Study details and key findings

In the study, researchers analyzed data from people ages 50 to 73 who participated in either the U.K. Biobank or the Whitehall II study. In total, 220,762 people, with a mean age of 60, in the U.K. Biobank study were examined to create a dementia risk assessment tool. Data from an additional 2,934 people, with a median age of 57, from the Whitehall II study was used to validate the tool.

In the U.K. Biobank group, patients' dementia status was determined by self-reports, primary or secondary diagnoses in medical or death records, or prescriptions for dementia treatment. In the Whitehall II group, dementia status was determined by either self-report or inpatient hospital records.

The researchers initially identified 28 risk and protective factors associated with dementia before completing a LASSO regression to determine which factors would be the strongest predictors of dementia. Using competing risk regression, the researchers developed a risk tool called the UK BioBank Dementia Risk Score (UKBDRS) with 11 predictive factors, including:

• Age
• Education
• History of diabetes
• History of depression
• History of stroke
• Parental history of dementia
• Levels of material deprivation
• High blood pressure
• High cholesterol
• Living alone
• Being male

The researchers also examined whether patients carried the APOE gene, which is a known risk factor for dementia. The risk tool that accounted for the APOE gene was called the UKBDRS-APOE. Both tools were used to determine whether someone would develop dementia within the next 14 years.

Overall, 3,813 people (1.7%) in the U.K. Biobank group and 93 people (3.2%) in the Whitehall II group developed dementia.

The UKBDRS-APOE returned the highest predictive score followed by the UKBDRS. According to the researchers, the tool "significantly outperforms" three other widely used risk assessments: the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) score, the Australian National University Alzheimer's Disease Risk Index (ANU-ADRI), and the Dementia Risk Score (DRS).

However, the researchers also noted that the study came with limitations, including the fact that dementia was defined differently in each patient cohort and that the Whitehall II study consisted mostly of men. Dementia risk scores may also not be effective outside of the populations they were initially developed in.

"There are still improvements required before this score is suitable for clinical practice," said Dr. Raihaan Patel, the study's lead author from the University of Oxford. "While the score performed well across two U.K. cohorts, further evaluation across more diverse groups of people both within and beyond the U.K. is required."

Commentary

Currently, the number of people living with dementia worldwide is projected to almost triple to 153 million by 2050, but health experts said targeting key risk factors could prevent around 40% of cases.

According to the researchers, the UKBDRS could be used as an initial screening tool for dementia and put people into different risk groups depending on their score. Individuals with a high risk of developing dementia could then be prioritized for additional tests, such as cognitive assessments, brain scans, and blood tests.

Sana Suri, the study's co-lead author and an associate professor at the University of Oxford, noted that "[i]t's important to remember that this risk score only tells us about our chances of developing dementia; it doesn’t represent a definitive outcome."

"The importance of each risk factor varies and given that some of the factors included in the score can be modified or treated, there are things we can all do to help reduce our risk of dementia," Suri said.

Separately, Dr. Gill Livingston, from University College London said, "Dementia risk scores are important as they indicate who is at highest risk of dementia, which is potentially reversible."

"This gives individuals information and therefore power to change the course of their life," Livingston added. "It helps doctors answer the question about what to do to prevent dementia and intervene. Finally, it helps researchers find out who they should target for interventions to prevent dementia -- if someone is not at risk, then the intervention will not help." (George, MedPage Today, 8/24; Gregory, The Guardian, 8/24)

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