Arterial stiffness as a cause of cognitive decline and dementia: a systematic review and meta-analysis

Background: Although arterial stiffness has recently been confirmed as a predictor of cardiovascular disease, the association between arterial stiffness and cognitive decline is less clear. Aim: We performed a systematic review and meta-analysis to examine the evidence for large artery stiffness as a cause of cognitive decline and dementia. Method: Electronic databases were systematically searched until September 2011 for studies reporting on the longitudinal relationship between any validated measure of large artery stiffness and cognitive decline or dementia. Meta-analysis was performed on four studies investigating the association between aortic pulse wave velocity and a decline in Mini-Mental State Examination scores. Results: Six relevant longitudinal studies were located, conducted over an average of 5 years follow up. Arterial stiffness was predictive of cognitive decline in five/six studies. In meta-analysis, higher aortic stiffness predicted lower Mini-Mental State Examination scores within the sample (beta=-0.03, 95% confidence interval (CI): -0.06 to 0.01, n= 3947), although studies were not all homogeneous, and statistical heterogeneity was present (I2= 71.9%, P= 0.01). Removal of one study with a relatively younger cohort and lower median aortic stiffness found higher aortic stiffness to significantly predict cognitive decline (beta=-0.04, 95% CI: -0.07 to -0.01, n= 3687) without evidence of heterogeneity (I2= 9.5%, P= 0.33). There was little research investigating the effects of aortic stiffness on the development of dementia. Conclusion: Aortic stiffness was found to predict cognitive decline in both qualitative review and quantitative analysis.