Haemorheological predictors of cognitive decline: the Edinburgh Artery Study

Cognitive functions in schizophrenia: the interplay between blood viscosity, serum osmolarity, and symptom severity

OBJECTIVE

Cognitive impairments-especially in executive function and attention-are core features of schizophrenia and major barriers to functional recovery. Although systemic physiological factors such as blood viscosity and serum osmolarity have been implicated in schizophrenia, their association with cognitive deficits remains largely unexplored. This study aimed to investigate these relationships in male patients with schizophrenia in remission.

METHODS

A total of 247 male patients diagnosed with schizophrenia in remission were recruited. Cognitive performance was assessed using the Frontal Assessment Battery (FAB), Stroop Test, and Trail Making Test (TMT). Hemorheological parameters, including whole blood viscosity (WBV) at low and high shear rates (LSR and HSR), and serum osmolarity were calculated. Regression analyses were conducted to determine predictors of cognitive outcomes.

RESULTS

In the multivariate analysis, higher WBV at HSR (β = 0.122, β = 0.037) was positively associated with executive function (FAB scores) and inversely associated with Stroop 5 time (β = -0.134, p = 0.025), TMT-A (β = -0.134, p = 0.032), and TMT-B (β = -0.137, p = 0.028) completion times, reflecting better cognitive performance. While higher serum osmolarity showed a positive correlation with FAB scores in univariate analysis, it did not remain an independent predictor in the multivariate model. The multivariate regression identified WBV at HSR, depressive symptoms, negative symptoms, use of long-acting injectable antipsychotics (LAI), and living arrangements as significant predictors of FAB scores, collectively explaining 16.9% of the variance (F(8,238) = 7.252, p < 0.001).

CONCLUSION

This study highlights the potential contribution of systemic physiological factors to cognitive function in schizophrenia. Higher WBV, within a physiological range, may support cerebral perfusion and be associated with better executive performance. Although serum osmolarity showed a positive association with executive function in univariate analysis, it was not an independent predictor in multivariate models, and its cognitive relevance remains to be clarified. These findings point to a possible role of physiological parameters in cognitive variability, but further studies are needed before drawing firm clinical implications.

CLINICAL TRIAL NUMBER

Not applicable.

Retinal vessel density and cognitive function in healthy older adults

The eye is considered a gateway to the brain, as the retina is the only tissue of the central nervous system not protected by bones. This enables non-invasive imaging to provide exceptional insights into the brain. Based on the similarity of brain and retinal structure, it is being investigated whether changes in retinal blood flow could serve as a potential biomarker for cognitive decline. Optical coherence tomography angiography (OCTA) enables an examination of the microcirculation of the retina on the basis of retinal flow registration. Retinal blood flow has been associated with cognitive function and changes have been shown for Alzheimer's patients, whereas data for healthy older subjects are contradictory. The aim of this study was to correlate OCTA parameters with the individual performance in tests assessing the executive functions (EFs) inhibition, updating and shifting in a group of healthy older adults (range: 65-79) using structural equation modeling, with hematocrit serving as a mediator. A model was obtained for vessel density (VD) of the retinal superficial vascular complex and the EF parameters inhibition and updating. The model revealed that only the mediator hematocrit correlated with EF, whereas neither the direct path VD to EF nor the indirect path VD via hematocrit to EF were significantly correlated. Regression analysis with hematocrit yielded significant results for the variable updating. We conclude that higher levels of hematocrit shorten reaction time and the coefficient of variation increases correspondingly, indicating a positive effect of hematocrit on EF.

Amyloid pathology mediates the associations between plasma fibrinogen and cognition in non-demented adults

Though previous studies revealed the potential associations of elevated levels of plasma fibrinogen with dementia, there is still limited understanding regarding the influence of Alzheimer's disease (AD) biomarkers on these associations. We sought to investigate the interrelationships among fibrinogen, cerebrospinal fluid (CSF) AD biomarkers, and cognition in non-demented adults. We included 1996 non-demented adults from the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study and 337 from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. The associations of fibrinogen with AD biomarkers and cognition were explored using multiple linear regression models. The mediation analyses with 10 000 bootstrapped iterations were conducted to explore the mediating effects of AD biomarkers on cognition. In addition, interaction analyses and subgroup analyses were conducted to assess the influence of covariates on the relationships between fibrinogen and AD biomarkers. Participants exhibiting low Aβ42 were designated as A+, while those demonstrating high phosphorylated tau (P-tau) and total tau (Tau) were labeled as T+ and N+, respectively. Individuals with normal measures of Aβ42 and P-tau were categorized as the A-T- group, and those with abnormal levels of both Aβ42 and P-tau were grouped under A+T+. Fibrinogen was higher in the A+ subgroup compared to that in the A- subgroup (p = 0.026). Fibrinogen was higher in the A+T+ subgroup compared to that in the A-T- subgroup (p = 0.011). Higher fibrinogen was associated with worse cognition and Aβ pathology (all p < 0.05). Additionally, the associations between fibrinogen and cognition were partially mediated by Aβ pathology (mediation proportion range 8%-28%). Interaction analyses and subgroup analyses showed that age and ApoE ε4 affect the relationships between fibrinogen and Aβ pathology. Fibrinogen was associated with both cognition and Aβ pathology. Aβ pathology may be a critical mediator for impacts of fibrinogen on cognition.

Midlife Hemostasis Measures, 20-Year Cognitive Decline, and Incident Dementia

BACKGROUND AND OBJECTIVES

Blood concentrations of hemostatic factors affect thrombosis and bleeding diathesis and may contribute to cognitive impairment through modifiable vascular pathologies. Whether hemostasis, assessed in middle age, is associated with late-life cognitive impairment remains largely unknown in a community-dwelling population.

METHODS

Using data from 14,128 participants with cognitive function measurements in 1990-1992 from the Atherosclerosis Risk in Communities study, we assessed the associations of hemostasis measures with 20-year changes in cognitive performance and incident dementia. Activated partial thromboplastin time (aPTT) and level of fibrinogen, von Willebrand factor (VWF), factor VIII, factor VII, factor XI, d-dimer, and soluble thrombomodulin were measured in 1987-1989 or 1993-1995. Hemostasis measures were categorized into quintiles, with the lowest quintile indicating low coagulability. Cognitive performance was characterized using a combined z-score from 3 tests (that is, delayed word recall test [DWRT], digit symbol substitution [DSST], and word fluency test [WFT]), assessed in 1990-1992, 1996-1998, and 2011-2013. Dementia was determined either from in-person evaluations or using dementia surveillance through 2017. Mixed-effects models and Cox proportional hazards models were used to assess cognitive trajectories and risk of dementia, respectively.

RESULTS

Among 12,765 participants with hemostasis measures in 1987-1989, who were aged 47-70 years at the first cognitive assessment, we observed significant trends of shorter aPTT (p for trend <0.001; difference in 20-year cognitive decline for fifth vs first quintile [Q5 vs Q1]: -0.104 [95% CI -0.160 to -0.048]) and higher levels of factor VII (p < 0.002; Q5 vs Q1: -0.085 [-0.142, -0.028]) and factor VIII (p = 0.033; Q4 vs Q1: -0.055 [-0.111, -0.000]) with greater 20-year cognitive declines. The associations with the decline in DSST were stronger than those with the decline in WFT or DWRT. Consistently, shorter aPTT and higher factor VIII levels were associated with higher dementia risk with HRs for Q5 vs Q1 of 1.23 (95% CI 1.07 to 1.42) and 1.17 (1.01-1.36), respectively, and p for trend of 0.008 and 0.024, respectively.

DISCUSSION

Overall, our study found consistent trend associations of aPTT and factor VIII measured in midlife with cognitive decline and incident dementia over 20 years, likely driven by vascular pathologies.

Heterogeneity of White Matter Hyperintensity and Cognitive Impairment in Patients with Acute Lacunar Stroke

Background: The severity of white matter hyperintensity (WMH) in patients with acute lacunar stroke (ALS) may be not completely parallel to cognitive impairment. Controversies persist about the effects of WMH on cognitive dysfunction. It is vital to explore whether the association may be affected by certain factors and whether a subsequent subgroup analysis is necessary. The aim of this study was to evaluate the relationship between WMH and cognitive impairment in acute lacunar stroke patients and the possible causal factors. Methods: We continuously enrolled patients with ALS who were hospitalized at the First Affiliated Hospital of Soochow University between October 2017 and June 2022. The cognitive function of all patients was assessed by using the Montreal Cognitive Assessment (MoCA) scale 14 ± 2 days after the onset of AIS, and the results were adjusted to the education level. The MoCA scale was reevaluated at the 6-month (day 182 ± 7) follow-up by outpatient visit or video. Demographic and clinical data were collected. The manifestations of chronic cerebral small-vessel disease (CSVD), including the total Fazekas score and total CSVD burden score, were assessed with an MRI scan. A mismatch refers to an inconsistency between the severity of WMH and cognitive dysfunction. A Type 1 mismatch refers to cognitive impairment with mild WMH (total Fazekas score = 0−1), and a Type 2 mismatch refers to severe WMH (total Fazekas score = 5−6) in patients with normal cognitive function. Results: Among 213 enrolled ALS patients, 66 patients (31.0%) had cognitive dysfunction, and 40 patients (18.8%) had mismatches. Twenty-seven cases (12.7%) were Type 1 mismatched, and seventeen cases (8.0%) were Type 2 mismatched. Age, gender, fibrinogen and cerebral infarction history were independent risk factors for cognitive impairment in ALS patients. Imaging features, including moderate to severe WMH, deep WMH and the total CSVD burden score, were also independently associated with cognitive impairment. The patients in the mismatched group were older, had more severe deep WMH and had a higher occurrence of depression (p < 0.05). The NIHSS score, depression and microbleeds were significantly different between the Type 1 mismatched group and the matched group (p = 0.018, p = 0.012 and p = 0.047). Patients in the Type 2 mismatched group were male (p = 0.04), had a lower level of fibrinogen (p = 0.005), a lower incidence of CMBs (p = 0.003), a lower total CSVD burden score (p = 0.017), more severe paraventricular WMH (p = 0.035) and milder deep WMH (p = 0.026). Conclusions: Our study examined a homogeneous study cohort of recruited patients with symptomatic ALS. We found heterogeneity between WMH and cognitive function in ALS patients. Despite a similar WMH severity, some baseline clinical features and other conventional CSVD imaging characteristics may account for this heterogeneity phenomenon. Our findings provide data for the early diagnosis and prevention of cognitive impairment in ALS patients and suggest that the severity of WMH is not completely parallel to cognitive impairment. The white matter microstructural injury and remote WMH effects may account for the mismatch phenomenon. More attention should be paid to understanding the underlying mechanisms and finding new imaging markers.

Fibrinogen Levels and Cognitive Profile Differences in Patients with Mild Cognitive Impairment

BACKGROUND

Fibrinogen is considered a marker of vascular pathology, indicating a weakened blood-brain barrier, and has a causative role in neuroinflammation and neurodegeneration. Little is known about the relationship between fibrinogen levels and cognitive function in patients with mild cognitive impairment (MCI). We aimed to investigate differences in cognitive profiles according to plasma fibrinogen levels in patients with MCI and the influence of plasma fibrinogen levels on cognitive decline.

METHODS

This retrospective cohort study included 643 patients with MCI: 323 patients in the high fibrinogen (high fib) group and 320 patients in the low fibrinogen (low fib) group. A multiple linear regression model was performed to compare cognitive test performance between groups. The Cox proportional hazard model was used to analyze the hazard ratio of fibrinogen level for disease progression.

RESULTS

The high fib group demonstrated poorer performance in attention, executive function, and confrontation naming than the low fib group. After adjustment for APOE genotype, the high fib group was associated with poor attention and executive function. After adjustment for vascular risk factors including body mass index, hypertension, diabetes mellitus, dyslipidemia, and smoking history, the high fib group showed declined attention and confrontation naming ability. High fibrinogen levels did not predict disease progression to CDR 1.

CONCLUSION

High plasma fibrinogen levels were associated with poor performance in attention in patients with MCI, regardless of APOE genotype or vascular risk factors.

Influence of angiotensin-converting enzyme inhibition on reversibility of alterations in arterial wall and cognitive performance associated with early hypertension: A follow-up study

The importance of optimal blood pressure control for preventing or reducing the impairment of vascular and cognitive functions is well known. However, the reversibility of early alterations in vascular and cognitive functions through antihypertensive agents is under-investigated. In this study, we evaluated the influence of 3 months of angiotensin-converting enzyme (ACE) inhibition treatment on the morphological and functional arterial wall and cognitive performance changes in 30 newly diagnosed primary hypertensive patients.Common carotid intima-media thickness (IMT) and brachial artery flow-mediated dilatation (FMD) were detected by ultrasonography. Arterial stiffness indicated by augmentation index (AIx) and pulse wave velocity (PWV) was assessed by arteriography. Cognitive functions were assessed by neuropsychological examination.The executive function overall score was significantly higher at 3-month follow-up than at baseline (median, 0.233 (IQR, 0.447) vs -0.038 (0.936); P = .001). Three-month ACE inhibition did not produce significant improvement in IMT, FMD, AIx and PWV values. Significant negative associations were revealed between IMT and complex attention (r = -0.598, P = .0008), executive function (r = -0.617, P = .0005), and immediate memory (r = -0.420, P = .026) overall scores at follow-up. AIx had significant negative correlations with complex attention (r = -0.568, P = .001), executive function (r = -0.374, P = .046), and immediate memory (r = -0.507, P = .005). PWV correlated significantly and negatively with complex attention (r = -0.490, P = .007).Timely and effective antihypertensive therapy with ACE inhibitors has significant beneficial effects on cognitive performance in as few as 3 months. Early ACE inhibition may have an important role in the reversal of initial impairments of cognitive function associated with hypertension-induced vascular alterations.

Hemostasis biomarkers and incident cognitive impairment: the REGARDS study

Essentials Cognitive disorders are increasing and vascular risk factors play a role in this. We performed a nested case control study of hemostasis biomarkers and cognitive impairment (CI). Higher baseline fibrinogen, factor VIII and D-dimer were related to incident CI over 3.5 years. Adjusted for other risk factors, 2+ abnormal markers (but not single ones) led to higher risk.

SUMMARY

Background Vascular risk factors are associated with cognitive impairment, a condition that imposes a substantial public health burden. We hypothesized that hemostasis biomarkers related to vascular disease would be associated with the risk of incident cognitive impairment. Methods We performed a nested case-control study including 1082 participants with 3.5 years of follow-up in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, a longitudinal cohort study of 30 239 black and white Americans aged ≥ 45 years. Participants were free of stroke or cognitive impairment at baseline. Baseline D-dimer, fibrinogen, factor VIII and protein C levels were measured in 495 cases who developed cognitive impairment during follow-up (based on abnormal scores on two or more of three cognitive tests) and 587 controls. Results Unadjusted odds ratios (ORs) for incident cognitive impairment were 1.32 (95% confidence interval [CI] 1.02-1.70) for D-dimer > 0.50 μg mL-1 , 1.83 (95% CI 1.24-2.71) for fibrinogen > 90th percentile, 1.63 (95% CI 1.11-2.38) for FVIII > 90th percentile, and 1.10 (95% CI 0.73-1.65) for protein C < 10th percentile. There were no differences in associations by race or region. Adjustment for demographic, vascular and health behavior risk factors attenuated these associations. However, having at least two elevated biomarkers was associated with incident cognitive impairment, with an adjusted OR of 1.73 (95% CI 1.10-2.69). Conclusion Elevated D-dimer, fibrinogen and FVIII levels were not associated with the occurrence of cognitive impairment after multivariable adjustment; however, having at least two abnormal biomarkers was associated with the occurrence of cognitive impairment, suggesting that the burden of these biomarkers is relevant.

Electrofluidic Circuit-Based Microfluidic Viscometer for Analysis of Newtonian and Non-Newtonian Liquids under Different Temperatures

This paper reports a microfluidic viscometer with an integrated pressure sensor based on electrofluidic circuits, which are electrical circuits constructed by ionic liquid-filled microfluidic channels. The electrofluidic circuit provides a pressure-sensing scheme with great long-term and thermal stability. The viscosity of the tested fluidic sample is estimated by its flow resistance, which is a function of pressure drop, flow rate, and the geometry of the microfluidic channel. The viscometer can be exploited to measure viscosity of either Newtonian or non-Newtonian power-law fluid under various shear rates (3-500 1/s) and temperatures (4-70 °C) with small sample volume (less than 400 μL). The developed sensor-integrated microfluidic viscometer is made of poly(dimethylsiloxane) (PDMS) with transparent electrofluidic circuit, which makes it feasible to simultaneously image samples under tests. In addition, the entire device is disposable to prevent cross-contamination between samples, which is desired for various chemical and biomedical applications. In the experiments, viscosities of Newtonian fluids, glycerol water solutions with different concentrations and a mixture of pyrogallol and sodium hydroxide (NaOH), and non-Newtonian fluids, xanthan gum solutions and human blood samples, have been characterized. The results demonstrate that the developed microfluidic viscometer provides a convenient and useful platform for practical viscosity characterization of fluidic samples for a wide variety of applications.

Increase in the Inflammatory Marker GlycA over 13 Years in Young Adults Is Associated with Poorer Cognitive Function in Midlife

Background

Inflammatory markers are elevated in patients with dementia. Evidence for an association between inflammation and cognitive function in dementia-free individuals is sparse, inconsistent, and predominantly restricted to the elderly. Assessment of inflammatory markers in young adults as predictors of cognitive function in midlife, well before the onset of overt dementia, is lacking. Furthermore, rarely has the relation with longitudinal change in inflammatory markers been examined.

Objective

To examine the association of the inflammatory markers C-reactive protein (CRP), fibrinogen, white blood cell count (WBC) and GlycA, a novel NMR-determined biomarker of systemic inflammation, measured in young adulthood and of GlycA change over 13 years follow-up with cognitive function in midlife.

Methods

507 participants of the Jerusalem Lipid Research Clinic (LRC) study were assessed at 3 time points over 18–22 years. First, the inflammatory variables GlycA, CRP, fibrinogen, and WBC were measured in blood samples drawn at ages 28–32. Then, in blood samples drawn a mean 13 years later (range, 12–16 years) at ages 41–46, GlycA was again measured (in 484 individuals). Subsequently at ages 48–52, on average 7 years later, global cognitive function and its five specific component domains were assessed with a NeuroTrax computerized test battery. Multiple regression and multivariable logistic models were applied.

Results

Inverse unadjusted associations were shown for baseline levels and longitudinal change in inflammatory markers and measures of cognition. Multiple regression models were adjusted for age at cognitive assessment, sex, socio-demographic characteristics, baseline measures of leisure-time vigorous activity, smoking status and body mass index (BMI) at ages 28–32, change in smoking status and BMI between ages 28–32 and 41–46, and depression assessed at the time of cognitive testing. The highest quintile of GlycA change, but not the baseline inflammation measures, was inversely related to global cognition (standardized β = -.109, p = .011) as well as to the information processing speed and memory domains (standardized β = -.124, p = .008 and-.117, p = .014, respectively). The multivariable-adjusted odds ratio for low ranked global cognitive function (lowest fifth) comparing the extreme quintiles of GlycA change was 4.8 (95%CI, 1.7–13.5, p = .003; p for trend = .031).

Conclusions

In this longitudinal study of a novel systemic inflammatory marker in a population-based cohort of young adults, GlycA increase over 13 years, but not baseline measures of inflammation, was associated with poorer cognitive function in midlife.

Blood viscosity as a forgotten factor and its effect on pulmonary flow

Background

The effect of smoking on blood viscosity is widely known. There are, however, few studies on the effect of blood viscosity on pulmonary circulation.

Methods

We aimed to observe the relationship between blood viscosity and pulmonary circulation among smokers and non-smokers. The study comprised 114 subjects in three groups: group 1, ex-smokers; group 2, smoked at least 10 packs/year and still smoking; group 3, never smoked. Blood viscosity (BV), pulmonary blood flow (PBF), and right ventricular systolic pressure (RVSP) were measured in all subjects.

Results

PBF was significantly lower in group 1 compared with group 3 (p < 0.05). BV in group 1 was significantly higher than group 3 (p < 0.05) while BV in group 2 was significantly higher than group 3 (p < 0.05). PBF in group 2 was significantly lower than group 3 (p = 0.01).

Conclusions

We believe that BV is a significant and forgotten factor that plays an important role in pulmonary and cardiovascular diseases. BV may affect PF even during the course of smoking, and before the clinical onset of chronic obstructive pulmonary disease (COPD). Therefore, individuals at risk of pulmonary hypertension could be detected earlier with a simple blood test.

Obstructive sleep apnea syndrome: blood viscosity, blood coagulation abnormalities, and early atherosclerosis

Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for atherosclerosis and arterial thrombosis, which are associated with high cardiovascular (CV) morbidity and mortality. In studies performed in clinical populations with elevated CV event risk profiles, the occurrence of moderate to severe OSAS was very often accompanied by a worsened vascular function and increased prevalence of structural abnormalities. Recent investigations of atherosclerosis in OSAS have focused on thrombotic tendency and blood viscosity, providing new insight into mechanisms of the disease. Despite that knowledge about the mechanisms of development of CV disease in patients with OSAS is still incomplete, observations confirm a relationship between sleep-disordered breathing and the rheological properties (flow properties) of blood. While platelet dysfunction and hypercoagulability (PDMPs, PaI-1, and SF) play important roles in the pathogenesis of vascular disease, there are limited studies on the potential role of blood viscosity in the development of vascular disease in OSAS.

Common carotid flow velocity is associated with cognition in older adults

AIMS

To assess the relationship between carotid flow velocity and cognitive impairment in patients with mild-moderate (<50%) carotid artery disease.

METHODS

We studied 407 participants with available carotid ultrasound and cognitive measures. We related peak systolic velocity (PSV) and end diastolic velocity (EDV) of internal carotid artery (ICA) and common carotid artery (CCA) and intimal medial thickness (IMT) to Mini Mental State Examination (MMSE), Clock Draw Test (CDT), Activities of Daily Living Scale (ADL)and Montreal Cognitive Assessment (MoCA).

RESULTS

EDV of CCA was significantly different in higher and lower MoCA (MMSE) groups. Multiple regression analysis demonstrated that lower EDV was significantly associated with lower MoCA (+0.459 per standard deviation (SD), p<0. 01 for the left; +0.539 per SD, p<0. 01 for the right) and CDT (odds ratio (OR) 0.093, p< 0.05 for the left; OR) 0.120, p<0. 01 for the right) scores. PSV of left CCA (-0.205 per SD, p<0.05) and IMT (+42.536 per SD, p< 0.001) were associated with ADL. PSV of right CCA was associated with MMSE (+0.081 per SD, p<0.001). No significant relationship between ICA flow velocity and cognitive performance was observed.

CONCLUSIONS

Our preliminary data show that common carotid artery flow velocity was associated with cognitive performance.

Genetic associations between fibrinogen and cognitive performance in three Scottish cohorts

There is increasing evidence to suggest that elevated plasma levels of fibrinogen are associated with late-life cognitive performance. This study tested the association of single nucleotide polymorphisms in the fibrinogen α (FGA) and β (FGB) genes with cognitive performance. Data were analysed from three community-dwelling populations of older persons (>50 years) in central Scotland: the Aspirin for Asymptomatic Atherosclerosis (AAA) Trial (n = 2,091), the Edinburgh Type 2 Diabetes Study (ET2DS, n = 1,066), and the Lothian Birth Cohort 1936 (LBC1936, n = 1,091). Cognition was assessed using a battery of five, seven, and four psychometric tests, respectively. This information was used to derive a general cognitive factor. Weakly significant associations were found between the rs4220 (FGB), and rs2227412 (FGB) SNPs and a single test of cognitive performance in the AAA Trial (p < 0.05). These findings did not replicate in the LBC1936 or ET2DS cohorts, except for the rs2227412 SNP, which was significantly associated with the general cognitive factor in the ET2DS (p = 3.3 × 10(-4)). A summary term that combined results from all three studies suggested that the rs2227412 genotype associated with reduced cognitive ability also associated with higher plasma fibrinogen levels. These findings suggest a tentative role for fibrinogen as a determinant of late-life cognitive performance and justify further attempts at replication in older persons.

Association between circulating hemostatic measures and dementia or cognitive impairment: systematic review and meta-analyzes

BACKGROUND AND OBJECTIVES

Hemostasis and thrombosis may be important contributors to cognitive decline and dementia. Certain blood markers may assist in diagnosis or management.

OBJECTIVES

To collate evidence for the association of circulating hemostatic variables and dementia or cognitive impairment.

METHODS

A systematic review of studies describing blood markers of hemostatic function and cognition/dementia. Abstracts were reviewed by two independent assessors and studies selected based on pre-specified criteria. We described methodological quality and performed meta-analyzes where data allowed.

RESULTS

From 7103 titles, 485 abstracts and included 21 studies (n = 32,773) were assessed. In two longitudinal studies, the incident of vascular dementia risk was greater for higher D-dimer [hazard ratio (HR): 1.50, 95% confidence interval (CI): 1.15-1.96]. For case-control data, we calculated standardized mean differences (SMD) and 95% CI. Higher levels of: factor (F)VII (SMD: 0.93; 95% CI: 0.60-1.26), fibrinogen (SMD: 1.53; 95% CI: 1.17-1.87), prothrombin fragment 1 and 2 (SMD: 0.64; 95% CI: 0.32-0.96), plasminogen activator inhibitor (SMD: 0.68; 95% CI: 0.26-1.10), D-dimer (SMD: 2.00; 95% CI: 1.59-2.40) and von Willebrand factor (VWF) (SMD: 1.68; 95% CI: 1.30-2.06) showed modest but significant associations with vascular dementia. For patients with any dementia diagnosis, associations were with higher D-dimer (SMD: 0.36; 95% CI: 0.15-0.56) and VWF (SMD: 0.31; 95% CI: 0.11-0.51). For specific cognitive domains, significant (P < 0.001) positive correlations were fibrinogen and speed of processing (0.76; 95% CI: 0.67-0.84), verbal memory (0.69; 95% CI: 0.59-0.79) and non-verbal reasoning (0.57; 95% CI: 0.49-0.65).

CONCLUSIONS

The present results suggest a modest association between hemostasis and vascular dementia including increased levels of thrombin generation markers (D-dimer and prothrombin fragment 1 + 2) and endothelial dysfunction (VWF and plasminogen activator inhibitor). Associations are weaker for specific cognitive tests and when all dementias are combined.

Plasma fibrinogen, global cognitive function, and cerebral small vessel disease: results of a cross-sectional study in community-dwelling Japanese elderly

OBJECTIVE

Recent studies suggest that hemostatic and endothelial factors play a pivotal role in the development of cerebral small vessel disease (SVD). Although plasma fibrinogen is an essential factor in the coagulation cascade, the relationship among fibrinogen, cognitive function, and SVD has not been clarified in community-based Asian populations. Because fibrinogen levels of Asians have been reported to be lower than these of Caucasians, the impact of fibrinogen on the development of SVD or dementia in Asians may be different from that of Caucasians.

METHODS

We performed a cross-sectional study using MRI to determine the relationships among fibrinogen, cognitive function, and subclinical SVD in community-based Japanese elderly.

RESULTS

Subjects with raised fibrinogen levels tended to have more lacunes and higher grades of white matter lesions (WMLs). Additionally, an independent association between fibrinogen and WMLs was determined by logistic regression analyses. Subjects with high fibrinogen levels accompanied by high von Willebrand factors or thrombomodulin levels had an increased tendency for the presence of WMLs. The relationship between the mean Mini-Mental State Examination (MMSE) scores and the quartiles of fibrinogen levels was not statistically significant after controlling for age, gender, and WMLs; however, the mean MMSE scores in subjects without WML were related to the tertiles of the fibrinogen levels even after adjusting for conventional risks and high sensitivity C-reactive protein.

CONCLUSION

The present study suggests that there is a close relationship between fibrinogen levels and subclinical WMLs, which are independent of conventional risk factors and inflammation, in community-based Japanese elderly.