Insulin, hypertension and antihypertensive drugs in elderly patients: The Rotterdam Study

Objective. To investigate the association between insulin, hypertension and antihypertensive drug use in elderly patients. Design and methods. Blood pressure, use of antihypertensive drugs and glucose metabolism were examined in 5453 men and women (mean age 68.8 years). This was part of the baseline examination of the Rotterdam Study, a population-based study of chronic diseases in elderly patients. Serum insulin was measured 2 h after an oral glucose load. Results. Patients with hypertension had a significantly higher mean post-load insulin level than those without: 71.3 mU/l versus 59.3 mU/l (P < 0.001, adjusted for age). Systolic blood pressure increased by 0.25 mmHg per 10 mU/l insulin (95% confidence interval 0.15-0.35, adjusted for age, sex and antihypertensive drugs), whereas the increase in diastolic blood was 0.07 mmHg per 10 mU/l (0.01-0.13). Whereas insulin resistance was higher in patients with hypertension, the increase in insulin resistance with age was much more apparent in normotensive patients, resulting in similar insulin levels at high ages. Those using antihypertensive drugs, however, had higher insulin levels at all ages. Conclusion. The results of this study show that hyperinsulinemia is associated with raised blood pressure in elderly people, and suggest that the age-associated increase in insulin resistance is diminished in patients with raised blood pressure. The use of antihypertensive drugs, however, appears to be accompanied by an independent additional increase in insulin resistance at all ages.