Researchers in Australia say there were 11.4 million new dementia cases globally in 2023 and they expect that number to more than double to 24.7 million by 2050.
Women and people from lower- and middle-income countries are most likely to be affected, according to the research.
Professor Henry Brodaty, co-author of the study, told the BBC this is because of what he called “an epidemic of ageing”.
The study, which was published in JAMA Neurology, looked at data from 38,418 people across 22 population-based studies spanning 18 countries and territories on six continents.
Researchers say global dementia incidence estimates are limited by underrepresentation of low- and middle-income countries and true understanding of the global dementia landscape remains incomplete.
Dementia currently affects more than 57 million people worldwide.