Vascular dysfunction and autonomic neuropathy in Type 2 diabetes.
OBJECTIVE
To test the hypothesis that arterial dysfunction in Type 2 diabetes is related to autonomic neuropathy.


METHODS
Arterial function and autonomic neuropathy were assessed over two consecutive days in 45 Type 2 diabetic and control subjects. Systemic arterial compliance (SAC), arterial stiffness (pulse-wave velocity, PWV) and carotid intima thickness (IMT) were assessed; these markers reflect early vascular disease and predict clinical vascular events. Autonomic neuropathy was assessed using heart rate variability with continuous ECG recording during various breathing and postural manoeuvres and an overall autonomic score was generated. Fasting metabolic parameters including glucose, insulin, HbA(1c) and lipid profile were measured.


RESULTS
Autonomic neuropathy tests were all repeatable in diabetic subjects. Compared with controls, diabetic subjects had arterial dysfunction with increased PWV (P = 0.009), IMT (P < 0.001) and reduced SAC (P = 0.053). After adjustment for age, central PWV correlated with fasting insulin (r(2) = 0.45, P < 0.05) and autonomic score (r(2) = 0.44, P < 0.05), peripheral PWV correlated with autonomic score (r(2) = 0.51, P < 0.005) and IMT correlated with fasting insulin (r(2) = 0.5, P < 0.005). The presence of autonomic neuropathy correlated with fasting insulin (P = 0.015), but not age, duration diabetes, lipids or blood pressure.


CONCLUSIONS
Using repeatable measures of autonomic neuropathy and vascular function in Type 2 diabetic subjects, we have demonstrated associations between autonomic neuropathy, vascular dysfunction and hyperinsulinaemia. This may help to explain the excess cardiovascular mortality seen in diabetic subjects with autonomic neuropathy.
Meyer
C
C
Monash University Department of Medicine, Dandenong Hospital, David Street, Dandenong,Victoria 3175, Australia.
Milat
F
F
McGrath
B P
BP
Cameron
J
J
Kotsopoulos
D
D
Teede
H J
HJ
D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D001783:Blood Flow Velocity; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D003925:Diabetic Angiopathies / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000150:complications; D008297:Male; D008875:Middle Aged; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology; D014655:Vascular Resistance