title: Carotid β-stiffness index is associated with slower processing speed but not working memory or white matter integrity in healthy middle-aged/older adults.
abstract: Aging is associated with increased carotid artery stiffness, a predictor of incident stroke, and reduced cognitive performance and brain white matter integrity (WMI) in humans. Therefore, we hypothesized that higher carotid stiffness/lower compliance would be independently associated with slower processing speed, higher working memory cost, and lower WMI in healthy middle-aged/older (MA/O) adults. Carotid β-stiffness (P< 0.001) was greater and compliance (P< 0.001) was lower in MA/O (n= 32; 64.4 ± 4.3 yr) vs. young (n= 19; 23.8 ± 2.9 yr) adults. MA/O adults demonstrated slower processing speed (27.4 ± 4.6 vs. 35.4 ± 5.0 U/60 s,P< 0.001) and higher working memory cost (-15.4 ± 0.14 vs. -2.2 ± 0.05%,P< 0.001) vs. young adults. Global WMI was lower in MA/O adults (P< 0.001) and regionally in the frontal lobe (P= 0.020) and genu (P= 0.009). In the entire cohort, multiple regression analysis that included education, sex, and body mass index, carotid β-stiffness index (B = -0.53 ± 0.15 U,P= 0.001) and age group (B = -4.61 ± 1.7,P= 0.012, adjustedR2= 0.4) predicted processing speed but not working memory cost or WMI. Among MA/O adults, higher β-stiffness (B = -0.60 ± 0.18,P= 0.002) and lower compliance (B = 0.93 ± 0.26,P= 0.002) were associated with slower processing speed but not working memory cost or WMI. These data suggest that greater carotid artery stiffness is independently and selectively associated with slower processing speed but not working memory among MA/O adults. Carotid artery stiffening may modulate reductions in processing speed earlier than working memory with healthy aging in humans.NEW & NOTEWORTHYPreviously, studies investigating the relation between large elastic artery stiffness, cognition, and brain structure have focused mainly on aortic stiffness in aged individuals with cardiovascular disease risk factors and other comorbidities. This study adds to the field by demonstrating that the age-related increases in carotid artery stiffness, but not aortic stiffness, is independently and selectively associated with slower processing speed but not working memory among middle-aged/older adults with low cardiovascular disease risk factor burden.
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa.
authors.forename: Lyndsey E
authors.initials: LE
authors.lastname: DuBose
authors.affiliation: Department of Psychological and Brain Sciences, University of Iowa, Iowa.|Aging, Mind and Brain Initiative, University of Iowa, Iowa.|Interdisciplinary Neuroscience Program, University of Iowa, Iowa.
authors.forename: Michelle W
authors.initials: MW
authors.lastname: Voss
authors.affiliation: Department of Psychological and Brain Sciences, University of Iowa, Iowa.
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Weng
authors.affiliation: Interdisciplinary Neuroscience Program, University of Iowa, Iowa.
authors.forename: James D
authors.initials: JD
authors.lastname: Kent
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa.
authors.forename: Kaitlyn M
authors.initials: KM
authors.lastname: Dubishar
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa.
authors.forename: Abbi
authors.initials: A
authors.lastname: Lane-Cordova
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa.
authors.forename: Gardar
authors.initials: G
authors.lastname: Sigurdsson
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.
authors.forename: Phillip
authors.initials: P
authors.lastname: Schmid
authors.affiliation: Department of Internal Medicine, University of Iowa, Iowa.
authors.forename: Patrick B
authors.initials: PB
authors.lastname: Barlow
authors.affiliation: Department of Health and Human Physiology, University of Iowa, Iowa; gary-pierce@uiowa.edu.|Center for Hypertension Research, University of Iowa, Iowa; and.|Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.
authors.forename: Gary L
authors.initials: GL
authors.lastname: Pierce
mesh_terms: D000375:Aging / Q000502:physiology*; D015992:Body Mass Index; D002339:Carotid Arteries / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D003187:Compliance / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000502:physiology; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D059289:Vascular Stiffness / Q000502:physiology*; D066127:White Matter / Q000502:physiology*; D055815:Young Adult
keywords: aging; cognitive performance; pulse wave velocity