But in the last year, three separate studies have suggested changes to improve the program's success.
But only 17 percent of those who had entered in the mid-1990's made the switch within five years, according to a separate study.
"These data are provocative enough to say that we should do separate studies on men and women," he said.
He added that each part of the project would include a separate environmental study.
A separate study showed 6% of 750 patients with the same incidence.
It's possible we need to test it in a separate study.
The findings of the new analysis were supported by a separate study in California.
However, in a separate study, the risk of heart attack increased by nearly 90%.
Administration officials said they would issue a separate study in several weeks to show the effects on hospitals, doctors and medical schools.
In the meantime, separate studies were pointing to new problems.