Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.

<h4>Background</h4>Head injury is reported to be associated with increased risks of dementia and Alzheimer's disease (AD) in many but not all the epidemiological studies. We conducted a systematic review and meta-analysis to estimate the relative effect of head injury on dementia an...

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Main Authors: Yanjun Li, Yongming Li, Xiaotao Li, Shuang Zhang, Jincheng Zhao, Xiaofeng Zhu, Guozhong Tian
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0169650
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author Yanjun Li
Yongming Li
Xiaotao Li
Shuang Zhang
Jincheng Zhao
Xiaofeng Zhu
Guozhong Tian
author_facet Yanjun Li
Yongming Li
Xiaotao Li
Shuang Zhang
Jincheng Zhao
Xiaofeng Zhu
Guozhong Tian
author_sort Yanjun Li
collection DOAJ
description <h4>Background</h4>Head injury is reported to be associated with increased risks of dementia and Alzheimer's disease (AD) in many but not all the epidemiological studies. We conducted a systematic review and meta-analysis to estimate the relative effect of head injury on dementia and AD risks.<h4>Methods</h4>Relevant cohort and case-control studies published between Jan 1, 1990, and Mar 31, 2015 were searched in PubMed, Web of Science, Scopus, and ScienceDirect. We used the random-effect model in this meta-analysis to take into account heterogeneity among studies.<h4>Results</h4>Data from 32 studies, representing 2,013,197 individuals, 13,866 dementia events and 8,166 AD events, were included in the analysis. Overall, the pooled relative risk (RR) estimates showed that head injury significantly increased the risks of any dementia (RR = 1.63, 95% CI 1.34-1.99) and AD (RR = 1.51, 95% CI 1.26-1.80), with no evidence of publication bias. However, when considering the status of unconsciousness, head injury with loss of consciousness did not show significant association with dementia (RR = 0.92, 95% CI 0.67-1.27) and AD (RR = 1.49, 95% CI 0.91-2.43). Additionally, this positive association did not reach statistical significance in female participants.<h4>Conclusions</h4>The findings from this meta-analysis indicate that head injury is associated with increased risks of dementia and AD.
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spelling doaj-art-18738bfcea134577875e9e6217d8a3e52025-08-20T03:32:25ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01121e016965010.1371/journal.pone.0169650Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.Yanjun LiYongming LiXiaotao LiShuang ZhangJincheng ZhaoXiaofeng ZhuGuozhong Tian<h4>Background</h4>Head injury is reported to be associated with increased risks of dementia and Alzheimer's disease (AD) in many but not all the epidemiological studies. We conducted a systematic review and meta-analysis to estimate the relative effect of head injury on dementia and AD risks.<h4>Methods</h4>Relevant cohort and case-control studies published between Jan 1, 1990, and Mar 31, 2015 were searched in PubMed, Web of Science, Scopus, and ScienceDirect. We used the random-effect model in this meta-analysis to take into account heterogeneity among studies.<h4>Results</h4>Data from 32 studies, representing 2,013,197 individuals, 13,866 dementia events and 8,166 AD events, were included in the analysis. Overall, the pooled relative risk (RR) estimates showed that head injury significantly increased the risks of any dementia (RR = 1.63, 95% CI 1.34-1.99) and AD (RR = 1.51, 95% CI 1.26-1.80), with no evidence of publication bias. However, when considering the status of unconsciousness, head injury with loss of consciousness did not show significant association with dementia (RR = 0.92, 95% CI 0.67-1.27) and AD (RR = 1.49, 95% CI 0.91-2.43). Additionally, this positive association did not reach statistical significance in female participants.<h4>Conclusions</h4>The findings from this meta-analysis indicate that head injury is associated with increased risks of dementia and AD.https://doi.org/10.1371/journal.pone.0169650
spellingShingle Yanjun Li
Yongming Li
Xiaotao Li
Shuang Zhang
Jincheng Zhao
Xiaofeng Zhu
Guozhong Tian
Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
PLoS ONE
title Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
title_full Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
title_fullStr Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
title_full_unstemmed Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
title_short Head Injury as a Risk Factor for Dementia and Alzheimer's Disease: A Systematic Review and Meta-Analysis of 32 Observational Studies.
title_sort head injury as a risk factor for dementia and alzheimer s disease a systematic review and meta analysis of 32 observational studies
url https://doi.org/10.1371/journal.pone.0169650
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AT xiaotaoli headinjuryasariskfactorfordementiaandalzheimersdiseaseasystematicreviewandmetaanalysisof32observationalstudies
AT shuangzhang headinjuryasariskfactorfordementiaandalzheimersdiseaseasystematicreviewandmetaanalysisof32observationalstudies
AT jinchengzhao headinjuryasariskfactorfordementiaandalzheimersdiseaseasystematicreviewandmetaanalysisof32observationalstudies
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