DIV-AD BARCELONA: Alzheimer's Blood-Based Biomakers for a Diverse Community

Background and Rationale Alzheimer's disease (AD) is the leading cause of dementia worldwide and represents a major public health challenge. Blood-based biomarkers (BBBs) for AD - including phosphorylated tau isoforms (p-tau181, p-tau217, p-tau231), amyloid-beta peptides (Aβ40, Aβ42), brain-derived tau (BD-tau), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NfL) - have emerged as accessible, scalable, and minimally invasive tools for the early and accurate detection of AD pathology. These biomarkers are increasingly being integrated into research studies, clinical trials, and prevention programs. Their accessibility makes them particularly promising for community-level screening and recruitment into prevention studies.

However, the vast majority of research on BBBs has been conducted in highly educated, non-Hispanic White (NHW) populations from the United States and Europe. Ethnic minorities and migrant communities remain substantially underrepresented in this body of literature, raising serious concerns about the generalizability and equity of current biomarker thresholds, reference ranges, and clinical applications. A growing number of studies suggest that BBB levels may differ across ethnic groups, potentially due to disparities in demographic, socioeconomic, lifestyle, and biological factors. Without a clear understanding of these differences, the implementation of BBBs in routine clinical care risks perpetuating or even widening existing health disparities.

Spain, and Barcelona in particular, occupies a leading position in the development and validation of BBBs. Yet, to date, no study has systematically examined the performance of BBBs in a diverse, multi-ethnic cohort within the Spanish or European context. The Primary Care Team Raval Sud (EAP Raval Sud) in Barcelona provides a unique real-world setting to address this gap: it serves a highly diverse population, with over 60% of its approximately 32,000 registered patients being foreign-born, representing a broad spectrum of ethnic backgrounds including South Asian (Pakistani, Indian, Bangladeshi), Filipino, Latin American, and Maghrebi communities.

Study Overview The DIV-AD BARCELONA study is a prospective, observational, cross-sectional investigation that will enroll 250 cognitively unimpaired (CU) adults aged 50-75 years from five self-identified ethnic groups, recruited at EAP Raval Sud. The study pursues two overarching goals: (1) to characterize and compare BBB levels across diverse ethnic groups and identify the demographic, socioeconomic, medical, and biological determinants of any observed differences; and (2) to assess the frequency of biomarker-defined AD pathology across these groups, validate a cross-cultural cognitive screening tool (RUDAS), evaluate dementia knowledge and stigma, and develop culturally tailored educational and healthcare interventions to promote equitable access to AD prevention.

Study Procedures