Increased Risk of Dementia and its Subtypes following Various Forms of Acquired Brain Injury: a Meta-analysis and Systematic Review

Abstract

In recent years, acquired brain injuries (ABIs) have been implicated in the development and pathogenesis of dementia; however, existing data is conflicting and often lacks precise classifications or comprehensive analyses. This review sought to synthesize available evidence to assess the association between four major ABI types—traumatic brain injury (TBI), cerebral atherosclerosis (AS), intracranial hemorrhage, and ischemic stroke—and risk of subsequent all-cause dementia (ACD) and dementia subtypes, including Alzheimer’s disease (AD), vascular dementia (VaD), frontotemporal lobar degeneration (FTLD), and dementia with Lewy bodies (DLB). A comprehensive literature review was conducted across public databases, assessing studies published until February 2025, and garnering 107 studies that met inclusion criteria. Meta-analysis of pooled odds ratios (ORs) and 95% confidence intervals (CIs) indicated that TBI was associated with increased ACD, AD, VaD, and FTLD (OR: 1.79, CI: 1.66–1.92, OR: 1.60, CI: 1.44–1.77, OR: 2.03, CI: 1.79–2.30, and OR: 3.99, CI: 2.20–7.20, respectively); cerebral AS was linked to increased odds of ACD, VaD, and FTLD (OR: 1.29, CI: 1.14–1.45, OR: 2.77, CI: 1.72–4.44, and OR: 1.16, CI: 1.07–1.26, respectively); and both intracranial hemorrhage and ischemic stroke conferred increased risks for ACD, AD, and VaD (OR: 2.40, CI: 2.27–2.55, OR: 1.28, CI: 1.03–1.59, and OR: 5.75, CI: 4.73–6.99, as well as OR: 1.24, CI: 1.18–1.31, OR: 1.89, CI: 1.79–2.00, and OR: 2.01, CI: 1.80–2.25, respectively). This meta-analysis indicates a significant relationship between various ABIs and subsequent dementia with variation in subtype-specific associations, underscoring the importance of ABI prevention and post-injury monitoring to mitigate dementia risk.