| Diabetes is an independent risk factor for the death of cardiovascular disease. Impaired glucose tolerance (IGT) has been regarded as a specific metabolic stage between normal glucose tolerance ( NGT) and diabetes mellitus (DM). With the increasing morbidity and mortality of vascular diseases, its mortality is similar to that of diabetes. Furthermore, IGT presents an opportunity for intervention which potentially could delay or prevent the development of diabetes. Thus it is pivotal for us to study the mechanism and risk factors of IGT in order to take interventions for preventing it from vascular diseases. A series of studies indicated that insulin resistance and resultant impaired beta cells function may play important roles in the mechanism of IGT. The obese gene product, leptin, is close associated with insulin resistance, impaired glucose metabolism, hypertension and serum lipids, therefore,it is beneficial for us to study mechanism of adiposity and linking diseases, such as hypertension and diabetes. Mi-croalbuminuria ( MA) is an early marker for hypertensive and diabetic nephrop-athy. It also signifies cardiovascular disease, as well as endothelial dysfunction. The latest investigation showed MA may precede diabetes, occurring with the insulin resistance syndrome and its components, including obesity and hypertension. We studied the independent relationship between leptin and the components , such as MA, blood pressure, glucose, insulin, and so forth. Then evaluate function of the correlation in hypertensives with IGT, and the result is likely to be fruitful in efforts on early diagnosis, prevention and treatment for patients.MethodsPatients158 consecutive hypertensives (63 men and 95 women,aged from 33 to 79 years old, mean 59. 8 ± 11.1 years) and 42 healthy subjects (14 men and 28 women,aged from 33 to 77 years old, mean 54 ± 10. 3 years) were enrolled after their informed consent was obtained. Hypertensives who were admitted to the first affiliated hospital of China medical university between May 2003 and December 2003, were divided into 3 groups according to their glucose tolerance: NGT, IGT and DM groups. IGT patients were taken as normoalbuminuria and microalbuminuria groups according to their urinary albumin excretion rate (UAER). All subjects were free of clinical evidence of coronary artery , cere-brovascular disease , renal failure and drugs known to interfere with glucose metabolism.Anthropometric DeterminationsWeight and height were measured by standard techniques. Body mass index ( BMI) was calculated as body weight divided by height squared. Waist circumference and hip circumference was measured with plastic tape, and the ratio between them provided the waist/hip ratio ( WHR). HOMA - IR was calculated as FPG multiplied by FINS and divided by 22. 5.Survey procedure and analysesSubjects presented after an overnight fast. Oral glucose tolerance testing (75g glucose as dextrose monohydrate) was used to determine glucose tolerance status. Fasting blood glucose concentrations and those 2 hours after the glucose load were immediately determined by the plasma glucose method. Serum samples were aliquoted, frozen at -70癈.Blood samples for insulin measurements were collected in heparinized tubes. After centrifugation , serum insulin was determined by a commercially a-vailable radioimmunoassay kit. Serum samples for leptin, beta2 - microglobulin (B2 -MG) concentrations were drawn, and both were determined by radioimmunoassay.Urinary samples were collected and frozen at -70癈. After centrifugation, urinary B2 - MG and UAER were determined by radiommunoassay.The baseline factors were compared individually between cases and controls using means and SDs. Univariate variance analysis (ANOVA) with the Scheffe test were used to compare the results between the groups. Simple correlations by the Pearson method allowed us to assess the univariate relations. Multiple regression analysis allowed us to investigate the different contribution of each cova-riate to the lept...
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