The number of worldwide dementia cases is set to triple within the next three decades, according to new research.
The Global Burden of Disease study estimates that a total of 153 million people across the globe will be living with the condition by 2050 – up from 57 million in 2019.
Published in The Lancet, the research says that population growth and an increase in people living longer will be primarily responsible for this trend.
It also examined four risk factors associated with dementia – smoking, obesity, high blood sugar, and low education – to assess how they will drive the prevalence of the condition.
The study found that improvements in global education access are projected to reduce the number of dementia cases by 6.2 million come 2050. However, this will be countered by anticipated trends in obesity, high blood sugar, and smoking, which are expected to result in an additional 6.8 million dementia cases.
“We need to focus more on prevention and control of risk factors before they result in dementia,” said lead author Emma Nichols, from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.
“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.
“And it also means continuing to invest in research to identify effective treatments to stop, slow, or prevent dementia.”
Dementia is currently the seventh leading cause of death worldwide and one of the major causes of disability and dependency among older people globally, with global costs in 2019 estimated at more than £737.9 billion.
The Lancet study predicts that dementia cases will rise in every country over the next three decades. The smallest estimated increases will be in high-income Asia Pacific (53 per cent) and western Europe (74 per cent), the estimates show.
In Japan, there will be a particularly small increase in cases of just 27 per cent.
The largest growth will be in north Africa and the Middle East (367 per cent), from 3 million in 2019 to nearly 14 million in 2050, and eastern sub-Saharan Africa (357 per cent) – 660,000 to 3 million.
Globally, more women are affected by dementia than men. In 2019, women with dementia outnumbered men with dementia 100 to 69. And this pattern is expected to remain in 2050.
“It’s not just because women tend to live longer”, said co-author Dr Jaimie Steinmetz, from the IHME. “There is evidence of sex differences in the biological mechanisms that underlie dementia.
“It’s been suggested that Alzheimer’s disease may spread differently in the brains of women than in men, and several genetic risk factors seem related to the disease risk by sex.”
Acknowledging the limitations of the analysis, which looked at different studies and datasources, the authors said there was a lack of high-quality data in several parts of the world, including sub-Saharan Africa, eastern Europe, and Central America.
They said they were also limited by studies using different methodologies and definitions of dementia.