Insulin as a potential factor influencing blood pressure in amputees.

War-injured, bilateral above-knee amputees are known to be at increased risk for cardiovascular mortality. To evaluate possible risk factors, we compared blood pressures and plasma glucose and insulin responses to orally administered glucose in 19 above-knee amputees from the Vietnam War (mean age, 36 +/- 1 years) with those of 12 age-matched unilateral below-elbow amputees. Body composition by densitometry and maximal oxygen consumption during arm or leg exercise were also determined. Nine of 19 leg amputees were hypertensive compared with one of 12 arm amputees. Their 3-hour average insulin responses were markedly increased (260 +/- 60 microU/ml) compared with those of normotensive leg (125 +/- 24 microU/ml) and arm amputees (101 +/- 20 microU/ml), and their mean body fat content (37.2%) also was elevated compared with that in both of these groups (23.2 and 22.6%, respectively). A unique finding was that both insulin response and body fat content were strongly and independently correlated with diastolic blood pressure (r = 0.55, p less than 0.01, and r = 0.62, p less than 0.01, respectively). We conclude that insulin may be a major factor in blood pressure regulation in the maturity-onset obesity that develops following traumatic leg amputation in young, healthy men.