The angiotensin receptor blockers (ARBs) help in cases of Alzheimer's disease and dementia.

US researches say that dementia affects nearly 35m people around the world, and the number of cases will grow as populations age. They also say the disease could have major implications for patients.

Benjamin Wolozin, and his team from Boston University, studied nearly 800,000 people in the US between 2002 and 2006.

He found that the group of people using ARBs were significantly less likely to develop Alzheimer's or dementia. Those taking an angiotensin-converting enzyme (ACE) inhibitor called lisinopril or other heart medications are less prone to develop dementia.

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.

So far there is no proper treatment for dementia.