Dementia Biomarker

A recent study by John O'Brien and colleagues focused on biomarker validation of the Cardiovascular Aging and Dementia (CAIDE) risk score in people at risk of dementia. The CAIDE score estimates 20-year dementia risk at midlife on the basis of eight variables - age, sex, education, systolic blood pressure, BMI, cholesterol level, physical activity and apolipoprotein E status - and ranges 0-18, with higher scores indicating increased dementia risk.

The O'Brien et al. PREVENT-Dementia study included 167 people aged 40-59 years, who were assigned CAIDE scores at baseline and were assessed for subsequent changes in brain and ventricular volumes on MRI2. The authors observed that individuals who were considered to be at risk of dementia, as defined by a baseline CAIDE score >6, exhibited 0.17% more brain volume loss and 1.78% greater ven- tricular enlargement than those with scores <6.

This study fills in a gap in the literature not only through biomarker validation of a risk score but also through longitudinal analysis of biomarker change. Although many risk scores have been developed, only a handful have been validated externally, mainly in relation to cog- nition alone3. Researchers are now emphasizing that risk scores should focus on biological out- comes, such as percentage changes in amyloid burden or brain structure at midlife or in at-risk states, rather than dementia. The few scores that have been validated in relation to bio- markers have been studied cross-sectionally4,5, and biomarker change over time is a rare con- sideration. The findings from the PREVENT- Dementia study indicate that longitudinal data collected at midlife are useful for track- ing and monitoring biomarker progression corresponding to a specific risk profile.