Insulin Resistance Can Predict Hypertension Development, Wake Forest Researchers Report

"We found you can predict who's at higher risk for developing high blood pressure based on their insulin resistance," said David Goff Jr., Ph.D., M.D., the study's lead researcher. "This study increases our understanding of how hypertension develops and points out possible new treatment targets."

Goff and colleagues followed 809 middle-age adults who were enrolled in the Insulin Resistance Atherosclerosis Study (IRAS). When the study began, all of the participants had normal blood pressure and varying levels of resistance to insulin. Five years later, researchers found that participants who were most resistant to the effects of insulin had a higher incidence of high blood pressure.

"The one-third of participants with the highest levels of insulin resistance had rates of hypertension that were 35 percent higher than the one-third with the least resistance," said Goff, associate professor of public health sciences and internal medicine. "These findings point out that reducing the body's resistance to insulin may help prevent hypertension and cardiovascular disease."

Previously reported results from IRAS also pointed to insulin resistance as a possible new risk factor for cardiovascular disease. WFUBMC researchers showed that a high resistance to the effects of insulin is related to thickened blood vessel walls, an early sign of the hardening of the arteries that can cause heart attacks and strokes.

Insulin is produced by the pancreas to help the body use sugars, such as carbohydrates, as energy. By helping the body process these sugars, insulin prevents a buildup of sugar in the blood.

When the body's resistance to insulin is high, the pancreas may produce more insulin to process the sugar. Scientists suspect these higher levels of insulin may act directly on the artery wall to cause thickening, as well as to cause an increase in blood pressure and higher levels of fats circulating in the blood.

"A person with high insulin resistance may eventually develop diabetes, but the condition isn't the same thing as diabetes," said Goff. "With diabetes, the body doesn't produce enough insulin. With insulin resistance, higher-than-normal levels of insulin are often produced."

Goff said the test to measure insulin sensitivity is too complex to be used on a routine basis. It requires glucose and insulin to be injected intravenously and multiple blood samples taken over a three-hour period. However, he said most people can keep their levels of insulin resistance within normal ranges through exercise and maintaining a healthy weight.

"We've long known that exercise and weight control have multiple benefits," said Goff. "These results point out one more reason for their importance."