Dementia is rising fast – 5 surprising ways to protect your brain 

This article has been updated.

While it is widely accepted that a healthy lifestyle can reduce the risk of dementia, recent research has identified more specific - and sometimes unexpected - factors that may also play a role.

Dementia is currently the seventh leading cause of death worldwide and a major cause of disability and dependency, according to the World Health Organization (WHO). As populations age in nearly every country, the number of people living with dementia is projected to rise sharply - from 57 million in 2021 to an estimated 139 million by 2050.

Research continues to shed light on both the causes of dementia and the factors that may - or may not - influence a person’s risk of developing the condition.

Last year, researchers at the University of Cambridge linked dementia to problems in the brain’s waste-clearance system. Meanwhile, a separate major review found that hormone replacement therapy (HRT), widely used to treat menopausal symptoms, does not appear to affect dementia risk, neither increasing or reducing it.

So, what does help? Recent studies have identified the following:

Doing the daily crossword is often encouraged to keep the brain active, but researchers in Chicago have taken this concept a step further. Their study examined almost 2,000 older people over the course of eight years to discover how much a lifetime of “cognitive enrichment” – covering activities like reading, writing, visiting museums and learning a foreign language – reduced their risk of developing either dementia or mild cognitive impairment. What they found was that the people with the highest lifetime enrichment were also associated with a 38% lower risk of developing dementia.

“Our findings are encouraging,” said the study’s author, Andrea Zammit, of Rush University Medical Center in Chicago, “suggesting that consistently engaging in a variety of mentally stimulating activities throughout life may make a difference in cognition. Public investments that expand access to enriching environments, like libraries and early education programmes designed to spark a lifelong love of learning, may help reduce the incidence of dementia.”

While caffeine often gets a bad rap in the health arena, it seems it may have something to offer when it comes to brain health. An observational study of the caffeine-drinking habits of more than 130,000 healthcare professionals over four decades indicated that 2-3 cups of coffee or 1-2 cups of tea a day “was associated with the greatest reductions in dementia risk and rate of cognitive decline”. Most strikingly, even for those who drank large amounts of coffee – up to five cups a day – dementia risk was found to be 18% lower than for those who drank little to none.

Alcohol, on the other hand, may increase the risk of dementia “even at low levels”, according to a comprehensive new study by Oxford, Cambridge and Yale Universities. Previous studies have suggested that light-to-moderate drinking could have a neuroprotective effect, but this large-scale analysis of 560,000 adults concluded that any alcohol consumption can increase the risk of dementia. “Reducing alcohol consumption across the population could play a significant role in dementia prevention,” said the lead author of the study, Anya Topiwala, Senior Clinical Researcher at Oxford Population Health.

Air pollution is a well-documented health hazard, but two studies published in The Lancet last year have revealed the impact poor air quality has on brain health – and how it can increase the risk of developing dementia. Researchers at the University of Cambridge reviewed 51 studies examining causal links and found that long-term exposure to fine-particulate matter (PM2.5), nitrogen dioxide and black carbon or soot are all associated with a higher risk of dementia.

They found that, for every 10 micrograms per cubic metre (μg/m³) increase in PM2.5, a person’s risk of dementia increased by 17%. For soot, the risk increased by 13% for every 1μg/m³. For nitrogen dioxide, there was a 3% risk increase for every 10μg/m³.

The study's authors concluded that “reduced exposure to pollution could reduce dementia rates and stricter air quality standards would likely provide substantial health, social and economic benefits”.

This was backed up by a 26-year study by King’s College London that tracked the brain health of over 1,700 people. Those who were exposed to higher levels of air pollution in their midlife were found to have “poorer cognition, processing speed and brain structural outcomes”, again supporting the notion that breathing better air could contribute to a reduction in dementia rates.

Repurposing existing drugs isn't a new concept – most recently, medication for type 2 diabetes was discovered to be an effective weight-loss aid. Researchers in the dementia field have been exploring which treatments already in existence might have the potential to cure, or at least reduce the prevalence of, the disease.

A review, led by the University of Exeter and funded by Alzheimer's Society, of 80 existing drugs found three that held promise:

More research and clinical trials are now needed on these 'priority candidates' to fully understand their potential benefit to people living with Alzheimer's, the most common form of dementia.

A 2024 Lancet Commission report identified "new compelling evidence that untreated vision loss and high LDL [or 'bad'] cholesterol are risk factors for dementia".

These are the latest risk factors The Lancet has added to a list of 14 that can be attributed to nearly half of dementia cases worldwide. The other 12 are: less education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution and social isolation.

The good news is, “it’s never too early or too late to reduce your dementia risk", says Fiona Carragher, Chief Policy and Research Officer at Alzheimer’s Society.

There are many organizations working to help accelerate advances in the prevention and treatment of the condition. Davos Alzheimer’s Collaborative is led by the World Economic Forum and the Global CEO Initiative on Alzheimer’s Disease, and is investing $700 million into drug development and healthcare diagnostics.

A new report, The Human Advantage: Stronger Brains in the Age of AI, makes the case for "scaling cost-effective interventions to prevent, treat and help people recover from brain health conditions". Better investment in brain health could avert 267 million disability-adjusted life years (DALYs) globally by 2050, according to the report, as well as generate up to $6.2 trillion in cumulative GDP gains.

The report also finds that new technologies such as AI can help with early diagnosis and monitoring of diseases like dementia, suggesting that "medical advances that delay the onset of Alzheimer's for five years could result in 41% lower prevalence of the disease and 40% lower cost in 2050".