Socioeconomic determinants of cognition among older adults in the Brazilian longitudinal study of aging (ELSI-Brazil): a life-course approach.

BACKGROUND: The prevalence of cognitive impairment no dementia (CIND) and dementia appears to be higher in low- and middle-income countries (LMICs) compared to high-income economies. Yet few nationally representative studies from Latin American LMICs have investigated life-course socioeconomic factors associated with the susceptibility to these two cognitive conditions. Hence, the present study aimed to examine the associations of early- (education and food insecurity), mid- (employment stability), and late-life (personal income and household per capita income) socioeconomic determinants of CIND and dementia among older adults from Brazil, while simultaneously exploring whether sex plays an effect-modifier role on these associations. METHODS: This population-based study comprised a nationally representative sample of older adults (N = 5,249) aged 60 years and over from the Brazilian Longitudinal Study of Aging (ELSI-Brazil). We fitted multinomial regressions and estimated odds ratios with the respective 95% confidence intervals (CIs). RESULTS: In multivariate analyses, participants with more years of early-life education (0.89, 95% CI [0.81, 0.97]) and mid-life employment stability (0.97, 95% CI [0.96, 0.99]) and higher late-life household per capita income (0.70, 95% CI [0.51, 0.95) were less likely to have dementia. Regarding CIND, more years of mid-life employment stability (0.97, 95% CI [0.96, 0.98]) was the only determinant to confer protection. Notably, secondary sex-based analyses showed the higher the early-life educational attainment, the lower the odds of dementia in women (0.81, 95% CI [0.75, 0.87]) but not in men (1.00, 95% CI [0.86, 1.16]). CONCLUSIONS: These findings may have implications for population health and health policy by advancing our understanding of socioeconomic determinants of CIND and dementia, especially in Latin America.

The Brazilian version of the Johns Hopkins dementia care needs assessment (JHDCNA-br 2.0): translation, cultural adaptation, and preliminary psychometric testing.

OBJECTIVES: People with dementia have several unmet needs during the syndrome progression. More unmet needs are related to hospitalizations, injuries, and death. Little is known about the care needs for people living with dementia in Brazil. This study aims to translate and adapt the Johns Hopkins Dementia Care Needs Assessment (JHDCNA 2.0), a tool design to identify the dementia-related needs of people with dementia and their caregivers, to Brazilian Portuguese, and to verify psychometric properties. METHOD: JHDCNA 2.0 underwent a translation, back-translation, and cultural adaptation. Preliminary psychometric testing of the Brazilian version (JHDCNA-Br 2.0) included pilot testing and experts' assessment, analyses of reliability, evidence based on test content and relations to other variables. We conducted 140 in-home interviews to assess several sociodemographic and health aspects and to be able to complete the JHDCNA-Br 2.0. RESULTS: The JHDCNA-Br 2.0 is reliable and has evidence based on test content and on relations to other variables for people living with dementia and caregivers. Preliminary results suggest high prevalence of unmet needs. CONCLUSION: JHDCNA-Br 2.0 is a reliable and valid tool. The availability of this tool brings new opportunities to the study of dementia care, taking into consideration cultural aspects and may help inform future approaches to dementia care delivery to support persons and families affected by these conditions.

Social Isolation, Loneliness, and Cognitive Performance in Older Adults: Evidence From the ELSI-Brazil Study.

BACKGROUND: The association between social isolation and cognitive performance has been less investigated in low-to-middle-income countries (LMIC) and the presence of depression as a moderator on this association has not been examined. The authors examined the associations of social isolation and perceived loneliness with cognitive performance in the Brazilian Longitudinal Study of Aging. METHODS: In this cross-sectional analysis, social isolation was evaluated by a composite score including marital status, social contact, and social support. The dependent variable was global cognitive performance, which considered memory, verbal fluency, and temporal orientation tests. Linear and logistic regressions were adjusted for sociodemographic and clinical variables. The authors added interaction terms of depressive symptoms with social isolation and loneliness to examine whether depression, measured through the Center for Epidemiologic Studies-Depression Scale, modified these associations. RESULTS: Among 6,986 participants (mean age = 62.1 ± 9.2 years), higher levels of social connections were associated with better global cognitive performance (B = 0.02, 95%CI: 0.02; 0.04). Perceived loneliness was associated with worse cognition (B = -0.26, 95%CI = -0.34; -0.18). Interactions of depressive symptoms with social connections scores were found on memory z-score and with loneliness on global and memory z-scores, suggesting a weaker association between social isolation or loneliness and cognition among those with depressive symptoms. CONCLUSION: In a large sample from an LMIC, social isolation and loneliness were associated with worse cognitive performance. Surprisingly, depressive symptoms decrease the strength of these associations. Future longitudinal studies are important to assess the direction of the association between social isolation and cognitive performance.

Subjective memory complaints: Prevalence, associated factors and sex differences in the ELSI-Brazil study.

BACKGROUND: Subjective memory complaints (SMCs) are a possible prodrome of cognitive decline but are understudied in low- and middle-income countries (LMIC). We aimed to estimate the prevalence of SMCs in a large, nationally representative sample of older adults from Brazil and to identify sociodemographic and health-related factors that are associated with SMCs independently of objective memory. METHODS: Baseline data (n = 7831) from the ELSI-Brazil study, a national representative sample of adults aged 50 and over. They were asked to rate their memory and then divided into two groups - having or not having SMCs. Logistic regression models were used to estimate the association of demographic characteristics, health related factors, objective memory performance and disability in basic (b-ADL), instrumental (i-ADL), and advanced (a-ADL) activities of daily living associated with SMCs. Whether sex was an effect modifier of the association between age and objective memory performance and SMCs was also tested. RESULTS: Of the sample, 42% (95% CI; 39.9-43.9) had SMCs, and it was higher among women (46.9%) than men (35.9%). SMC prevalence decreased with age among women and increased among men, and for both it decreased with better cognitive performance. Fully adjusted logistic regression model showed that older age, higher education, higher b-ADL scores, and better cognitive performance were associated with decreased SMCs, while being female, with higher number of chronic conditions, higher i-ADL scores, worst self-rated health, and an increased number of depressive symptoms were associated with increased SMCs. However, the interaction test (p < 0.001) confirmed that increased age was associated with decreased SMCs only among women, and that better objective memory performance was associated with decreased SMCs only among men. CONCLUSIONS: SMCs are common in the Brazilian older population and are associated with health and sociodemographic factors, with different patterns between men and women. There is a need for future studies looking at the cognitive trajectory and dementia risk in older adults with subjective cognitive complaints.

Association between carotid intima-media thickness and cognitive decline differs by race.

INTRODUCTION: Common carotid intima-media thickness (cIMT) is a marker of subclinical atherosclerosis and is associated with cognitive decline. Although carotid atherosclerosis is more frequent in White than in Black participants, little is known whether race modifies the association between cIMT and cognitive decline. METHODS: In this longitudinal analysis of the ELSA-Brasil, we assessed cIMT using ultrasound and cognitive performance using different domain tests. We used linear mixed models, interaction analysis, and race stratified analyses. RESULTS: Baseline high IMT values were associated with memory (p < 0.001), verbal fluency (p < 0.001), TMT-B (p < 0.001)), and global cognitive decline (p < 0.001). Race was an effect modifier in the association between IMT and global cognitive decline (0.043), with stronger association in White (p < 0.001) than in Black (p = 0.009) participants. DISCUSSION: Baseline IMT was associated with global and domain-specific cognitive decline and race modified this relationship, with stronger associations in White participants. HIGHLIGHTS: Carotid intima-media thickness (cIMT) was associated with cognitive decline. cIMT and cognitive decline association was stronger in White than in Black participants. We used inverse probability weighting to address attrition bias.

Dissipating the fog: Cognitive trajectories and risk factors 1 year after COVID-19 hospitalization.

INTRODUCTION: Cognitive impairment is common after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. However, associations between post-hospital discharge risk factors and cognitive trajectories have not been explored. METHODS: A total of 1105 adults (mean age ± SD 64.9 ± 9.9 years, 44% women, 63% White) with severe coronavirus disease 2019 (COVID-19) were evaluated for cognitive function 1 year after hospital discharge. Scores from cognitive tests were harmonized, and clusters of cognitive impairment were defined using sequential analysis. RESULTS: Three groups of cognitive trajectories were observed during the follow-up: no cognitive impairment, initial short-term cognitive impairment, and long-term cognitive impairment. Predictors of cognitive decline after COVID-19 were older age (ß = -0.013, 95% CI = -0.023;-0.003), female sex (ß = -0.230, 95% CI = -0.413;-0.047), previous dementia diagnosis or substantial memory complaints (ß = -0.606, 95% CI = -0.877;-0.335), frailty before hospitalization (ß = -0.191, 95% CI = -0.264;-0.119), higher platelet count (ß = -0.101, 95% CI = -0.185;-0.018), and delirium (ß = -0.483, 95% CI = -0.724;-0.244). Post-discharge predictors included hospital readmissions and frailty. DISCUSSION: Cognitive impairment was common and the patterns of cognitive trajectories depended on sociodemographic, in-hospital, and post-hospitalization predictors. HIGHLIGHTS: Cognitive impairment after coronavirus disease 2019 (COVID-19) hospital discharge was associated with higher age, less education, delirium during hospitalization, a higher number of hospitalizations post discharge, and frailty before and after hospitalization. Frequent cognitive evaluations for 12-month post-COVID-19 hospitalization showed three possible cognitive trajectories: no cognitive impairment, initial short-term impairment, and long-term impairment. This study highlights the importance of frequent cognitive testing to determine patterns of COVID-19 cognitive impairment, given the high frequency of incident cognitive impairment 1 year after hospitalization.

Education, but not occupation, is associated with cognitive impairment: The role of cognitive reserve in a sample from a low-to-middle-income country.

INTRODUCTION: Education, and less frequently occupation, has been associated with lower dementia risk in studies from high-income countries. We aimed to investigate the association of cognitive impairment with education and occupation in a low-middle-income country sample. METHODS: In this cross-sectional study, cognitive function was assessed by the Clinical Dementia Rating sum of boxes (CDR-SOB). We investigated the association of occupation complexity and education with CDR-SOB using adjusted linear regression models for age, sex, and neuropathological lesions. RESULTS: In 1023 participants, 77% had < 5 years of education, and 56% unskilled occupations. Compared to the group without education, those with formal education had lower CDR-SOB (1-4 years: ß $\beta \;$ = -0.99, 95% confidence interval [CI] = -1.85; -0.14, P = .02; ≥5 years: ß $\beta \;$ = -1.42, 95% CI = -2.47; -0.38, P = .008). Occupation complexity and demands were unrelated to cognition. DISCUSSION: Education, but not occupation, was related to better cognitive abilities independent of the presence of neuropathological insults.

Early life socioeconomic status predicts cognition regardless of education level.

BACKGROUND AND PURPOSE: Early life socioeconomic status (SES) may impact cognitive performance later in life. We investigated the effect on cognitive performance of early life SES, education, and late life SES in the Brazilian Longitudinal Study of Adult Health. METHODS: Path analysis was used to decompose associations between SES measures across the lifespan and cognition. The model included direct paths to cognition from early life SES, education, and late life SES, and indirect paths from early life passing through education and late life SES. We investigated whether the effects of early life SES are similar across middle-aged and older adults. RESULTS: In 13,395 adults, the mean age was 51.5 (8.9) years, 54% were female, 53% were white, and 56% had at least college education. The direct path from early life SES remained significant in the presence of mediation paths through education, late life SES, or both, contributing to cognitive performance in both middle-aged and older adults. The indirect and total effect of early life SES was smaller for middle-aged compared to older adults. Early life SES continues to impact cognitive performance later in life independently of educational attainment and late life SES. The higher percent of mediation through education suggests that education may improve later life cognition even in the presence of low early life SES. CONCLUSIONS: Our results highlight the importance of public health initiatives to improve early life SES and education to foster cognitive aging in low- and middle-income countries.

Normative Data for the ELSA-Brasil Neuropsychological Assessment and Operationalized Criterion for Cognitive Impairment for Middle-Aged and Older Adults.

OBJECTIVES: Normative data should consider sociodemographic diversity for the accurate diagnosis of cognitive impairment. This study aims to provide normative data for a brief neuropsychological battery and present diagnostic criteria for cognitive impairment that could be used in primary care settings. METHODS: We selected 9618 Brazilian middle-aged and older adults after detailed exclusion criteria to avoid subtle cognitive impairment. We analyzed age, sex, and education influence on cognitive performance. To verify the evidence of criterion validity, we compared the cognitive performance of subjects with and without a depressive episode. Additionally, we verified the percentage of spurious scores under three different cutoffs. RESULTS: Age and education had the greatest impact on cognition. Normative scores were provided according to age and education groups. Participants with a depressive episode performed poorer than control subjects. The clinical cutoff of at least two scores below the 7th percentile revealed the adequate percentage of spurious and possible clinical performance. CONCLUSIONS: The Longitudinal Study on Adult Health (ELSA-Brasil) provided normative data based on a unique selected set of cognitively normal subjects. Normative groups were selected based on age and education, and the battery was sensitive to the presence of a depressive episode. We suggested clinical cutoffs for the tests in this battery that could be used in primary care settings to improve the accurate diagnosis of cognitive impairment.

Predictors of Episodic Memory Performance Across Educational Strata: Multiple-Group Comparisons.

OBJECTIVES: Low educational attainment is a risk factor for more rapid cognitive aging, but there is substantial variability in cognitive trajectories within educational groups. The aim of this study was to determine the factors that confer resilience to memory decline within educational strata. METHODS: We selected 2573 initially nondemented White, African American, and Hispanic participants from the longitudinal community-based Washington Heights/Inwood Columbia Aging Project who had at least two visits. We estimated initial memory (intercept) and the rate of memory decline (slope) using up to five occasions of measurement. We classified groups according to the educational attainment groups as low (≤5 years), medium (6-11 years), and high (≥12 years). We used a multiple-group latent growth model to identify the baseline predictors of initial memory performance and rate of memory decline across groups. The model specification considered the influence of demographic, socioeconomic, biomedical, and cognitive variables on the intercept and the slope of memory trajectory. RESULTS: Our results indicated that the three educational groups do not benefit from the same factors. When allowed to differ across groups, the predictors were related to cognitive outcomes in the highly educated group, but we found no unique predictor of cognition for the low educated older adults. CONCLUSIONS: These findings highlight that memory-protective factors may differ across older adults with distinct educational backgrounds, and the need to evaluate a broader range of potential resilience factors for older adults with few years of school.

Evaluating the Stroop Test With Older Adults: Construct Validity, Short Term Test-Retest Reliability, and Sensitivity to Mental Fatigue.

We conducted two studies to evaluate the construct validity, short term test-retest reliability, and sensitivity to mental fatigue of the Stroop task when used with older adults. In Study 1, 40 participants visited our lab on two separate days. On the first visit, they took five screening scales, and we measured their height and body mass. On the second visit, they completed the Stroop task twice with a 30-minute interval between assessments. In Study 2, 15 different participants took a 30-minute Flanker/Reverse Flanker task during the interval between the two administrations of the Stroop tasks and they gave subjective ratings of their mental fatigue on the Visual Analogue Scale (VAS) prior to taking either of the Stroop tasks. In Study 1, participants showed a ceiling effect on the Stroop accuracy measure, there was strong concurrent validity for the Stroop with significant score differences between the Stroop's congruent and incongruent conditions (p < .001), and there was excellent response time reliability (ICC = 0.926) on day two when participants took the Stroop twice within a 30-minute inter-test interval. However, there were significant test-retest performance differences with respect to cognitive inhibition (p < .001). In Study 2, mental fatigue from the Flanker/Reverse Flanker test resulted in a significantly worse second Stroop performance (p = .045). We concluded that the Stroop task demonstrated strong concurrent validity and response time reliability among older adults, but it showed sensitivity to mental fatigue, and repeated administrations within the short 30-minute test-retest interval revealed that the most important Stroop measure (cognitive inhibition) was unreliable. We discuss the implications of these findings.

Rural-urban disparities in fruit and vegetable consumption and cognitive performance in Brazil.

OBJECTIVES: Rural residents are exposed to many risk factors for poor diet quality, such as low socioeconomic status and food insecurity. However, the differences between urban and rural residents regarding the association of fruit and vegetable consumption with cognitive performance have not been explored. The aim of this study was to investigate the association of fruit and vegetable consumption with cognitive performance in urban and rural areas in a nationally representative sample of Brazilian older adults. METHODS: The sample included 9,412 adults aged 50 years or older from the Brazilian Longitudinal Study of Aging (Estudo Longitudinal da Saúde dos Idosos Brasileiros [ELSI]). The association between consumption of fruits and vegetables and cognitive performance was evaluated using linear regression. RESULTS: In 8,158 participants (mean age 61.6 ± 9.3 years, 54% women, 44% White, and 15% from rural areas), the mean frequency of fruit and vegetable consumption was 2.0 ± 1.3 times a day. Higher intake of fruits and vegetables was associated with better memory (ß = 0.031, 95%CI 0.014-0.049), verbal fluency (ß = 0.030, 95%CI 0.004-0.056), and global cognition (ß = 0.035, 95%CI 0.015-0.055) performance in urban, but not rural residents (p for interaction = 0.036). CONCLUSIONS: Higher frequency of fruit and vegetable intake was associated with better cognitive performance in urban, but not in rural areas in Brazil.

Education and cognitive function among older adults in Brazil and Mexico.

Education is protective against cognitive impairment. We used nationally representative data from Mexico and Brazil to assess the association between education and cognitive function. The sample included adults ≥ 50 years from the Brazilian Longitudinal Study of Aging (ELSI) and the Mexican Health and Aging Study (MHAS). Participants were classified as cognitively impaired or not impaired. We used logistic regression models to estimate the association between education and cognitive function. Education level was higher in MHAS than in ELSI. Participants with at least 1 year of education were less likely to have cognitive impairment than those with no formal education in both cohorts. Men in ELSI had higher odds for cognitive impairment compared to men in MHAS. In both cohorts, higher educational level was associated with lower odds of cognitive impairment compared to no formal education. Sex was an effect modifier in MHAS but not in ELSI. HIGHLIGHTS: Cognitive test batteries were harmonized using a regression-based approach.Even very low levels of education were associated with reduced odds of cognitive impairment compared to no formal education.Brazilians were more likely to have cognitive impairment than Mexicans given the same education level.The differences in the association of education with cognition between Brazil and Mexico were only observed among men.

Prevalence of Dementia and Cognitive Impairment No Dementia in a Large and Diverse Nationally Representative Sample: The ELSI-Brazil Study.

BACKGROUND: Approximately 77% of older adults with dementia in Brazil have not been diagnosed, indicating a major public health issue. Previous epidemiological dementia studies in Brazil were based on data from 1 geopolitical region. METHODS: We aimed to estimate the general and subgroup-specific (age, education, and sex) prevalence of dementia and cognitive impairment no dementia (CIND) classification using data from 5 249 participants aged 60 years and older from the ELSI-Brazil, a large nationally representative sample. Participants were classified as having normal cognitive function, CIND, or dementia based on a combination of the individual's cognitive and functional status. RESULTS: We found a general prevalence of 5.8% (95% CI = 4.7-7.2) for dementia and 8.1% (95% CI = 6.8-9.5) for CIND. Dementia prevalence ranged from 3.2% (60-64 years old) to 42.8% (≥90 years old) by age, and from 2.1% (college level or higher) to 16.5% (illiterates) by education. Females had a higher dementia prevalence (6.8%) than males (4.6%). CIND prevalence was similar across age, sex, and education. CONCLUSIONS: The estimated dementia prevalence is lower than that in previous Brazilian epidemiological studies, but is in line with other Latin American studies. Only 1.2% of the ELSI-Brazil participants reported having a previous diagnosis of dementia, revealing that underdiagnosis is rampant and a common reality. Based on our results and national statistics projections, we estimate that in 2019, there were 1 757 480 people aged 60 years and older living with dementia in Brazil and, at least, another 2 271 314 having to deal with some form of cognitive impairment.

The (in)visible Brazilians: A perspective review on the need for brain health and dementia research with Brazilian immigrants in the United States.

Introduction: The Brazilian population in the United States (U.S.), a Latinx subgroup, is rapidly growing and aging but remains underrepresented in U.S. health research. In addition to group-specific genetic and environmental risks, Brazilian immigrants and their offspring in the U.S. likely have cumulative risks for health inequities.It is estimated that 71% of Brazilian immigrants in the U.S. are undocumented, which may limit healthcare access/utilization. Furthermore, mental health is reported as a health priority by Brazilian immigrants in the U.S., and there is a lack of research on Alzheimer's disease and related dementia (AD/ADRD) in this population. Methods: We reviewed the scientific literature using traditional (e.g., PubMed) sources and databases generated by U.S. and Brazilian governments, as well as international organizations, and press articles. Results: This perspective review lists recommendations for researchers, health providers, and policymakers to promote greater inclusion of U.S. Brazilian populations in health research and care. The review identifies research areas in need of attention to address health inequities and promote mental/brain health in Brazilian immigrants and their offspring living in the U.S. These research areas are: 1) epidemiological studies to map the prevalence and incidence of mental/brain health conditions; 2) research on aging and AD/ADRD risk factors among Brazilian populations in the U.S.; and 3) the need for greater representation of U.S-residing Brazilian population in other relevant research areas involving genetics, neuropathology, and clinical trials. Conclusions: The recommendation and research efforts proposed should help to pave the way for the development of community-engagement research and to promote mental/brain health education, improvement of mental/brain health and AD/ADRD services, and the development of culturally-informed intervention to the U.S.-residing Brazilian communities. HIGHLIGHTS: The Brazilian population in the United States is growing but is underrepresented in U.S. health research.Approximately 71% of Brazilian immigrants in the United States are undocumented, with an increased risk for health inequities.Mental health is reported as a central health priority by Brazilian immigrants in the United States.There is a lack of research on Alzheimer's disease and other dementias (ADRD) in Brazilian immigrants in the United States.Epidemiological research is needed to map the prevalence/incidence of mental health conditions and ADRD risk factors among Brazilian immigrants in the United States.

Predictors of Incident Mild Cognitive Impairment and Its Course in a Diverse Community-Based Population.

BACKGROUND AND OBJECTIVES: To investigate sociodemographic and medical predictors of incident mild cognitive impairment (MCI) and subsequent course of MCI at follow-up, including sustained MCI diagnosis, classification as cognitively normal, and progression to dementia. METHODS: Within a community-based cohort, diagnoses of MCI were made with a published algorithm. Diagnosis of dementia was based on clinical consensus. Cox regressions estimated hazard ratios of incident MCI associated with several predictors. Modified Poisson regressions estimated relative risks associated with predictors of diagnostic status at follow-up after incidence. RESULTS: Among 2,903 cognitively normal participants at baseline, 752 developed MCI over an average of 6.3 (SD 4.5) years (incidence rate 56 per 1,000 person-years). Presence of APOE ε4 and higher medical burden increased risk of incident MCI, while more years of education, more leisure activities, and higher income decreased this risk. Of the incident MCI cases, after an average of 2.4 years of follow-up, 12.9% progressed to dementia, 9.6% declined in functioning and did not meet the algorithmic criteria for MCI but did not meet the clinical criteria for dementia, 29.6% continued to meet MCI criteria, and 47.9% no longer met MCI criteria. Multidomain MCI, presence of APOE ε4, depressive symptoms, and antidepressant use increased the risk of progression to dementia. DISCUSSION: This community-based study showed that almost half of the individuals with incident MCI diagnoses were classified as cognitively normal at follow-up. Predictors of incident MCI demonstrably differed from those of subsequent MCI course; these findings can refine expectations for cognitive and functional course of those presenting with MCI.

Validating intrinsic capacity to measure healthy aging in an upper middle-income country: Findings from the ELSI-Brazil.

Background: While efforts have been made to validate intrinsic capacity (IC) as a multidimensional indicator of healthy aging in high-income countries, we still need evidence from lower-income countries. We examined associations of IC with wide ranges of activities of daily living in a nationally representative sample of Brazilians aged≥50 years. Methods: This cross-sectional analysis included 7175 participants from the Brazilian Longitudinal Study of Aging. IC domains (cognitive, psychological, sensory, locomotor, and vitality) were determined using self-reported and physical performance measures. IC was operationalized through factorial analysis. We investigated associations of IC and its domains with functional ability in basic, instrumental, and advanced activities of daily living (ADL, IADL, and AADL) using logistic regressions adjusted for sociodemographic, clinical, and modifiable risk factors. Findings: The IC bi-factorial model revealed satisfactory goodness-of-fit. Preserved ability in ADL and IADL, respectively, ranged from 69% and 29% to 89% and 74% across IC quartiles. In adjusted analyses, every standard deviation increment in IC composite score was associated with almost twice the odds of preserved ADL (OR=1·72; 95%CI=1·54-1·93), preserved IADL (OR=1·95; 95%CI=1·77-2·16), and high performance in AADL (OR=1·79; 95%CI=1·59-2·00). Similar results were reported using the IC domains as predictors. Although age, race/ethnicity, and education did not modify associations of IC with functional ability, we found sex differences with stronger relationships of IC with preserved ADL or IADL in females. Interpretation: Our results support IC validity and reliability to measure healthy aging in diverse socioeconomic and cultural settings. Incorporating IC in routine practices can promote holistic and person-centered care approaches in aging societies. Funding: The Brazilian Ministry of Health and Ministry of Science, Technology, Innovation, and Communication.

Retest effects in a diverse sample: sociodemographic predictors and possible correction approaches.

Repeated cognitive assessment in longitudinal studies favors the occurrence of retest effects, usually increasing the scores obtained at the follow-up assessments when compared to baseline. Therefore, retest effects can compromise the evaluation of cognitive decline in older adults. Objectives: We aimed to verify the occurrence of the retest effect and the impact of sociodemographic characteristics on the follow-up scores in a sample of 5,592 participants with a diverse sociodemographic profile, who were assessed twice during 4 years of follow-up. Methods: We tested two possible approaches to correct the retest effect and calculated the Reliable Change Index. Results: We observed increased scores at the follow-up assessment after 4 years, but the results indicate a modest occurrence of retest effects. The regression difference correction successfully generated follow-up corrected scores, while the mean difference did not provide effective corrections. Sociodemographic characteristics had a minor impact on the retest. Conclusions: We recommend the regression difference correction for retest effects. The absence of this methodological approach might lead to biased results using longitudinal cognitive scores.

Avaliações cognitivas repetidas em estudos longitudinais favorecem a ocorrência de efeitos de retestagem ou de prática, geralmente aumentando os escores obtidos nas avaliações de acompanhamento quando comparados aos da primeira avaliação. Sendo assim, os efeitos do retestagem podem comprometer a verificação do declínio cognitivo em idosos. Objetivos: Objetivamos verificar a ocorrência do efeito de prática e o impacto das características sociodemográficas nos escores de seguimento em uma amostra de 5.592 participantes com perfil sociodemográfico diverso, avaliada duas vezes durante quatro anos de seguimento. Métodos: Testamos duas abordagens possíveis para corrigir o efeito de prática e calculamos o índice de mudança confiável. Resultados: Observamos escores sutilmente maiores na avaliação de seguimento após quatro anos, o que sugere a ocorrência de efeitos de retestagem. A correção pela diferença da regressão gerou escores corrigidos de acompanhamento satisfatórios, enquanto a correção pela diferença média não forneceu correções eficazes. As características sociodemográficas tiveram impacto mínimo no efeito de prática. Conclusões: Recomendamos a forma de correção pela diferença da regressão para efeitos de retestagem. A ausência dessa abordagem metodológica, quando utilizamos escores cognitivos longitudinais, pode levar a resultados enviesados.

Cross-national harmonization of cognitive measures across HRS HCAP (USA) and LASI-DAD (India).

BACKGROUND: As global populations age, cross-national comparisons of cognitive health and dementia risk are increasingly valuable. It remains unclear, however, whether country-level differences in cognitive function are attributable to population differences or bias due to incommensurate measurement. To demonstrate an effective method for cross-national comparison studies, we aimed to statistically harmonize measures of episodic memory and language function across two population-based cohorts of older adults in the United States (HRS HCAP) and India (LASI-DAD). METHODS: Data for 3,496 HRS HCAP (≥65 years) and 3,152 LASI-DAD (≥60 years) participants were statistically harmonized for episodic memory and language performance using confirmatory factor analysis (CFA) methods. Episodic memory and language factor variables were investigated for differential item functioning (DIF) and precision. RESULTS: CFA models estimating episodic memory and language domains based on a priori adjudication of comparable items fit the data well. DIF analyses revealed that four out of ten episodic memory items and five out of twelve language items measured the underlying construct comparably across samples. DIF-modified episodic memory and language factor scores showed comparable patterns of precision across the range of the latent trait for each sample. CONCLUSIONS: Harmonization of cognitive measures will facilitate future investigation of cross-national differences in cognitive performance and differential effects of risk factors, policies, and treatments, reducing study-level measurement and administrative influences. As international aging studies become more widely available, advanced statistical methods such as those described in this study will become increasingly central to making universal generalizations and drawing valid conclusions about cognitive aging of the global population.

Subtle Thyroid Dysfunction Is Not Associated with Cognitive Decline: Results from the ELSA-Brasil.

BACKGROUND: Subtle thyroid alterations have a controversial role in cognition. OBJECTIVE: We investigated the longitudinal association of baseline thyroid function, thyrotropin (TSH), and thyroxine (FT4) levels with cognitive performance after 4 years of follow-up in middle-aged and older adults without overt thyroid dysfunction. METHODS: We included 4,473 individuals, age≥55 years at the second study wave, without overt thyroid dysfunction at baseline. Individuals were divided according to thyroid function and TSH and FT4 tertiles. Cognition was assessed at baseline and after 4 years of follow-up by the word recall (DWR), semantic verbal fluency (SVF), and trail making (TMT) tests. The longitudinal association of thyroid function and TSH and FT4 tertiles with cognitive performance was investigated using generalized estimating equations adjusted for sociodemographic characteristics, lifestyle, cardiovascular risk factors and depression. RESULTS: There was no longitudinal association of thyroid function and TSH and FT4 baseline levels with performance on the cognitive tests. However, there was a baseline cross-sectional U-shaped association of FT4 tertiles with poorer performance in the SVF (first FT4 tertile: ß= -0.11, 95% CI = -0.17; -0.04; third FT4 tertile: ß= -0.10, 95% CI = -0.17; -0.04) and of the third FT4 tertile with poorer performance in the DWR (ß= -0.09, 95% CI = -0.16; -0.02). CONCLUSION: Thyroid function and hormone levels were not associated with cognitive decline during 4 years of follow-up in middle-aged and older adults without overt thyroid dysfunction. Future studies with longer follow-up could clarify the implications of subtle thyroid alterations in cognition.