Object: The association of obesity and hypertension is well recognized. However, the nature of the relationship between increased body weight and blood pressure (BP) elevation has remained obscure. Patients and Methods: We evaluated BP, insulin sensitivity, insulin clearance and fasting plasma insulin concentration in 19 younger (over 40 years) and in 15 older (more than 40 years) obese subjects to determine the relationships between BP and other factors. Insulin sensitivity and clearance were determined with the euglycemic clamp technique. Results: BP was not associated with insulin sensitivity although most of the subjects showed insulin resistance. In the younger obese group, a positive correlation between diastolic BP and body mass index (kg/m²) was found (r=0.740; p=0.043). In the older obese group, systolic and diastolic BP were correlated with fasting plasma insulin levels (r=0.705; p=0.003; r=0.574; p=0.025, respectively), and systolic BP was inversely correlated with insulin clearance (r=-0.715, p=0.003). Conclusion: These results suggest that insulin is an important factor in BP elevation in older obese subjects, but not in younger obese subjects.
(Internal Medicine 38: 467-471, 1999)