The number of adults living with dementia worldwide is on course to nearly triple to 153 million by 2050, according to the first study of its kind.
Experts described the data as shocking and said it was clear that dementia presented “a major and rapidly growing threat to future health and social care systems” in every community, country and continent.
US researchers said the dramatic rise from an estimated 57 million cases in 2019 would be primarily due to population growth and ageing. However, several risk factors for dementia – including obesity, smoking and high blood sugar – would also fuel the increase, they said.
Improvements in global education access are projected to reduce global dementia prevalence by 6.2 million cases by 2050. But this will be countered by anticipated trends in obesity, high blood sugar and smoking, which are expected to result in an extra 6.8 million dementia cases.
The Global Burden of Disease study is the first to provide forecasting estimates for adults aged 40 and older across 195 countries worldwide. The findings are published in the Lancet Public Health.
Dementia cases will rise in every country, with the largest growth in north Africa and the Middle East (367%) and eastern sub-Saharan Africa (357%). The countries projected to record the largest rises worldwide are Qatar (1,926%), the United Arab Emirates (1,795%) and Bahrain (1,084%).
The smallest estimated increases are in the high-income Asia Pacific (53%) and western Europe (74%), the study suggests. Japan is expected to have the smallest increase in the world at 27%.
In the UK, the number of dementia cases is projected to increase by 75%, from just over 907,000 in 2019 to almost 1.6 million in 2050.
Hilary Evans, the chief executive of Alzheimer’s Research UK, who was not involved in the study, said the figures “lay bare the shocking scale of dementia across the world”.
She said: “We need to see concerted global action to avoid this number tripling. Dementia doesn’t just affect individuals, it can devastate whole families and networks of friends and loved ones. The heartbreaking personal cost of dementia goes hand in hand with huge economic and societal impacts, strengthening the case to governments across the world to do more to protect lives now and in the future.”
Dementia is already one of the major causes of disability and dependency among older people globally, with costs in 2019 estimated at more than $1tn (£750bn).
Although dementia mainly affects older people, it is not an inevitable consequence of ageing. A Lancet commission in 2020 suggested up to 40% of cases could be prevented or delayed if exposure was eliminated to 12 known risk factors: low education, high blood pressure, hearing impairment, smoking, midlife obesity, depression, physical inactivity, diabetes, social isolation, excessive alcohol consumption, head injury and air pollution.
The researchers behind the new study called for more aggressive prevention efforts to reduce dementia risk through lifestyle factors such as education, diet and exercise, alongside research to discover effective disease-modifying treatments and new modifiable risk factors to reduce the future burden of disease.
The lead author, Emma Nichols, from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, said: “To have the greatest impact, we need to reduce exposure to the leading risk factors in each country. For most, this means scaling up locally appropriate, low-cost programmes that support healthier diets, more exercise, quitting smoking, and better access to education.”
The authors acknowledged their analysis was limited by a lack of high-quality data in several parts of the world and by studies using different methodologies and definitions of dementia.
