Incidence of dementia in elderly Latin Americans: Results of the Maracaibo Aging Study

Association of longitudinal changes in 24-h blood pressure level and variability with cognitive decline

OBJECTIVE

A high office blood pressure (BP) is associated with cognitive decline. However, evidence of 24-h ambulatory BP monitoring is limited, and no studies have investigated whether longitudinal changes in 24-h BP are associated with cognitive decline. We aimed to test whether higher longitudinal changes in 24-h ambulatory BP measurements are associated with cognitive decline.

METHODS

We included 437 dementia-free participants from the Maracaibo Aging Study with prospective data on 24-h ambulatory BP monitoring and cognitive function, which was assessed using the selective reminding test (SRT) and the Mini-Mental State Examination (MMSE). Using multivariate linear mixed regression models, we analyzed the association between longitudinal changes in measures of 24-h ambulatory BP levels and variability with cognitive decline.

RESULTS

Over a median follow-up of 4 years (interquartile range, 2-5 years), longitudinal changes in 24-h BP level were not associated with cognitive function (P ≥ 0.09). Higher longitudinal changes in 24-h and daytime BP variability were related to a decline in SRT-delayed recall score; the adjusted scores lowered from -0.10 points [95% confidence interval (CI), -0.16 to -0.04) to -0.07 points (95% CI, -0.13 to -0.02). We observed that a higher nighttime BP variability during follow-up was associated with a decline in the MMSE score (adjusted score lowered from -0.08 to -0.06 points).

CONCLUSION

Higher 24-h BP variability, but not BP level, was associated with cognitive decline. Prior to or in the early stages of cognitive decline, 24-h ambulatory BP monitoring might guide strategies to reduce the risk of major dementia-related disorders including Alzheimer's disease.

Impact of Dementia in Colorectal Cancer Patients: United States Population-Based Cohort Study

Background/Aims

Various socioeconomic and racial disparities are well-documented for colon cancer. However, the association of dementia, which is a growing cause of mortality in the elderly, remains unexplored. We aim to understand the association between these two conditions, in the elderly population group.

Methods

We utilized the 2020 National Inpatient Sample to investigate records admitted for colorectal cancer identified through ICD-10 CM codes. We divided records by the presence of dementia. Adjusted odds ratios (aORs) for predefined outcomes were determined using multivariable logistic and linear regression models, adjusting for comorbidities. The primary outcome assessed was inpatient mortality, while secondary outcomes include other inpatient complications.

Results

We identified 33,335 hospitalizations with ages more than 60. The mean age was 75.2 and males constituted 50.4%. In a survey multivariable logistic and linear regression model adjusting for patient and hospital factors, utilizing propensity score matching, the presence of dementia is associated with lower inpatient mortality (aOR 0.49, 95% confidence interval [CI] [0.26, 0.92], p=0.03), lower hospitalization costs (beta coefficient -2,823, 95% CI [-5,266, -440], p=0.02), lower odds of acute respiratory failure (aOR 0.54, p=0.01), lower mechanical ventilation usage (aOR 0.26, p<0.01) but higher odds of mental status change (aOR 1.97, 95% CI [1.37, 2.84], p<0.01).

Conclusions

The presence of dementia is associated with a lower risk of inpatient mortality, and other clinical outcomes, in colorectal cancer cases admitted for hospitalization. Etiologies behind this relationship should be explored to understand this inverse relationship.

Sex differences in dementia risk and risk factors: Individual-participant data analysis using 21 cohorts across six continents from the COSMIC consortium

INTRODUCTION

Sex differences in dementia risk, and risk factor (RF) associations with dementia, remain uncertain across diverse ethno-regional groups.

METHODS

A total of 29,850 participants (58% women) from 21 cohorts across six continents were included in an individual participant data meta-analysis. Sex-specific hazard ratios (HRs), and women-to-men ratio of hazard ratios (RHRs) for associations between RFs and all-cause dementia were derived from mixed-effect Cox models.

RESULTS

Incident dementia occurred in 2089 (66% women) participants over 4.6 years (median). Women had higher dementia risk (HR, 1.12 [1.02, 1.23]) than men, particularly in low- and lower-middle-income economies. Associations between longer education and former alcohol use with dementia risk (RHR, 1.01 [1.00, 1.03] per year, and 0.55 [0.38, 0.79], respectively) were stronger for men than women; otherwise, there were no discernible sex differences in other RFs.

DISCUSSION

Dementia risk was higher in women than men, with possible variations by country-level income settings, but most RFs appear to work similarly in women and men.

Global incidence of young-onset dementia: A systematic review and meta-analysis

INTRODUCTION

Reliable data on the incidence rates for young-onset dementia (YOD) are lacking, but are necessary for research on disease etiology and to raise awareness among health care professionals.

METHODS

We performed a systematic review and meta-analysis on population-based studies on the incidence of YOD, published between January 1, 1990 and February 1, 2022, according to Meta-analyses of Observational Studies in Epidemiology (MOOSE) guidelines. Data were analyzed using random-effects meta-analyses. Results were age-standardized, and heterogeneity was assessed by subgroup analyses and meta-regression.

RESULTS

Sixty-one articles were included. Global age-standardized incidence rates increased from 0.17/100,000 in age 30 to 34 years, to 5.14/100,000 in age 60 to 64 years, giving a global total age-standardized incidence rate of 11 per 100,000 in age 30 to 64. This corresponds to 370,000 new YOD cases annually worldwide. Heterogeneity was high and meta-regression showed geographic location significantly influenced this heterogeneity.

DISCUSSION

This meta-analysis shows the current best estimate of YOD incidence. New prospective cohort studies are needed.

Consideration of sex and gender in Alzheimer's disease and related disorders from a global perspective

Sex or gender differences in the risk of Alzheimer's disease and related dementias (ADRD) differ by world region, suggesting that there are potentially modifiable risk factors for intervention. However, few epidemiological or clinical ADRD studies examine sex differences; even fewer evaluate gender in the context of ADRD risk. The goals of this perspective are to: (1) provide definitions of gender, biologic sex, and sexual orientation. and the limitations of examining these as binary variables; (2) provide an overview of what is known with regard to sex and gender differences in the risk, prevention, and diagnosis of ADRD; and (3) discuss these sex and gender differences from a global, worldwide perspective. Identifying drivers of sex and gender differences in ADRD throughout the world is a first step in developing interventions unique to each geographical and sociocultural area to reduce these inequities and to ultimately reduce global ADRD risk. HIGHLIGHTS: The burden of dementia is unevenly distributed geographically and by sex and gender. Scientific advances in genetics and biomarkers challenge beliefs that sex is binary. Discrimination against women and sex and gender minority (SGM) populations contributes to cognitive decline. Sociocultural factors lead to gender inequities in Alzheimer's disease and related dementias (ADRD) worldwide.

Prevalence of dementia in Latin America and Caribbean countries: Systematic review and meta-analyses exploring age, sex, rurality, and education as possible determinants

BACKGROUND

Studies have shown that the prevalence of dementia in Latin America and the Caribbean (LAC) may be higher than in high-income countries. Thus, we sought to systematically analyse the prevalence of dementia and explore possible drivers that lead to this disparity in LAC countries.

METHOD

We searched Pubmed, Web of Knowledge, Scopus, Lilacs, and SciELO for studies on dementia in LAC countries published in English, Spanish, and Portuguese. Random-effects model was applied.

RESULTS

Thirty-one studies from 17 LAC countries were included. Pooled prevalence of all-cause dementia was 10.66%. Further analyses with studies providing raw prevalence by sex, area, and educational level showed a higher prevalence for women (8.97%) than for men (7.26%). Also, dementia prevalence was higher for rural than urban residents (7.71% vs 8.68%, respectively). Participants without formal education presented more than double the prevalence of dementia (21.37%) compared to those with at least one year of formal education (9.88%). Studies with more recent data collection showed higher dementia prevalence.

CONCLUSION

Our findings suggest a high global dementia prevalence in LAC countries and an unequal burden of dementia for women, lower-educated, and rural residents. Secular increases in dementia prevalence call for greater public health efforts for preventative actions.

Prevalence of Dementia and Main Subtypes in Mexico: The Study on Aging and Dementia in Mexico (SADEM)

BACKGROUND

Dementia is a priority public health issue due to its high prevalence worldwide and its economic, social, and health impact. However, there are few reports in Mexico based on formal tests and with a clinical approach based on the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5).

OBJECTIVE

This study estimates the prevalence of the main types of dementia among elderly people living in the community in Mexico City.

METHODS

A population-based, two-step study was conducted, including 6,204 elderly individuals aged 60 or above with in-home assessment. All participants were screened for cognitive impairment; those who presented some cognitive problem underwent a standardized neurological examination. Each diagnosis was based on the criteria for dementia in the DSM-5, and the final consensus diagnosis of dementia was determined by an expert panel.

RESULTS

The global estimated prevalence of dementia in the Mexican population was 7.8% met the criteria for Alzheimer's disease, 4.3% for vascular dementia, and 2.1% for mixed dementia. The prevalence of dementia was higher in women than in men (15.3% versus 12.5%, respectively).

CONCLUSION

These results provide evidence to propose strategies for Latin American countries where dementia represents a challenge due to the heterogeneity of the populations and socioeconomic disparities, requiring early diagnosis and at the first levels of care.

Incidence of dementia in a population cohort of older people from São Paulo, Brazil

OBJECTIVES

To estimate the incidence of dementia in a community-dwelling older population from São Paulo city, Brazil.

METHODS/DESIGN

This two-phase prospective cohort study evaluated a representative cluster sample of 1370 individuals aged 60 years old and over from three different socioeconomic levels. The community screening phase consisted of a tested combination of cognitive and functional tests administered among the subjects and informants. In the hospital diagnosis phase, the Cambridge Examination was performed; the diagnosis of dementia and dementia subtypes was made according to DSM IV criteria. Incidence rates were expressed in person-years, multiplied by 1000. The risk of developing dementia was calculated using Cox regression.

RESULTS

Among 1370 eligible subjects, 678 were accessed, and 489 completed the evaluation. Forty-two subjects were diagnosed with dementia. The incidence rate of dementia and Alzheimer's disease (AD) were 11.2 (95% CI: 8.0-15.1) and 8.9 (95% CI: 6.1-12.5) per 1000 person-years, respectively; there were high age-specific rates of dementia among younger individuals. There was a trend of a higher risk of developing AD for women than for men. Multivariate analysis showed that older age, the presence of diabetes and the presence of amnestic MCI increased the risk of developing dementia.

CONCLUSIONS

The age-specific rates in younger individuals were expressively higher than in worldwide studies and supposedly affected by cardiovascular morbidity. The higher risk in women in a younger sample corroborated the interaction between sex and AD. The increased risk of amnestic MCI reinforced its contribution to the progression to dementia and AD.

Incidence of dementia in a Brazilian population: The Tremembé Epidemiologic Study

INTRODUCTION

Few dementia incidence studies have been performed in Latin America. We aimed to provide the incidence of dementia in a Brazilian community-dwelling elderly population.

METHODS

This study was conducted in urban and rural areas of Tremembé. The 520 participants without dementia at baseline were invited to participate in the follow-up.

RESULTS

After a median follow-up of 5 years, the incidence rate of dementia was 26.1 per 1000 person-years (PY) (95% confidence interval  = 18.7-36.6/1000PY). This rate increased exponentially with age (8.3/1000PY for 60- to 64-year-olds to 110.2/1000PY for ≥80-year-olds) and lower education (10.5/1000PY for > 8 years of education to 59.2/1000PY for illiterates). Higher dementia risk was found among individuals with cognitive impairment no dementia at baseline.

DISCUSSION

The dementia incidence rate found was higher than in other countries in people under 65 years. Higher incidence in younger individuals is expected in developing countries probably due to low education and a high burden of cardiovascular diseases.

Prevalence and incidence of possible vascular dementia among Mexican older adults: Analysis of the Mexican Health and Aging Study

Introduction

Vascular dementia is the second most common cause of dementia. Physical disability and cognitive impairment due to stroke are conditions that considerably affect quality of life. We estimated the prevalence and incidence of possible vascular dementia (PVD) in older adults using data from the Mexican Health and Aging Study (MHAS 2012 and 2015 waves).

Methods

The MHAS is a representative longitudinal cohort study of Mexican adults aged ≥50 years. Data from 14, 893 participants from the 2012 cohort and 14,154 from the 2015 cohort were analyzed to estimate the prevalence and incidence of PVD. Self-respondents with history of stroke were classified as PVD if scores in two or more cognitive domains in the Cross-Cultural Cognitive Examination were ≥ 1.5 standard deviations below the mean on reference norms and if limitations in ≥ 1 instrumental activities of daily living were present. For proxy respondents with history of stroke, we used a score ≥3.4 on the Informant Questionnaire on Cognitive Decline in the Elderly. Crude and standardized rates of prevalent and incident PVD were estimated.

Results

Prevalence of PVD was 0.6% (95% CI, 0.5–0.8) (0.5 with age and sex- standardization). Rates increased with age reaching 2.0% among those aged 80 and older and decreased with educational attainment. After 3.0 years of follow-up, 87 new cases of PVD represented an overall incident rate of 2.2 (95% CI, 1.7–2.6) per 1,000 person-years (2.0 with age and sex- standardization). Incidence also increased with advancing age reaching an overall rate of 9.4 (95% CI, 6.3–13.6) per 1,000 person-years for participants aged >80 years. Hypertension and depressive symptoms were strong predictors of incident PVD.

Conclusion

These data provide new estimates of PVD prevalence and incidence in the Mexican population. We found that PVD incidence increased with age. Males aged 80 years or older showed a greater incidence rate when compared to females, which is comparable to previous estimates from other studies.

Caregiving for Patients With Frontotemporal Dementia in Latin America

Latin America is a vast heterogeneous territory where chronic diseases such as mild cognitive impairment or dementia are becoming higher. Frontotemporal dementia (FTD) prevalence in this region is estimated to be around 12-18 cases per thousand persons. However, this prevalence is underestimated given the lack of awareness of FTD even among healthcare professionals. Family members are responsible for the care of patients with FTD at home. These caregivers deliver care despite being ill-equipped and living in the context of austerity policies and social inequities. They often face unsurmountable financial and social burdens that are specific to the region. The most important step to support caregivers in Latin America is to increase awareness of the disease at all levels. Healthcare diplomacy is fundamental to create joint efforts that push policies forward to protect caregivers of FTD patients.

Research on aging during the Venezuelan humanitarian crisis: the experience of the Maracaibo aging study

BACKGROUND

Venezuela is in the throes of a complex humanitarian crisis that is one of the worst in decades to impact any country outside of wartime. This case analysis describes the challenges faced by the ongoing Maracaibo Aging Study (MAS) during the deteriorating conditions in Venezuela. When the MAS began in 1997, it focused on memory-related disorders. Since then, strategic planning and proactive community participation allowed us to anticipate and address logistical, funding, and ethical challenges, and facilitated the enrollment and retention of more than 2500 subjects over 55 years of age. All participants, who are residents of the city of Maracaibo, Venezuela, underwent various assessments on several occasions. Here, we discuss how our approach to implementing a longitudinal, population-based study of age-related conditions has allowed our research program to continue throughout this period of political, economic, and social upheaval.

DISCUSSION

As the social context in Venezuela became more complicated, new challenges emerged, and strategies to sustain the study and participation were refined. We identified five main mechanisms through which the evolving humanitarian crisis has affected implementation of the MAS: 1) community dynamics; 2) morale of researchers, staff, and participants; 3) financial feasibility; 4) components of the research process; and 5) impact on the health of staff, participants, and their families. Strategies to compensate for the impact on these components were implemented, based on inputs from community members and staff. Improved communication, greater involvement of stakeholders, broadening the scope of the project, and strengthening international collaboration have been the most useful strategies. Particular demands emerged, related to the increased mortality and comorbidities of participants and staff, and deterioration of basic services and safety.

CONCLUSION

Although the MAS has faced numerous obstacles, it has been possible to continue a longitudinal research project throughout the humanitarian crisis, because our research team has engaged the community deeply and developed a sense of mutual commitment, and also because our project has provided funding to help keep researchers employed, somewhat attenuating the brain drain.

Neuropsychiatric Symptoms Among Hispanics: Results of the Maracaibo Aging Study

BACKGROUND

Neuropsychiatric symptoms play an important role in diagnosing and clinical follow-up of cognitive impairment and dementia.

OBJECTIVE

We investigated the relationship between neuropsychiatric symptoms, cognitive impairment, and dementia in Hispanics.

METHODS

We included 529 participants (age ≥40 years) from the Maracaibo Aging Study with standardized neuropsychiatric assessments, including the Neuropsychiatric Inventory (NPI). Based on the Clinical Dementia Rating and the Mini-Mental State Examination scores, participants' cognitive status was categorized into normal cognition, mild/moderate, and severe cognitive impairment. Diagnosis of dementia was established in a consensus conference. Statistical analyses included multivariable logistic regression models and area under the curve (AUC).

RESULTS

The mean age of participants was 59.3 years, and 71.8%were women. The proportion of dementia was 6.8%. Disturbed sleep, anxiety, and depression were the most common neuropsychiatric symptoms in the study sample. In crude analyses, the proportions of hallucinations, aberrant motor behavior, agitation/aggression, apathy, delusions, irritability, eating disturbance, depression, and euphoria were differently distributed among cognitive status groups (p < 0.05). After accounting for confounders, aberrant motor behavior and agitation/aggression remained significantly associated with cognitive impairment and dementia (p < 0.05). The inclusion of the NPI domains significantly improved the AUC to discriminate severe cognitive impairment and dementia compared to a basic model that included sex, age, education, alcohol, obesity, serum glucose, total cholesterol, hypertension, and stroke.

CONCLUSION

Neuropsychiatric symptoms are associated with severe cognitive impairment and dementia. The addition of NPI items to the global cognitive assessment might help early detection of dementia in primary care settings.

Pinocembrin Ameliorates Cognitive Impairment Induced by Vascular Dementia: Contribution of Reelin-dab1 Signaling Pathway

Background

As a substrate of apoER2, Reelin has been verified to exert neuroprotection by preventing memory impairment. Pinocembrin is the most abundant natural flavonoid found in propolis, and it has been used to exert neuroprotection, blood–brain barrier protection, anti-oxidation, and inflammation diminishing, both in vitro and in vivo. However, the roles and molecular mechanisms of pinocembrin in neurobehavioral outcomes and neuronal repair after vascular dementia are still under investigation.

Purpose

To explore the role of pinocembrin in the involvement of the Reelin-dab1 signaling pathway in improving memory impairment, both in cell culture and animals experiments.

Material and Methods

Behavioral tests were conducted on day 48 to confirm the protection of pinocembrin against cognitive impairment. Cell and molecular biology experiments demonstrated that the Reelin-dab1 pathway mediates the underlying mechanism of cognitive improvement by pinocembrin.

Results

It was showed that pinocembrin alleviated learning and memory deficits induced by vascular dementia, by inducing the expression of Reelin, apoER2, and p-dab1 in the hippocampus. The expression of Reelin and p-dab1 was both inhibited following Reelin RNA interference in SH-SY5Y prior to oxygen glucose deprivation (OGD) injury, suggesting that Reelin played a core role in pinocembrin’s effect on OGD in vitro.

Conclusion

Pinocembrin improves the cognition via the Reelin-dab1 signaling pathway.

Systematic Review of the Diagnostic Validity of Brief Cognitive Screenings for Early Dementia Detection in Spanish-Speaking Adults in Latin America

Objectives: The aim of this study was to evaluate the validity of brief cognitive screening (BCS) tools designed to diagnose mild cognitive impairment (MCI) or dementia in Spanish-speaking individuals over the age of 50 years from Latin America (LA).

Methods: A systematic search of titles and abstracts in Medline, Biomed Central, Embase, Scopus, Scirus, PsycINFO, LILACS, and SciELO was conducted. Inclusion criteria were papers written in English or Spanish involving samples from Spanish-speaking Latin American individuals published until 2018. Standard procedures were applied for reviewing the literature. The data related to the study sample, methodology, and procedures applied, as well as the performance obtained with the corresponding BCS, were collected and systematized.

Results: Thirteen of 211 articles met the inclusion criteria. The studies primarily involved memory clinic-based samples, with the exception of two studies from an adult day-care center, one from a primary care clinic, and one from a community-based sample. All the studies originated from five of the 20 countries of LA and all used standardized diagnostic criteria for the diagnosis of dementia and MCI; however, the diagnostic protocols applied differed. Most studies reported samples with an average of 10 years of education and only one reported a sample with an average of <5 years of education. No publication to date has included an illiterate population. Although the Montreal cognitive assessment (MoCA) is the most widely-used BCS tool in LA, it is significantly influenced by education level.

Conclusions: Although evidence is still limited, the findings from studies on LA populations suggest that MoCA requires cultural adaptations and different cutoff points according to education level. Moreover, the diagnostic validity of the INECO frontal screening (IFS) test should be evaluated in populations with a low level of education. Given the heterogeneity that exists in the levels of education in LA, more studies involving illiterate and indigenous populations are required.

Differential Methylation Levels in CpGs of the BIN1 Gene in Individuals With Alzheimer Disease

INTRODUCTION

Late-onset Alzheimer disease (LOAD) is the most common dementia worldwide. APOE-[Latin Small Letter Open E]4 and BIN1 (Bridging Integrator 1) have been implicated in the pathogenesis of this disease, but, although DNA methylation of dinucleotide CpGs in the BIN1 gene influences alterations, it has not been studied in Hispanics.

OBJECTIVE

The objective of this study was to evaluate the BIN1 3' intergenic region DNA methylation patterns in a Colombian sample of LOAD patients.

METHODS

A case-control study was conducted in 50 individuals with LOAD and 50 age-sex matched controls to determine associations of LOAD with DNA methylation. DNA was isolated from peripheral blood, and methylation levels of 8 CpGs were estimated by bisulfite conversion followed by Sanger sequencing with direct PCR analysis. Logistic regression models adjusted by age, sex, and APOE were used to calculate risk associations between methylation levels and LOAD.

RESULTS

Overall, participants with LOAD had significantly lower methylation levels on CpG26 (0.86±0.11 vs. 0.95±0.05; P>0.001), CpG44 (0.84±0.09 vs. 0.94±0.06; P=0.001), and CpG87 (0.64±0.12 vs. 0.82±0.10; P>0.001). Adjusted regression models showed that decreased methylation levels of these CpGs remained as risk factors for LOAD (P<0.05).

CONCLUSIONS

Hypomethylation of CpGs in BIN1 might play an important role in the expression of BIN1 and may be a biomarker for identifying individuals at high risk of developing LOAD.

Cerebrovascular Correlates of Dementia in Community-Dwelling Older Adults Living in Rural Communities - The Three Villages Study. Rationale and Protocol of a Population-Based Prospective Cohort Study

BACKGROUND

Despite the assumption that dementia is increasing in rural areas of Latin America, there is no information on the burden and risk factors leading to dementia in these settings.

AIMS

To assess prevalence and incidence of dementia, and its cerebrovascular correlates in an established cohort of community-dwelling older adults living in rural Ecuador, and to explore the impact of dementia on functional disability and the role of the social determinants of health in the above-mentioned relationships.

DESIGN

Population-based, cohort study with cross-sectional and longitudinal components. Baseline clinical interviews will focus on the assessment of cognitive performance and dementia by means of the clinical dementia rating scale (CDRS). Functional disability and social determinants of health will be correlated with CDRS scores. In addition, participants will undergo interviews and procedures to assess cardiovascular risk factors and signatures of brain damage, cerebral small vessel disease, and other stroke subtypes. The CDRS and the Functional Activities Questionnaire will be administered every year to assess the rate of incident dementia and the severity of functional disability. Neuroimaging studies will be repeated at the end of the study (5 years) to assess the impact of newly appeared cerebral and vascular lesions on cognitive decline.

COMMENT

This study will allow determine whether cerebrovascular diseases are in the path of dementia development in these rural settings. This may prove cost-effective for the development of preventive strategies aimed to control modifiable factors and reduce disability in patients with dementia living in underserved populations.

Nighttime Blood Pressure Interacts with APOE Genotype to Increase the Risk of Incident Dementia of the Alzheimer's Type in Hispanics

BACKGROUND

Dementia of the Alzheimer's type (DAT) impacts Hispanics disproportionately, with almost a twofold elevated risk of developing DAT, as well as earlier onset of the disease, than in non-Hispanic Whites. However, the role of main risk factors for DAT, such as APOE-ɛ4 and blood pressure (BP) levels, remains uncertain among Hispanics.

OBJECTIVE

To investigate the association of APOE-ɛ4 and BP levels, measures with 24-h ambulatory BP monitoring, with incidence of DAT in an elderly cohort of Hispanics.

METHODS

1,320 participants from the Maracaibo Aging Study, free of dementia at the baseline, and with ambulatory BP measurements and APOE genotype available were included. Adjusted Cox proportional models were performed to examine 1) the incidence of DAT and 2) the relationship between BP levels and DAT according to APOE genotypes. Models were adjusted by competing risk of death before the onset of DAT. Model performance was assessed by likelihood test.

RESULTS

The average follow-up time was 5.3 years. DAT incidence was 5.8 per 1000 person-year. APOE-ɛ4 carriers had a higher risk of DAT. In unadjusted analyses, conventional, 24-h, and nighttime systolic BP levels were significantly higher in participants who developed DAT and of APOE-ɛ4 carriers (p < 0.05). After adjustment for competing risks, only higher nighttime systolic BP was associated with DAT incidence, but only among subjects carrying APOE-ɛ4.

CONCLUSION

In this Hispanic population, both APOE-ɛ4 genotype and assessment of nocturnal systolic BP (rather than diurnal or office BP) were necessary to estimate DAT risk.

Cognitive decline is not influenced by the marital status or living arrangements in community-dwelling adults living in a rural setting. A population-based prospective cohort study

Little is known on factors influencing cognitive decline in rural communities. Using the Atahualpa Project cohort, we aimed to assess whether the marital status or living arrangements influenced cognitive decline in community-dwelling adults living in an Ecuadorian rural village. The study included 629 Atahualpa residents aged ≥40 years who had a follow-up Montreal Cognitive Assessment (MoCA) repeated at least one year after baseline. Multivariate longitudinal linear models were fitted to assess differences between the marital status and living arrangements and cognitive decline (as the outcome). A total of 411 participants were married. The remaining 218 were either single, divorced or widowed (191 of them lived with family members and the others lived alone). Enrolled individuals contributed 2088.4 person-years of follow-up (mean: 3.3 ± 1.1 years). The mean baseline MoCA was 22.1 ± 4.5 points and the follow-up MoCA was 20.6 ± 4.8 points (p = 0.001). Overall, 394 (63%) individuals had lower MoCA scores at follow-up. A fully-adjusted longitudinal linear model showed no differences in MoCA decline across married and non-married individuals (β: -0.15; 95% C.I.: -0.55 - 0.26; p = 0.477). When the subset of non-married individuals was taken into account for analyses, multivariate longitudinal linear models showed no differences in the severity of cognitive decline across individuals living alone versus those living with family members (β: 0.28; 95% C.I.: -0.68 - 1.24; p = 0.572). In this study, the marital status or living arrangements had no influence on cognitive decline in the follow-up.

Differential Methylation in APOE (Chr19; Exon Four; from 44,909,188 to 44,909,373/hg38) and Increased Apolipoprotein E Plasma Levels in Subjects with Mild Cognitive Impairment

BACKGROUND

Biomarkers are essential for identification of individuals at high risk of mild cognitive impairment (MCI) for potential prevention of dementia. We investigated DNA methylation in the APOE gene and apolipoprotein E (ApoE) plasma levels as MCI biomarkers in Colombian subjects with MCI and controls.

METHODS

In total, 100 participants were included (71% women; average age, 70 years; range, 43⁻91 years). MCI was diagnosed by neuropsychological testing, medical and social history, activities of daily living, cognitive symptoms and neuroimaging. Using multivariate logistic regression models adjusted by age and gender, we examined the risk association of MCI with plasma ApoE and APOE methylation.

RESULTS

MCI was diagnosed in 41 subjects (average age, 66.5 ± 9.6 years) and compared with 59 controls. Elevated plasma ApoE and APOE methylation of CpGs 165, 190, and 198 were risk factors for MCI (p < 0.05). Higher CpG-227 methylation correlated with lower risk for MCI (p = 0.002). Only CpG-227 was significantly correlated with plasma ApoE levels (correlation coefficient = -0.665; p = 0.008).

CONCLUSION

Differential APOE methylation and increased plasma ApoE levels were correlated with MCI. These epigenetic patterns require confirmation in larger samples but could potentially be used as biomarkers to identify early stages of MCI.

Naomaitai Ameliorated Brain Damage in Rats with Vascular Dementia by PI3K/PDK1/AKT Signaling Pathway

Background/Aims

Naomaitai can improve blood perfusion and ameliorate the damage in the paraventricular white matter. This study was focused on observing the neuroprotective effect of Naomaitai on the vascular dementia of rat and exploring the action mechanism of PI3K/PDK1/AKT signaling pathway.

Methods

A vascular dementia model of rats was established by permanent, bilateral common carotid artery occlusion. Rats' behavior was tested by Neurological deficit score and the Morris water maze. The pathology and apoptosis were detected through HE staining and TUNEL assay. Myelin sheath loss and nerve fiber damage were detected by LFB staining. Inflammatory factors, oxidative stress, and brain damage markers were detected through ELISA. The expression of apoptosis-related proteins and PI3K/PDK1/AKT signaling pathway related proteins were measured by western blot. The expressions of PI3K, PDK1, AKT, and MBP in paraventricular white matter cells were detected by immunofluorescence.

Results

Naomaitai treatment decreased neurological function score in rats with vascular dementia, ameliorated paraventricular white matter damage caused by long-term hypoxia, and hypoperfusion reduced the brain injury markers S-100β and NSE contents, suppressed inflammatory reaction and oxidative stress, reduced IL-1β, IL-6, TNF-α, and MDA contents, and remarkably increased IL-10 and SOD contents. TUNEL and western blot assay showed that Naomaitai treatment decreased neuronal cell apoptosis, increased Bcl-2 expression, and reduced caspase-3 and Bax expression. Furthermore, we found Naomaitai inhibited PI3K and PDK1 expression and activated phosphorylated AKT protein in rats with vascular dementia. However, the protective effect of Naomatai in rats with vascular dementia was inhibited, and expression of PI3K signaling pathway-related proteins was blocked after administration of PI3K inhibitor.

Conclusion

Naomaitai can ameliorate brain damage in rats with vascular dementia, inhibit neuronal apoptosis, and have anti-inflammatory and antioxidative stress effects, which may be regulated by the PI3K/PDK1/AKT signaling pathway.

Reasons for Declining Consent in a Population-Based Cohort Study Conducted in a Rural South American Community

There is limited information on participants' adherence and reasons for declining consent in observational cohort studies conducted in remote rural communities. We aimed at sharing lessons learned during the Atahualpa Project, a population-based cohort study conducted in a rural Ecuadorian village. Atahualpa residents aged ≥40 years identified during door-to-door surveys who signed a consent form were enrolled. Annual surveys were conducted to assess the number of participants who moved out of the village, as well as those who died, declined consent, and newly entered the study. Reasons for declining consent were tabulated. Abstracted data included age, sex, education, disability, time between enrollment and declining consent, and reasons for withdrawal. We also counted participants who, despite expressing their willingness to continue in the study, refused specific procedures. After five years of follow-up, 54 (6.3%) of 863 enrolled individuals declined consent. Increasing age and disability had no impact on declining consent. In contrast, refusal was higher among relatives or neighbors of a given participant declining consent. Most people who declined consent did so after one or two years of enrollment. Less than 20% of enrolled individuals refused certain procedures. "Fear of the needle" was the most frequent reason for refusing blood tests, and common reasons for declining complimentary exams were lack of interest and time constraints. Cohort retention in the Atahualpa Project is high. Main reasons for this adherence include adequate selection of the village, detailed planning of procedures, assurance of sponsorship, and field personnel who continuously engage with study participants. This trial is registered with NCT01627600.

Impaired Cerebral Vasomotor Reactivity in Alzheimer's Disease

Background

Recent studies have shown that cerebral vascularity may be impaired in Alzheimer's disease. Cerebral vasomotor reactivity could be an important biomarker for this pathology.

Aims

The aim of this study was to investigate the alterations in cerebral vascular motor reactivity in Alzheimer's disease subjects and to associate these changes with their cognitive scores.

Methods

We recruited subjects with a diagnosis of Alzheimer's disease and healthy controls. Demographic, clinical, imaging, and cognitive test were obtained. Then all participants performed a cerebral vascular motor reactivity test with 7% CO2 and cerebral blood flow velocities (CBFV) were recorded with transcranial doppler ultrasound before and after the test.

Results

We recruited 45 subjects, 26 (21 female) Alzheimer's disease participants and 19 (15 female) healthy controls. There were no differences in baseline cerebral blood flow velocities between the groups. After the cerebral vasomotor reactivity test, absolute mean difference in mean CBFV (ΔCBFV-m) was 8.70±4.14 versus 4.81±6.96 (p<0.01), respectively. Calculated percentage of change (%CVMR) was lower in the AD group 7.45±18.25 versus 23.29±17.48, and there was a positive but weak correlation with mini-mental scores (ρ=0.337, p=0.023).

Conclusions

In this study, Alzheimer's disease subjects showed significant changes in all absolute cerebral blood flow velocities after the cerebral vasomotor reactivity test with CO2, but only diastolic phase responses were statistically significant. There was a positive but weak correlation between cerebral vasomotor reactivity and cognitive scores. Further studies are needed to investigate these effects in larger Latin-American samples.