Due to the "lousy American diet, the American way of life leads to high cholesterol," said Dr. Frank M. Sacks, lead author of a new study showing that using drug therapy to lower cholesterol below normal level is futile.

For years, doctors have advised their patients to cut down on foods high in cholesterol and exercise to prevent heart disease. However, the appeal of a greasy hamburger has often outweighed the doctor's advice.

"Drug therapy is important because people won't change their lifestyles," said Sacks, an associate professor of medicine at the School of Public Health.

The study, published last week in Lancet by researchers at the School of Public Health, showed that using drug therapy to lower cholesterol to sub-normal levels does not decrease the plaque build-up in coronary arteries.

The study shows that "drug therapy has no effect on lowering levels of blockage already present in arteries," said Sacks.

Aggressive drug therapy to lower cholesterol levels below normal is therefore unnecessary, as reversing build-up is only "mildly possible," Sacks said.

"We should be more conservative in our use of drug therapy," Snacks said. Sacks said he still prescribes drug therapy when necessary for those with high cholesterol, but advocates diet and exercise therapy as the primary treatment.

Previous studies have shown that lowering cholesterol levels can reduce the rate at which plaque is deposited in coronary arteries, and thus prevent blood circulation problems, lessening the chance of heart disease.

A majority of patients with coronary disease do not have high cholesterol, but for those who do, physicians now prescribe a healthy diet, exercise and drug therapy to lower cholesterol levels.

Sacks said he proposed to determine whether drug therapy is useful for patients with coronary disease and normal cholesterol, to lower their cholesterol level further.

Sacks said he proposed to determine "whether you get bonus points by using drugs to lower cholesterol to below average levels."

"We hypothesized that it is better to have a lower than average cholesterol level, like 160, than an average one," said Sacks. The study disproved the original hypothesis.

Sacks' research team tested the guidelines established by the National Institutes of Health (NIH), which recommends drug therapy to patients with heart disease and normal cholesterol to lower their cholesterol levels below average.

The two and a half year study, which included 79 patients, found no significant difference between plaque build-up in patients given drug treatment and a group given only diet and exercise therapy.

A second, more extensive study involving 4001 patients will be completed in about a year and a half, Sacks said.