THURSDAY, Jan. 8 (HealthDay News) -- After nearly a year of review, U.S. health officials said Thursday that they supported the continued use of the controversial cholesterol-lowering drug Vytorin.

The U.S. Food and Drug Administration said there was no significant difference in carotid artery thickness between patients taking Vytorin and patients taking the drug Zocor.

But, the agency reported, the levels of LDL (bad) cholesterol decreased by 56 percent in the Vytorin group compared to 39 percent for the Zocor group.

The debate over Vytorin began early last year when preliminary results of the so-called Enhance trial showed that the drug had little benefit. A study released Jan. 14, 2008, by Vytorin's makers found that the drug -- a combination of Zocor (simvastatin) and Zetia (ezetimibe) -- might not be any more effective at reducing the build-up of plaque in the arteries than Zocor alone.

In a statement released Thursday, the FDA said it had finished its review of the final clinical study report of the Enhance trial.

"Following two years of treatment," the statement said, "carotid artery thickness increased by 0.011 mm (millimeters) in the Vytorin group and by 0.006 mm in the simvastatin group. The difference in the changes in carotid artery thickness between the two groups was not statistically significant. However . . . the difference in the reductions in LDL cholesterol between the two groups was statistically significant."

Measuring the thickness of the carotid arteries in the neck through ultrasound imaging is considered a biomarker of risk for cardiovascular disease, the agency said.

In its statement Thursday, the FDA reiterated its position that "elevated amounts of low-density lipoprotein (LDL) . . . are a risk factor for cardiovascular diseases such as heart attack, stroke and sudden death, and that lowering LDL cholesterol reduces the risk of these diseases."

Vytorin was back in the news last September when a study found no definitive link between the drug and cancer risk.