Citation

Gardner RC, Bahorik A, Kornblith ES, Allen IE, Plassman BL, Yaffe KC. J. Neurotrauma 2022; ePub(ePub): ePub.

Copyright

(Copyright © 2022, Mary Ann Liebert Publishers)

DOI

10.1089/neu.2022.0041

PMID

36305374

Abstract

Traumatic brain injury (TBI) is an established risk factor for dementia. However, the magnitude of risk is highly variable across studies. Identification of sub-populations at highest risk, with careful consideration of potential sources of bias, is urgently needed to guide public health policy and research into mechanisms and treatments. We conducted a systematic review and meta-analysis of risk of all-cause dementia after all-severity TBI. We assessed for effect of participant age and sex, Veteran status, research methods, and region. The search window covered 1/1990 -1/2019. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. 32 studies met inclusion criteria. Data were pooled using random effects models. Population attributable risk (PAR) of dementia due to TBI in the U.S. was calculated by sex and Veteran status. Pooled risk ratio (RR) for dementia after TBI was 1.66 (95% CI 1.42-1.93). Younger age, male sex, and studies from Asia were associated with significantly higher risk; Veteran status was not. Risk of dementia associated with "head injury/trauma" was not significantly different from that associated with "TBI" diagnosis specifically. PAR of dementia due to TBI among U.S. Veterans was twice that of the general U.S. population, largely due to the high prevalence of TBI exposure in the majority male Veteran population. This meta-analysis found that TBI is associated with nearly 70% increased risk of dementia. Risk may be highest among younger adults, men, and cohorts in Asia. Efforts to prevent TBI and also to prevent post-TBI dementia are of high importance. Additionally, improved methods for diagnosing and tracking TBI on a public health level, such as national registries, may improve the quality and generalizability of future epidemiological studies investigating the association between TBI and dementia.

Language: en

Keywords

TRAUMATIC BRAIN INJURY; COGNITIVE FUNCTION; DEGENERATION; HEAD TRAUMA; HUMAN STUDIES