Nearly half of global dementia cases could be delayed or prevented, scientists say

Nearly half of all dementia cases could be delayed or prevented altogether by addressing 14 possible risk factors, including vision loss and high cholesterol.

That is the key finding of a new study that we and our colleagues published in the journal The Lancet.

Dementia, a rapidly increasing global challenge, affects an estimated 57 million worldwide, and this number is expected to increase to 153 million by 2050 worldwide. Although the prevalence of dementia is on the decline in high-income countries, it continues to increase in low- and middle-income countries.

This third updated report of the Lancet Commission on Dementia offers good news and a strong message: Policymakers, clinicians, individuals and families can be ambitious about prevention and reduce dementia risk; and for those living with dementia and their caregivers, support their quality of life using evidence-based approaches.

The new report confirms 12 previously identified potentially modifiable risk factors from two previous reports, published in 2017 and 2020. It also offers new evidence supporting two additional modifiable risk factors: vision loss and high levels of low-density lipoprotein (LDL) cholesterol, often called “bad” cholesterol.

Our study of published evidence found that collectively, addressing 14 modifiable risk factors could potentially reduce the prevalence of dementia by 45% worldwide. Even greater risk reductions could be possible in low- and middle-income countries and for people with low income in higher-income countries given the higher prevalence of dementia, health disparities and risk factors in these populations.

The report further indicates that reducing these 14 risks can increase the number of healthy years of life and reduce the length of time with poor health in people with dementia.