The role of systemic microvascular function in the association between large artery stiffness and cognitive function...

We determined whether large artery stiffness (LAS) and systemic microvascular function were associated with cognitive function in older adults, and whether systemic microvascular function mediated the association between LAS and cognitive function.

Older adults with diverse cardiovascular risk ( n  = 435, 162F) participated in this study. Estimated pulse wave velocity (ePWV) as an estimate of LAS was calculated from age and blood pressure. Skin microvascular function was assessed by acetylcholine (ACh) and sodium nitroprusside (SNP) responses using iontophoresis, and expressed as the area under the curve of each vasodilator (ACh_auc and SNP_auc, respectively). Validated cognitive tasks [Addenbrooke's Cognitive Examination Revised (ACE-R), Trail Making Test Part-A (TMT-A) and Part-B (TMT-B)] were administered to assess participants' cognitive function.

One standard deviation (SD) increase in ePWV was positively associated with TMT-A [ β  = 0.339 (0.226, 0.467), P  < 0.001] and TMT-B [ β  = 0.342 (0.232, 0.451), P  < 0.001] after accounting for conventional cardiovascular risk factors. One SD increase in ACh_auc was also associated inversely with TMT-B after similar adjustments [ β  = -0.113 (-0.201, -0.024), P  = 0.013]. A mediation analysis revealed that the association between ePWV and TMT-B was partially mediated by ACh_auc explaining about 3% of the total effect in the crude model, but this did not persist in the adjusted model.

Increased LAS and skin microvascular dysfunction were associated with poorer cognitive function in older adults, but LAS and skin microvascular function may independently influence cognitive function in our cohort.