Abstract
It is well established that sex differences exist in the manifestation of vascular diseases. Arterial stiffness (AS) has been associated with changes in cerebrovascular reactivity (CVR) and cognitive decline in aging. Specifically, older adults with increased AS show a decline on executive function (EF) tasks. Interestingly, the relationship between AS and CVR is more complex, where some studies show decreased CVR with increased AS, and others demonstrate preserved CVR despite higher AS. Here, we investigated the possible role of sex on these hemodynamic relationships. Acquisitions were completed in 48 older adults. Pseudo-continuous arterial spin labeling (pCASL) data were collected during a hypercapnia challenge. Aortic pulse wave velocity (PWV) data was acquired using cine phase contrast velocity series. Cognitive function was assessed with a comprehensive neuropsychological battery, and a composite score for EF was calculated using four cognitive tests from the neuropsychological battery. A moderation model test revealed that sex moderated the relationship between PWV and CVR and PWV and EF, but not between CVR and EF. Together, our results indicate that the relationships between central stiffness, cerebral hemodynamics and cognition are in part mediated by sex.
Highlights
The literature has found conflicting results, where some have reported reductions in cerebrovascular reactivity (CVR) among older adults with greater aortic stiffness using positronemission tomography (PET) and transcranial doppler (TCD) [30,32], while others demonstrate preserved CVR in the presence of higher aortic pulse wave velocity (PWV) [31,33] using arterial spin labeling (ASL), an magnetic resonance imaging (MRI) technique for noninvasive quantification of cerebral blood flow (CBF). Because these imaging modalities (TCD, PET, ASL) are sensitive to CVR arising from different vessel sizes, these results indicate that the relationship between PWV and CVR is complex
The moderation effect (SEX PWV) was a significant predictor of CVR (β = -1.013, SE = 0.2957, 95% CI [-1.610, -0.4169], p = 0.0014) showing that the effect of PWV on CVR was a function of sex
Further analysis revealed that the effect of PWV on CVR was significantly positive in males (β = 0.6170, SE = 0.2184,95% CI [0.1762, 1.0577], p = 0.0072) and significantly negative in females (β = -0.3967, SE = 0.1902, 95% CI [-0.7805, -0.0129], p = 0.0431) (Fig 2)
Summary
The purpose of this study is to clarify the impact of sex-related differences on the link between PWV, cognitive performance and CVR
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