Association between hyperinsulinemia and hypertension in elderly subjects, independent of obesity, hyperglycemia, and hypercholesterolemia

The association between hyperinsulinemia and hypertension has attracted much attention in recent years. The aim of the study was to examine the extent to which hyperinsulinemia is associated with hypertension in the elderly Chinese and whether interventional therapy can improve hyperinsulinemia. This study included 144 institutionalized, healthy, nondiabetic elderly Chinese subjects were examined. Their ages ranged from 65 to 83 years, with a mean of 74 years. There were 72 men and 72 women. Forty-eight subjects were normotensive, and 96 were hypertensive; average body mass index (BMI) was 23. The hypertensive subjects could be divided into two groups: (A) untreated hypertensive (n = 48) and (B) treated hypertensive (n = 48). Fasting venous blood samples from every subject were collected with background data such as age, gender, and BMI. Fasting, 1-h, and 2-h insulin level were all measured after a 75-g oral glucose load. Plasma insulin levels (fasting, 1-h, 2-h) were significantly higher in the untreated hypertensive group. For the treated hypertensive group, plasma insulin levels were higher than normotensive group, but did not reach statistical significance and the insulin levels were lower than the untreated hypertensive group. Age, BMI, waist/hip ratio, and levels of fasting glucose, triglyceride, and cholesterol were not significantly different between normotensive and hypertensive subjects. This study indicates that hyperinsulinemia - independent of hyperglycemia, hypercholesterolemia, and obesity - is associated with hypertension in these nondiabetic, healthy Chinese elderly. Lifestyle modification probably accounts for lower levels of fasting and postabsorptive insulin levels in the treated hypertensive subjects.