Alzheimer disease's cerebrospinal fluid biomarkers differences between immigrants and natives in a Belgian memory clinic.

Background: Diagnosis of neurodegenerative diseases can raise difficulties among immigrant patients due to language, educational or sociocultural differences with natives. CSF biomarkers of Alzheimer's disease are useful tools to early diagnose neurodegeneration. Yet very few studies have investigated differences of those biomarkers between immigrant and native populations.

Objective: We aimed to characterize differences between CSF biomarkers of Alzheimer's disease within Belgian native and immigrant patients analyzed at Saint Luc Neurochemistry Lab (Brussels, Belgium).

Methods: CSF samples from patients consulting at Saint Luc Memory Clinic (n = 356) or at others hospitals (n = 2430) were analyzed by Saint Luc Neurochemistry Lab between 2010 and 2014. We conducted linear regressions predicting CSF biomarkers with demographic data: age, sex and presumed ethnic origin. For the last one, we subdivided the cohort in natives and immigrants according to their surnames.

Results: Immigrant patients benefit from a CSF sample analysis at a younger age than natives (p < 0.001). After linear regressions, age showed a significant impact on all biomarkers (p < 0.005). Ethnicity showed a significant impact on T-Tau (p = 0.007) and on T-Tau/amyloid-β42 ratio (p = 0.009). Sex showed a significant impact on T-Tau (p = 0.002). ANCOVA analysis suggested that the effect of Age on Aβ manifests differently according to the ethnicity of the individual.

Conclusion: This study shows higher T-Tau and T-Tau/amyloid-β42 ratio values in younger native patients from a Belgian Memory Clinic. Aβ values tend to follow a different dynamic in time according to the ethnic origin of patients, with pathological values at older ages in immigrants.