Forecast - 81 million dementia cases by 2040

A team of experts is predicting that the number of people suffering from dementia will double every 20 years and could reach more than 81 million worldwide by 2040.

The scientists from Alzheimer's Disease International (ADI) estimate 24.3 million people currently suffer from dementia and the number of cases is rising by 4.6 million a year or one every 7 seconds.

Unless some form of prevention is introduced the number will hit 42 million in 20 years and nearly double again by 2040 with the bulk of the increase in India, China, south Asia and the western Pacific.

Cleusa Ferri and her colleagues say that the rate of increase in numbers of people with dementia is predicted to be three to four times higher in developing areas than in developed regions.

According to the study the figures will have important implications for policy makers and health care providers.

As an example, residential care for 224,000 dementia sufferers in Britain is estimated to cost about 4.6 billion pounds, or 0.6 percent of the UK gross domestic product.

Alzheimer's is the leading cause of dementia in the elderly, there is no cure for it and it is characterised by the loss of two or more brain functions such as memory and language skill.

People with advanced dementia often need round-the-clock care, but drugs can slow down the progression or reduce the symptoms.

In the study the scientists from ADI, an umbrella organisation of Alzheimer associations around the world, reviewed published studies on dementia and used UN population studies and projections to estimate the number of people who will suffer from dementia in coming decades.

They believe that the detailed estimates contained in the paper are the best currently available and a sound basis for policy-making, planning and allocation of health welfare resources, says Ferri.

The study is published in The Lancet.