Association of ACE I/D Gene Polymorphism With Vascular Dementia: A Meta-Analysis

Background: Vascular dementia is the second common cause of dementia, only second to Alzheimer's disease in later life, and has a greater mortality risk than Alzheimer's disease among the elderly population group. The angiotensin-converting enzyme insertion/deletion polymorphism as a risk factor in vascular dementia has been suggested, but direct evidence from genetic association studies remain inconclusive. We performed a meta-analysis pooling data from all relevant studies in order to determine the effect of the insertion/deletion polymorphism on the vascular dementia. Methods: We applied a random-effects model or fixed-effects model to combine odds ratio and 95% confidence intervals. Q statistic was used to evaluate the homogeneity, and Egger's test and Funnel plot were used to assess publication bias. Results: A total of 10 studies were included worldwide. Publication bias was not observed. There was no evidence of the association of angiotensin-converting enzyme insertion/deletion polymorphism with the vascular dementia in general or in the Asian populations or in the Caucasian populations. Conclusions: The angiotensin-converting enzyme insertion/deletion polymorphism might be neutral to vascular dementia.