'Scary' dementia modelling shows how cases will surge by 2050

By 2050 an estimated 24.7 million people will be diagnosed with dementia each year and women will be disproportionately affected, according to a landmark new study.

The research found approximately 11.4 million people developed dementia globally in 2023 and that by 2050 that figure will double and demand for care will explode.

The study's authors said women's brain health needed to be prioritised and risk factors like hormonal changes and unequal education or job opportunities needed investigating.

"Understanding these differences is critical if we are to develop dementia prevention, diagnosis and care strategies that respond to the populations facing the greatest future risk," lead author Dr Ashleigh Vella said.

The research from the Centre for Healthy Brain Ageing (CHeBA) at the University of NSW analysed 38,418 people through population-based studies from 18 countries and territories.

It is one of the most comprehensive studies looking at the incidence rate of dementia. The study found cases were highest among women and people living in low income and middle income countries.

Nearly two thirds of current dementia diagnoses in Australia are women and this has long been considered a symptom of their longer life expectancy but researchers said there may be more at play.

The paper, published in the Journal of the American Medical Association Neurology, suggested the higher prevalence could be caused by other factors such as:

• Menopause
• Disproportionate educational and occupational opportunities
• Cardiometabolic factors such as body mass index and physical activity

Co-director of the CHeBA and Senior Australia of the Year Professor, Henry Brodaty, said historically women had less access to education and fewer career opportunities which could lead to poorer cognitive resilience.

"[Studies have shown] people who are in more complex occupations, particularly where they have complexity in managing people, they have a lower rate of cognitive decline and dementia," he said.

"Education has its most benefit in childhood and early development through to young adulthood but you can still build up your cognitive reserve or buffer against pathology building up in the brain throughout your life."

Higher rates of depression, anxiety and obesity among women could also be contributing factors, Professor Brodaty said, and more research was needed on the role menopause might play.

"Perhaps stopping oestrogen production may play a role but it's not established … and there's been conflicting results about whether hormone replacement therapy makes a difference."

Leading dementia researcher Matthew Pase at Monash University said the research was ambitious and provided important comparisons on dementia rates between low income and high income countries.

He described the figures as "scary".

"To see what rates are projected to be in low-income countries is alarming because they are less equipped to deal with this … so any solutions need to be scalable and not just be available for people who can pay to see an academic at a medical centre in Sydney or Melbourne."

Reducing dementia risk

Professor Brodaty, whose father passed away with Alzheimer's at just 52, said having a clear idea of what was coming meant there must be more investment in diagnosis, care and prevention.

Almost half of dementia cases could be prevented or delayed by addressing 14 risk factors.

Professor Brodaty urged Australians to "embrace" brain health by:

• Engaging in at least half an hour of physical activity five days a week
• Staying socially connected and "stretching the brain" by learning new things
• Eating a diet rich in vegetables, legumes and extra olive oil aka the Mediterranean diet
• Talking to their GP about brain health when they have their subsidised health check between the ages of 45 and 49

Professor Pase said given the high cost of the two dementia drug therapies approved in Australia, which are not subsidised through the Pharmaceutical Benefits Scheme, prevention was still key.