Hemoglobin, Anemia, and Cognitive Function: The Atherosclerosis Risk in Communities Study

Relationship between hemoglobin and specific cognitive domain among older adults using network analysis

OBJECTIVES

Hemoglobin (Hgb) is associated with cognitive function, with low and high levels of Hgb leading to impaired cerebral oxygenation and perfusion. Yet, current studies focused on understanding the association between Hgb and cognitive function without consideration for each cognitive domain. Thus, this study aims to identify and visualize potentially interactive associations between Hgb and specific cognitive domains among older adults.

METHOD

This is a secondary data analysis using Wave II data from the National Social Life, Health, and Aging Project (NSHAP) and included 1022 older adults aged between 65 and 85 years. The network structure of three different models was estimated to understand the association between specific cognitive domains and Hgb in a mixed graphical model using the R-package 'mgm'. Model 1 did not adjust for any covariates, Model 2 adjusted for age and gender, and Model 3 adjusted for all covariates.

RESULTS

Among all cognitive domains, the visuospatial (edge weight = 0.06-0.10) and memory domains (0.04-0.07) were associated with Hgb in all three models Though not present in Model 3, the attention domain was associated with Hgb in Model 1 and Model 2 (0.08-0.11). In addition, the predictability of Hgb was the highest (8.1%) in Model 3.

CONCLUSION

Findings from this study suggest that cognition should be considered as a multidimensional construct, and its specific cognitive domain should be carefully assessed and managed in relation to Hgb among older adults.

Association between hemoglobin trajectories and the incidence of dementia in a cohort of females aged 55-79 years

PURPOSE

To assess the association between pattern changes in hemoglobin levels over time and the incidence of dementia using trajectories in females aged 55-79 years.

MATERIALS AND METHODS

We conducted a retrospective cohort study using females of aged 55-79 years from the National Health Insurance Service National Health Screening Cohort in Korea. To identify hemoglobin trajectories over eight years (2002-2009), we performed a three-step approach comprising measures of change, factor analysis, and cluster analysis. Univariate and multivariate Cox proportional hazard models were used to assess the associations between hemoglobin trajectories and the incidence of dementia.

RESULTS

We included 20,195 of 235,742 female participants. New dementia (N = 2664) was developed during follow-up period (2010-2015). Five hemoglobin trajectories were identified: high, mid, low, increasing, and decreasing. With high as a reference, the hazard ratios (HRs) for low and decreasing trajectories were significant, 1.28 (95% confidence interval [CI], 1.13-1.45) and 1.21 (95% CI, 1.10-1.34) in univariate models, respectively. However, only the HR for the decreasing trajectory was significant, 1.12 (95% CI, 1.01-1.24) after adjustment for confounders.

CONCLUSION

The decreasing trajectory of hemoglobin levels within the normal range was associated with dementia. Even females aged 55-79 years without anemia might be vulnerable to dementia development risk.

Lower serum ferritin levels are associated with worse cognitive performance in aging

OBJECTIVES

Iron is important for neurogenesis, synaptic development, and neurotransmitter synthesis. Serum ferritin (SF) is a reliable marker for assessing iron stores. Therefore, we evaluated the cognitive function associated with SF levels. We also assessed brain iron content using R2* Magnetic Resonance Imaging (MRI) and its association with SF levels.

DESIGN

Data from three cross-sectional observational studies were used. Aging Imageomics (n = 1030) was conducted on aged subjects. Health Imageomics (n = 971) and IR0NMET (n = 175) were conducted in middle-aged subjects.

SETTING AND PARTICIPANTS

Participants were enrolled at Dr. Josep Trueta University Hospital facilities. The three cohorts included a total of 2176 subjects (mean age, 52 years; 48% men).

MEASUREMENTS

SF levels were measured by standard laboratory methods. Total Digits Span (TDS), and Phonemic Verbal Fluency (PVF) were used to assess executive function. Language function was assessed by semantic verbal fluency (SVF), attention by the Symbol Digit Modalities Test, and memory by the Memory Binding Tests - Total Free Recall and Total Delayed Free Recall. MRI was used to assess the iron content of the brain by R2*.

RESULTS

In subjects aged 65 years or older, SF levels were associated with increased TDS (β = 0.003, p = 0.02), PVF (β = 0.004, p = 0.01), and SVF (β = 0.004, p = 0.002) scores. After stratification by sex, these findings were significant only in men, where SF was associated with increased TDS (β = 0.003, p = 0.01), PVF (β = 0.004, p = 0.03), and SVF (β = 0.004, p = 0.009) scores. In middle-aged subjects, SF was also associated with increased SVF scores (β = 0.005, p = 0.011). Lastly, in men, SF levels were negatively associated with R2*, a surrogate marker of brain iron content, in both the left frontal inferior opercular area (r = -0.41, p = 0.005) and the right frontal inferior opercular area (r = -0.44, p = 0.002).

CONCLUSIONS

SF is significantly and positively associated with cognition. In older people with low SF levels, iron supplementation may be a promising therapy to improve cognition.

An Examination of the Non-linear Relationship Between Cognition and Total Hemoglobin Among the Cognitively Normal Older Adults by Gender

Objectives: This exploratory study aimed to identify the potential non-linear relationship between hemoglobin (Hgb) and cognition among cognitively normal older adults and how this relationship differs in terms of gender in generalized additive models (GAM). Methods: This is a secondary data analysis using Wave II (2010-2011) data from the National Social Life, Health, and Aging Project. A generalized additive model was used to understand the non-linear relationship between Hgb and cognition, and to identify critical Hgb point related to cognition. Results: While both genders had a non-linear association between Hgb and cognition, the degree of non-linearity was more pronounced in male older adults with EDF value close to 2. The inflection point of 15.10 g/dL for male older adults and inflection point of 11.72 g/dL for female older adults were obtained. Conclusion: Further studies are needed to validate these results and develop precision medicine approaches to integrate these results into clinical practice.

Lower haemoglobin concentrations are associated with impaired cognition in patients with carotid artery occlusion

Background

Patients with carotid artery occlusion (CAO) are vulnerable to cognitive impairment (CI). Anaemia is associated with CI in the general population. We hypothesized that lower haemoglobin is associated with cognitive impairment (CI) in patients with CAO and that this association is accentuated by cerebral blood flow (CBF).

Methods

104 patients (mean age 66±8 years, 77% men) with complete CAO from the Heart-Brain Connection study were included. Anaemia was defined as haemoglobin < 12 g/dL for women and < 13 g/dL for men. Cognitive test results were standardized into z-scores (using a reference group) in four cognitive domains. Patients were classified as cognitively impaired when ≥ one domain was impaired. The association between lower haemoglobin and both cognitive domain z-scores and the presence of CI was assessed with adjusted (age, sex, education and ischaemic stroke) regression models. Total CBF (measured with phase contrast MRI) and the interaction term haemoglobin*CBF were additionally added to the analyses.

Results

Anaemia was present in 6 (6%) patients and was associated with CI (RR 2.54, 95% CI 1.36; 4.76). Lower haemoglobin was associated with the presence of CI (RR per minus 1 g/dL haemoglobin 1.15, 95% CI 1.02; 1.30). This association was strongest for the attention-psychomotor speed domain (RR for impaired attention-psychomotor speed functioning per minus 1 g/dL haemoglobin 1.27, 95% CI 1.09;1.47) and ß for attention-psychomotor speed z-scores per minus 1 g/dL haemoglobin -0.19, 95% CI -0.33; -0.05). Adjustment for CBF did not affect these results and we found no interaction between haemoglobin and CBF in relation to cognition.

Conclusion

Lower haemoglobin concentrations are associated with CI in patients with complete CAO, particularly in the domain attention-psychomotor speed. CBF did not accentuate this association. If validated in longitudinal studies, haemoglobin might be a viable target to prevent cognitive deterioration in patients with CAO.

Association of cognition and brain reserve in aging and glymphatic function using diffusion tensor image-along the perivascular space (DTI-ALPS)

The glymphatic system is a fluid-clearance pathway that clears cerebral waste products, and its dysfunction has been associated with protein aggregation diseases such as Alzheimer's disease. To understand how the glymphatic system changes with aging, we enrolled 433 cognitive unimpaired participants (236 women and 197 men, 13 to 88 years) and evaluated the glymphatic function by calculating diffusion tensor imaging analysis along the perivascular space (ALPS) index and explored how the ALPS index is associated with cortical atrophy and cognitive decline in older people. We found a significant inverse correlation between ALPS index and age (ρ=-0.45, p<0.001), with a peak value in people in their thirties. A higher ALPS index indicated a better cortical reserve in regions coincided with the default mode network. Declines in mental manipulation and short-term memory performance in the older participants were associated with a lower ALPS index and cortical atrophy in the amygdala, anterior and posterior cingulate, thalamus and middle frontal regions. Our findings highlight that the ALPS index could be used to evaluate brain reserve and cognitive reserve in older people.

Factors Associated With Cognitive Impairment in Heart Failure With Preserved Ejection Fraction

BACKGROUND

Cognitive impairment is prevalent in heart failure and is associated with higher mortality rates. The mechanism behind cognitive impairment in heart failure with preserved ejection fraction (HFpEF) has not been established.

OBJECTIVE

The aim of this study was to evaluate associations between abnormal cardiac hemodynamics and cognitive impairment in individuals with HFpEF.

METHODS

A secondary analysis of Atherosclerosis Risk in Communities (Atherosclerosis Risk in Communities) study data was performed. Participants free of stroke or dementia who completed in-person assessments at visit 5 were included. Neurocognitive test scores among participants with HFpEF, heart failure with reduced ejection fraction (HFrEF), and no heart failure were compared. Sociodemographics, comorbid illnesses, medications, and echocardiographic measures of cardiac function that demonstrated significant (P < .10) bivariate associations with neurocognitive test scores were included in multivariate models to identify predictors of neurocognitive test scores among those with HFpEF. Multiple imputation by chained equations was used to account for missing values.

RESULTS

Scores on tests of attention, language, executive function, and global cognitive function were worse among individuals with HFpEF than those with no heart failure. Neurocognitive test scores were not significantly different among participants with HFpEF and HFrEF. Worse diastolic function was weakly associated with worse performance in memory, attention, and language. Higher cardiac index was associated with worse performance on 1 test of attention.

CONCLUSIONS

Cognitive impairment is prevalent in HFpEF and affects several cognitive domains. The current study supports the importance of cognitive screening in patients with heart failure. An association between abnormal cardiac hemodynamics and cognitive impairment was observed, but other factors are likely involved.

Red Cell Distribution Width, Anemia, and Brain Volumetric Outcomes Among Middle-Aged Adults

BACKGROUND

Anemia and red cell distribution width (RDW) have been linked to poor cognitive performance, pending studies of underlying mechanisms.

OBJECTIVE

We examined cross-sectional relationships of initial RDW status (v1), RDW change (δ), and anemia with brain structural magnetic resonance imaging (sMRI) markers, including global and cortical brain and hippocampal and white matter lesion (WML) volumes, 5-6 years later.

METHODS

Data were used from three prospective visits within the Healthy Aging in Neighborhoods of Diversity Across the Life Span (HANDLS) study with complete v1 (2004-2009) and v2 (2009-2013) exposures and ancillary sMRI data at vscan (2011-2015, n = 213, mean v1 to vscan time: 5.7 years). Multivariable-adjusted linear regression models were conducted, overall, by sex, by race, and within non-anemics, correcting for multiple testing with q-values.

RESULTS

In minimally adjusted models (socio-demographics and follow-up time), anemiav1 and RDWv1 were consistently associated with smaller bilateral hippocampal volumes overall, and among females (q < 0.05), without significant sex differences. RDWv1 was related to smaller select regional cortical brain gray and white matter volumes in hematological measure-adjusted models; anemiav1 was associated with larger WML volumes only among whites.

CONCLUSION

In summary, baseline anemia and RDW were consistently associated with smaller bilateral hippocampal volumes, particularly among females, while anemia was linked to larger WML volume among Whites. In hematological measure-adjusted models, baseline RDW was linked to smaller regional gray and white matter volumes. Pending studies with sMRI repeats, randomized controlled trials are needed, demonstrating associations of anemia and elevated RDW with reduced brain volumes and cognitive dysfunction.

Red cell distribution width, anemia and their associations with white matter integrity among middle-aged urban adults

Anemia (blood hemoglobin [Hb] <13 g/dL among males; <12 g/dL among females) and elevated red cell distribution width (RDW) are potential risk factors for reduced brain white matter integrity (WMI), reflected by lower fractional anisotropy or increased mean diffusivity. Cross-sectional data with exposure-outcome lag time was used, whereby hematological exposures (RDW and Hb) and covariates were compiled from the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study with available visit 1 (v1; 2004-2009) and/or v2 (2009-2013) data; while diffusion tensor magnetic resonance imaging (dMRI) outcome data were collected at HANDLS SCAN visit (vscan: 2011-2015, n = 214, mean follow-up from v1 ±SD: 5.6 ± 1.8 year). Multivariable-adjusted linear regression analyses were conducted, overall, stratifying by sex, and further restricting to the nonanemic for RDW exposures in part of the analyses. Among males, RDW(v1) was linked with lower global mean fractional anisotropy (standardized effect size b = -0.30, p= 0.003, q < 0.05; basic model), an association only slightly attenuated with further covariate adjustment. Anemia was not a risk factor for poor WMI, independently of RDW. Ultimately, pending further longitudinal evidence, initial RDW appears to be associated with poorer WMI among males.

Mortality in Patients With Late-Onset Epilepsy: Results From the Atherosclerosis Risk in Communities Study

OBJECTIVE

To determine the risk of mortality and causes of death in persons with late-onset epilepsy (LOE) compared to those without epilepsy in a community-based sample, adjusting for demographics and comorbid conditions.

METHODS

This is an analysis of the prospective Atherosclerosis Risk in Communities (ARIC) study, initiated in 1987-1989 among 15,792 mostly black and white men and women in 4 U.S. communities. We used Centers for Medicare Services fee-for-service claims codes to identify cases of incident epilepsy starting at or after age 67. We used Cox proportional hazards analysis to identify the hazard of mortality associated with LOE and to adjust for demographics and vascular risk factors. We used death certificate data to identify dates and causes of death.

RESULTS

Analyses included 9090 participants, of whom 678 developed LOE during median 11.5 years of follow-up after age 67. Participants who developed LOE were at an increased hazard of mortality compared to those who did not, with adjusted hazard ratio 2.39 (95% CI 2.12-2.71). We observed excess mortality due to stroke, dementia, neurologic conditions, and end-stage renal disease in participants with compared to without LOE. Only 4 deaths (1.1%) were directly attributed to seizure-related causes.

CONCLUSIONS

Persons who develop LOE are at increased risk of death compared to those without epilepsy, even after adjusting for comorbidities. The majority of this excess mortality is due to stroke and dementia.

Cerebral Hypoxia: Its Role in Age-Related Chronic and Acute Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) has been reported with widely varying frequency but appears to be strongly associated with aging. Outside of the surgical arena, chronic and acute cerebral hypoxia may exist as a result of respiratory, cardiovascular, or anemic conditions. Hypoxia has been extensively implicated in cognitive impairment. Furthermore, disease states associated with hypoxia both accompany and progress with aging. Perioperative cerebral hypoxia is likely underdiagnosed, and its contribution to POCD is underappreciated. Herein, we discuss the various disease processes and forms in which hypoxia may contribute to POCD. Furthermore, we outline hypoxia-related mechanisms, such as hypoxia-inducible factor activation, cerebral ischemia, cerebrovascular reserve, excitotoxicity, and neuroinflammation, which may contribute to cognitive impairment and how these mechanisms interact with aging. Finally, we discuss opportunities to prevent and manage POCD related to hypoxia.

Association between anemia, physical performance and cognitive function in Iranian elderly people: evidence from Bushehr Elderly Health (BEH) program

Background and objectives

The present study aimed to investigate the relation between anemia and hemoglobin (Hgb) concentration, physical performance, and cognitive function in a large sample of Iranian elderly population.

Methods

Data were collected from Bushehr elderly health (BEH) program. A total of 3000 persons aged ≥60 years were selected through multistage random sampling. Hemoglobin values lower than 12 and 13 g/dL were considered as anemia for women and men, respectively. The cognitive function was measured using the Mini-cog test and Category fluency test (CFT), and the physical function was measured using handgrip strength (muscle strength), Relative handgrip strength (RHGS), and 4.57-m usual gait speed. Univariate and adjusted multivariate logistic regression and linear regression with Stata MP (version 15) were run, and a p-value of < 0.05 was used as statistically significant for all analyses.

Results

Among participants, 7.43% were anemic, and 115 (51.57%) simultaneously had anemia and cognitive disorder. There were significant associations between red blood cell count (RBC), hemoglobin (Hgb), platelet count (PLT), and hematocrit percentage (HCT) with cognitive impairment. Additionally, Hgb concentration was significantly associated with all physical measures (Mean handgrip, Relative handgrip, and usual gait speed) and late recall (mini-cog) among the whole participants. This association remained statistically significant after considering multi-cofounders. In contrast, after stratifying the participants by gender, the association between Hgb concentration and usual gait speed was decreased in both men and women; moreover, Hgb association with cognitive measures (category fluency test and late recall) was no longer significant (all p-values > 0.05).

Conclusion

There was a cross-sectional and significant association between anemia and functional variables (e.g., Relative and mean handgrip) in Iranian elderly population, whereas Semantic memory, Late recall, and walking were more affected by gender.

Anemia and Cognitive Performance in the ELSA-Brasil Cohort Baseline

OBJECTIVE

The association between cognitive performance and hemoglobin concentration has long been a topic of debate, but few data for middle-aged persons have been explored. The authors examined the association between anemia and cognitive performance at baseline assessment in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort study of individuals from six Brazilian cities.

METHODS

A total of 13,624 participants (mean age=51.6 years [SD=9.0]) were included in this cross-sectional study. Cognitive performance was evaluated by using standardized scores for verbal learning, late recall, word recognition, a semantic verbal fluency test, and the Trail-Making Test, Part B (TMT-B). The association between anemia and cognitive performance was examined by using linear regression models adjusted for sociodemographic characteristics and cardiovascular risk factors.

RESULTS

Anemia was diagnosed in 713 (5.2%) participants. No association was found between anemia and worse cognitive performance for the main models. Global cognitive scores were similar between participants with and without anemia in adjusted models for the entire sample (β=-0.004; 95% CI=-0.052, 0.044) or for men (β=0.047; 95% CI=-0.053, 0.146) and women (β=-0.015; 95% CI=-0.070, 0.040) separately. In addition, hemoglobin levels (in quintile groups) were not associated with global cognitive scores. Similarly, no significant associations with anemia or hemoglobin levels were observed when each cognitive performance test was evaluated separately.

CONCLUSIONS

Anemia and hemoglobin levels were not associated with worse cognitive performance in this large cohort.

Global cognition modifies the relationship between anemia and depression in old age: A longitudinal analysis of the IMIAS Study

OBJECTIVES

To examine the relationship between anemia and depression and whether sex and global cognition modify this relationship over a 4-year follow-up.

DESIGN

Longitudinal analysis of an international cohort study SETTINGS AND PARTICIPANTS: Older adults from the International Mobility in Aging Study (IMIAS) aged between 65 and 74 years at baseline.

METHODS

Participants were recruited in Natal (Brazil), Manizales (Colombia), Kingston (Ontario, Canada), and Saint-Hyacinthe (Quebec, Canada). The study outcome was depression, defined by a score of ≥16 in the Center for Epidemiologic Studies Depression Scale. Longitudinal associations over a 4-year follow-up were examined using generalized estimating equations. Cognition was ascertained with the Leganes Cognitive Test with scores ≤ 22 indicating poor cognition. Models were also adjusted for research sites, marital status, alcohol drinking status, body mass index, chronic conditions, activities of daily life disabilities, and polypharmacy.

RESULTS

Anemia and poor cognition at baseline were associated with an increased risk of depression at follow-up (OR = 5.73, 95% CI: 1.58-20.78). Global cognition was also an effect modifier of the longitudinal association between the severity of anemia and depression.

CONCLUSIONS

In international samples of older adults, anemia, as well as the severity of anemia, were independent risk factors for depression, and the effect of these associations was modified by global cognition. The findings highlight an important issue as to whether depression in old age may be at least partially preventable through public health interventions to correct low Hb levels.

Investigating Predictors of Preserved Cognitive Function in Older Women Using Machine Learning: Women's Health Initiative Memory Study

BACKGROUND

Identification of factors that may help to preserve cognitive function in late life could elucidate mechanisms and facilitate interventions to improve the lives of millions of people. However, the large number of potential factors associated with cognitive function poses an analytical challenge.

OBJECTIVE

We used data from the longitudinal Women's Health Initiative Memory Study (WHIMS) and machine learning to investigate 50 demographic, biomedical, behavioral, social, and psychological predictors of preserved cognitive function in later life.

METHODS

Participants in WHIMS and two consecutive follow up studies who were at least 80 years old and had at least one cognitive assessment following their 80th birthday were classified as cognitively preserved. Preserved cognitive function was defined as having a score ≥39 on the most recent administration of the modified Telephone Interview for Cognitive Status (TICSm) and a mean score across all assessments ≥39. Cognitively impaired participants were those adjudicated by experts to have probable dementia or at least two adjudications of mild cognitive impairment within the 14 years of follow-up and a last TICSm score < 31. Random Forests was used to rank the predictors of preserved cognitive function.

RESULTS

Discrimination between groups based on area under the curve was 0.80 (95%-CI-0.76-0.85). Women with preserved cognitive function were younger, better educated, and less forgetful, less depressed, and more optimistic at study enrollment. They also reported better physical function and less sleep disturbance, and had lower systolic blood pressure, hemoglobin, and blood glucose levels.

CONCLUSION

The predictors of preserved cognitive function include demographic, psychological, physical, metabolic, and vascular factors suggesting a complex mix of potential contributors.

Red Cell Distribution Width and Dementia Among Rural-Dwelling Older Adults: The MIND-China Study

BACKGROUND

Evidence has emerged that anemia is associated with dementia, but data on the relationships of red blood cell distribution width (RDW) with dementia and cognitive function in older adults are sparse.

OBJECTIVE

We sought to investigate the associations of RDW with dementia and global cognitive performance among rural-dwelling Chinese older adults and further to examine their associations by anemia status.

METHODS

This population-based cross-sectional study included 5,115 participants (age≥65 years, 57.0%women) in the baseline examination (March-September 2018) of the Multimodal Interventions to Delay Dementia and Disability in rural China (MIND-CHINA). We collected data through face-to-face interviews, clinical examinations, and laboratory tests. Global cognitive function was evaluated using the Mini-Mental State Examination (MMSE). We defined dementia, Alzheimer's disease (AD), and vascular dementia (VaD) following the respective international criteria. Data were analyzed using multinomial logistic and general linear regression models.

RESULTS

Of all participants, 300 were diagnosed with dementia, including 195 with AD and 95 VaD. The multiple-adjusted odds ratio of dementia associated with quartiles of RDW were 1.45 (95%CI: 0.87-2.44), 1.00 (reference), 1.77 (1.07-2.93), and 2.28 (1.40-3.72). Similar J-shaped patterns existed for the association of RDW with odds ratio of AD and VaD. Anemia was not significantly associated with dementia. The J-shaped associations of RDW with dementia and subtypes were statistically evident only among participants without anemia. There was an inverted J-shaped relationship between RDW quartiles and β-coefficients of MMSE score.

CONCLUSION

There is a J-shaped association between RDW level and likelihood of dementias among rural-dwelling Chinese older adults, especially among people without anemia.

The Impact of Low Hemoglobin Levels on Cognitive Brain Functions

The prevalence of dementia is around 5% worldwide in people above 65 years, which increases with aging. Alzheimer's disease is the most common cause of dementia in the elderly. On the other hand, anemia is considered one of the most prevalent comorbidities in the elderly with a prevalence of 11% in those above the age of 65. It is crucial that we find the association between anemia and dementia, as this linkage can prove beneficial. Many currently conducted studies support the idea that anemia is a significant risk factor for dementia. However, some studies still consider anemia and dementia as just an aging process, nothing more. In our study, we found that there are a lot of theories, such as low brain hemoglobin associated with low oxygen levels, which leads to neuron damage. One article mentioned that it is dependent on the level of hemoglobin as an effect with mild to moderate anemia, but apparent with severe forms of it. Researchers are expected to further explore and identify the exact relationship between anemia and dementia. We used the PubMed database as the principal source for data search and extracted articles exploring the relationship and role of anemia in decreasing the cognitive brain functions in the elderly. We reviewed 35 different articles, including clinical trials, review papers, randomized controlled trials (RCTs), and original research published between 2010 and 2020 to find commonly accepted pathophysiology that highlights how anemia causes a decrease in cognitive brain functions.

Physical Activity Amount and Cognitive Impairment in Korean Elderly Population

The relationship between physical activity amount and cognitive function in elderly Koreans has received little attention. This study therefore aimed to understand the independent and common link between cognitive function and physical activity levels among elderly Korean adults. This study recruited a total of 2746 elderly adults (1348 males and 1398 females). All participants were assessed for cognitive functioning using the Korean Dementia Screening Questionnaire Cognition (KDSQ-C). The computerized Korean version short form of the International Physical Activity Questionnaire (IPAQ) used in this study was entirely based on the long, self-administered, usual week-long IPAQ found in the IPAQ manual of operation. In the unadjusted model, elderly adults who met the recommended level of moderate-to-vigorous physical activity were more likely to have a sufficient level of cognitive function. Hemoglobin, creatinine, cholesterol (TC), triglycerides (TG), LDL-C, and HDL-C differed significantly between groups. A negative correlation was found between KDSQ-C score and the moderate-to-vigorous physical activity (MVPA) amount per week. Physical activity amount is associated with cognition function in Korean elderly adults. Increasing physical activity may improve hemoglobin and creatinine and be involved in improving serum lipid profiles in elderly adults. Thus, physical activity has been suggesting as a useful tool to reduce the risk of cognitive function associated with aging.

Anemia and incidence of dementia in patients with new-onset type 2 diabetes: a nationwide population-based cohort study

INTRODUCTION

This study aimed to examine the association between anemia and the incidence of dementia in patients with new-onset type 2 diabetes.

RESEARCH DESIGN AND METHODS

This study used the Korean National Health Insurance Service-Health Screening Cohort and included 32 590 participants aged ≥40 years who were diagnosed with new-onset type 2 diabetes between 2004 and 2007 and followed up until 2013. Anemia was defined according to the criteria provided by the WHO, hemoglobin <120 g/L for women and <130 g/L for men, and was measured from after diagnosis date of type 2 diabetes to 2007. Dementia was defined by the Classification of Diseases 10th revision code as primary diagnosis and was measured from after hemoglobin measurement to 2013. We calculated the adjusted HR (AHR) and 95% CI to assess the risk of dementia using multivariable Cox proportional hazards regression models.

RESULTS

We identified 1682 patients who developed dementia within a 7.5-year follow-up. Among patients with type 2 diabetes, patients with anemia were associated with an increased risk of dementia than those without anemia (AHR, 1.21; 95% CI 1.06 to 1.39). Patients with mild (AHR, 1.18; 95% CI 1.03 to 1.38) and moderate (AHR, 1.39; 95% CI 1.06 to 1.83) anemia were associated with an increased risk of dementia than those without anemia among patients with type 2 diabetes. Men (AHR, 1.47; 95% CI 1.16 to 1.83) and middle-aged adults (AHR, 1.31; 95% CI 1.03 to 1.75) with anemia were associated with an increased risk of dementia than their counterparts without anemia among patients with type 2 diabetes.

CONCLUSIONS

Our findings suggest that anemia is significantly associated with an increased risk of dementia among patients with newly diagnosed type 2 diabetes.

Hemoglobin, anemia, and poststroke cognitive impairment: A cohort study

OBJECTIVES

Several studies have demonstrated that anemia was associated with cognitive impairment. The aim of this study was to explore the relationship between hemoglobin and cognitive impairment in patient with acute ischemic stroke.

METHODS

In total, 326 patients with acute ischemic stroke were followed up for 1 month. The main outcome was the incidence and severity of poststroke cognitive impairment (PSCI) assessed by Mini-Mental State Examination (MMSE). The impact of hemoglobin levels and anemia on PSCI was assessed by multiple regression models controlling for potential confounders.

RESULTS

During the 1-month follow-up, 193 (59.2%) patients developed PSCI. Anemia was independently associated with PSCI (OR = 3.637; 95% CI, 1.216-10.881; P = .021) after adjusting for demographics, vascular risk factors, stroke severity, and functional outcome. When the hemoglobin levels stratified into tertiles, higher hemoglobin levels were associated with better cognitive function. This result was however not significant after adjusting for the same confounders above.

CONCLUSIONS

Low hemoglobin levels are associated with an increased risk of PSCI. Targeted interventions in this population may reduce the incidence of PSCI and require further evaluation.

Vitamins and Minerals for Energy, Fatigue and Cognition: A Narrative Review of the Biochemical and Clinical Evidence

Vitamins and minerals are essential to humans as they play essential roles in a variety of basic metabolic pathways that support fundamental cellular functions. In particular, their involvement in energy-yielding metabolism, DNA synthesis, oxygen transport, and neuronal functions makes them critical for brain and muscular function. These, in turn, translate into effects on cognitive and psychological processes, including mental and physical fatigue. This review is focused on B vitamins (B1, B2, B3, B5, B6, B8, B9 and B12), vitamin C, iron, magnesium and zinc, which have recognized roles in these outcomes. It summarizes the biochemical bases and actions of these micronutrients at both the molecular and cellular levels and connects them with cognitive and psychological symptoms, as well as manifestations of fatigue that may occur when status or supplies of these micronutrients are not adequate.

Red Cell Distribution Width Is Directly Associated with Poor Cognitive Performance among Nonanemic, Middle-Aged, Urban Adults

BACKGROUND

Epidemiological evidence suggests that both anemia and elevated red cell distribution width (RDW) are associated with cognitive impairment. However, the interplay between these 2 predictors has been understudied.

OBJECTIVES

We examined sex- and anemia-specific associations between RDW and cognitive performance among urban adults in the United States.

METHODS

Data from the Healthy Aging in Neighborhoods of Diversity Across the Life Span Study (Baltimore, MD; participants aged 30-65 y at baseline, ∼59% African-American, 45% men) were used. Participants were selected based on the completion of 11 cognitive tasks at baseline (2004-2009) and follow-up (2009-2013) visits (mean time between visits: 4.64 ± 0.93 y) and availability of exposure and covariate data, yielding a sample of between 1526 and 1646 adults out of the initial 3720 adults recruited at baseline. Multiple linear mixed-effects regression models were conducted with RDW as the main exposure of interest and anemia/sex as the key effect modifiers.

RESULTS

Overall, high RDWs were linked to poorer baseline performance on the California Verbal Learning Test (CVLT) List A (per 1 unit increase in RDW %, main effect: γ01 = -0.369 ± 0.114; P = 0.001) and to slower rates of decline on the CVLT Delayed Free Recall (per 1 unit increase in RDW %, RDW × time: γ11 = +0.036 ± 0.013; P = 0.007). Among nonanemic participants, RDWs were consistently associated with poorer baseline performance on the Trailmaking Test, Part A (γ01 = +3.11 ± 0.89; P < 0.001) and on the CVLT List A (γ01 = -0.560 ± 0.158; P < 0.001). Moreover, RDWs were associated with poorer baseline performance on the Brief Test of Attention in the total population (γ01 = -0.123 ± 0.039; P = 0.001) and among men (γ01 = -0.221 ± 0.068; P = 0.001). We did not detect an association between hemoglobin (Hb) and baseline cognitive performance or changes over time.

CONCLUSIONS

Elevated RDW had a consistent cross-sectional association with poor cognitive performance in the domains of verbal memory and attention among the nonanemic group in a sample of middle-aged, urban adults. Anemia and Hb concentrations were not associated with cognition. More longitudinal studies are needed to replicate our findings.

Association between anemia and cognitive decline among Chinese middle-aged and elderly: evidence from the China health and retirement longitudinal study

Background

Our objective was to characterize the relationship of anemia and hemoglobin concentrations with cross-sectional cognitive functions and changes in cognitive functions over 2 years in a large sample of Chinese middle aged and elderly.

Methods

Ten thousand nine hundred eighteen adults aged 45 years or older participating in the China Health and Retirement Longitudinal Study (CHARLS) were used for cross-sectional analyses and 9324 were used for longitudinal analysis. Cognitive functions were assessed by memory recall (episodic memory), mental status (TICS), and global cognitive function at baseline survey (Visit 1) and first follow-up survey (Visit 2). The lower the cognitive test score, the worse the cognitive function. Anemia was defined as hemoglobin concentrations lower than 13 g/dl for men and lower than 12 g/dl for women. Adjusted multivariate regression analyses were used to explore the relationships of different cognitive domains with anemia and hemoglobin concentration.

Results

Overall, the prevalence of anemia was 12.86% and the mean hemoglobin concentration was 14.37 ± 2.20 g/dl. After adjusting for socio-demographic and health-related covariates, the cross-sectional association between anemia and global cognitive function [β (95%CI) = − 0.49(− 0.69~ − 0.29)], episodic memory [β (95%CI) = − 0.14(− 0.23~ − 0.05)], and TICS [β (95%CI) = − 0.23(− 0.38~ − 0.08)] were significant and did not differ by gender. The hemoglobin concentration was also associated with global cognitive function among the whole sample (P < 0.05 for all). The longitudinal analyses showed global cognitive function and episodic memory were associated with anemia independent of covariates (P < 0.05 for all). Sensitivity analyses further provided significant results showing the association between anemia and cognition decline (P < 0.05).

Conclusion

There was a cross-sectional and longitudinal association between anemia and accelerated decline in cognitive functions in Chinese middle-aged and elderly. This suggests that anemia and low hemoglobin concentrations are independent risk factors of cognitive decline.

Anemia prevalence and its impact on health-related quality of life in Indian diabetic kidney disease patients: Evidence from a cross-sectional study

AIM

The aim of the study was to determine the prevalence, predictors of anemia, and its impact on health-related quality of life among diabetic kidney disease (DKD) patients.

METHODS

Patients with a confirmed diagnosis of type 2 diabetes mellitus (T2DM), and had any stages of CKD (stages I to IV), based on their estimated glomerular filtration rate (eGFR) were enrolled in the study. Anemia was defined using the World Health Organization (WHO) criteria and quality of life was assessed using the EQ-5D scale. All the statistical analysis was performed using SAS v9.4.

RESULTS

A total of 323 patients completed the study. The mean ± SD age of patients was 56 ± 11.25 years, and 51.7% were female. Mean duration of diabetes was 9.6 ± 4.57 years. A total of 227 (70.27%) had anemia as per the WHO criteria. Linear association was observed between the eGFR and hemoglobin. After controlling for the possible confounders in multivariate logistic regression analysis, older age (odds ratio [OR]: 2.46 [95% CI: 1.16 to 5.28], P = .021), diabetes duration (OR: 1.53 [95% CI: 1.04 to 2.25], P = .022), and CKD stage III (OR: 3.63 [95% CI: 0.99 to 13.32], P = .004) were found to be significantly associated with the anemia. Consistently lower EQ-5D index values were observed for the anemic group.

CONCLUSION

This study reported a high prevalence of anemia and impaired quality of life among DKD patients. Routine screening of anemia can be the most preventive measure to deal with this burdening co-morbid condition.

Anemia predicts lower white matter volume and cognitive performance in sickle and non-sickle cell anemia syndrome

Severe chronic anemia is an independent predictor of overt stroke, white matter damage, and cognitive dysfunction in the elderly. Severe anemia also predisposes to white matter strokes in young children, independent of the anemia subtype. We previously demonstrated symmetrically decreased white matter (WM) volumes in patients with sickle cell disease (SCD). In the current study, we investigated whether patients with non-sickle anemia also have lower WM volumes and cognitive dysfunction. Magnetic Resonance Imaging was performed on 52 clinically asymptomatic SCD patients (age = 21.4 ± 7.7; F = 27, M = 25; hemoglobin = 9.6 ± 1.6 g/dL), 26 non-sickle anemic patients (age = 23.9 ± 7.9; F = 14, M = 12; hemoglobin = 10.8 ± 2.5 g/dL) and 40 control subjects (age = 27.7 ± 11.3; F = 28, M = 12; hemoglobin = 13.4 ± 1.3 g/dL). Voxel-wise changes in WM brain volumes were compared to hemoglobin levels to identify brain regions that are vulnerable to anemia. White matter volume was diffusely lower in deep, watershed areas proportionally to anemia severity. After controlling for age, sex, and hemoglobin level, brain volumes were independent of disease. WM volume loss was associated with lower Full Scale Intelligence Quotient (FSIQ; P = .0048; r² = .18) and an abnormal burden of silent cerebral infarctions (P = .029) in males, but not in females. Hemoglobin count and cognitive measures were similar between subjects with and without white-matter hyperintensities. The spatial distribution of volume loss suggests chronic hypoxic cerebrovascular injury, despite compensatory hyperemia. Neurocognitive consequences of WM volume changes and silent cerebral infarction were strongly sexually dimorphic. Understanding the possible neurological consequences of chronic anemia may help inform our current clinical practices.

Association between Anemia and Cognitive Impairment among Elderly Patients with Heart Failure

Cognitive impairment is more prevalent in heart failure (HF) patients. Anemia can influence cognitive ability and is likely more prevalent in elderly patients with HF. However, there are limited data on the association of anemia with cognitive impairment in elderly HF patients. This study aimed to identify the association between anemia and cognitive impairment in elderly HF patients. This secondary data analysis included 181 patients aged 60 years or older with HF. Patients were categorized into an anemic or non-anemic group based on World Health Organization (WHO) criteria. We assessed the cognitive function using the Modified Mini-Mental State (3MS) at the time of enrollment. The prevalence of anemia and cognitive impairment in older patients with HF was the same at 35.4%. The main finding of the multiple logistic regression indicated that compared to a non-anemic status, anemia increased the risk of cognitive impairment (odds ratio (OR) = 4.268, 95% confidence interval (CI) = 1.898–9.593, p < 0.001). Healthcare providers should recognize the value of the significance of early assessment of anemic status and cognitive function following HF. A prospective cohort study should identify the pathway of the association between anemia and incidence of cognitive impairment.

Short-Term Stability of Hematologic Parameters in Frozen Whole Blood

BACKGROUND

Complete blood counts (CBCs) are commonly obtained in large multicenter studies. We assessed the stability of 10 parameters after short-term (up to 30 days) frozen storage.

METHODS

We compared CBC measurements from fresh samples (n = 53) with samples stored for up to 30 days at -70 °C. We calculated the CVs and intraclass correlation coefficients.

RESULTS

Mean values of most parameters, with the exception of hemoglobin and platelet count, were significantly different by 15 days of storage. White blood cell count (CV, 38.3%; 95% CI, 31.3%-46.2%) and red cell distribution width (CV, 37.7%; 95% CI, 34.1%-41.3%) were the most variable. After 30 days, only hemoglobin remained stable and reliable (CV, 0.8%; 95% CI, 0.4%-1.3%).

CONCLUSIONS

Hemoglobin remained stable in frozen blood samples stored for up to 30 days at -70 °C and may be reliably used in research studies using short-term frozen specimens. Other CBC parameters measured in stored blood are not sufficiently reliable for research or patient care.

Disease activity is associated with cognitive impairment in patients with rheumatoid arthritis

OBJECTIVE

To investigate the association between disease activity and cognitive impairment in patients with rheumatoid arthritis (RA).

METHODS

A total of 464 patients from the rheumatoid arthritis registry of two academic centers, Siriraj and Phramongkutklao hospitals, were included. Demographic, clinical, and laboratory data related to disease activity and functional status were collected. Cognitive function was assessed using the Thai version of the Montreal Cognitive Assessment (MoCA-T). Subjects were classified as cognitively impaired if they scored less than 25.

RESULTS

Most subjects (85%) were female with a mean age ± SD of 59.2 ± 11.4 years old and a median (range) educational level of 9 (4-14) years. They were long-standing RA patients (median disease duration (range) of 9.9 (5.1-16.6) years) and had moderate cumulative disease activity (mean DAS28 ± SD of 3.5 ± 0.81) and mild functional impairment (median HAQ (range) 0.5 (0.13-1.10)). Seventy percent of the patients were classified as having cognitive impairment. The patients with cognitive impairment significantly impaired in all domains, especially in visuospatial/executive, language, and abstraction. In multiple logistic regression analyses, old age (RR 3.45, 95% CI 2-6, p < 0.001), low education (RR 10.8, 95% CI 5.3-22.1, p < 0.001), and high cumulative disease activity (RR 2.2, 95% CI 1.07-4.7, p = 0.033) were independently associated with cognitive impairment.

CONCLUSION

High cumulative RA disease activity is associated with cognitive impairment. Therefore, treat-to-target aimed at low disease activity or remission may be beneficial for preventing cognitive decline in RA patients.

Astrocyte HIF-2α supports learning in a passive avoidance paradigm under hypoxic stress

BACKGROUND

The brain is extensively vascularized, useŝ20% of the body's oxygen, and is highly sensitive to changes in oxygen. While synaptic plasticity and memory are impaired in healthy individuals by exposure to mild hypoxia, aged individuals appear to be even more sensitive. Aging is associated with progressive failure in pulmonary and cardiovascular systems, exposing the aged to both chronic and superimposed acute hypoxia. The HIF proteins, the "master regulators" of the cellular response to hypoxia, are robustly expressed in neurons and astrocytes. Astrocytes support neurons and synaptic plasticity via complex metabolic and trophic mechanisms. The activity of HIF proteins in the brain is diminished with aging, and the increased exposure to chronic and acute hypoxia with aging combined with diminished HIF activity may impair synaptic plasticity.

PURPOSE

Herein, we test the hypothesis that astrocyte HIF supports synaptic plasticity and learning upon hypoxia.

MATERIALS AND METHODS

An Astrocyte-specific HIF loss-of-function model was employed, where knock-out of HIF-1α or HIF-2α in GFAP expressing cells was accomplished by cre-mediated recombination. Animals were tested for behavioral (open field and rotarod), learning (passive avoidance paradigm), and electrophysiological (long term potentiation) responses to mild hypoxic challenge.

RESULTS

In an astrocyte-specific HIF loss-of-function model followed by mild hypoxia, we identified that the depletion of HIF-2α resulted in an impaired passive avoidance learning performance. This was accompanied by an attenuated response to induction in long-term potentiation (LTP), suggesting that the hippocampal circuitry was perturbed upon hypoxic exposure following HIF-2α loss in astrocytes, and not due to hippocampal cell death. We investigated HIF-regulated trophic and metabolic target genes and found that they were not regulated by HIF-2α, suggesting that these specific targets may not be involved in mediating the phenotypes observed.

CONCLUSION

Together, these results point to a role for HIF-2α in the astrocyte's regulatory role in synaptic plasticity and learning under hypoxia and suggest that even mild, acute hypoxic challenges can impair cognitive performance in the aged population who harbor impaired HIF function.

The impact of treatment for iron deficiency and iron deficiency anemia on nutritional status, physical performance, and cognitive function in geriatric patients

OBJECTIVE

Iron deficiency in older people is common and affects physical and cognitive performance. The effects of iron deficiency on nutrition and cognitive status are well established. However, there are few studies demonstrating the impact of iron deficiency treatment on functional and cognitive outcomes in the geriatric population. The aim of this study was to determine whether iron replacement treatment was associated with an improvement in the nutritional, cognitive, and functional status of older patients with iron deficiency (ID) and iron deficiency anemia (IDA).

METHODS

Geriatric patients with iron deficiency and iron deficiency anemia presenting to the geriatric clinic were included in the study. Comprehensive geriatric assessment (CGA) and blood samples to investigate iron deficiency were performed at baseline and 6 month later. 81 patients were included in the study and were evaluated at follow-up in the 6th month. The CGA included the following tests: the Katz Index of Independence in Activities of Daily Living Scale (Katz ADL), the Lawton-Brody Instrumental Activities of Daily Living Scale (IADL), the Mini-Mental State Examination (MMSE), and the Mini Nutritional Assessment Short-Form (MNA-SF), as well as the assessments of hand grip strength and walking speed.

RESULTS

Of the 81 participating patients, 69.1% were women and 30.9% were men. The mean age was 76.8 ± 7.28 years. Follow-up after iron supplementation treatment was performed with a mean of 6.23 ± 1.58 months. Improvements occurred in the following geriatric and laboratory assessments: Lawton-Brody (IADL), MNA-SF, MMSE, hand grip strength, and walking speed evaluations and the levels of hemoglobin, iron, total iron-binding capacity, transferrin saturation, and ferritin.

CONCLUSIONS

It was shown that iron replacement treatment has a positive impact on functional and cognitive status and nutritional parameters in older patients with ID and IDA.

Anemia is associated with incidence of dementia: a national health screening study in Korea involving 37,900 persons

BACKGROUND

The aim of this study was to investigate whether anemia is associated with dementia incidence in the elderly.

METHODS

Using the Korean National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) database, we identified 66-year-old subjects (n = 37,900) who were free of dementia and stroke. Anemia (hemoglobin < 12 g/dl for women and < 13 g/dl for men) and the severity of anemia (mild, moderate, or severe) were defined using World Health Organization criteria. The incidence of dementia was identified using International Classification of Diseases, Tenth Revision, dementia diagnosis codes (F00, F01, F02, F03, and G30) with prescription of an antidementia drug. Cox proportional hazards regression models were used to assess HRs for dementia incidence according to anemia.

RESULTS

After adjusting for sex, baseline cognitive state, body mass index, smoking status, household income, disability, depression, hypertension, diabetes, and dyslipidemia, we found a significant association between anemia and dementia incidence (adjusted HR 1.24; 95% CI 1.02-1.51). The adjusted HRs for incidence of dementia according to the severity of anemia were 1.19 (95% CI 0.98-1.45) for those with mild anemia, 1.47 (95% CI 0.97-2.21) for those with moderate anemia, and 5.72 (95% CI 1.84-17.81) for those with severe anemia, showing a significant p value for trend (p = 0.003).

CONCLUSIONS

Anemia is an independent risk factor for dementia incidence, with a marked increase of risk associated with severe anemia.

Elevated Soluble Vascular Cell Adhesion Molecule-1 Is Associated With Cerebrovascular Resistance and Cognitive Function

BACKGROUND

Elevated plasma soluble vascular cell adhesion molecule-1 (sVCAM-1) is a presumed marker of endothelial dysfunction, both in the brain and systemic circulation. Impairments in memory and cognition have been associated with cardiovascular diseases, but little is known about their relationships to abnormal cerebral endothelial function.

METHODS

We studied the cross-sectional association between sVCAM-1 and markers of cerebrovascular hemodynamics and cognitive function in 680 community-dwelling participants in the MOBILIZE Boston Study, aged 65 years and older. Cognitive function was assessed using the Hopkins Verbal Learning Memory Test and Trail Making Tests (TMTs) A and B. Global cognitive impairment was defined as Mini-Mental State Examination (MMSE) score less than 24. sVCAM-1 was measured by ELISA assay. Beat-to-beat blood flow velocity (BFV) and cerebrovascular resistance (CVR = mean arterial pressure / BFV) in the middle cerebral artery were assessed at rest by transcranial Doppler ultrasound.

RESULTS

sVCAM-1 concentrations were higher among participants with an MMSE score <24 versus ≥24 (1,201±417 vs 1,122±494ng/mL). In regression models adjusted for sociodemographic characteristics and health conditions, increasing levels of sVCAM-1 were linearly associated with higher resting CVR (p = .006) and lower performance on the Hopkins Verbal Learning Memory (immediate recall and delayed recall) and adjusted TMT B tests (p < .05). Higher levels of sVCAM-1 were also associated with global cognitive impairment on the MMSE (odds ratio = 3.9; 95% confidence interval: 1.4-10.9; p = .011).

CONCLUSIONS

In this cohort of elderly participants, we observed a cross-sectional association between elevated sVCAM-1 levels and both cognitive impairment and increased cerebrovascular resistance. Longitudinal studies are needed to determine whether elevated sVCAM-1 is a cause or consequence of cerebrovascular damage.