Search

Diabetes mellitus affects approximately 135 million people in the world. Diabetes and hypertension are both relatively common diseases in westernised countries. Both entities increase with age. Essential hypertension accounts for the majority of hypertension in people with type 2 diabetes, who constitute more than 90% of those with a dual diagnosis of diabetes and hypertension. The benefit conferred per mm Hg blood pressure reduction appears to be greater in persons with type 2 diabetes than in those with hypertension and non-coexistent diabetes mellitus. Similar to a subset of patients with essential hypertension, type 2 diabetic patients manifest dietary NaCl-induced exacerbation of hypertension. Recent guidelines have emphasised that the target blood pressure levels for patients with diabetes should be lower than in other hypertensive groups. An increased total body sodium and enhanced vascular reactivity are found in people with diabetes and most type 2 diabetic patients are salt sensitive. Type 2 diabetes with hypertension is associated with reduced renal plasma flow when dietary salt intake is high. Experimental, observational and interventional evidence support the benefits of sodium restriction in hypertensives. However, the full effects of sodium restriction are usually not obvious for at least 5 weeks. Other favourable effects of moderate reduction in sodium intake are a regress left ventricular hypertrophy, decrease in diuretic-induced potassium wastage, reduction in proteinuria, protection against stroke and from osteoporosis and renal stones, and enhancement of the antihypertensive effect of the antihypertensive agents.

The aim of the study was to elucidate the role of hyperinsulinaemia/insulin resistance in hypertension of lean postmenopausal women. Twenty-four women with essential hypertension (systolic/diastolic > or =140/90 mm Hg) and a body mass index (BMI) less than 26 kg/m(2) not receiving antihypertensive treatment or who had been without treatment for a 4-week washout period, and 10 normotensive postmenopausal weight- and aged-matched controls were compared. Both groups were not receiving hormone replacement therapy. Hip and waist circumferences were measured and waist/hip ratios were calculated. Casual blood pressure was measured in triplicate. Neither the fasting plasma glucose nor serum insulin levels in hypertensive women and normotensives differed significantly. During 2 h oral glucose (75 g)-tolerance test the mean plasma glucose levels after 30 min (172.5 +/- 40.24 mg/dl vs. 143.67 +/- 20.16 mg/dl), 60 min (134.88 +/- 38.78 mg/dl vs. 112.33 +/- 5.44 mg/dl) and 120 min (116.08 +/- 26.65 mg/dl vs. 95.56 +/- 20.17 mg/dl) were significantly higher in hypertensives than that for normotensives (P < 0.05 for all three comparisons). The mean serum insulin levels of hypertensive women were significantly higher than that in normotensives after 15 min (92.04 +/- 59.90 microU/ml vs. 54.89 +/- 33.67 microU/ml) and 120 min (49.63 +/- 44.45 microU/ml vs. 19.22 +/- 24.10 microU/ml; P< 0.05 for both comparisons). The mean serum insulin: plasma glucose ratio for hypertensive women was significantly higher than that for normotensives after 15 min (0.596 +/- 0.46 vs. 0.359 +/- 0.20 microU/mg), 60 min (0.406 +/- 0.30 vs. 0.329 +/- 0.25 microU/mg) and 120 min (0.436 +/- 0.35 vs. 0.205 +/- 0.26 microU/mg) (P < 0.05 for all three comparisons). Significant correlations were observed between the daytime period and 24-h average ambulatory systolic blood pressure and the area under the serum insulin curve (r = 0.41 and 0.36, respectively). For non-dippers we found higher fasting insulinaemias but the AUC(insulin) did not differ. Plasma glucose levels did not differ either during fasting or during OGTT (AUC(glucose)). Insulinogenic index was higher in dippers than in non-dippers. We conclude that in lean, postmenopausal hypertensive women insulin resistance is increased compared with age- and weight-matched normotensive women. Also, hyperinsulinaemia correlates with ambulatory systolic blood pressure. Thus, insulin resistance may possibly be involved as a pathogenetic factor in lean, postmenopausal hypertensive women.

To determine the relationships between the circadian blood pressure profile and left ventricular mass, hormonal pattern and insulin sensitivity indices in patients with active acromegaly, ambulatory 24-h blood pressure monitoring (ABPM) was recorded in 25 subjects (47.0 +/- 15.1 years, range 23-72). Serum growth hormone (GH) and insulin-like growth factor-1, fasting and mean plasma glucose and insulin during oral glucose tolerance test (OGTT), insulinogenic index, the sum of the plasma insulin levels and the homeostasis model insulin resistance index (Homa's index) were determined. Left ventricular mass index (LVMI) was calculated from two-dimensional guided M-mode echocardiogram. The prevalence of hypertension was 56% (n = 14) and 40% (n = 10) according to sphygmomanometric measurements and ABPM, respectively. Non-dipping profile was observed in six of 10 hypertensives and in six of 15 normotensives. Serum growth hormone, fasting glucose, the area under the serum insulin curve and LVMI were higher for acromegalics with non-dipping profile than for dippers (all of them, P < 0.05). In non-dippers daytime heart rate was higher than night time (P < 0.001). In conclusion, the main observations in the present study suggested that both normotensive and hypertensive acromegalics had a highly prevalent non-dipping profile with a preserved circadian pattern of heart rate, that was associated with higher levels of serum GH. The disturbance in nocturnal blood fall in normotensives was associated with a decreased insulin sensitivity. The role of GH in blood pressure circadian rhythm regulation in essential hypertension deserves further studies.