart rate ch anges during three standardized tests (deep breathing at 6 cycles/min, Valsalva manoeuver, orthostatism) which all mainly explore the parasy mpathetic function. The bronchial response to methacholine was similar in the healthy subjects and in the diabetic patients without CAN. How ever, the fall in forced expiratory volume in 1 seconde induced by the highest dose of methacholine was significantly less marked in the dia betic subjects with CAN than in the two other groups. These results su ggest that the diabetic autonomic neuropathy also involves the vagal i nnervation of the respiratory tract.