Metabolic Syndrome and cognitive decline in the elderly: A systematic review

Abstract

BackgroundMetabolic Syndrome (MetS) refers to a cluster of metabolic disturbances which is associated with increased risk for vascular and degenerative conditions in general population. Although the relationship between vascular risk factors and dementia is undisputable, additional hazard for cognitive decline in older population with concurrent metabolic disorders still waits to be demonstrated. The present review aims to analyze data on MetS and risk for cognitive decline in elderly persons.MethodsDatabase searches were performed in Medline, ISI and PsycINFO for articles assessing cognitive performances of older subjects with MetS.ResultsOf a total of 505 studies, 25 were selected for the review. Risk of selection biases was identified in all the studies. Although all articles followed recognized diagnostic recommendations for MetS, minor criteria modifications were detected in most of them. Hyperglycemia was consistently associated with impaired cognitive performances in older individuals, but the role of MetS for cognitive decline and for the onset of dementia showed heterogeneous results.DiscussionCurrent available data in the literature concerning the impact of MetS on the cognition of older population is inconclusive and based on inconsistent evidence. Differential effects of individual MetS components and factors associated with the age of the sample may have accounted for divergent findings among articles, but larger and higher quality studies in this field are still needed.

Metabolic Syndrome and Cognitive Impairment among High Socioeconomic, Nondemented Older US Adults

“…Age, sex, education, CRF, and APOE‐ε4 did not modify the MetS‐CI association, providing further confidence in our overall results. In contrast with existing literature, MetS and CI may not be associated among high socioeconomic, nondemented older US adults.…”

“…MetS, CI, and dementia have complex etiologies with interrelated predictors that vary by populations . These intricacies can be reflected in the varying methodological approaches in MetS‐cognitive research . For example, sociodemographic factors like age, sex, and education are the only confounders consistently adjusted for, and important clinical, behavioral, and genetic confounders are often overlooked.…”

“…Extensive research and multiple reviews have explored the association between MetS and cognitive outcomes, uncovering inconsistent results . The lack of cohesion may be attributable to differing population characteristics.…”

“…Overall, we hypothesized that MetS would be associated with a higher prevalence of CI and the association would attenuate when adjusting for confounders beyond sociodemographic characteristics. Based on previous literature, we also examined age, sex, education, CRF, and APOE‐ε4 as modifiers to explore the complex MetS‐CI association . We hypothesized that participants with MetS aged 75 years and older would have a lower prevalence of CI and the positive MetS‐CI association would be strongest among those with the least education, those who were APOE‐ε4 carriers, and those with the lowest CRF.…”

Risk of dementia associated with cardiometabolic abnormalities and depressive symptoms: a longitudinal cohort study using the English longitudinal study of ageing

“…4,5 Cardiometabolic abnormalities include cardiovascular risk factors such as central obesity, raised triglycerides, low high-density lipoprotein (HDL) cholesterol, hypertension, high blood glucose, and increased inflammation. [8][9][10][11][12] Some studies indicate cardiometabolic abnormalities increase the risk of dementia, 9,12 whereas others find no association. [8][9][10][11][12] Some studies indicate cardiometabolic abnormalities increase the risk of dementia, 9,12 whereas others find no association.…”