Biobank Alzheimer Center Limburg study: A multimodal longitudinal dementia biobank

There is an urgent need to better understand the mechanisms of dementia, particularly Alzheimer's disease (AD), the most common subtype. The BioBank Alzheimer Center Limburg (BBACL) study is an ongoing prospective cohort, including consecutive patients from the memory clinic of the Alzheimer Center Limburg, Maastricht University Medical Center+, the Netherlands. It aims to investigate the natural course of cognitive complaints and identify early clinical and biological determinants of disease progression.

To describe the BBACL study design and procedures and present the baseline characteristics of the currently included participants.

Patients undergo standardized assessment, including demographics, comorbidities, cognitive and functional assessments, neuropsychiatric symptoms, MRI cerebrum, and biomaterials [blood and cerebrospinal fluid (CSF) samples (subset)]. Additional blood and CSF samples are stored for future biomarkers research. Follow-up is scheduled at 1, 2, 5, and 10 years.

Since its start in 2009, 920 patients have been included at baseline. The mean baseline age was 68.4 (SD 11.3) years, with 41.6% being females. The mean Mini-Mental State Examination score was 27.0 (SD 2.6). At baseline, 39.6% had subjective cognitive decline, 40.0% mild cognitive impairment, and 20.4% dementia (58.0% probable/possible AD and 19.7% mixed AD/vascular dementia), reflecting the study's emphasis on early diagnostics. Cognitive, functional, and biomarker measures varied across diagnostic groups as expected.

BBACL combines extensive biospecimens with rich multimodal phenotyping and longitudinal follow-up, creating opportunities for future integrative analyses and omics-based analyses to uncover novel biological signatures.