[Relationship between serum leptin levels and left ventricular hypertrophy in obese hypertensive patients]

Previous studies showed relation between elevated serum leptin levels (SLL) and hypertension. The aim of this study was to evaluate relationship between SLL and left ventricular hypertrophy (LVH) and body mass index (BMI) in obese hypertensive patients.

Eighty patients with newly diagnosed essential hypertension were included in this cross-sectional, case-controlled study. Hypertensive patients were classified as; level-I or level-II according to JNC-VII classification and as normal weighted (18-24.99 kg/m2), over weighted (25-26.99 kg/m2) and obese (27 kg/m2 and above) according to BMI's. All the patients were evaluated by echocardiography and blood samples were withdrawn for determination SLL. Statistical analysis was performed using Wilcoxon sign rank, Mann Whitney U and Kruskal Wallis tests. Logistic regression analysis was applied for the evaluation of relationship between SLL and clinical variables.

Mean levels of arterial blood pressure (ABP) of total 80 patients (36 males and 44 females) was 155+/-1.1/95.1+/-0.7 mmHg and the mean age was 48.9+/-1.3 years. Patients with level I hypertension (n=32) had mean ABP of 149.7+/-0.5/90.9+/-0.6 mmHg and with level-II hypertension (n=48)--mean ABP 168.5+/-1.6/102.9+/-0.9 mmHg. The mean BMI in normal weighted group (n=26) was 22.7+/-0.3 kg/m2, over weighted group (n=19)-26.1+/-0.2 kg/m2 and obese group (n=35)-30.9+/-0.5 kg/m2. There were no differences in LVH incidence between hypertension level groups and BMI groups (p>0.05). Serum leptin levels were similar in patients with level I and level II hypertension (33.5+/-2.9 ng/ml and 37.3+/-3.6 ng/ml, respectively, p>0.05). However, leptin levels were higher in obese patients as compared with normal and over weighted patients (40.9+/-3.2 ng/ml versus 28.5+/-3.6 ng/ml and 32.8+/-4.9 ng/ml, p<0.01). Patients with LVH had significantly higher levels of leptin as compared with patients without LVH (51.40+/-5.1 ng/ml versus 28.30+/-4.20 ng/ml, p<0.05). Logistic regression analysis demonstrated that SLL independently of blood pressure and BMI is related with LVH (OR--1.7, %95 CI--1.2-1.9, p<0.05).

Our study showed that elevated serum leptin levels are significantly related with LVH independently of body mass index and level of blood pressure. Thus, elevated SLLs, independently of hypertension level and BMI classification, coexist with LVH. Sympathetic activation or direct cardiac receptor activation or proliferative effects of leptin may be responsible for this coexistence.