Medicines commonly used to treat high blood pressure and heart disease may cut the risk of developing Alzheimer's disease and dementia, U.S. scientists said on Wednesday.
Researchers from Boston found that older people taking a certain type of blood pressure medication known as angiotensin receptor blockers (ARBs) were significantly less likely to develop the brain-wasting illnesses.
Dementia affects some 35 million people around the world and the number of cases — and their impact on health policy and the economic and social costs of healthcare — is set to grow dramatically as populations age.
Despite decades of research, doctors still have few effective weapons against dementia and experts commenting on the latest study said it could have major implications.
Alzheimer's Disease International predicts the number of dementia sufferers globally will almost double every 20 years — to 66 million in 2030 and more than 115 million in 2050 — with much of the rise coming in poorer nations.
The study, led by Benjamin Wolozin from Boston University School of Medicine, looked at the incidence of dementia in 800,000 mostly male patients in the United States from 2002 to 2006. They all had heart disease and were 65 or older.
One group was using ARBs, another was taking a different type of the blood pressure lowering drug, an ACE inhibitor called lisinopril, and a third was on other heart medications.
The results, published in the British Medical Journal, show that those taking ARBs were significantly less likely to develop Alzheimer's disease or dementia, Wolozin said.
High blood pressure is a known risk factor for vascular dementia, where brain function is damaged by a series of small strokes.
Diovan, or valsartan, made by Swiss drug firm Novartis, and Atacand, or candesartan, made by the Anglo-Swedish firm AstraZeneca, are two of the biggest selling ARB medicines.
The team also found that ARBs have an added effect when combined with angiotensin-converting enzyme (ACE) inhibitors in patients who had already developed Alzheimer's or dementia. Those taking both drugs were less likely to die early or be admitted to nursing homes.
"The public health implications of finding an effective way of preventing dementia are immense," said Colleen Maxwell and David Hogan, experts in geriatric medicine at the University of Calgary, Canada, who wrote a commentary on the study.
But they said further work was needed to verify whether blood pressure drugs, and ARBs in particular, could help.
Previous studies have suggested that taking steps to stave off heart disease and diabetes may also improve the chances of avoiding dementia and Alzheimer's.
Research found that people who take cholesterol-lowering drugs known as statins have a lower risk of developing all forms of dementia. And diabetics who take pills that help their bodies use insulin better have a lower risk of Alzheimer's.