Plasma and cerebrospinal fluid amyloid-β levels in late-life depression: A systematic review and meta-analysis

This study aimed to evaluate differences in plasma and cerebrospinal fluid (CSF) levels of Aβ peptides in older adults with late-life depression compared to non-depressed older controls. We conducted a systematic review and meta-analysis of the literature using PubMed, Web of science and Scopus databases with no search limits for publication dates or languages. Two independent reviewers extracted data and assessed quality. Six hundred references were retrieved, and we included 12 studies in the meta-analysis after eligibility screening. Older adults with late-life depression (LLD) had a higher plasma Aβ40:Aβ42 ratio compared to non-depressed participants (SMD = 1.10, CI95% [0.28; 1.96], p = 0.01), and marginally significant reduction of CSF Aβ42 levels (SMD = −1.12, CI95% [−2.47; 0.22], p = 0.1). The present results evidence that older adults with depression have significant differences in Aβ metabolism, in the same direction observed in individuals with AD. These differences in the Aβ metabolism may help identify a subgroup of subjects with LLD at higher risk of developing AD.