Anemia and dementia among the elderly: the São Paulo Ageing & Health Study

Anaemia and its causes at the Brazilian Longitudinal Study of Adult Health: a cross-sectional analysis of baseline data

BACKGROUND

Most anaemia studies focus on children and women of childbearing age. We assessed the frequency and main aetiologies of anaemia according to sociodemographic characteristics at the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a cohort of middle-aged adults.

METHODS

The primary analyses included 15,051 participants aged 35-74 years with a valid blood cell count. We built logistic models to analyse the association between socioeconomic characteristics and anaemia diagnosis. We also described the main aetiologies in a subset (n = 209) of participants with anaemia.

RESULTS

Anaemia was present in 3.0% (95% confidence interval [95%CI]: 2.6-3.4%) of men and 7.4% (95%CI: 6.9-8.0%) of women. The frequency of anaemia diagnosis was higher in women in all subgroups except for the oldest age stratum (65-74 years). The frequency of anaemia was particularly high in Blacks (6.0% and 15.5% in men and women, respectively). The most common causes of anaemia were iron deficiency (in women), chronic kidney disease, and chronic inflammation (in men). The frequency of unexplained anaemia was respectively 33.3% and 34.2% for men and women, and this condition was more frequent among participants of Black or Mixed races.

CONCLUSIONS

Anaemia was associated with age, female sex, Black race, and low socioeconomic status. Unexplained anaemia was common and more frequent in individuals of Black and Mixed races. ELSA-Brasil follow-up data may provide further insight into the relevance of unexplained anaemia in this setting.

Association of Anemia with Cognitive Function and Dementia Among Older Adults: The Role of Inflammation

BACKGROUND

The association of anemia with cognitive function and dementia remains unclear.

OBJECTIVE

We aimed to investigate the association of anemia with cognitive function and dementia risk and to explore the role of inflammation in these associations.

METHODS

Within the UK Biobank, 207,203 dementia-free participants aged 60+ were followed for up to 16 years. Hemoglobin (HGB) and C-creative protein (CRP) were measured from blood samples taken at baseline. Anemia was defined as HGB <13 g/dL for males and <12 g/dL for females. Inflammation was categorized as low or high according to the median CRP level (1.50 mg/L). A subset of 18,211 participants underwent cognitive assessments (including global and domain-specific cognitive). Data were analyzed using linear mixed-effects model, Cox regression, and Laplace regression.

RESULTS

Anemia was associated with faster declines in global cognition (β= -0.08, 95% confidence interval [CI]: -0.14, -0.01) and processing speed (β= -0.10, 95% CI: -0.19, -0.01). During the follow-up of 9.76 years (interquartile range 7.55 to 11.39), 6,272 developed dementia. The hazard ratio of dementia was 1.57 (95% CI: 1.38, 1.78) for people with anemia, and anemia accelerated dementia onset by 1.53 (95% CI: 1.08, 1.97) years. The risk of dementia tended to be higher in people with both anemia and high CRP (1.89, 95% CI: 1.60, 2.22). There was a statistically significant interaction between anemia and CRP on dementia risk (p-interaction = 0.032).

CONCLUSIONS

Anemia is associated with cognitive decline (specifically for processing speed) and increased risk of dementia, especially in people with high inflammation.

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.

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.

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.

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 cross-sectional association between mean corpuscular volume level and cognitive function in Chinese over 45 years old: Evidence from the China Health and Retirement Longitudinal Study

Fewer studies have focused on the independent association between mean corpuscular volume (MCV) and cognitive performance. This study was designed to characterize the cross-sectional association between MCV and cognitive performance in a large sample of Chinese residents (age≥45 years) from the China Health and Retirement Longitudinal Study (CHARLS). A total of 4023 male and 4173 female adults with MCV ≥ 80 fl were included for analysis. By multivariable linear regression analysis, for the total subjects, MCV level was significantly negatively associated with global cognitive function and episodic memory. When adjusted by sex, only in male subjects, higher MCV level was associated with reduced scores for global cognitive function, episodic memory and mental status. Via binary logistic regression analysis, the higher MCV level (MCV>100 fl) was associated with poor global cognitive function (OR = 1.601; 95% CI = 1.198–2.139; p = 0.001), episodic memory (OR = 1.679; 95% CI = 1.281–2.201; p<0.001), and mental status (OR = 1.422; 95% CI = 1.032–1.959; p = 0.031) for the whole participants. When testing this association by sex, the significant relationship between higher MCV level with worse episodic memory was observed both in male (OR = 1.690; 95% CI = 1.211–2.358; p = 0.002) and female (OR = 1.729; 95% CI = 1.079–2.770; p = 0.023) subjects; while the association between higher MCV level and poor global cognitive function (OR = 1.885; 95% CI = 1.329, 2.675; p<0.001) and mental status (OR = 1.544; 95% CI = 1.034, 2.306; p = 0.034) only existed in male subjects. Further studies are warranted to clarify the association between MCV level and cognitive performance by considering sex into consideration both cross-sectionally and longitudinally.

Anemia in Association with Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Prevalence of both anemia and cognitive impairment tends to increase with age. Individual studies have recently shown that anemia could be associated with cognitive impairment.

OBJECTIVE

To investigate the association between anemia and cognitive impairment including dementia.

METHODS

Two of the authors systematically searched PubMed, EMBASE, and the Cochrane library to retrieve observational studies reporting a relationship between anemia and cognitive impairment from 1964 to July 10, 2019. Case-control and cohort studies were included, and odds ratios (ORs) or relative risks (RRs) with 95% confidence intervals (CIs) for the risk of cognitive impairment were calculated using a random-effects model.

RESULTS

In total, 16 observational studies including eight case-control studies and eight cohort studies were included in the final analysis. Anemia was significantly linked to cognitive impairment (OR or RR 1.51; 95% CI: 1.32-1.73) in a random-effects meta-analysis, albeit with medium heterogeneity (I2 = 47.8%). Meta-estimates of dementia from prospective population-based cohort studies were similar (RR 1.46; 95% CI: 1.22-1.76) without substantial heterogeneity (I2 = 23.2%).

CONCLUSION

Our meta-analysis indicates that anemia is associated with cognitive impairment. Further prospective research is warranted to determine the cause-effect relationship of anemia with cognitive impairment and whether treatment of anemia might reduce the risk of dementia.

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.

A associação entre anemia e alguns aspectos da funcionalidade em idosos

Resumo O objetivo deste artigo é avaliar a associação entre a anemia e algumas atividades de vida diária associadas à alimentação e o relato de dificuldade de mastigação e deglutição. Estudo transversal, que analisou 1.256 indivíduos de 60 anos ou mais, que fizeram parte da terceira coleta do Estudo SABE (Saúde, Bem-estar e Envelhecimento). Considerou-se anêmicos homens com hemoglobina sanguínea ≤ 13g/dL e mulheres com valores ≤ 12g/dL. Houve prevalência de anemia maior nos indivíduos que relataram redução no consumo alimentar devido a queixas de mastigação e deglutição, naqueles com dificuldade de mastigação e nos que relataram dificuldade em alimentar-se devido queixas de mastigação e deglutição. A prevalência também foi maior nos indivíduos com dificuldade de alimentar-se sozinho e de fazer compras de alimentos. Nas análises, a presença de uma queixa de mastigação e deglutição foi associada à chance de anemia quase 2 vezes maior que aqueles indivíduos sem queixas, e a presença de 2 ou 3 queixas de mastigação e deglutição foi associada à chance de 2,7. Os idosos com dificuldades de deglutição e mastigação apresentaram maior prevalência de anemia, mesmo após ajuste de outros fatores associados, com efeito dose-resposta, evidenciando a importância de um trabalho multidisciplinar com o idoso.

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

The scope of this study was to determine the prevalence of anemia and the correlation between the concentration of hemoglobin and cognitive factors in an elderly population group resident in Campina Grande, Paraiba, Brazil. It was a cross-sectional study with individuals aged 60 or older. Men with hemoglobin levels <13 g / dL and women with levels <12 g / dL were considered anemic. Sociodemographic, cognitive condition and nutritional status variables were analyzed. Statistical analysis was performed by means of simple and multiple linear regression. Among the 360 elderly patients evaluated (67.2% women), the prevalence of anemia was 12.5%. The average concentration of hemoglobin found was 13.5 g / dL and was correlated to sex variables (β = -0.44, 95% CI: -1.35, -0.85), age (β = -0.14 ; 95% CI: -0.03, -0.01), nutritional status (β = 0.16; 95% CI: 0.01, 0.06), memory impairment (β = 0.12; 95% CI: - 0.06, -0.01), and dementia (β = -0.13, 95% CI: -0.06, -0.01). Routine blood testing among the elderly makes it possible to detect and treat anemia at an early stage. Actions geared towards the elderly who show a cognitive decline should be developed in the Basic Family Health Units in order to improve the quality of life of this population.

Prevalência e fatores associados à presença de anemia em idosos do município de Viçosa (MG), Brasil

Resumo A anemia é o problema hematológico mais comum encontrado na população idosa. Com objetivo de avaliar a prevalência e os fatores associados à anemia em idosos no município de Viçosa (MG), foi realizado um estudo transversal, de base populacional. Os dados foram coletados de junho a dezembro de 2009, mediante inquérito domiciliar e realização de exames bioquímicos em 349 idosos. A prevalência de anemia foi de 11,7% (IC95% 8,3%-15,1%) e mostrou-se mais elevada entre os homens (15,4%), entre idosos com 80 anos e mais (30,0%) e naqueles que praticavam polifarmácia (16,8%). Os resultados evidenciaram determinantes de anemia semelhantes ao observado em países desenvolvidos. A real necessidade da polifarmácia deve ser avaliada na atenção à saúde dos idosos, com vistas a prevenir iatrogenias, dentre as quais a anemia está incluída.

Prevalence of anemia and associated factors in older adults: evidence from the SABE Study

OBJECTIVE

To assess the prevalence of anemia and associated factors in older adults.

METHODS

The prevalence and factors associated with anemia in older adults were studied on the basis of the results of the Saúde, Bem-Estar e Envelhecimento (SABE – Health, Welfare and Aging) study. A group of 1,256 individuals were interviewed during the third wave of the SABE study performed in Sao Paulo, SP, in 2010. The study included 60.4% females; the mean age of the participants was 70.4 years, and their average education was 5.3 years. The dependent variable was the presence of anemia (hemoglobin levels: 12 g/dL in women and 13 g/dL in men). Descriptive analysis and hierarchical logistic regression were performed. The independent variables were as follows: a) demographics: gender, age, and education and b) clinical characteristics: self-reported chronic diseases, presence of cognitive decline and depression symptoms, and body mass index.

RESULTS

The prevalence of anemia was 7.7% and was found to be higher in oldest adults. There was no difference between genders, although the hemoglobin distribution curve in women showed a displacement toward lower values in comparison with the distribution curve in men. Advanced age (OR = 1.07; 95%CI 0.57;1.64; p < 0.001), presence of diabetes (OR = 2.30; 95%CI 1.33;4.00; p = 0.003), cancer (OR = 2.72; 95%CI 1.2;6.11; p = 0.016), and presence of depression symptoms (OR = 1.75; 95%CI 1.06;2.88; p = 0.028) remained significant even after multiple analyses.

CONCLUSIONS

The prevalence of anemia in older adults was 7.7% and was mainly associated with advanced age and presence of chronic diseases. Thus, anemia can be an important marker in the investigation of health in older adults because it can be easily diagnosed and markedly affects the quality of life of older adults.

[Anemia and hemoglobin level as prognostic factors of mortality in community-dwelling elderly: evidence from the Bambuí Cohort Study on Aging, Minas Gerais State, Brazil]

The aim of this study was to examine the influence of low hemoglobin (Hb) and anemia on mortality in the elderly in a ten-year follow-up (1997-2007). Among the 1,742 elderly participants in the baseline cohort from Bambuí, Minas Gerais State, Brazil, 1,322 (82.3%) were followed for an average of 8.9 years. Probability of survival was estimated by Kaplan-Meier and Cox's proportional hazard ratios (HR), and confidence intervals (95%CI) were used, considering potential confounders. Anemia and low Hb (lowest tertile) were associated with increased risk of death (HR = 2.63, 95%CI: 1.83-3.76 and HR = 1.38, 95%CI: 1.07-1.79, respectively). The results show that anemia or low Hb (regardless of a diagnosis of anemia) should be interpreted and managed as independent determinants of mortality in this elderly population.

The association of hemoglobin concentration with disability and decreased mobility among older Brazilians

OBJECTIVE

To examine the association between hemoglobin concentration and disability and mobility difficulty among older adults living in São Paulo, Brazil.

DESIGN

Cross-sectional study.

SETTING

Population-based study conducted in São Paulo, Brazil.

PARTICIPANTS

Adults age 60 and over (n=1,256) from the third data collection wave of the SABE Study (Health, Well-being, and Aging) conducted in 2010.

MEASUREMENTS

Two outcome measures were included in the analyses: 1) a difficulty to perform at least one of the instrumental activities of daily living (IADL) and 2) mobility difficulty, which was assessed using the Short Physical Performance Battery (SPPB). Logistic regression models assessed the association between hemoglobin and each of the outcome measures. All analyses were adjusted for sociodemographic and health characteristics.

RESULTS

The prevalence of IADL disability was 26.8% and 10.7% of participants had mobility difficulty. The mean hemoglobin concentration was significantly lower in older adults who already presented disability (13.7g/dL versus 14.4g/dL among independent elderly) or decreased mobility (13.4g/dL versus 14.3g/dL among elderly with preserved mobility). Higher values of hemoglobin concentration were associated with lower the risk of IADL disability (OR=0.88; p=0.04) and mobility difficulty (OR=0.81; p=0.02). Hemoglobin concentrations showed a dose-response effect in the probability of each outcome.

CONCLUSIONS

Lower hemoglobin concentration was associated with a higher probability of IADL disability and mobility difficulty, showing a clear dose-response effect.

Nível de hemoglobina entre idosos e sua associação com indicadores do estado nutricional e uso de serviços de saúde: Projeto Bambuí

O objetivo deste estudo foi descrever a prevalência de anemia e avaliar a associação de nível de hemoglobina (Hb) com indicadores do estado nutricional e uso de serviços de saúde em uma população idosa (≥ 60 anos). Dos 1.742 idosos participantes da linha de base da coorte de Bambuí, Minas Gerais, Brasil, foram incluídos 1.441 (82,7%). A variável dependente foi o nível de Hb e as independentes foram número de hospitalizações e visitas ao médico nos 12 meses precedentes à entrevista, índice de massa corporal (IMC) e albumina sérica. Foi realizada regressão linear multivariada estratificada por sexo e ajustada por fatores de confusão. A prevalência de anemia foi baixa na população (4,5%), sem diferenças entre sexos e significativamente maior em idosos mais velhos (10,2%). Baixos níveis de Hb foram associados ao maior número de consultas médicas e a menores valores de albumina sérica e IMC em ambos os sexos. O estudo sugere um ciclo complexo entre baixos níveis de Hb, desnutrição e atendimento médico, o que deve ser considerado na estruturação de programas de saúde para idosos.