About 44 million people around the world currently suffer from dementia and by 2050 this figure is expected to reach 135 million, according to a policy brief.

The report by Alzheimer Disease International also predicts that by 2050, most dementia cases will be from low to middle-income countries.

Back in 2010, experts had estimated that 35 million were living with the condition. The latest report comes just days before a major summit on dementia scheduled to take place in London, Wednesday, Dec 11.

Dementia isn't a specific disease but is a term that describes loss of brain function that can occur due to many reasons. It generally occurs after 60 years of age and is characterized by loss of memory, language, thinking and behavioral changes. The condition is among the world's fastest growing diseases.

The brief is called 'The Global Impact of Dementia 2013-2050' and can be read, here.

"At the eve of the G8 Dementia Summit in London, UK, it is not just the G8 countries, but all nations, that must commit to a sustained increase in dementia research," said Marc Wortmann, Executive Director of ADI, according to a news release.

The world currently spends about $604 billion annually (2010). The medical and social costs of the disease are expected to rise in the future, especially in developing countries.

"The governments of the world's richest nations are focusing today upon dementia. This is a global problem that is, increasingly, impacting on developing countries with limited resources and little time to develop comprehensive systems of social protection, health and social care," Martin Prince, from King's College London and author of the Policy Brief.

A monthly injection to prevent Alzheimer's disease

According to a new study, a drug called solamezumab could help delay the disease. Clinical trials on people suffering from mild dementia have found the drug effective in preventing disease progression, The Telegraph reported.