A "global epidemic" of Alzheimer's disease could take hold by 2050 with the number affected set to quadruple, experts predicted yesterday.

The number of people living with the condition, which is estimated at 26 million worldwide, will grow to more than 106 million by 2050, with about half of them needing high-level care, the researchers said. The Alzheimer's Society said that about 1.7 million people will be living with the condition in the UK by 2050.

There are currently 700,000 people with dementia in the UK and 60,000 people die from it every year.

The research author Professor Ron Brookmeyer, from the Bloomberg School of Public Health in Maryland, told the International Conference on the Prevention of Dementia in Washington DC: "We face a looming global epidemic of Alzheimer's disease as the world's population ages.

"By 2050, one in 85 persons worldwide will have Alzheimer's disease. However, if we can make even modest advances in preventing Alzheimer's disease or delay its progression, we could have a huge global public health impact."

Mr Brookmeyer said that the biggest rise in the number of cases would occur in Asia where currently 48 per cent of sufferers live. Prevalence there will grow from 12.65 million in 2006 to 62.85 million in 2050, accounting for 59 per cent of all cases, the study said.

It comes as other experts announced a new test that can predict a person's risk of getting dementia in the next six years.

The test combines medical history, cognitive function and a physical examination and is 87 per cent accurate, according to experts at San Francisco VA Medical Centre in California. Neil Hunt, chief executive of the Alzheimer's Society, said that tools to predict dementia and encourage healthy life-styles were important to combat the disease. But he added: "There is a risk with any tool which predicts the likelihood of developing dementia of clinicians becoming reliant on diagnosis by numbers.

"Dementia is incurable and discovering you have a high chance of developing the condition may frighten people rather than empowering them into action to reduce their risk.

"Any risk model should be used alongside guidance on how people can reduce their chances of developing dementia."

He said the Maryland research painted a "stark picture of the impact of Alzheimer's disease on a global scale". He added: " "A national dementia strategy must consider the global scale of Alzheimer's disease and other types of dementia."