BAKERSFIELD, Calif. -- The exact cause of dementia and Alzheimer's disease remains a mystery, but research consistently links poor blood circulation and memory loss.

This connection between heart and brain health has led scientists to wonder: if treating high blood pressure improves blood flow to the brain, could it also reduce the odds of dementia?

A new study has suggested the answer may be yes -- at least for a particular class of hypertension medications.

Doctors at the Boston University School of Medicine analyzed results from more than 800,000 patients -- mostly male U.S. veterans -- who were over age 65 and had heart disease.

The participants were taking different types of drugs to treat their heart problems, and researchers found those using blood pressure medications called angiotensin receptor blockers were 15 to 25 percent less likely to develop Alzheimer's disease or dementia.

This class of medications includes Atacand, Cozaar, and Diovan -- pills that are often highly effective at lowering blood pressure.

But researchers said the drugs may also have direct effects on the brain, making them a promising target for reducing dementia risk.