Narrator: This is Science Today. Using a computer simulation model, researchers have projected the impact of national cholesterol guidelines between the years 2000 and 2020. Dr. Lee Goldman, a professor of medicine at the University of California, San Francisco who led the study, says the results were surprising.

Goldman: We found that the public health benefit is greatest in people who already have heart disease. And that came as a bit of a surprise to me because one would have thought - there are five or ten million people with heart disease, but that means there are more than 250 million Americans without heart disease. And you would have thought somehow that aggregate, they would have had more benefit than five or ten million with it.

Narrator: These projections were validated by results in randomized trials.

Goldman: If there's some unforeseen change in medical care - someone creates a sugar pill that wipes out heart disease - obviously our projections will no longer be accurate. But within the context of what we currently know today, our projections have proven accurate.

Narrator: For Science Today, I'm Larissa Branin.