# The association of Alzheimer's disease and related dementias blood‐based biomarkers with depressive symptoms

## TL;DR

This study finds that higher levels of a brain protein in the blood are linked to more depressive symptoms in older adults.

## Contribution

The study identifies plasma glial fibrillary acidic protein (GFAP) as a biomarker associated with depressive symptoms in older adults.

## Key findings

- Higher glial fibrillary acidic protein (GFAP) levels were associated with higher depressive symptoms.
- No significant associations were found for amyloid beta 42/40 ratio, phosphorylated tau181, or neurofilament light chain with depressive symptoms.
- Interactions between sex or APOE ε4 carrier status and depressive symptoms were not significant.

## Abstract

Depressive symptoms are common in older adults and have been associated with the risk of Alzheimer's disease/Alzheimer's disease and related dementias (AD/ADRD), but the mechanisms and biomarkers underlying this association remain unclear.

We included baseline data from 11,947 non‐demented adults aged ≥ 70 years at enrollment in the Aspirin in Reducing Events in the Elderly (ASPREE) clinical trial. Linear regressions were used to examine cross‐sectional associations between AD/ADRD blood‐based biomarkers (BBMs) and baseline depressive symptoms. Interactions between sex or apolipoprotein E (APOE) ε4 carrier status and BBMs were examined.

Higher glial fibrillary acidic protein (GFAP) was associated with higher depressive symptoms. We did not observe an association between amyloid beta 42/40 ratio, phosphorylated tau181, or neurofilament light chain with depressive symptoms; interactions between sex or APOE ε4 with depressive symptoms were not significant.

In this large, community‐based cohort of older adults, plasma GFAP was associated with greater depressive symptoms.

Plasma glial fibrillary acidic protein was associated with depressive symptoms.Neuroinflammation may underlie depressive symptoms in this group.Future research is needed to examine sex differences in this association.

Plasma glial fibrillary acidic protein was associated with depressive symptoms.

Neuroinflammation may underlie depressive symptoms in this group.

Future research is needed to examine sex differences in this association.