There are over 50 million people worldwide living with dementia in 2020. This number will almost double every 20 years, reaching 82 million in 2030 and 152 million in 2050. Much of the increase will be in developing countries. Already 60% of people with dementia live in low and middle income countries, but by 2050 this will rise to 71%. These figures are estimates based on the best currently available evidence.
The 2015 estimates
The World Alzheimer Report 2015, ‘The global impact of dementia: An analysis of prevalence, incidence, cost and trends’, presented ADI’s global dementia data. By carrying out a full update of previous systematic reviews, the report made key recommendations to provide a global framework for action on dementia.
The report also included a systematic review of the evidence for and against recent trends in the prevalence and incidence of dementia over time, as well as an analysis of the broader societal impact of dementia.
The global estimates of the number of people living with dementia were updated by the authors in December 2017, to be published for the launch of the World Health Organization’s Global Dementia Observatory. The updated estimates are presented below. Full details of the methodology, and further discussion, can be found in the World Alzheimer Report 2015.
Previous systematic reviews estimating global prevalence of dementia carried out for the World Alzheimer Report 2009 and 2015 were updated (up to April 2017). Numbers of people living with dementia were estimated by applying the age- and sex-specific prevalence of dementia for each region to the UN population estimates for 2015 and the population projections until 2050.
The noticeable increase in the projected numbers of people living with dementia worldwide from the 2015 estimates to these 2017 estimates is mainly due to the revised UN population estimates (2015 UN estimates instead of the 2013 UN estimates used in the World Alzheimer Report 2015) and new evidence which impacted on the strategies used to estimate numbers for some of the Global Burden of Disease (GBD) regions, rather than secular trends in the prevalence of dementia.
Estimated numbers of people with dementia by region (millions)
|Asia Pacific High Income||3.57||4.23||4.86||5.48||6.10||6.67||7.04||7.40|
|North America High Income||4.40||5.01||5.79||6.77||8.00||9.25||10.29||11.10|
|Latin America Andean||0.42||0.52||0.63||0.77||0.94||1.15||1.40||1.68|
|Latin America Central||1.80||2.22||2.73||3.37||4.19||5.19||6.39||7.71|
|Latin America Southern||0.90||1.04||1.20||1.39||1.62||1.89||2.19||2.51|
|Latin America Tropical||1.69||2.14||2.70||3.38||4.19||5.18||6.30||7.48|
|North Africa / Middle East||2.49||2.99||3.62||4.44||5.52||6.85||8.40||10.10|
|Sub-Saharan Africa Central||0.21||0.25||0.30||0.36||0.44||0.53||0.65||0.79|
|Sub-Saharan Africa East||0.85||1.02||1.21||1.46||1.77||2.17||2.70||3.38|
|Sub-Saharan Africa Southern||0.25||0.28||0.32||0.36||0.42||0.49||0.58||0.68|
|Sub-Saharan Africa West||0.66||0.76||0.89||1.05||1.26||1.53||1.86||2.26|
Estimated numbers of people with dementia by World Bank income group (millions)
As before, the projections assume that age-specific and age- and sex-specific prevalence of dementia in each region will remain constant over time, which is unlikely to be the case, particularly in regions undergoing rapid demographic, epidemiologic and social changes.
As highlighted in the World Alzheimer Report 2015, there is a need for more and better monitoring of the prevalence of dementia worldwide.