Sympathetic activity and body mass index contribute to blood pressure levels

The purpose of this study was to clarify the relationships between obesity( BMI) and BP levels, leptin levels, sympathetic activity, and insulin sensit ivity in a Japanese male population. In 912 young, non diabetic, Japanese m en with a wide range of BMI (16.5-33.6 kg/m(2)), blood pressure(BP), fastin g plasma norepinephrine (NE), insulin and leptin levels were measured after an overnight fast. The cohort consisted of 603 normotensive and 309 hypert ensive subjects. The study was carried out using a cross-sectional de sign. When the subjects were subdivided by tertile in relation to BMI, the 101 s ubjects in the heaviest group (EMI > 27.9 kg/m(2)) had a significantly high er systolic BP (p < 0.05) and pulse rate (p < 0.05) as well as higher NE (p < 0.01), insulin (p < 0.01), and leptin (p < 0.01) revels than 86 subjects in the leanest group (BMI < 22.2 kg/m(2)). In the whole cohort, BMI correl ated with mean BP (p < 0.01), plasma NE (p < 0.05), insulin (p < 0.001) and leptin (p < 0.001). The mean BP correlated with BMI (p < 0.001), plasma NE (p < 0.01), insulin (p < 0.01) and leptin (p < 0.05). Plasma leptin levels correlated with fasting plasma insulin levels (p < 0.05), but not with pla sma NE levels (NS). As analyzed by multiple regression analysis, only plasm a NE (p < 0.05) and BMI (p < 0.001), but not plasma insulin levels, were si gnificant, independent predictors of BP levels (r(2) = 0.125, F = 10.51, p = 0.0001). These results suggest that obesity(BMI) and heightened sympathet ic nervous system activity contribute to BP elevation (hypertension).