A group led by Dr. Patrick G. O'Malley, chief of the division of general and internal medicine at Walter Reed Army Medical Center, reports that only a continuing effort at changing a person's lifestyle can reduce that risk.
The images they used came from electron beam tomography (EBT), which shows calcium deposits in the heart and blood vessels that are the early signs of future trouble. The subjects were 450 symptom-free active duty Army personnel aged 39 to 45.
They were divided into four groups. Some were shown the EBT images immediately and left on their own. Others were not told about their results for a year, without advice about lifestyle changes. A third group got advice about lifestyle changes and they were shown the EBT images a year later. People in the fourth group saw their EBT images immediately and were given continuing advice on changing lifestyle.
One year later, an overall reduction in risk factors -- smoking, blood pressure, better diet -- was seen only in that fourth group, says a report in the May 7 issue of the Journal of the American Medical Association. Using the assessment scale developed by the Framingham Heart Study, which includes all known cardiovascular risk factors, they found a reduction about double that of the other groups.
It's an important finding because "this technology has been widely used, based on a self-referral basis," O'Malley says. There are for-profit EBT centers around the country that will provide blood vessel images, leaving the follow-up to a family doctor or cardiologist.
But "general behavioral change is a difficult thing," O'Malley says. "Life is complex. Health can be affected by societal reasons, social reasons."
Still, in some communities people are exposed to "fairly aggressive advertising and marketing," says Dr. Philip Greenland, chairman of the department of preventive medicine at Northwestern University and author of an accompanying editorial. "The people who run the scanners frequently justify making them available to the public on the grounds that it will lead people to make changes and follow appropriate medical advice."
O'Malley's study shows that "EBT is no more potent than other methods of describing risk" as a way to achieve lifestyle changes, Greenland says. He acknowledges that he has been skeptical all along, and the study results "tend to support what I would have believed anyway."
It's not just EBT that Greenland is skeptical about. "The evidence is pretty strong in relation to other tests as well that information alone is not potent in changing behavior."
The fact that the people in the study were young and healthy might have influenced the results, O'Malley says. "This is worth testing in a group with higher prevalence of coronary disease," he says. "We're looking for funding for a study of a higher-prevalence cohort."