Central obesity and hypertension. Relationship between fasting serum insulin, plasma renin activity, and diastolic blood pressure in young obese subjects

This study was designed to evaluate the role of fasting serum insulin and plasma renin activity in obesity-induced hypertension. In view of this, plasma catecholamines, fasting serum insulin (IRI), urinary sodium excretion (NaU), plasma renin activity (PRA), and plasma aldosterone (PA) levels were assessed in young (age less than 40 years) normotensive (n = 27) and hypertensive (n = 14) subjects with central obesity and in lean normotensives (n = 20). Central obesity was evaluated by waist-to-hip ratio (WHR) according to the indication of the Italian Consensus Conference of Obesity. PRA, PA, IRI, and plasma norepinephrine levels were significantly (P < .05) higher in both obese groups than in lean normotensives. PRA was significantly (P < .05) higher and NaU was significantly (P < .05) lower in obese hypertensives than in obese normotensives. Diastolic blood pressure correlated directly with WHR and PRA in normotensive and hypertensive obese subjects and with IRI but only in normotensive obese subjects. Multiple regression analysis indicated that diastolic blood pressure values increased with WHR (P < .05), IRI (P < .005), and PRA (P < .002), but not with body mass index, NaU, and norepinephrine levels. Our results indicated that increased PRA could play an important role in the development of hypertension in subjects with central obesity.