The associations between metabolic abnormalities, 24-h blood pressure cicardian rhythm and morning cortisol serum level in patients with essential hypertension

Abstract

Background To assess an impact of morning cortisol level on metabolic abnormalities and 24-h ambulatory blood pressure profile in patients with dipping and non-dipping hypertension.
Material and methods The study was performed on 96 subjects (47 F, 49 M) with essential hypertension. The anthropometric assessments included height, weight, waist circumference and body mass index (BMI). In all patients a 24-h blood pressure monitoring (ABPM) protocol was performed using a Spacelabs 90207 monitor. Blood pressure was measured every 20 min during the daytime (from 06.00 to 22.00) and every 30 min at night-time (22.00–06.00). The following parameters were recorded: 24-h mean (MAP), daytime mean (dMAP) and night-time mean (nMAP) systolic (SBP) and diastolic (DBP) blood pressures. The non-dippers hypertension was defined if the declines in blood pressure at night were below 10% of the daytime values. The morning blood samples for serum cortisol, glucose, uric acid, cholesterol, and triglycerides levels were drawn. All patients had also a 75 g oral glucose tolerance test (OGTT) and a 1 mg dexamethasone suppression test.
Results Of 96 patients we identified 47 non-dippers (24 F, 27 M; mean age 45.9 ± 14.5 years) and 49 dippers (23 F, 26 M; mean age 44 ± 13.6 years); BMI, MAP, serum uric acid, total cholesterol and its LDL and HDL fractions, triglycerides, fasting glucose were similar in both groups. All patients had normal dexamethasone suppression test. Non-dipperes had significantly higher waist circumference (99.8 ± 10.8) and glucose results of the OGTT (139.3 ± 67.30 as compared to dippers (respectively: 92.8 ± 11.9; 129.8 ± 32.6). Furthermore, the morning cortisol level was significantly higher in non-dippers group as compared to dippers (20.7 ± 6.7 v.18.3 ± 5.6 μg/dl; p < 0.05) and in non-dippers was positively correlated with BMI (r = 0.6; p < 0.005), waist circumference (r = 0.54; p < 0.005), fasting glucose (r = 0.39; p < 0.05), 2-h post load glucose (r = 0.65; p < 0.005) and inversely with HDL cholesterol (r = –0.38; r < 0.05). Similarly, in non-dippers, but not in dippers, the morning cortisol level correlated with the following ABPM values.
Conclusions In patients with essential hypertension, an increased morning cortisol level is associated with metabolic abnormalities, circadian blood pressure profile and non-dipping pattern of blood pressure.
Arterial Hypertension 2011, vol. 15, no 4, pages 236–241.