Nearly half of dementia cases could be prevented or delayed by tackling 14 risk factors
Addressing 14 modifiable risk factors, starting in childhood and continuing throughout life, could prevent or delay nearly half of dementia cases, according to a new report led by UCL researchers.
The third Lancet Commission on dementia prevention, intervention, and care, led by UCL Professor Gill Livingston is being presented today at the Alzheimer’s Association International Conference (AAIC 2024).
Even as people around the world live longer and the number of people with dementia is set to rise dramatically in all countries, the potential to prevent and better manage dementia is high if action is taken to tackle these risk factors, even in people with high genetic risk for dementia.
Based on the latest available evidence, the new report adds two new risk factors that are associated with nine per cent of all dementia cases — with an estimated seven per cent of cases attributable to high low-density lipoprotein (LDL) or “bad” cholesterol in midlife from around age 40 years, and two per cent of cases attributable to untreated vision loss in later life.
These new risk factors are in addition to 12 risk factors previously identified by the Lancet Commission in 2020 (lower levels of education, hearing impairment, high blood pressure, smoking, obesity, depression, physical inactivity, diabetes, excessive alcohol consumption, traumatic brain injury, air pollution and social isolation), which are linked with 40 per cent of all dementia cases.
The new report estimates that the risk factors associated with the greatest proportion of people developing dementia in the global population are hearing impairment and high LDL cholesterol (seven per cent each), along with less education in early life and social isolation in later life (five per cent each).
The Commission, authored by 27 world-leading dementia experts, calls for governments and individuals to be ambitious about tackling risks across the life course for dementia, arguing that the earlier we can address and reduce risk factor levels, the better. The report outlines a new set of policy and lifestyle changes to help prevent and better manage dementia.
Because of the rapidly ageing population around the world, the number of people living with dementia is expected to almost triple by 2050, rising from 57 million in 2019 to 153 million. Increasing life expectancy is also driving a surge in people with dementia in low-income countries. Global health and social costs related to dementia are estimated at over $1 trillion every year.
However, in some high-income countries, including the USA and UK, the proportion of older people with dementia has fallen, particularly among those in socio-economically advantaged areas.
The report authors say that this decline in people developing dementia is probably in part due to building cognitive and physical resilience over the life course and less vascular damage as a result of improvements in healthcare and lifestyle changes, demonstrating the importance of implementing prevention approaches as early as possible.
Nevertheless, most national dementia plans do not make specific recommendations about diversity, equity, or inclusion of people from underserved cultures and ethnicities who are disproportionately affected by dementia risks.
Lead author Professor Gill Livingston (UCL Psychiatry) said: “Our new report reveals that there is much more that can and should be done to reduce the risk of dementia. It’s never too early or too late to take action, with opportunities to make an impact at any stage of life.
“We now have stronger evidence that longer exposure to risk has a greater effect and that risks act more strongly in people who are vulnerable. That’s why it is vital that we redouble preventive efforts towards those who need them most, including those in low- and middle-income countries and socio-economically disadvantaged groups. Governments must reduce risk inequalities by making healthy lifestyles as achievable as possible for everyone.”
To reduce dementia risk throughout life, the Commission outlines a number of recommendations to be adopted by governments and individuals. These include making hearing aids available for all those with hearing loss and reduce harmful noise exposure, improving the detection and treatment of high LDL cholesterol in midlife, and making screening and treatment for vision impairment accessible for all.
These actions are especially important given new evidence which shows that reducing the risks of dementia not only increases years of healthy life but also reduces the time people who develop dementia spend in ill health.
Professor Livingston added: “Healthy lifestyles that involve regular exercise, not smoking, cognitive activity in midlife (including outside formal education) and avoiding excess alcohol can not only lower dementia risk but may also push back dementia onset.
“So, if people do develop dementia, they are likely to live less years with it. This has huge quality of life implications for individuals as well as cost-saving benefits for societies.”
In response to the report, Dr Jeremy Isaacs, NHS National Clinical Director for Dementia said: “This research is really important as it suggests there are additional risk factors for dementia, which means that there are more opportunities for all of us to take action throughout our lives to reduce our risk of developing dementia or delay its onset. The findings also offer real hope that we can reduce the number of people who experience this devastating illness.
“Ensuring that people with dementia receive a timely diagnosis is a priority and NHS staff have worked hard to ensure the number of people with a dementia diagnosis has risen significantly over the last year, and is now at a record level, but we know there is more work to be done.”
New research carried out recently by pharmaceutical firm Luye Pharma as part of its ‘Let’s talk Dementia’ campaign has revealed a lack of understanding around dementia and the impact it has on society.
