A new report by leading experts from around the world has listed 14 modifiable risk factors associated with 40% of all dementia cases. These factors, if addressed throughout a person’s life, can reduce the likelihood of developing the disease or delay its onset.
With advances in public health, nutrition and medicine, people are living longer. But in a cruel irony, increasing longevity means that the number of people with dementia continues to rise.
The Lancet Commission most recently published its report on dementia prevention, intervention and care in 2020. In this report, the Commission updated the list of modifiable dementia risk factors from nine in the 2017 report to 12. Now, with the publication of the 2024 report, this list has been increased again – to 14.
“Our new report reveals that there is much more that can and should be done to reduce the risk of dementia,” said Gill Livingston, professor of psychiatry at University College London (UCL) and lead author of the study. “With opportunities to make an impact at any stage of life, it is never too early or too late to take action.”
The 2020 report’s 12 modifiable risk factors accounted for around 40% of dementia cases worldwide: low 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. The two new risk factors added to the updated report, authored by 27 leading dementia experts, were high low-density lipoprotein (LDL or ‘bad’) cholesterol levels around age 40 and untreated vision loss in old age.
Of all the updated risk factors, hearing impairment and high LDL cholesterol are estimated to be associated with the greatest proportion of people developing dementia worldwide (7% each), followed by less education early in life and social isolation later in life (5% each).
“We now have stronger evidence that longer exposures to risk have a greater impact and that risks work more strongly in vulnerable people,” Livingston said. “It is therefore vital that we redouble prevention efforts to those who need them most, including low- and middle-income countries and socioeconomically disadvantaged groups. Governments must reduce risk inequalities by making healthy lifestyles as accessible as possible to all.”
While some high-income countries, such as the US and the UK, have seen a decline in the number of people with dementia, particularly in socioeconomically advantaged areas, the report's authors say this decline is likely due in part to building cognitive and physical resilience throughout life, and a reduction in blood vessel (vascular) damage due to improvements in health care and lifestyle changes. They say this underscores the need to implement prevention strategies as early as possible.
The Commission has put forward 13 recommendations that individuals and governments should adopt to reduce the risk of dementia throughout life:
- Provide children with quality education and maintain cognitive activity in middle age.
- Make hearing aids available to those who need them and reduce exposure to harmful noise.
- Test for and treat high LDL cholesterol starting in middle age.
- Screen all people for vision impairment and treat as appropriate.
- Treat depression effectively.
- Wear head protection and a helmet during contact sports and cycling.
- Prioritize supportive community environments and housing to increase social contact.
- Reduce exposure to air pollution with strict clean air policies.
- Take stricter measures to reduce smoking, such as increasing prices or raising the minimum purchasing age.
- Reduce the sugar and salt content of foods sold in stores and restaurants.
“Healthy lifestyles that include regular exercise, not smoking, cognitive activity in middle age (including outside of formal education) and avoiding excessive alcohol not only reduce the risk of dementia, but can also push back the onset of dementia,” Livingston said. “So if people develop dementia, they are likely to live fewer years with it. This has huge quality-of-life implications for individuals, as well as cost-saving benefits for societies.”
The report also discusses promising progress in identifying blood biomarkers to diagnose dementia, calls for more research on the disease and calls for greater transparency about the short- and long-term side effects of new treatments, such as anti-amyloid beta antibody therapy for Alzheimer's disease.
The report authors note that the prevention estimates appearing in the report assume a causal relationship between the listed risk factors and dementia. They are careful to include only risk factors for which there is compelling evidence, but they note that some associations may be only partially causal. They also note that the risk changes they advocate affect the entire population and do not guarantee that an individual will avoid dementia.
2024 update Lancet Dementia Commission published Lancet and presented at the Alzheimer's Association International Conference (AAIC 2024) in Toronto, Canada, at the end of July.
Source: UCL