"In order to do that, it would have to change people's beliefs about coffee," said Assistant Professor of Economics David I. Laibson '88. "I wasn't even aware it was meant to have effects on heart disease."

Willett, the author of the study, said students should still be cautious even though the study showed no increased risk for heart disease.

He said coffee drinkers may face increased risks of osteoporosis and fractures.

"Some studies, and our study included, show increased [risk] with heavy coffee consumption," Willett said.

"Even though coffee consumption seems to be remarkably safe, it is probably a good idea to get a good night's sleep and not depend on straight java to pass exams," Willett said. He added that he "only drinks about half cup a day, unless I really need it."

The study, sponsored by the National Institute of Health, was based at Brigham and Women's Hospital, one of Harvard Medical School's teaching hospitals, according to Willett.

The findings are based on ten years of follow-up to an examination of the diet, lifestyle and health of 121,700 nurses who participate in the Harvard Nurses' Health Study.

Douglas M. Pravda contributed to the reporting of this story.