Kidney Disease and Cognitive Function

We provide a brief review of research on chronic kidney disease and cognitive performance, including dementia. We touch briefly on the literature relating end-stage-renal disease to cognitive function, but focus on studies of modest and moderate forms of chronic kidney disease (CKD) that precede dialysis and transplantation. We summarize previous reviews dealing with case control studies of patients but more fully examine community-based studies with large samples and necessary controls for demographic risk factors, cardiovascular variables, and other confounds such as depression. In addition we suggest potential biological and social-psychological mediators between CKD and cognition. Studies follow in two categories of design: (1) cross-sectional studies; (2) longitudinal studies. In each, CKD is related to a wide range of deficits in cognitive functioning including, verbal and visual-memory and organization, and components of executive functioning and fluid intellect. In general, prior to the need to treat with hemodialysis (HD) or kidney transplant (KT), magnitude of effect with relation to CKD and function are small or modest in persons free from acute stroke and dementia. However, HD and KT can result in major impairment. We discuss needed controls, the greater demand on controls after HD and KT begin, and suggest that mechanisms intervening relations between hypertension, or diabetes, and cognitive performance may be similar to those intervening between hypertension and cognitive performance and the hypertension and diabetes literature on cognition provides a good model for the study of early stage kidney disease and cognitive ability. We posit that the mechanisms linking CKD and cognition may be similar to those linking hypertension or diabetes to cognition. We identify the need for more studies with multiple cognitive test batteries, measures of every-day cognitive abilities relevant to patient understanding of the disease and treatments, and more studies with prevalent and incident dementia outcomes

From Blood Pressure to Physical Disability: The Role of Cognition

We examined the hypothesis that lowered cognitive performance plays a role in the relation between elevated blood pressure and physical disability in performing basic physical tasks. A community-based sample (N = 1025) free from stroke and dementia (mean age: 61.1 years; SD: 13.0 years; 59.8% women) was used. Using path analysis, systolic and diastolic blood pressures (predictor variable) measured over multiple longitudinal examinations were averaged and related to multiple measures of cognition (intermediate variable) and physical ability (PA; outcome variable) measured at wave 6 of the Maine-Syracuse Study. PA was indexed by time required to execute standing, walking, and turning tests. A best-fit path model including blood pressure and multiple demographic and cardiovascular disease covariates was used. Paths from systolic blood pressure toglobal performance, verbal memory, andabstract reasoning (Similarities test) were significant (

Systolic orthostatic hypotension is related to lowered cognitive function: Findings from the Maine-Syracuse Longitudinal Study

The aim of the present study was to examine the relationship between orthostatic changes in blood pressure (BP) and cognition, with consideration given to cardiovascular risk factors and lifestyle variables. The cross-sectional analysis included 961 community-dwelling participants of the Maine-Syracuse Longitudinal Study, for whom BP clinic measures (five sitting, five recumbent, and five standing) were obtained. Eighteen percent of participants had orthostatic hypotension (fall in systolic BP ≥20 mm Hg or diastolic BP ≥10 mm Hg upon standing) and 6% had orthostatic hypertension (rise in systolic BP ≥20 mm Hg). Orthostatic hypotension and hypertension defined using traditional criteria were unrelated to cognition with covariate adjustment. However, an examination of systolic and diastolic BP change independently revealed that participants with systolic orthostatic hypotension had poorer global cognition, verbal memory, and scanning and tracking scores than those with normal systolic BP change. The authors conclude that systolic orthostatic hypotension is significantly associated with reduced cognitive function

Higher HDL cholesterol is associated with better cognitive function: The Maine-Syracuse Study

AbstractFew studies have examined associations between different subcategories of cholesterol and cognitive function. We examined relationships between total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), triglyceride levels and cognitive performance in the Maine-Syracuse Longitudinal Study, a community-based study of cardiovascular risk factors. Cross-sectional analyses were undertaken on data from 540 participants, aged 60 to 98 years, free of dementia and stroke. TC, HDL, LDL, and triglyceride levels were obtained. Cognitive function was assessed using a thorough neuropsychological test battery, including domains of cognitive function indexed by multiple cognitive tests. The cognitive outcomes studied were as follows: Visual-Spatial Memory and Organization, Verbal and Working Memory, Scanning and Tracking, Abstract Reasoning, a Global Composite score, and the Mini-Mental State Examination (MMSE). Significant positive associations were observed between HDL-cholesterol and the Global Composite score, Working Memory, and the MMSE after adjustment for demographic and cardiovascular risk factors. Participants with desirable levels of HDL (≥60 mg/dL) had the highest scores on all cognitive outcomes. There were no significant associations observed between TC, LDL, or triglyceride concentrations and cognition. In older individuals, HDL-cholesterol was related to a composite of Working Memory tests and for general measures of cognitive ability when adjusted for cardiovascular variables. We speculate that persons over 60 are survivors and thus less likely to show cognitive deficit in relation to TC, LDL-cholesterol, and triglycerides. Longitudinal studies are needed to examine relations between specific cognitive abilities and the different subcategories of cholesterol. (JINS, 2014, 20, 1–10)</jats:p