WASHINGTON--Anti-cholesterol drugs known as statins, the world's top-selling prescription drugs, may modestly help reduce blood pressure and bring additional cardiovascular benefits, said a medical study published Monday.

Physicians at University of California, San Diego conducted a double-blind trial with 973 people who did not have diabetes or cardiovascular disease.

The group was divided in three equal parts, with one given 20 milligrams of simvastatin, another 40 milligrams of pravastatin and the third placebo, every day for six months, said Beatrice Golomb, chief author of the study published by the Archives of Internal Medicine.

Doctors took the blood pressure of the study participants at the beginning of the clinical trial, at one and six months into the treatment and two months after the trial ended.

"Blood pressure reductions ranged from 2.4 to 2.8 millimeters of mercury for both systolic blood pressure (normal is 120 millimeters) and diastolic blood pressure (normal is 80 millimeters) with both simvastatin and pravastatin," the authors said.

There was no practical difference in blood pressure among the group given placebo, they added.

The effect of statins on blood pressure was not evident at one month of treatment, was significant at six months of treatment and dissipated two months after treatment ended," they said.

"This study adds to our understanding of the effects of statins, currently the best-selling prescription drugs in the world," the authors said.

"The reduction in blood pressure seen with statins may contribute -- among other identified factors -- to some of the rapid' cardiovascular benefits of statins, arising too swiftly to be explained by effects of statins on plaque accumulation," they concluded.

Statins may activate compounds that widen blood vessels and improve their function, the authors theorized.

Several previous studies had already suggested statins may have an effect on blood pressure, particularly in patients with hypertension (high blood pressure).

Dr. John LaRosa, President of SUNY Downstate Medical Center in Brooklyn, New York, who did not participate in the clinical trial, warned in a statement that statins "should not be used solely for the purpose of blood pressure lowering since these results are modest and inconsistent from one study to another."

"Some studies have shown moderate pressure reduction with statin as this one," he added.