Cortisol Secretion in Patients With Type 2 Diabetes

OBJECTIVE: The presence of an enhanced cortisol secretion in patients with type 2 diabetes is debated. In type 2 diabetic subjects, cortisol secretion was found to be associated with the complications and metabolic control of diabetes. We evaluated cortisol secretion in 170 type 2 diabetic subjects and in 71 sex-, age-, and BMI-matched nondiabetic subjects. RESEARCH DESIGN AND METHODS: In all subjects, we evaluated ACTH at 8:00 a.m. in basal conditions and serum cortisol levels at 12:00 p.m. (F24) and at 9:00 a.m. after a 1-mg overnight dexamethasone suppression test and 24-h urinary free cortisol (UFC). In diabetic patients, we evaluated the presence of chronic complications (incipient nephropathy, asymptomatic neuropathy, background retinopathy, and silent macroangiopathy). Patients were subdivided according to the absence (group 1, n = 53) or presence (group 2, n = 117) of diabetes complications. RESULTS: In group 2, UFC (125.2 +/- 4.6 nmol/24 h) and F24 (120.6 +/- 4.1 nmol/l) were higher than in group 1 (109.2 +/- 6.8 nmol/24 h, P = 0.057, and 99.7 +/- 6.1 nmol/l, P = 0.005, respectively) and in nondiabetic patients (101.7 +/- 5.9 nmol/24 h, P = 0.002, and 100.3 +/- 5.3 nmol/l, P = 0.003, respectively). In diabetic patients, the number of complications was associated with F24 (R = 0.345; P < 0.0001) and diabetes duration (R = 0.39; P < 0.0001). Logistic regression analysis showed that the presence of diabetes complications was significantly associated with F24, sex, duration of diabetes, and glycated hemoglobin. CONCLUSIONS: In type 2 diabetic subjects, hypothalamic-pituitary-adrenal activity is enhanced in patients with diabetes complications and the degree of cortisol secretion is related to the presence and number of diabetes complications.