Juliana Nery de Souza-Talarico

Peripheral Oxidative Stress Biomarkers in Mild Cognitive Impairment and Alzheimer's Disease

Oxidative stress has been associated with normal aging and Alzheimers disease (AD). However, little is known about oxidative stress in mild cognitive impairment (MCI) patients who present a high risk for developing AD. The aim of this study was to investigate plasma production of the lipid peroxidation marker, malonaldehyde (MDA) and to determine, in erythrocytes, the enzymatic antioxidant activity of catalase, glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST) in 33 individuals with MCI, 29 with mild probable AD and 26 healthy aged subjects. GR/GPx activity ratio was calculated to better assess antioxidant defenses. The relationship between oxidative stress and cognitive performance was also evaluated by the Mini Mental State Examination (MMSE). AD patients showed higher MDA levels than both MCI and healthy elderly subjects. MCI subjects also exhibited higher MDA levels compared to controls. Catalase and GPx activity were similar in MCI and healthy individuals but higher in AD. GR activity was lower in MCI and AD patients than in healthy aged subjects. Additionally, GR/GPx ratio was higher in healthy aged subjects, intermediate in MCI and lower in AD patients. No differences in GST activity were detected among the groups. MMSE was negatively associated with MDA levels (r = -0.31, p = 0.028) and positively correlated with GR/GPx ratio in AD patients (r = 0.68, p < 0.001). MDA levels were also negatively correlated to GR/GPx ratio (r = -0.31, p = 0.029) in the AD group. These results suggest that high lipid peroxidation and decreased antioxidant defenses may be present early in cognitive disorders.

Performance of a Brazilian population on the test of functional health literacy in adults

OBJECTIVE To analyze the scoring obtained by an instrument, which evaluates the ability to read and understand items in the health care setting, according to education and age. METHODS The short version of the Test of Functional Health Literacy in Adults was administered to 312 healthy participants of different ages and years of schooling. The study was conducted between 2006 and 2007, in the city of São Paulo, Southeastern Brazil. The test includes actual materials such as pill bottles and appointment slips and measures reading comprehension, assessing the ability to read and correctly pronounce a list of words and understand both prose passages and numerical information. Pearson partial correlations and a multiple regression model were used to verify the association between its scores and education and age. RESULTS The mean age of the sample was 47.3 years(sd=16.8) and the mean education was 9.7 years(sd=5; range: 1 - 17). A total of 32.4% of the sample showed literacy/numeracy deficits, scoring in the inadequate and marginal functional health literacy ranges. Among the elderly (65 years or older) this rate increased to 51.6%. There was a positive correlation between schooling and scores (r=0.74; p<0.01) and a negative correlation between age and the scores (r=-0.259; p<0.01). The correlation between the scores and age was not significant when the effects of education were held constant (rp=-0.031, p=0.584). A significant association (B=3.877, Beta =0.733; p<0.001) was found between schooling and scores. Age was not a significant predictor in this model (B=-0.035, Beta=-0.22; p=0.584). CONCLUSIONS The short version of the Test of Functional Health Literacy in Adults was a suitable tool to assess health literacy in the study population. The high number of individuals classified as functional illiterates in this test highlights the importance of special assistance to help them properly understand directions for healthcare.OBJETIVO: Analisar os escores de instrumento que avalia habilidade de leitura e compreensao de materiais da area da saude segundo escolaridade e idade. METODOS: Foram avaliados 312 participantes saudaveis de diferentes idades por meio da versao reduzida do instrumento Test of Functional Health Literacy in Adults. O estudo foi realizado entre 2006 e 2007 na cidade de Sao Paulo (SP). O instrumento envolve materiais como frascos de medicamentos e cartoes de agendamento de consultas, avaliando a compreensao de leitura e de conceitos numericos. Os testes de correlacao parcial e de Pearson e um modelo de regressao multipla foram usados para verificar a associacao entre os escores no instrumento, escolaridade e idade. RESULTADOS: As medias de idade e de escolaridade da amostra foram respectivamente 47,3 (dp=16,8 ) e 9,7 (dp=5; de um a 17 anos de estudo). O total de 32,4% da amostra mostraram deficits de alfabetizacao funcional/ uso de conceitos numericos na area de saude, com desempenho inadequado ou limitrofe no instrumento. Entre idosos (65 anos ou mais) esta taxa atingiu 51,6%. Encontrou-se correlacao positiva entre anos de estudo e escores no instrumento (r=0,740; p<0,01) e correlacao negativa entre idade e escores no instrumento (r=-0,259; p<0,01). A correlacao entre escores no instrumento e idade nao foi significante quando os efeitos da escolaridade foram controlados (r=-0,031, p=0,584). Uma associacao significante (B=3,877, Beta=0,733; p<0,001) foi encontrada entre anos de estudo e escores no instrumento. A idade nao foi uma variavel preditiva no modelo (B=-0,035, Beta=-0,22; p=0,584). CONCLUSOES: O instrumento e adequado para avaliar a alfabetizacao funcional em saude na populacao brasileira. O elevado numero de individuos classificados como analfabetos funcionais indica a importância de adocao de medidas especiais para ajudar estes individuos a compreenderem corretamente as orientacoes para cuidados de saude.

Relationship Between Cortisol Levels and Memory Performance may be Modulated by the Presence or Absence of Cognitive Impairment: Evidence from Healthy Elderly, Mild Cognitive Impairment and Alzheimer's Disease Subjects

An inverted U-shape function between cortisol levels and memory performance has been reported in studies on both young animals and humans. Yet little is known about this relationship in normal aging or in older subjects with cognitive impairment. This issue is particularly significant since increased levels of cortisol have been reported in Alzheimers disease (AD). The present study examined the association between cortisol levels and visual memory performance in healthy subjects as well as in individuals presenting mild cognitive impairment (MCI) or AD. Salivary cortisol was measured in 40 healthy elderly subjects, 31 individuals with amnestic MCI, and 40 subjects with mild probable AD. Memory performance was evaluated using the Brief Cognitive Screening Battery. Higher cortisol levels were associated with better memory performance in healthy elderly (p=0.005), while higher cortisol levels were correlated with poorer memory performance in MCI subjects (p=0.011). No correlation between cortisol and memory was found in the AD group (p > 0.05). These results suggest that the relationship between cortisol levels and memory performance in the aging process could vary according to the presence or absence of cognitive impairment.

Stress and coping in older people with Alzheimer's disease

AIM To investigate stress intensity and coping style in older people with mild Alzheimers disease. BACKGROUND The potential risk assessment of a stress event and the devising of coping strategies are dependent on cognitive function. Although older individuals with Alzheimers disease present significant cognitive impairment, little is known about how these individuals experience stress events and select coping strategies in stress situations. DESIGN Survey. METHOD A convenient sample of 30 cognitively healthy older people and 30 individuals with mild Alzheimers disease were given an assessment battery of stress indicators (Symptom Stress List, Cornell Scale for Depression in Dementia, State-Trait Anxiety Inventory), coping style (Jalowiec Coping Scale) and cognitive performance (mini-mental state exam) were applied in both groups. Statistical analysis of the data employed the Mann-Whitney test to compare medians of stress indicators and coping style, Fischers exact test to compare proportions when expected frequencies were lower than five, and Spearmans correlation coefficient to verify correlation between coping style and cognitive performance. RESULTS Both groups suffered from the same stress intensity (p = 0.254). Regarding coping styles, although differences were not statistically significant (p = 0.124), emotion-oriented coping was predominant in the patients with Alzheimers disease. However, those individuals displaying better cognitive performance in the Alzheimers disease group had selected coping strategies focused on problem solving (p = 0.0074). CONCLUSIONS Despite a tendency for older people with Alzheimers disease to select escape strategies and emotional control, rather than attempting to resolve or lesser the consequences arising from a problem, coping ultimately depends on cognitive performance of the individual. RELEVANCE TO CLINICAL PRACTICE The findings of this study provide information and data to assist planning of appropriate support care for individuals with Alzheimers disease who experience stress situations, based on their cognitive performance.

Cross-country differences in basal and stress-induced cortisol secretion in older adults.

Objective Several studies have emphasized the association between socioeconomic status (SES) and inadequate response of the biological stress system. However, other factors related to SES are rarely considered, such as cultural values, social norms, organization, language and communication skills, which raises the need to investigate cross-country differences in stress response. Although some studies have shown differences in cortisol levels between immigrants and natives, there is no cross-country evidence regarding cortisol levels in country-native elders. This is particularly important given the high prevalence of stress-related disorders across nations during aging. The current study examined basal diurnal and reactive cortisol levels in healthy older adults living in two different countries. Methods Salivary cortisol of 260 older adults from Canada and Brazil were nalyzed. Diurnal cortisol was measured in saliva samples collected at home throughout two working days at awakening, 30 min after waking, 1400 h, 1600 h and before bedtime. Cortisol reactivity was assessed in response to the Trier Social Stress Test (TSST) in both populations. Results Our results showed that even under similar health status, psychological and cognitive characteristics, Brazilian elders exhibited higher basal and stress-induced cortisol secretion compared to the Canadian participants. Conclusion These findings suggest that country context may modulate cortisol secretion and could impact the population health.

Effect of cortisol levels on working memory performance in elderly subjects with Alzheimer's disease

BACKGROUND Subjects with Alzheimers disease (AD) have elevated cortisol levels as a result of hypothalamic-pituitary-adrenal (HPA) axis dysfunction. Acute administration of hydrocortisone has been associated with working memory (WM) performance in young adults. OBJECTIVE To investigate whether cortisol levels are associated with WM performance in subjects with AD. METHOD Eighty subjects were included, comprising 40 patients with mild AD and 40 healthy elderly controls. WM was assessed using the Digit Span Backward test (DSB). Saliva samples were collected to determine cortisol levels. RESULTS AD subjects had poorer performance on the DSB than controls (p=0.002) and also presented higher levels of cortisol than control group (p=0.04). No significant correlation was observed between the DSB and cortisol levels in both groups (r= -0.29). CONCLUSION In this study, elevated cortisol levels were not associated with poorer WM performance in patients with AD or in healthy elderly subjects.

The infl uence of schooling on working memory performance in elderly individuals without cognitive decline

Over recent decades, research on cognition has been developed rapidly toward better understanding the cognitive changes that usually occur during normal aging. There is evidence that elderly individuals have worse working memory performance than young adults. However, the effect of education on this cognitive function remains unclear. Objectives To analyze the performance of healthy elderly subjects on working memory tasks and to verify the influence of educational level on this performance. Methods Forty elderly individuals without cognitive impairment and fully independent, were randomly chosen from a group of subjects participating in cultural activities at the university campus. The Digit Span Forward (DSF) test was used to evaluate attention performance. The working memory performance was assessed by the Digit Span Backward (DSB) and the difference between DSF and DSB. The data were statistically analyzed using the Spearman’s correlation coefficient to verify the correlation between the Digit Span (DS) scores and the variables age and schooling, while the Multiple Linear Regression Model was used to verify the effect of these variables on the DS scores. Results A significant positive correlation (r=0.41, p<0.01) as well as a significant association (β=0.506; p=0.001; CI 95%= 0.064/0.237) were found between years of schooling and DSB scores. It was not observed statistical correlation (r= –0.08, p=0.64) or association (β=0.41; p=0.775; CI 95%= –0.049/0.065) between age and DSB scores. Conclusion In this study, higher levels of schooling were associated with better working memory performance in cognitively healthy elders.

Dementia and Cognitive Impairment Prevalence and Associated Factors in Indigenous Populations: A Systematic Review.

Population aging has been accompanied by worldwide growth in dementia. However, little is known about the prevalence of dementia and cognitive impairment not dementia in ethnically diverse populations, such as indigenous populations conceptualized as groups of persons who self-identify as indigenous and who are recognized as distinctive communities reproducing ancestral, historical, and territorial culture. This is particularly relevant in view of increasing life expectancy in indigenous populations and, consequently, in the number of elderly people, as well as the changes in their multimorbidity profile. In this study, a systematic review of the literature on the subject “cognitive impairment in indigenous elderly population” in the databases MEDLINE via PubMed, Lilacs, and Scopus showed that the prevalence of dementia in indigenous populations between 45 and 94 years old, originally from different countries, varied between 0.5% and 26.8% for age 60 and older, whereas the prevalence of cognitive impairment not dementia varied between 4.4% and 17.7%. Early onset of the disease, older age, low education level, and several poor health conditions were associated with prevalence rates and conversion from normal to any cognitive impairment. Cultural inadequacy of neuropsychological tests was the main factor reported in the selected studies, which makes the investigation of dementia a challenge in indigenous populations. These data reveal that the prevalence rates of dementia ranged from low to very high for those aged 60 years and older, with early onset of the disease and elevated mortality rate after initial diagnosis compared with the current global prevalence studies, suggesting that these individuals may be more vulnerable to cognitive disorders. Cognitive reserve and exposure to poor health status throughout life span may be considered in the interpretation of results.

[Subjective memory complain in healthy elderly: influence of depressive symptoms, perceived stress and self-esteem].

O presente estudo analisou a relacao entre percepcao de estresse, sintomas depressivos e autoestima em idosos com e sem queixa subjetiva de comprometimento de memoria. Foram incluidos 204 idosos (104 sem e 100 com queixa de memoria) avaliados a partir do instrumento Memory Assessment Complain Questionnaire (MAC-Q). O protocolo de estudo incluiu a Escala de Estresse Percebido (EEP), a Escala de Depressao Geriatrica (GDS) e a Escala de Autoestima de Rosenberg (EAE). Os idosos com queixa de comprometimento apresentaram escores significativamente maiores na EEP e GDS e menores na EAE (p < 0.001). Foi observada correlacao negativa entre o escore do MAC-Q e EPP (p < 0.001) e EAE (p = 0.01). A analise de regressao multivariada identificou somente o estresse como fator preditor da queixa subjetiva de memoria. Esses dados sugerem que a percepcao de estresse e os sintomas depressivos estao associados com a queixa de memoria em idosos.The current study analyzed the relationship between perceived stress, depressive symptoms and self-esteem in elderly with and without subjective memory complain. Two-hundred four elderly were included (104 without and 100 with subjective memory complain) assesse using the Memory Assessment Complain Questionnaire (MAC-Q). The study protocol was composed by the Perceived Stress Scale (PSS), the Geriatric Depression Scale (GDS) and the Self-Esteem Scale of Rosenberg (SES). The elderly with subjective memory complain showed higher PSS and GDS scores (p < 0.001) and lower SES scores (p = 0.045). Negative correlation was observed between MAC-Q and PSS (p < 0.001) and GDS (p = 0.01). Multiple regression analysis showed predictor effect of perceived stress in the subjective memory complain. These findings suggest that the perceived stress and depressive symptoms are associated with subjective memory complain in elderly.

Association between heavy metal exposure and poor working memory and possible mediation effect of antioxidant defenses during aging

BACKGROUND Inverse associations have been observed between memory performance and blood concentrations of cadmium (Cd) and lead (Pb). Low antioxidant cell activity has also been linked to decline in memory due to aging. However, it has not yet been established whether the heavy metal-memory relationship is mediated by differences in antioxidant activity. METHODS We examined Cd and Pb levels, as well as oxidative stress parameters, in blood samples from 125 older adults (age range 50-82years). The Counting Span Test (CST) was used to evaluate working memory capacity (WMC). The Monte Carlo Method for Assessing Mediation (MCMAM) was used to analyze the mediation role of antioxidant activity in the heavy metals-memory association. RESULTS High blood Cd (BCd) concentration alone, and in combination with elevated blood Pb (BPb) concentration, was associated with poor WMC (p≤0.001) and low enzymatic antioxidant defenses (p≥0.006). The variance in WMC accounted for by BCd or by BCd combine with BPb was 20.6% and 18.6%, respectively. The MCMAM revealed that the influence of BCd and BPb concentrations on WMC was mediated by low antioxidant capacity (confidence interval - CI: 0.072 to -0.064 for BCd; CI: -0.062 to -0.045 for BPb). CONCLUSION These findings showed Pb and Cd blood concentration in older adults, even at levels below the current recommended threshold, was negatively associated with WMC and that this relationship may be partly mediated by low antioxidant defenses. Knowledge on the environmental factors that negatively influence brain and cognition during aging can help inform public policy strategies to prevent and control the adverse effects of environmental contaminant exposure during aging.