Hippocampal volume mediates the association of arterial stiffness with cognitive impairment in adult population

Objectives: To investigate the association of arterial stiffness with brain perfusion, brain tissue volume and cognitive impairment in the general adult population. Materials and methods: This prospective study included 1488 adult participants (age range: 22.8–83.9 years) from the Kailuan study. All participants underwent brachial–ankle pulse wave velocity (PWV) measurement, brain MRI, and Montreal Cognitive Assessment (MoCA). The association of PWV with cerebral blood flow (CBF), brain tissue volume and MoCA score was investigated. Mediation analysis was used to determine whether CBF and brain tissue volume changes mediated the associations between PWV and MoCA score. Results: A 1 standard deviation (SD) increase in PWV was associated with lower total brain CBF β (95% CI) −0.67 (−1.2 to −0.14), total gray matter CBF β (95% CI) −0.7 [−1.27 to −0.13), frontal lobe CBF β (95% CI) −0.59 (−1.17 to −0.01), parietal lobe CBF β (95% CI) −0.8 (−1.43 to −0.18), and temporal lobe CBF β (95% CI) −0.68 (−1.24 to −0.12). Negative associations were found for PWV and total brain volume β (95% CI) −4.8 (−7.61 to −1.99) and hippocampus volume β (95% CI) −0.08 (−0.13 to −0.04). A 1 SD increase PWV was significantly associated with elevated odds of developing cognitive impairment odds ratio (95% CI) 1.21 (1.01–1.45). Mediation analysis showed that hippocampal volume partially mediated the negative association between PWV and MoCA scores (proportion: 14.173%). Conclusion: High arterial stiffness was associated with decreased total and regional CBF, brain tissue volume, and cognitive impairment. Hippocampal volume partially mediated the effects of arterial stiffness on cognitive impairment.