The World Alzheimer Report 2015 led by King's College London found that there are currently around 46.8 million people living with dementia around the world, with numbers projected to nearly double every 20 years, increasing to 74.7 million by 2030 and 131.5 million by 2050.
Researchers also found that there are more than 9.9 million new cases of dementia each year worldwide, implying one new case every 3.2 seconds.
These regions are closely followed by South Asia with 5.1 million and North America with 4.8 million.
At the country level, ten countries are home to over a million people with dementia in 2015: China (9.5 million), US (4.2 million), India (4.1 million), Japan (3.1 million), Brazil (1.6 million), Germany (1.6 million), Russia (1.3 million), Italy (1.2 million), Indonesia (1.2 million) and France (1.2 million).
The estimates are based on new research led by Professor Martin Prince from King's College London's Global Observatory for Ageing and Dementia Care.
"We now believe that we underestimated the current and future scale of the epidemic by 12-13 per cent in the 2009 World Alzheimer Report, with costs growing more rapidly than the numbers of people affected," said Prince.
According to the report, the current annual societal and economic cost of dementia is USD 818 billion, and it is expected to become a trillion dollar disease in just three years' time.
