Vascular Health Indices and Cognitive Domain Function: Singapore Longitudinal Ageing Studies

Article type: Research Article

Authors: Lim, Shir Lynn^a | Gao, Qi^b | Nyunt, Ma Shwe Zin^b | Gong, Lingli^c | Lunaria, Josephine B.^c | Lim, May Li^b | Ling, Audrey^b | Lam, Carolyn Su-Ping^{a; c; f; g} | Richards, Arthur Mark^{c; d; e} | Ling, Lieng Hsi^{a; c} | Ng, Tze Pin^{b; *}

Affiliations: [a] Department of Cardiology, National University Heart Center, Singapore | [b] Gerontology Research Programme, Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore | [c] Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore | [d] Cardiovascular Research Institute, National University Health System, Singapore | [e] Christchurch Heart Institute, University of Otago, New Zealand | [f] Department of Cardiology, National Heart Center, Singapore | [g] Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School Singapore, Singapore

Correspondence: [*] Correspondence to: Associate Professor, Tze-Pin Ng, Gerontology Research Programme, National University of Singapore, Department of Psychological Medicine, NUHS Tower Block, 9th Floor, 1E Kent Ridge Road, Singapore 119228. Tel.: +65 67723478; Fax: +65 67772191; E-mail: pcmngtp@nus.edu.sg.

Abstract: Background:Few studies have comprehensively evaluated the relationship between vascular disease and cognition of older adults without cardiac disease. Objective:We explored the associations of structural atherosclerosis, vascular stiffness, and reactivity with global, memory, attention, language, visuospatial ability, and executive function in community-dwelling, non-demented older Asians without cardiac diseases. Methods:Cognition was assessed by Mini-Mental State Examination (MMSE) (n = 308) and detailed neuropsychological tests (n = 155). Vascular measures included carotid intima-media thickness; aortic stiffness [carotid-femoral pulse wave velocity (CFPWV), aortic augmentation index (AI), and aortic pulse pressure (PP)]; carotid stiffness [elasticity modulus (Ep), beta index (β), arterial compliance (AC), carotid AI]; and endothelial function [reactive hyperemia index (RHI)]. Multivariable analyses controlled for potential confounding by demographics, apolipoprotein E genotype and cardiovascular risk factors. Results:The participants’ mean age was 63.0 ± 6.1 years. Inverse associations with MMSE were found for AC (β= 0.128, p = 0.019), Ep (β= –0.151, p = 0.008), β index (β= –0.122, p = 0.029), carotid stiffness z-score (β= –0.154, p = 0.007); with executive function for CFPWV (β= –0.209, p = 0.026), AC (β= 0.214, p = 0.005), Ep (β= –0.160, p = 0.050), β index (β= –0.165, p = 0.041), and both aortic (β= –0.229, p = 0.010) and carotid (β= –0.208, p = 0.010) stiffness z-scores; with verbal memory for AI (β= –0.229, p = 0.004) and aortic (β= –0.263, p = 0.004) stiffness z-score; with language for AI (β= –0.155, p = 0.025), aortic stiffness z-score (β= –0.196, p = 0.011). RHI positively correlated with visuospatial ability (β= 0.195, p = 0.013) and executive function (β= 0.151, p = 0.045). Conclusion:The results support a link between systemic vascular health and neurocognitive function in older Asian adults. Subclinical noninvasive measures of arterial stiffness and reactivity may identify individuals vulnerable to cognitive impairment.

Keywords: Arterial stiffness, carotid intima-media thickness, cognition, endothelial function

DOI: 10.3233/JAD-150516

Journal: Journal of Alzheimer's Disease, vol. 50, no. 1, pp. 27-40, 2016