The findings suggest that Crestor, manufactured by AstraZeneca, should probably be reserved for patients who have had a hard time lowering their overall cholesterol levels with other statins, said Dr. Richard H. Karas of the Tufts-New England Medical Center in Boston, who led the study.

Comparing the number of reported events with the number of prescriptions written, the team concluded that Crestor, whose generic name is rosuvastatin, was responsible for 2.2 times as many reports as simvastatin, sold by Merck & Co. under the brand name Zocor, and 6.8 times as many as atorvastatin, sold by Pfizer Inc. under the name Lipitor.

The latest study contradicts an FDA study, announced this year, that concluded that Crestor was no more dangerous than other statins.