Wake Forest's Largest Study Will Examine Whether Weight Control Can Slow Hardening of the Arteries in Diabetics

December 14, 1999

A major seven-year national study on whether weight control can slow the advance of heart disease in persons with diabetes will be headquartered at Wake Forest University School of Medicine, under a $40.6 million grant from the National Institute of Diabetes and Digestive and Kidney Disorders.

The grant, by far the largest in the school''s history, includes funds to pay for 15 clinics across the country. No clinics will be located in Winston-Salem.

Mark Espeland, Ph.D., professor of public health sciences (biostatistics), will be principal investigator of the national coordinating center of the Study of Health Outcomes of Weight loss (SHOW).

The SHOW trial will involve 6,000 obese people who have adult-onset (type 2) diabetes, and test whether weight loss will reduce the adverse health problems commonly encountered by diabetics, especially cardiovascular disease.

"Weight loss is associated with improvements in numerous cardiovascular disease risk factors, including decreased LDL cholesterol [the bad cholesterol], reduced blood pressure, decreased blood glucose levels and improved insulin sensitivity," Espeland said.

But he said he knew of no studies that directly measure whether weight loss slows progression of atherosclerosis. "SHOW will be the first large trial designed in a manner to measure this."

Each of the 15 centers will enroll about 400 participants. They will be assigned randomly to community care or interventions aimed at reducing daily food consumption, reducing dietary fat and increasing physical activity each week. A weight-loss drug may be used by participants for whom weight loss is more difficult.

Experts in nutrition, exercise and behavior change from across the country will design these interventions so they will be effective, safe and appropriate for women and men of different ages and cultural groups. After the design is complete, recruiting of patients will begin, probably in late 2000 or early 2001.

Participants in the community-care arm will receive medical care from their personal physicians. They will also receive SHOW mailings and be invited to regular education sessions on diabetes-related subjects- except weight control.

Ultrasound will be used to measure the thickness of carotid artery walls to gauge the buildup of atherosclerosis - hardening of the arteries - and will be a key measure on whether the weight reduction program is having an effect.

For more than a decade, Wake Forest University has been a world leader in using carotid ultrasound to measure the pace of advancing atherosclerosis and developing statistical methods to interpret these data.

In the study, the researchers will keep track of all heart attacks and strokes in the groups as well as recording deaths from all causes. And they''ll be looking at how well weight loss leads to a reduction in other cardiovascular risk factors and whether it leads to reduction or elimination of oral diabetes drugs.

Lynne E. Wagenknecht, Dr. P.H., associate professor of public health sciences (epidemiology), one of the project co-directors, has been instrumental is demonstrating the increased risks of atherosclerosis borne by people with diabetes

Wagenknecht said that the reasons why diabetes accelerates the risk of heart disease are not fully understood. One explanation is that diabetics have a number of adverse risk factors including obesity. "This study could have an important impact on the 15 million diabetics in the United States, nearly half of whom are overweight."

The study results from close collaboration between Wake Forest''s Bowman Gray and Reynolda campuses. Investigators from four departments - seven academic units - make up the study team.. Besides Wagenknecht, co-directors are David M. Reboussin, Ph.D., associate professor of public health sciences (biostatistics), W. Jack Rejeski, professor of health and exercise sciences, and Judy Bahnson, research associate.


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