Traumatic Brain Injury and Risk of Dementia and Alzheimer’s Disease: A Systematic Review and Meta-Analysis

Abstract

Introduction: Previous studies have investigated the potential role of traumatic brain injury (TBI) in subsequent development of dementia and Alzheimer’s disease (AD) but reported inconsistent results. We aimed to determine the association between TBI and subsequent occurrence of dementia and AD. Methods: We performed a systematic search in PubMed and Web of Science for studies that quantitatively investigated the association between TBI and risk of dementia and AD and were published on or before September 21, 2021. A random-effects model was used to combine the estimates. Results: Twenty-five eligible articles were included in this meta-analysis. The results suggested that TBI was associated with an increased risk of dementia (pooled odds ratio [OR] = 1.81, 95% confidence interval [CI] = 1.53–2.14). However, no association was observed between TBI and AD (pooled OR = 1.02, 95% CI = 0.91–1.15). In the subgroup analysis, TBI with loss of consciousness was not associated with risk of dementia (pooled OR = 0.96, 95% CI = 0.84–1.09). Besides, Asian ethnicity, male gender, and mean age of the participants less than 65 years were associated with a higher risk of dementia. Conclusion: Our study suggests an increased risk of dementia among individuals with TBI, highlighting the need for more intensive medical monitoring and health education in individuals with TBI. Biological mechanisms linking TBI and the development of dementia are needed in future studies.