Impaired glucose and insulin metabolism in borderline hypertension

This study investigated glucose and insulin metabolism in borderline hypertension (BHT) defined as repeated diastolic blood pressures (DBP) of 85-94 mmHg. Seventy-five BHT and 75 age-matched normotensive (NT, DBP < or = 80 mmHg) men were recruited from a population screening programme. Plasma lipoproteins were determined and an oral glucose tolerance test was performed (WHO criteria). Fasting insulin was significantly higher in the BHT group (17.2 vs 14.2 mU/ml, p < 0.001), whereas fasting blood glucose levels were similar in the two groups, indicating a reduced insulin sensitivity. The BHT group had significantly lower levels of HDL cholesterol and higher levels of plasma triglycerides, VLDL cholesterol and VLDL triglycerides. When adjusted for BMI these differences disappeared, whereas the basal insulin levels remained significantly elevated (F = 10.7, p < 0.001). These results indicate that an altered glucose and insulin metabolism is present already in the early stages of hypertension. They also suggest that these disturbances are only partly dependent on BMI. This supports the hypothesis that reduced insulin sensitivity could be of importance in the early phases of essential hypertension.