Dataset Information

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

ABSTRACT:

Background

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.

Methods

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.

Results

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.

Conclusions

The findings from this meta-analysis indicate that head injury is associated with increased risks of dementia and AD.

SUBMITTER: Li Y

PROVIDER: S-EPMC5221805 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Publications

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

Li Yanjun Y Li Yongming Y Li Xiaotao X Zhang Shuang S Zhao Jincheng J Zhu Xiaofeng X Tian Guozhong G

PloS one 20170109 1

<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 i ...[more]

PMID: 28068405

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Project description:BackgroundAssociations between endogenous estrogen exposure indicators and risk of subtypes of dementia have been unclear.MethodsDatabases (PubMed, EMBASE and Web of Science) were searched electronically on 1st July and updated regularly until 12nd November 2021. Observational studies of English language were selected if reported an effect estimate [e.g., odds ratio (OR), rate ratio (RR) or hazard ratio (HR)] and 95% CI for the association between any exposure (age of menarche, age at menopause, reproductive period, estradiol level) and any endpoint variable [all-cause dementia, Alzheimer's disease (AD), vascular dementia (VD), cognitive impairment (CI)]. Random-effects models and dose-response meta-analyses were used to calculate estimates and to show the linear/nonlinear relationship. PROSPERO CRD42021274827.FindingsWe included 22 studies (475 9764 women) in this analysis. We found no clear relationship between late menarche (≥14 vs <14 years) and dementia, CI in categorical meta-analysis compared to a J-shape relationship in dose-response meta-analyses. Later menopause (≥45 vs <45 years) was consistently associated with a lower risk of all-cause dementia (pooled RR: 0.87, 95%CI: 0.78-0.97, I2=56.0%), AD (0.67, 0.44-0.99, I2=78.3%), VD (0.87, 0.80-0.94) and CI (0.82, 0.71-0.94, I2=19.3%) in categorical meta-analysis, showing similar results in dose-response meta-analyses. An inverse relationship between longer reproductive duration (≥35 vs <35 years) and dementia was observed in dose-response meta-analysis. In addition, estradiol levels after menopause were inversely correlated with the risk of AD and CI.InterpretationIn this study, later menopause and longer reproductive period were associated with a lower risk of dementia, while the relationship for menarchal age was J-shaped. There was an inverse relationship between higher postmenopausal estrogen levels and risk of AD and CI. Longitudinal study are needed to further explore the association between life-time estrogen exposure and risk of subtypes of dementia.FundingStart-up Foundation for Scientific Research in Shandong University.

Dataset Information

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

Background

Methods

Results

Conclusions

Publications

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

Similar Datasets

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