Study of American Indians shows reversal of damage to arteries.

Reducing cholesterol and blood pressure levels below current targets in adults with type 2 diabetes may help to prevent -- and possibly reverse -- hardening of the arteries, according to new research supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Hardening of the arteries, also known as atherosclerosis, is the number-one cause of heart disease and can lead to heart attack, stroke and death.

The three-year study of 499 participants is the first to compare two treatment targets for LDL (“bad”) cholesterol and systolic blood pressure levels -- key risk factors for heart disease in people with diabetes.

“This study provides good news for adults with type 2 diabetes,” said Elizabeth G. Nabel, MD, NHLBI director. “These patients are two to four times more likely than people without diabetes to die from heart disease. For the first time, we have evidence that aggressively lowering LDL cholesterol and blood pressure can actually reverse damage to the arteries in middle-aged adults with diabetes.”

In the “Stop Atherosclerosis in Native Diabetics Study,” about one-half of the participants (247) were asked to lower to standard levels their LDL cholesterol (to 100 milligrams per deciliter) and blood pressure (systolic blood pressure of 130 mmHg or lower). The other half (252) aimed for more aggressive lowering of LDL cholesterol to 70 mg/dL or lower and systolic blood pressure to 115 mmHg or lower.

All participants were American Indians 40 years or older (average age of 56) who had diabetes, high blood cholesterol, and high blood pressure but no history of heart attack or other evidence of heart disease.

“American Indians have a high rate of diabetes and cardiovascular disease related to diabetes, but there are few clinical trials that address these issues in this population,” said Barbara V. Howard, PhD, of MedStar Research Institute in Hyattsville, MD, lead author of the study.

“These study results provide needed evidence to help develop community-based programs to treat and prevent the epidemic of cardiovascular disease among American Indians. At the same time, we are increasing our understanding of the effects of intensively lowering cholesterol and blood pressure in adults with type 2 diabetes, which might also apply to other populations.”

During the three-year study, participants were examined by study clinicians one month after enrollment, then every three months, to assess their blood cholesterol and blood pressure levels and general well-being. Participants were also encouraged to follow a healthy lifestyle by adhering to a heart-healthy eating plan, being physically active, maintaining a healthy weight and not smoking.

Researchers used ultrasound to measure the thickness of the carotid (neck) artery -- an indication of hardening of the arteries, a leading effect of high blood pressure and cholesterol and an early sign of cardiovascular disease.

On average, participants in both groups reached and maintained their target goals for blood cholesterol and blood pressure levels. The numbers of heart attacks and other cardiovascular events were similar between the two groups and lower than expected.

In addition, measurements of carotid artery thickness of participants in the aggressive treatment group were significantly lower than those in the standard treatment group. Researchers report that, compared to baseline, carotid artery thickness increased slightly in the standard group and regressed in the aggressive treatment group, indicating a partial reversal of atherosclerosis. Furthermore, although heart size decreased from baseline in both groups, the beneficial change was significantly greater among participants in the aggressive treatment group.