[Prevalence of anemia and correlation between the concentration of hemoglobin and cognitive factors among the elderly]

Relationship Between Vitamin D Insufficiency and Anemia in Older Adults: An Approach Considering Clinical Aspects and Food Insecurity

BACKGROUND/OBJECTIVES

Studies have shown a high prevalence of anemia and vitamin D insufficiency in older adults, and the literature suggests a relationship between these two conditions, as vitamin D insufficiency may impair erythrocyte synthesis. Food insecurity refers to the lack of regular access to sufficient and nutritious food, which can directly affect health by worsening conditions such as anemia and vitamin D insufficiency. This study evaluated the association between vitamin D insufficiency and anemia in older adults.

METHODS

We conducted a cross-sectional study with 430 individuals aged 60 and older, using personal interviews and blood tests for data collection. Anemia was identified with serum hemoglobin levels of <12 g/dL for women and <13 g/dL for men, while vitamin D insufficiency was defined as serum levels <30 ng/mL. We used multiple logistic regression to analyze associations through Stata version 17.0 software.

RESULTS

The prevalence of anemia was identified in 14.7% of the sample, and vitamin D insufficiency was observed in 63.5%. We found an association between vitamin D insufficiency and anemia (OR = 2.4; 95% CI = 1.2-4.7). In the final model, factors such as male sex (OR = 2.7; 95% CI = 1.5-4.9) and polypharmacy use (OR = 2.0; 95% CI = 1.0-3.9) were also associated, regardless of age group, food insecurity, and multimorbidity.

CONCLUSIONS

Vitamin D insufficiency increased the likelihood of anemia among the older adults evaluated, suggesting that prevention and treatment strategies for anemia should consider vitamin D serum levels.

Factors Associated with Anemia among Adults and the Elderly Family Farmers

The majority of studies on anemia are focused on children and women of reproductive age. Although the disease is a widespread public health problem, studies that include the rural population are scarce. This study determined the prevalence of anemia and associated factors in adults and the elderly living in the rural area of a municipality in Minas Gerais. Twelve rural communities were included. During home visits, hemoglobin levels were measured using a hemoglobinometer to check for the presence or absence of anemia. Additionally, anthropometric data and food insecurity data based on the Brazilian Food Insecurity Scale (EBIA) were collected. A questionnaire about socioeconomic, demographic, and housing conditions was applied. Analyses were performed using the Stata software version 13.0. Spearman correlation and regression analysis logistics were performed (p < 0.05) on 124 families (n = 297 farmers). The prevalence of anemia was 41.1%, being higher among women (55.7%). Additionally, 40.1% of the farmers were food insecure; 52.7% and 80.5% presented excess weight and cardiovascular risk, respectively. Poverty was a reality for 39.7% of individuals. A positive correlation between hemoglobin levels and per capita income was found as well as a negative correlation with EBIA scores and cardiovascular risk. Multivariate analysis showed that individuals experiencing food insecurity, the elderly, and those who do not own a property, were more likely to be anemic. Farmers with per capita income above 1/2 minimum wage were less likely to have anemia. The prevalence of anemia in the group studied was higher than previous studies. The disease is associated with factors that also predispose to food insecurity. The improvement of the determinants of insecurity can contribute to the fight against anemia.

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.

Anemia and the Risk of Cognitive Impairment: An Updated Systematic Review and Meta-Analysis

BACKGROUND

Cognitive impairment is one of the most common, burdensome, and costly disorders in the elderly worldwide. The magnitude of the association between anemia and overall cognitive impairment (OCI) has not been established.

OBJECTIVE

We aimed to update and expand previous evidence of the association between anemia and the risk of OCI.

METHODS

We conducted an updated systematic review and meta-analysis. We searched electronic databases, including EMBASE, PubMed, and Web of Science for published observational studies and clinical trials between 1 January 1990 and 1 June 2020. We excluded articles that were in the form of a review, letter to editors, short reports, and studies with less than 50 participants. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. We estimated summary risk ratios (RRs) with random effects.

RESULTS

A total of 20 studies, involving 6558 OCI patients were included. Anemia was significantly associated with an increased risk of OCI (adjusted RR (aRR) 1.39 (95% CI, 1.25-1.55; p < 0.001)). In subgroup analysis, anemia was also associated with an increased risk of all-cause dementia (adjusted RR (aRR), 1.39 (95% CI, 1.23-1.56; p < 0.001)), Alzheimer's disease [aRR, 1.59 (95% CI, 1.18-2.13; p = 0.002)], and mild cognitive impairment (aRR, 1.36 (95% CI, 1.04-1.78; p = 0.02)).

CONCLUSION

This updated meta-analysis shows that patients with anemia appear to have a nearly 1.39-fold risk of developing OCI than those without anemia. The magnitude of this risk underscores the importance of improving anemia patients' health outcomes, particularly in elderly patients.

Association of Antioxidant Vitamins A, C, E and Carotenoids with Cognitive Performance over Time: A Cohort Study of Middle-Aged Adults

Carotenoids may strengthen the association of antioxidant vitamins A, C, and E with favorable cognitive outcomes over time, though a few prospective studies have examined this hypothesis. We evaluated the longitudinal data from 1251 participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study (Age at visit 1 in 2004–2009 (v₁): 30–65 years). Vitamins A, C, and E dietary intakes and total and individual dietary carotenoids were computed using two 24-h recalls at v₁. Cognitive tests, covering global mental status and domains of memory/learning, attention, psychomotor speed, visuo-spatial, language/verbal, and executive function were conducted at v₁ and/or v₂ (2009–2013); mean ± SD follow-up: 4.66 ± 0.93 years. Mixed-effects linear regression models detected an interaction between vitamin E and total (and individual) carotenoids for three of 11 cognitive tests at v₁, with only one meeting the statistical significance upon multiple testing correction whereby vitamin E was linked with greater verbal memory performance in the uppermost total carotenoid tertile (γ_0a = +0.26 ± 0.08, p = 0.002), a synergism largely driven by carotenoid lycopene. Vitamins A and C showed no consistent interactions with carotenoids. In conclusion, we provide partial evidence for synergism between vitamin E and carotenoids in relation to better baseline cognitive performance, pending further studies with time-dependent exposures and randomized trials directly examining this synergism.

Unannotated single nucleotide polymorphisms in the TATA box of erythropoiesis genes show in vitro positive involvements in cognitive and mental disorders

BACKGROUND

Hemoglobin is a tetramer consisting of two α-chains and two β-chains of globin. Hereditary aberrations in the synthesis of one of the globin chains are at the root of thalassemia, one of the most prevalent monogenic diseases worldwide. In humans, in addition to α- and β-globins, embryonic zeta-globin and fetal γ-globin are expressed. Immediately after birth, the expression of fetal Aγ- and Gγ-globin ceases, and then adult β-globin is mostly expressed. It has been shown that in addition to erythroid cells, hemoglobin is widely expressed in nonerythroid cells including neurons of the cortex, hippocampus, and cerebellum in rodents; embryonic and adult brain neurons in mice; and mesencephalic dopaminergic brain cells in humans, mice, and rats. Lately, there is growing evidence that different forms of anemia (changes in the number and quality of blood cells) may be involved in (or may accompany) the pathogenesis of various cognitive and mental disorders, such as Alzheimer's and Parkinson's diseases, depression of various severity levels, bipolar disorders, and schizophrenia. Higher hemoglobin concentrations in the blood may lead to hyperviscosity, hypovolemia, and lung diseases, which may cause brain hypoxia and anomalies of brain function, which may also result in cognitive deficits.

METHODS

In this study, a search for unannotated single-nucleotide polymorphisms (SNPs) of erythroid genes was initially performed using our previously created and published SNP-TATA_Z-tester, which is a Web service for computational analysis of a given SNP for in silico estimation of its influence on the affinity of TATA-binding protein (TBP) for TATA and TATA-like sequences. The obtained predictions were finally verified in vitro by an electrophoretic mobility shift assay (EMSA).

RESULTS

On the basis of these experimental in vitro results and literature data, we studied TATA box SNPs influencing both human erythropoiesis and cognitive abilities. For instance, TBP-TATA affinity in the HbZ promoter decreases 6.6-fold as a result of a substitution in the TATA box (rs113180943), thereby possibly disrupting stage-dependent events of "switching" of hemoglobin genes and thus causing erythroblastosis. Therefore, rs113180943 may be a candidate marker of severe hemoglobinopathies with comorbid cognitive and mental disorders associated with cerebral blood flow disturbances.

CONCLUSIONS

The literature data and experimental and computations results suggest that the uncovered candidate SNP markers of erythropoiesis anomalies may also be studied in cohorts of patients with cognitive and/or mental disorders with comorbid erythropoiesis diseases in comparison to conventionally healthy volunteers. Research into the regulatory mechanisms by which the identified SNP markers contribute to the development of hemoglobinopathies and of the associated cognitive deficits will allow physicians not only to take timely and adequate measures against hemoglobinopathies but also to implement strategies preventing cognitive and mental disorders.

Prevalence of anemia in Brazilian adults and elderly

OBJECTIVE

To verify the prevalence of anemia in Brazilian adults and elderly.

METHODS

This is a cross-sectional study consisted of 8,060 subjects aged over 18 years old in all Brazilian states. We used data from laboratory tests of the Brazilian National Health Survey (Pesquisa Nacional de Saúde - PNS). The following indicators obtained by erythrogram were used: hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and red cell distribution width (RDW). Reference values of the World Health Organization (WHO) were used to determine anemia, which considers hemoglobin levels below 13.0 g/dL for men and less than 12.0 g/dL for women. Sociodemographic information was obtained by interview.

RESULTS

The prevalence of anemia among Brazilian adults and elderly was 9.9%. Higher prevalence of anemia and more severe cases were found among women, elderly, people with low schooling, black skin color and residents of the North and Northeast regions. Normocytic normochromic anemia was the most common type of anemia (56.0%).

CONCLUSION

The anemia prevalence found in the study was in agreement with the literature. It must be stressed that higher anemia prevalence was found in disadvantaged and older population. Considering the increase of the population over 60 years of age, interventions to prevent and treat anemia among adults and elderly is imperative in the health service network.

A Novel Perspective Linkage Between Kidney Function and Alzheimer's Disease

It has long been believed that kidney function is linked to brain activity. Clinical studies demonstrate that patients with chronic kidney disease (CKD) are more prone to cognitive impairment and Alzheimer's disease (AD), and the degree of cognitive impairment is closely related to CKD progression and renal failure. Moreover, the fact that cognitive function in CKD patients is significantly improved after successful kidney transplantation reveals a linkage between CKD and AD. However, the mechanisms behind this linkage are unclear. The physiological function of the kidney is to maintain the stability of the internal environment, including the cerebrovascular circulation, whereas abnormal kidney function often leads to ischemia and hypoxia. Many CKD patients experience chronic hypoxia, and many urinary toxins accumulate after renal function is impaired. In this mini review, we will propose a novel perspective on the association between AD and CKD and the connection between the kidney and brain.