Is the risk of developing Alzheimer's disease greater for women than for men?

The utility of remote cognitive screening tools in identifying cognitive impairment in older surgical patients: An observational cohort study

STUDY OBJECTIVES

To determine the prevalence of suspected cognitive impairment using the Centers for Disease Control and Prevention (CDC) cognitive question, Ascertain Dementia Eight-item Questionnaire (AD8), Modified Telephone Interview for Cognitive Status (TICS-M), and Telephone Montreal Cognitive Assessment (T-MoCA), the agreement between each tool beyond chance, and the risk factors associated with a positive screen.

DESIGN

Multicenter prospective study.

SETTING

Remote preoperative assessments.

PATIENTS

307 non-cardiac surgical patients aged ≥65 years.

MEASUREMENTS

Prevalence, Cohen's kappa (κ).

MAIN RESULTS

The T-MoCA detected the highest prevalence of suspected cognitive impairment (28%), followed by the AD8 (17%), CDC cognitive question (9%), and TICS-M (6%). The four screening tools showed poor agreement beyond chance with one another, with the CDC cognitive question and AD8 approaching the threshold for weak agreement (κ = 0.39). Depression was associated with screening positive on the CDC cognitive question (OR: 2.81; 95% CI: 1.04, 7.68). Obstructive sleep apnea (OSA) (OR: 3.10; 95% CI: 1.26, 7.71) and functional disability (OR: 3.74; 95% CI: 1.34, 11.11) were associated with a positive AD8 screen. Older age (OR: 1.56; 95% CI: 1.01, 2.41), male sex (OR: 3.08; 95% CI: 1.09, 9.40), and higher pain level (OR: 1.21; 95% CI: 1.01, 1.47) were associated with a positive TICS-M screen. Similarly, older age (OR: 1.33; 95% CI: 1.03, 1.73), male sex (OR: 2.02; 95% CI: 1.09, 3.83), and higher pain level (OR: 1.15; 95% CI: 1.02, 1.30) were associated with a positive T-MoCA screen.

CONCLUSIONS

The CDC cognitive question, AD8, TICS-M, and T-MoCA were easily implemented during preoperative assessment among older surgical patients. OSA, functional disability, and depression were associated with complaints on the CDC cognitive question and AD8. Older age, male sex, and higher pain level were associated with screening positive on the TICS-M and T-MoCA. Early remote cognitive screening may enhance risk stratification of vulnerable patients.

Sex and Gender Differences in Alzheimer's Disease: Genetic, Hormonal, and Inflammation Impacts

Two-thirds of Americans with Alzheimer's disease are women, indicating a profound variance between the sexes. Variances exist between the sexes in the age and intensity of the presentation, cognitive deficits, neuroinflammatory factors, structural and functional brain changes, as well as psychosocial and cultural circumstances. Herein, we summarize the existing evidence for sexual dimorphism and present the available evidence for these distinctions. Understanding these complexities is critical to developing personalized interventions for the prevention, care, and treatment of Alzheimer's disease.

Pregnancy as a window of opportunity for dementia prevention: a narrative review

Dementia is a debilitating condition with a disproportionate impact on women. While sex differences in longevity contribute to the disparity, the role of the female sex as a biological variable in disease progression is not yet fully elucidated. Metabolic dysfunctions are drivers of dementia etiology, and cardiometabolic diseases are among the most influential modifiable risk factors. Pregnancy is a time of enhanced vulnerability for metabolic disorders. Many dementia risk factors, such as hypertension or blood glucose dysregulation, often emerge for the first time in pregnancy. While such cardiometabolic complications in pregnancy pose a risk to the health trajectory of a woman, increasing her odds of developing type 2 diabetes or chronic hypertension, it is not fully understood how this relates to her risk for dementia. Furthermore, structural and functional changes in the maternal brain have been reported during pregnancy suggesting it is a time of neuroplasticity for the mother. Therefore, pregnancy may be a window of opportunity to optimize metabolic health and support the maternal brain. Healthy dietary patterns are known to reduce the risk of cardiometabolic diseases and have been linked to dementia prevention, yet interventions targeting cognitive function in late life have largely been unsuccessful. Earlier interventions are needed to address the underlying metabolic dysfunctions and potentially reduce the risk of dementia, and pregnancy offers an ideal opportunity to intervene. This review discusses current evidence regarding maternal brain health and the potential window of opportunity in pregnancy to use diet to address neurological health disparities for women.

2024 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including prevalence and incidence, mortality and morbidity, use and costs of care and the ramifications of AD for family caregivers, the dementia workforce and society. The Special Report discusses the larger health care system for older adults with cognitive issues, focusing on the role of caregivers and non-physician health care professionals. An estimated 6.9 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060, barring the development of medical breakthroughs to prevent or cure AD. Official AD death certificates recorded 119,399 deaths from AD in 2021. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death in the United States. Official counts for more recent years are still being compiled. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2021, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 140%. More than 11 million family members and other unpaid caregivers provided an estimated 18.4 billion hours of care to people with Alzheimer's or other dementias in 2023. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $346.6 billion in 2023. Its costs, however, extend to unpaid caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Members of the paid health care and broader community-based workforce are involved in diagnosing, treating and caring for people with dementia. However, the United States faces growing shortages across different segments of the dementia care workforce due to a combination of factors, including the absolute increase in the number of people living with dementia. Therefore, targeted programs and care delivery models will be needed to attract, better train and effectively deploy health care and community-based workers to provide dementia care. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2024 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $360 billion. The Special Report investigates how caregivers of older adults with cognitive issues interact with the health care system and examines the role non-physician health care professionals play in facilitating clinical care and access to community-based services and supports. It includes surveys of caregivers and health care workers, focusing on their experiences, challenges, awareness and perceptions of dementia care navigation.

Cognition is selectively impaired in males with spinal pain: A retrospective analysis of data from the Longitudinal Study of Ageing Danish Twins

Cognitive decline and spinal pain (back pain [BP] and neck pain [NP]) represent a major public health challenge, yet the potential relationship between them remains elusive. A retrospective analysis of the Longitudinal Study of Ageing Danish Twins was performed to determine any potential relationships between BP/NP and cognitive function adjusting for age, sex, educational and socioeconomic status. A total of 4731 adults (2788 females/1943 males) aged 78 ± 6 (SD) years were included in the analysis. We observed a 1-month prevalence of 25% with BP, 21% with NP and 11% for combined BP/NP. While there were no differences in cognition scores for males and females reporting combined BP/NP, compared to those without combined BP/NP (34.38 points [95% confidence interval (CI) = 31.88, 36.88] vs. 35.72 points [95% CI = 35.19, 36.26]; P = 0.180; and 35.72 points [95% CI = 35.19, 36.26] vs. 35.85 points [95% CI = 35.39, 36.31]; P = 0.327; for male and females, respectively), an adjusted analysis revealed that males with combined BP/NP presented with lower cognitive scores compared to males without combined BP/NP (81.26 points [95% CI = 73.80, 88.72] vs. 79.48 points [95% CI = 70.31, 88.66]; P = 0.043). The findings of this hypothesis-generating study may highlight a potential sex-specific association between spinal pain and later-life neurodegeneration.

Variability in Alzheimer's disease mortality from European vital statistics, 2012-2020

OBJECTIVE

Data regarding the trends in Alzheimer's disease (AD) mortality in the modern European Union (EU-27) member states are lacking. We assess the sex- and age-specific trends in AD mortality in the EU-27 member states between years 2012 and 2020.

METHODS

Data on cause-specific deaths and population numbers by sex for each country of the EU-27 were retrieved through publicly available European Statistical Office (EUROSTAT) dataset from 2012 to 2020. AD-related deaths were ascertained when the ICD-10 code G30 was listed as the primary cause of death in the medical death certificate. To calculate annual trends, we assessed the average annual percent change (AAPC) with relative 95% confidence intervals (CIs) using Joinpoint regression.

RESULTS

During the study period, 751,493 deaths (1.7%, 233,271 males and 518,222 females) occurred in the EU-27 because of AD. Trends in the proportion of AD-related deaths per 1000 total deaths slightly increased from 16.8% to 17.5% (p for trend <0.001). The age-adjusted mortality rate was higher in women over the entire study period. Joinpoint regression analysis revealed a stagnation in age-adjusted AD-related mortality from 2012 to 2020 among EU-27 Member States (AAMR: -0.1% [95% CI: -1.8-1.79], p = 0.94). Stratification by Country showed relevant regional disparities, especially in the Northern and Eastern EU-27 member states.

CONCLUSIONS

Over the last decade, the age-adjusted AD-related mortality rate has plateaued in EU-27. Important disparities still exist between Western and Eastern European countries.

Sex significantly predicts medial temporal volume when controlling for the influence of ApoE4 biomarker and demographic variables: A cross-ethnic comparison

OBJECTIVE

To explore the relationship between age, education, sex, and ApoE4 (+) status to brain volume among a cohort with amnestic mild cognitive impairment (aMCI).

METHOD

One hundred and twenty-three participants were stratified into Hispanic (n = 75) and White non-Hispanic (WNH, N = 48). Multiple linear regression analyses were conducted with age, education, sex, and ApoE4 status as predictor variables and left and right combined MRI volumes of the hippocampus, parahippocampus, and entorhinal cortex as dependent variables. Variations in head sizes were corrected by normalization with a total intracranial volume measurement.

RESULTS

Bonferroni-corrected results indicated that when controlling for ApoE4 status, education, and age, sex was a significant predictor of hippocampal volume among the Hispanic group (β = .000464, R2 = .196, p < .01) and the WNH group (β = .000455, R2 = .195, p < .05). Education (β = .000028, R2 = .168, p < .01) and sex (β = .000261, R2 = .168, p < .01) were significant predictors of parahippocampal volume among the Hispanic MCI group when controlling for the effects of ApoE4 status and age. One-way ANCOVAs comparing hippocampal and parahippocampal volume between males and females within groups revealed that females had significantly larger hippocampal volumes (p < .05). Hispanic females had significantly larger hippocampal (p < .001) and parahippocampal (p < .05) volume compared to males. No sex differences in parahippocampal volume were noted among WNHs.

CONCLUSIONS

Biological sex, rather than ApoE4 status, was a greater predictor of hippocampal volume among Hispanic and WNH females. These findings add to the mixed literature on sex differences in dementia research and highlight continued emphasis on ethnic populations to elucidate on neurodegenerative disparities.

Women and the risk of Alzheimer's disease

Purpose of the review

This review will elucidate reasons to explain why women may be at greater risk for Alzheimer's disease.

Recent findings

Potential mechanisms to explain sex and gender differences in Alzheimer dementia include: differences in risk associated with the apolipoprotein E 4 allele; telomere shortening- which is linked with neurodegeneration, higher incidence of depression and insomnia in women as psychiatric co-morbidities which are linked with an increased Alzheimer disease risk, disorders of pregnancy including gestational hypertension and preeclampsia and psychosocial factors such as educational level which may contribute to differences in cognitive reserve.

Summary

The sex and gender differences in Alzheimer's disease can be explained by biological and psychosocial factors.

Investigation of sex differences in mutation carriers of the Dominantly Inherited Alzheimer Network

INTRODUCTION

Studies suggest distinct differences in the development, presentation, progression, and response to treatment of Alzheimer's disease (AD) between females and males. We investigated sex differences in cognition, neuroimaging, and fluid biomarkers in dominantly inherited AD (DIAD).

METHODS

Three hundred twenty-five mutation carriers (55% female) and one hundred eighty-six non-carriers (58% female) of the Dominantly Inherited Alzheimer Network Observational Study were analyzed. Linear mixed models and Spearman's correlation explored cross-sectional sex differences in cognition, cerebrospinal fluid (CSF) biomarkers, Pittsburgh compound B positron emission tomography (11 C-PiB PET) and structural magnetic resonance imaging (MRI).

RESULTS

Female carriers performed better than males on delayed recall and processing speed despite similar hippocampal volumes. As the disease progressed, symptomatic females revealed higher increases in MRI markers of neurodegeneration and memory impairment. PiB PET and established CSF AD markers revealed no sex differences.

DISCUSSION

Our findings suggest an initial cognitive reserve in female carriers followed by a pronounced increase in neurodegeneration coupled with worse performance on delayed recall at later stages of DIAD.

Clinical profile and survival analysis of Alzheimer's disease patients in a Brazilian cohort

OBJECTIVE

To investigate the clinical and epidemiological characteristics of a large sample of patients with dementia due to Alzheimer's disease (AD) who were followed up at a cognitive neurology outpatient clinic.

METHODS

Retrospective, longitudinal, and descriptive design. We collected data from patients with dementia due to AD who visited the outpatient clinic of the SARAH Network of Rehabilitation Hospitals in Rio de Janeiro, Brazil, between May 2009 and June 2019. The evaluated characteristics included age of onset, sex, education, family history, comorbidities, time until diagnosis, and survival rates.

RESULTS

Overall, 1434 patients were evaluated, 74% of whom were women, with a mean age at symptom onset of 72.7 years and 75.8 at diagnosis. A positive family history was reported in 602 patients, with a first-degree relative in 86.3% of them. Hypertension was the most prevalent comorbidity, affecting 61.2% of the sample, and 16.2% were classified as having early-onset AD. The mean survival rate for the sample population was 112.8 months (9.4 years). The sample population was positively affected by dyslipidaemia.

CONCLUSIONS

This study presents a clinical and epidemiological analysis of a large and diverse group of patients with AD. The study confirms previous observations such as a higher prevalence of AD in women, low education among sufferers, and the presence of a family history. The study also found that comorbidities significantly affected patient survival and provides new data on the survival rates of patients with early and late AD in the Brazilian population.

Signalling Pathways Involved in Microglial Activation in Alzheimer's Disease and Potential Neuroprotective Role of Phytoconstituents

Alzheimer's disease (AD) is a commonly reported neurodegenerative disorder associated with dementia and cognitive impairment. The pathophysiology of AD comprises Aβ, hyperphosphorylated tau protein formation, abrupt cholinergic cascade, oxidative stress, neuronal apoptosis, and neuroinflammation. Recent findings have established the profound role of immunological dysfunction and microglial activation in the pathogenesis of AD. Microglial activation is a multifactorial cascade encompassing various signalling molecules and pathways such as Nrf2/NLRP3/NF-kB/p38 MAPKs/ GSK-3β. Additionally, deposited Aβ or tau protein triggers microglial activation and accelerates its pathogenesis. Currently, the FDA-approved therapeutic regimens are based on the modulation of the cholinergic system, and recently, one more drug, aducanumab, has been approved by the FDA. On the one hand, these drugs only offer symptomatic relief and not a cure for AD. Additionally, no targetedbased microglial medicines are available for treating and managing AD. On the other hand, various natural products have been explored for the possible anti-Alzheimer effect via targeting microglial activation or different targets of microglial activation. Therefore, the present review focuses on exploring the mechanism and associated signalling related to microglial activation and a detailed description of various natural products that have previously been reported with anti-Alzheimer's effect via mitigation of microglial activation. Additionally, we have discussed the various patents and clinical trials related to managing and treating AD.

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.

Sex difference in evolution of cognitive decline: studies on mouse model and the Dominantly Inherited Alzheimer Network cohort

Women carry a higher burden of Alzheimer's disease (AD) compared to men, which is not accounted entirely by differences in lifespan. To identify the mechanisms underlying this effect, we investigated sex-specific differences in the progression of familial AD in humans and in APPswe/PS1ΔE9 mice. Activity dependent protein translation and associative learning and memory deficits were examined in APPswe/PS1ΔE9 mice and wild-type mice. As a human comparator group, progression of cognitive dysfunction was assessed in mutation carriers and non-carriers from DIAN (Dominantly Inherited Alzheimer Network) cohort. Female APPswe/PS1ΔE9 mice did not show recall deficits after contextual fear conditioning until 8 months of age. Further, activity dependent protein translation and Akt1-mTOR signaling at the synapse were impaired in male but not in female mice until 8 months of age. Ovariectomized APPswe/PS1ΔE9 mice displayed recall deficits at 4 months of age and these were sustained until 8 months of age. Moreover, activity dependent protein translation was also impaired in 4 months old ovariectomized APPswe/PS1ΔE9 mice compared with sham female APPswe/PS1ΔE9 mice. Progression of memory impairment differed between men and women in the DIAN cohort as analyzed using linear mixed effects model, wherein men showed steeper cognitive decline irrespective of the age of entry in the study, while women showed significantly greater performance and slower decline in immediate recall (LOGIMEM) and delayed recall (MEMUNITS) than men. However, when the performance of men and women in several cognitive tasks (such as Wechsler's logical memory) are compared with the estimated year from expected symptom onset (EYO) we found no significant differences between men and women. We conclude that in familial AD patients and mouse models, females are protected, and the onset of disease is delayed as long as estrogen levels are intact.

2023 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease, including prevalence and incidence, mortality and morbidity, use and costs of care, and the overall impact on family caregivers, the dementia workforce and society. The Special Report examines the patient journey from awareness of cognitive changes to potential treatment with drugs that change the underlying biology of Alzheimer's. An estimated 6.7 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, and Alzheimer's disease was officially listed as the sixth-leading cause of death in the United States. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. This trajectory of deaths from AD was likely exacerbated by the COVID-19 pandemic in 2020 and 2021. More than 11 million family members and other unpaid caregivers provided an estimated 18 billion hours of care to people with Alzheimer's or other dementias in 2022. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $339.5 billion in 2022. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Members of the paid health care workforce are involved in diagnosing, treating and caring for people with dementia. In recent years, however, a shortage of such workers has developed in the United States. This shortage - brought about, in part, by COVID-19 - has occurred at a time when more members of the dementia care workforce are needed. Therefore, programs will be needed to attract workers and better train health care teams. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2023 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $345 billion. The Special Report examines whether there will be sufficient numbers of physician specialists to provide Alzheimer's care and treatment now that two drugs are available that change the underlying biology of Alzheimer's disease.

Mortality of Alzheimer's Disease and Other Dementias in China: Past and Future Decades

Objectives: This study aimed to explore the distribution features and trends of dementia mortality in China from 2011 to 2020 and make a prediction for the next decade. Methods: Mortality-relevant data were gathered from the Chinese Center for Disease Control and Prevention's Disease Surveillance Points system. Joinpoint regression was applied to evaluate the trends. Results: Crude Mortality Rate (CMR) of AD and other dementias increased from 3.7 per 100,000 to 6.2 per 100,000 in 2011-2020, with an Average Annual Percent Change (AAPC) of 5.3% (95% CI 4.4%-6.3%). Age-Standardized Mortality Rate (ASMR) slightly decreased from 5.0 per 100,000 to 4.1 per 100,000 in 2011-2020, with AAPC of -0.4% (95% CI -2.5%-1.8%). CMR will increase to 9.66 per 100,000 while ASMR will decline to 3.42 per 100,000 in the following decade. Conclusion: The upward trend in CMR and downward trend in ASMR suggested the further development of population aging and dementia mortality in the past and future decades. In China, there were gender, urban-rural, regional and age differences.

Biological and Clinical Implications of Sex-Specific Differences in Alzheimer's Disease

Mounting evidence indicates that the female sex is a risk factor for Alzheimer's disease (AD), the most common cause of dementia worldwide. Decades of research suggest that sex-specific differences in genetics, environmental factors, hormones, comorbidities, and brain structure and function may contribute to AD development. However, although significant progress has been made in uncovering specific genetic factors and biological pathways, the precise mechanisms underlying sex-biased differences are not fully characterized. Here, we review several lines of evidence, including epidemiological, clinical, and molecular studies addressing sex differences in AD. In addition, we discuss the challenges and future directions in advancing personalized treatments for AD.

Sex-Specific Heterogeneity of Mild Cognitive Impairment Identified Based on Multi-Modal Data Analysis

BACKGROUND

Mild cognitive impairment (MCI), a prodromal phase of Alzheimer's disease (AD), is heterogeneous with different rates and risks of progression to AD. There are significant gender disparities in the susceptibility, prognosis, and outcomes in patients with MCI, with female being disproportionately negatively impacted.

OBJECTIVE

The aim of this study was to identify sex-specific heterogeneity of MCI using multi-modality data and examine the differences in the respective MCI subtypes with different prognostic outcomes or different risks for MCI to AD conversion.

METHODS

A total of 325 MCI subjects (146 women, 179 men) and 30 relevant features were considered. Mixed-data clustering was applied to women and men separately to discover gender-specific MCI subtypes. Gender differences were compared in the respective subtypes of MCI by examining their MCI to AD disease prognosis, descriptive statistics, and conversion rates.

RESULTS

We identified three MCI subtypes: poor-, good-, and best-prognosis for women and for men, separately. The subtype-wise comparison (for example, poor-prognosis subtype in women versus poor-prognosis subtype in men) showed significantly different means for brain volumetric, cognitive test-related, also for the proportion of comorbidities. Also, there were substantial gender differences in the proportions of participants who reverted to normal function, remained stable, or converted to AD.

CONCLUSION

Analyzing sex-specific heterogeneity of MCI offers the opportunity to advance the understanding of the pathophysiology of both MCI and AD, allows stratification of risk in clinical trials of interventions, and suggests gender-based early intervention with targeted treatment for patients at risk of developing AD.

Subjective cognitive decline is a better marker for future cognitive decline in females than in males

BACKGROUND

The identification of biomarkers for early detection of Alzheimer's disease (AD) is critical to the development of therapies and interventions targeted at symptom management and tracking the pathophysiology of disease. The endorsement of subjective cognitive decline (SCD) has emerged as a potential indicator of early change in cognitive status that may be predictive of future impairment at a time when measurable declines in neuropsychological performance cannot be detected. While there are numerous findings revealing sex differences in the prevalence of AD, there is a paucity of research examining sex differences in SCD. Therefore, the goal of this project was to determine if the relationship between the endorsement of SCD and future cognitive changes differ as a function of biological sex.

METHODS

A sample of 3019 male and female healthy older adults (2188 without SCD, 831 with SCD), with a mean follow-up time of 5.7 years, were included from the Rush Alzheimer's Disease Center Research Sharing Hub. Linear regressions were performed to determine group differences in baseline cognitive scores, while linear mixed-effects models were completed to determine group differences in the rate of cognitive change over time.

RESULTS

Individuals endorsing SCD had significantly lower baseline cognitive scores and increased rates of decline in all cognitive domains compared to those without SCD. Males exhibited significantly lower scores in baseline performance in global cognition, episodic memory, and perceptual speed regardless of SCD classification. Females with SCD were found to decline at significantly faster rates than both males with SCD and males and females without SCD in all cognitive domains over a maximum 15-year follow-up period.

CONCLUSIONS

SCD is related to lower baseline cognitive performance and faster cognitive decline compared to those who do not endorse SCD. Females with SCD have the fastest rate of decline suggesting that SCD may be more predictive of future decline in females than in males. Targeted assessments of SCD may allow for the identification of individuals for inclusion in intervention trials, and other research studies, aiming to attenuate casual disease processes, which may ultimately aid in the mitigation of sex disparities in AD.

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.

Estimating the Prevalence of Dementia and Mild Cognitive Impairment in the US: The 2016 Health and Retirement Study Harmonized Cognitive Assessment Protocol Project

Importance

Nationally representative data are critical for understanding the causes, costs, and outcomes associated with dementia and mild cognitive impairment (MCI) in the US and can inform policies aimed at reducing the impact of these conditions on patients, families, and public programs. The nationally representative Health and Retirement Study (HRS) is an essential resource for such data, but the HRS substudy providing dementia diagnostic information was fielded more than 20 years ago and more recent data are needed.

Objective

The Harmonized Cognitive Assessment Protocol (HCAP) was developed to update national estimates of the prevalence of MCI and dementia in the US and examine differences by age, race, ethnicity, and sex.

Design, Setting, and Participants

HRS is an ongoing longitudinal nationally representative study of people 51 years and older with staggered entry dates from 1992 to 2022 and follow-up ranging from 4 to 30 years. HCAP is a cross-sectional random sample of individuals in HRS who were 65 years or older in 2016. Of 9972 age-eligible HRS participants, 4425 were randomly selected for HCAP, and 3496 completed a comprehensive neuropsychological test battery and informant interview, none of whom were excluded. Dementia and MCI were classified using an algorithm based on standard diagnostic criteria and comparing test performance to a robust normative sample.

Exposures

Groups were stratified by age, sex, education, race, and ethnicity.

Main Outcomes and Measures

National prevalence estimates using population weights.

Results

The mean (SD) age of the study population sample (N = 3496) was 76.4 (7.6) years, and 2095 participants (60%) were female. There were 551 participants who self-identified as Black and not Hispanic (16%), 382 who self-identified as Hispanic regardless of race (16%), 2483 who self-identified as White and not Hispanic (71%), and 80 who self-identified as another race (2%), including American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or another self-described race. A total of 393 individuals (10%; 95% CI, 9-11) were classified as having dementia and 804 (22%; 95% CI, 20-24) as having MCI. Every 5-year increase in age was associated with higher risk of dementia (weighted odds ratio [OR], 1.95 per 5-year age difference; 95%, CI, 1.77-2.14) and MCI (OR, 1.17 per 5-year age difference, 95% CI, 1.09-1.26). Each additional year of education was associated with a decrease in risk of dementia (OR, 0.93 per year of school, 95% CI, 0.89-0.97) and MCI (OR, 0.94, 95% CI, 0.91-0.97). Dementia was more common among non-Hispanic Black individuals (OR, 1.81; 95% CI, 1.20-2.75) and MCI in Hispanic individuals (OR, 1.42; 95% CI, 1.03-1.96) compared with non-Hispanic White individuals. Other group comparisons by race and ethnicity were not possible owing to small numbers. No differences in prevalence were found between female individuals and male individuals.

Conclusions and Relevance

Using a comprehensive neuropsychological test battery and large sample, the national prevalence of dementia and MCI in 2016 found in this cross-sectional study was similar to that of other US-based studies, indicating a disproportionate burden of dementia and MCI among older Black and Hispanic adults and those with lower education.

Sex-specific transcriptional rewiring in the brain of Alzheimer’s disease patients

Sex-specific differences may contribute to Alzheimer’s disease (AD) development. AD is more prevalent in women worldwide, and female sex has been suggested as a disease risk factor. Nevertheless, the molecular mechanisms underlying sex-biased differences in AD remain poorly characterized. To this end, we analyzed the transcriptional changes in the entorhinal cortex of symptomatic and asymptomatic AD patients stratified by sex. Co-expression network analysis implemented by SWItchMiner software identified sex-specific signatures of switch genes responsible for drastic transcriptional changes in the brain of AD and asymptomatic AD individuals. Pathway analysis of the switch genes revealed that morphine addiction, retrograde endocannabinoid signaling, and autophagy are associated with both females with AD (F-AD) and males with (M-AD). In contrast, nicotine addiction, cell adhesion molecules, oxytocin signaling, adipocytokine signaling, prolactin signaling, and alcoholism are uniquely associated with M-AD. Similarly, some of the unique pathways associated with F-AD switch genes are viral myocarditis, Hippo signaling pathway, endometrial cancer, insulin signaling, and PI3K-AKT signaling. Together these results reveal that there are many sex-specific pathways that may lead to AD. Approximately 20–30% of the elderly have an accumulation of amyloid beta in the brain, but show no cognitive deficit. Asymptomatic females (F-asymAD) and males (M-asymAD) both shared dysregulation of endocytosis. In contrast, pathways uniquely associated with F-asymAD switch genes are insulin secretion, progesterone-mediated oocyte maturation, axon guidance, renal cell carcinoma, and ErbB signaling pathway. Similarly, pathways uniquely associated with M-asymAD switch genes are fluid shear stress and atherosclerosis, FcγR mediated phagocytosis, and proteoglycans in cancer. These results reveal for the first time unique pathways associated with either disease progression or cognitive resilience in asymptomatic individuals. Additionally, we identified numerous sex-specific transcription factors and potential neurotoxic chemicals that may be involved in the pathogenesis of AD. Together these results reveal likely molecular drivers of sex differences in the brain of AD patients. Future molecular studies dissecting the functional role of these switch genes in driving sex differences in AD are warranted.

Exploring the role of sex differences in Alzheimer's disease pathogenesis in Down syndrome

Women are disproportionately affected by Alzheimer's disease (AD), yet little is known about sex-specific effects on the development of AD in the Down syndrome (DS) population. DS is caused by a full or partial triplication of chromosome 21, which harbors the amyloid precursor protein (APP) gene, among others. The majority of people with DS in their early- to mid-40s will accumulate sufficient amyloid-beta (Aβ) in their brains along with neurofibrillary tangles (NFT) for a neuropathological diagnosis of AD, and the triplication of the APP gene is regarded as the main cause. Studies addressing sex differences with age and impact on dementia in people with DS are inconsistent. However, women with DS experience earlier age of onset of menopause, marked by a drop in estrogen, than women without DS. This review focuses on key sex differences observed with age and AD in people with DS and a discussion of possible underlying mechanisms that could be driving or protecting from AD development in DS. Understanding how biological sex influences the brain will lead to development of dedicated therapeutics and interventions to improve the quality of life for people with DS and AD.

Sex and gender differences in dementia

The dementia landscape has undergone a striking paradigm shift. The advances in understanding of neurodegeneration and proteinopathies has changed our approach to patients with cognitive impairment. Firstly, it has recently been shown that the various proteinopathies that are the cause of the dementia begin to build up long before the appearance of any obvious symptoms. This has cemented the idea that there is an urgency in diagnosis as it occurs very late in the pathophysiology of these diseases. Secondly, that accurate diagnosis is required to deliver targeted therapies, that is precision medicine. With this latter point, the realization that various factors of a person need to be considered as they may impact the presentation and progression of disease has risen to the forefront. Two of these factors aside from race and age are biological sex and gender (social construct), as both can have tremendous impact on manifestation of disease. This chapter will cover what is known and remains to be known on the interaction of sex and gender with some of the major causes of dementia.

The hidden link between circadian entropy and mental health disorders

The high overlapping nature of various features across multiple mental health disorders suggests the existence of common psychopathology factor(s) (p-factors) that mediate similar phenotypic presentations across distinct but relatable disorders. In this perspective, we argue that circadian rhythm disruption (CRD) is a common underlying p-factor that bridges across mental health disorders within their age and sex contexts. We present and analyze evidence from the literature for the critical roles circadian rhythmicity plays in regulating mental, emotional, and behavioral functions throughout the lifespan. A review of the literature shows that coarse CRD, such as sleep disruption, is prevalent in all mental health disorders at the level of etiological and pathophysiological mechanisms and clinical phenotypical manifestations. Finally, we discuss the subtle interplay of CRD with sex in relation to these disorders across different stages of life. Our perspective highlights the need to shift investigations towards molecular levels, for instance, by using spatiotemporal circadian "omic" studies in animal models to identify the complex and causal relationships between CRD and mental health disorders.

Risk Factors Affecting Cognitive Impairment of the Elderly Aged 65 and Over: A Cross-Sectional Study

Objectives

Elderly population with cognitive impairment has been accelerating in China. This study aimed to explore the relationship between each risk factor and each cognitive domain to provide evidence for risk prevention of controlling impaired cognitive function in elderly.

Methods

This cross-sectional study analyzed the cognitive status of the elderly aged 65 and above in three communities in Shizhong District of Jinan City. Cognitive status was assessed by MMSE. The influencing factors of cognitive impairment were analyzed by chi square test, correlation analysis and regression analysis.

Results

Among 1,171 participants, 643 were defined as cognitive impairment with an incidence of 54.9%. And we found that there were significant differences in the incidence of cognitive impairment among residents with different gender, age, education level, hypertension and LDL-C (P &lt; 0.05). However, BMI, marital status, smoking, physical exercise, T2DM, TC, TG and HDL-C had no significant differences in the incidence of cognitive impairment. In addition, education level (b = 1.194, P &lt;0.001), age (b = −0.040, P = 0.001), LDL-C (b = 0.169, P = 0.018) had statistical significance on the total score of MMSE according to binary logistic regression analysis.

Conclusion

Gender, age, education level, hypertension and LDL-C had significant differences in the incidence of cognitive impairment. And these risk factors could provide a basis for the early screening and intervention of cognitive impairment in the elderly.

The Moderating Effect of Community Environment on the Association Between Social Support and Chinese Older Adults' Health: An Empirical Analysis Study

Background

The aging population conundrum and the gradual weakening of older adults' health and ability to obtain resources as they age have drawn attention to this population's health. Older adults' health relates not only to their own quality of life, but also to the development of families/society.

Methods

We analyzed micro data from the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study Follow-up Questionnaire, using the probit model, ordinary least squares model, and other methods.

Results and Conclusions

Both formal and informal social support significantly impacted the physical and mental health of Chinese older adults, and the community environment moderated this relationship. To build a reasonable and effective social support system for older adults and improve their health, we suggest that stakeholders should continue to strengthen the formal and informal social support provided to older adults; they should also build a community-based care system, which will allow for the moderating role of community environment on the relationship between social support and older adults' health. Family and social support factors are important for older adults' health. We should enable the moderating role of community environment on the relationship between social support and health to be fully exerted, as well as build a community-based pension system.

Risk Factors Associated With Alzheimer Disease and Related Dementias by Sex and Race and Ethnicity in the US

Importance

Previous estimates suggested that 1 in 3 cases of Alzheimer disease and related dementia (ADRDs) in the US are associated with modifiable risk factors, the most prominent being physical inactivity, depression, and smoking. However, these estimates do not account for changes in risk factor prevalence over the past decade and do not consider potential differences by sex or race and ethnicity.

Objective

To update estimates of the proportion of ADRDs in the US that are associated with modifiable risk factors and to assess for differences by sex and race and ethnicity.

Design, Setting, and Participants

For this cross-sectional study, risk factor prevalence and communality were obtained from the nationally representative US Behavioral Risk Factor Surveillance Survey data from January 2018 to December 2018, and relative risks for each risk factor were extracted from meta-analyses. Data were analyzed from December 2020 to August 2021. Respondents included 378 615 noninstitutionalized adults older than 18 years. The number before exclusion was 402 410. Approximately 23 795 (~6%) had missing values on at least 1 of the variables of interest.

Exposures

Physical inactivity, current smoking, depression, low education, diabetes, midlife obesity, midlife hypertension, and hearing loss.

Main Outcomes and Measures

Individual and combined population-attributable risks (PARs) associated with ADRDs, accounting for nonindependence between risk factors.

Results

Among 378 615 individuals, 171 161 (weighted 48.7%) were male, and 134 693 (weighted 21.1%) were 65 years and older. Race and ethnicity data were self-reported and defined by the US Behavioral Risk Factor Surveillance System Data; 6671 participants (weighted 0.9%) were American Indian and Alaska Native, 8043 (weighted 5.1%) were Asian, 29 956 (weighted 11.7%) were Black, 28 042 (weighted 16.0%) were Hispanic (any race), and 294 394 (weighted 64.3%) were White. Approximately 1 in 3 of ADRD cases (36.9%) in the US were associated with 8 modifiable risk factors, the most prominent of which were midlife obesity (17.7%; 95% CI, 17.5-18.0), physical inactivity (11.8%; 95% CI, 11.7-11.9), and low educational attainment (11.7%; 95% CI, 11.5-12.0). Combined PARs were higher in men (35.9%) than women (30.1%) and differed by race and ethnicity: American Indian and Alaska Native individuals, 39%; Asian individuals, 16%; Black individuals, 40%; Hispanic individuals (any race), 34%; and White individuals, 29%. The most prominent modifiable risk factors regardless of sex were midlife obesity for American Indian and Alaska Native individuals, Black individuals, and White individuals; low education for Hispanic individuals; and physical inactivity for Asian individuals.

Conclusions and Relevance

The findings suggest that risk factors associated with ADRDs have changed over the past decade and differ based on sex and race and ethnicity. Alzheimer risk reduction strategies may be more effective if they target higher-risk groups and consider current risk factor profiles.

Advancements in the development of multi-target directed ligands for the treatment of Alzheimer's disease

Alzheimer's disease (AD) is a multifactorial irreversible neurological disorder which results in cognitive impairment, loss of cholinergic neurons in synapses of the basal forebrain and neuronal death. Exact pathology of the disease is not yet known however, many hypotheses have been proposed for its treatment. The available treatments including monotherapies and combination therapies are not able to combat the disease effectively because of its complex pathological mechanism. A multipotent drug for AD has the potential to bind or inhibit multiple targets responsible for the progression of the disease like aggregated Aβ, hyperphosphorylated tau proteins, cholinergic and adrenergic receptors, MAO enzymes, overactivated N-methyl-d-aspartate (NMDA), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor etc. The traditional approach of one disease-one target-one drug has been rationalized to one drug-multi targets for the chronic diseases like AD and cancer. Thus, over the last decade research focus has been shifted towards the development of multi target directed ligands (MTDLs) which can simultaneously inhibit multiple targets and stop or slow the progression of the disease. The MTDLs can be more effective against AD and eliminate any possibility of drug-drug interactions. Many important active pharmacophore units have been fused, merged or incorporated into different scaffolds to synthesize new potent drugs. In the current article, we have described various hypothesis for AD and effectiveness of the MTDLs treatment strategy is discussed in detail. Different chemical scaffolds and their synthetic strategies have been described and important functionalities are identified in the chemical scaffold that have the potential to bind to the multiple targets. The important leads identified in this study with MTDL characteristics have the potential to be developed as drug candidates for the effective treatment of AD.

Trajectories of Mini-Mental State Examination Scores over the Lifespan in General Populations: A Systematic Review and Meta-Regression Analysis

Objectives: Over the lifespan cumulative changes to the brain lead to cognitive decline and eventually to dementia in 20-25% of adults 85 years and older. A commonly used screening tool for cognitive function is the Standard 30 point Mini-Mental State Examination (MMSE). Though the MMSE is used to screen for dementia, little is known about the changes in scores over the lifespan in general populations.Method: A systematic search was conducted using Cochrane, EMBASE, MEDLINE and PsycINFO for articles published from January 1, 2007 to May 25, 2017. Articles were included if they had a longitudinal design reporting at least two MMSE scores. A mixed-effect meta-regression analysis was conducted to examine the influence of age on MMSE score followed by a change-point regression analysis determining the age at which MMSE declines.Results: 45 articles including 58,939 individuals (age range 18-108 years, 61.2% female) summarized 222 MMSE point estimates from 35 cohorts. The meta-regression demonstrated a significant decrease in MMSE scores with higher age (regression coefficient of age: -0.10 (Confidence Interval (CI) -0.15, -0.05)). The average annual decline in MMSE scores identified by the change-point analysis at the age of 41 years and 84 years were -0.04 (95% CI: -0.05, -0.03) and -0.53 (95% CI: -0.55, -0.50), respectively.Conclusions: Between the age of 29 and 105 years MMSE scores decline, with the highest decline between age 84 and 105 years.Clinical Implementations: The use of MMSE should be restricted to higher age categories in aging general populations.

The Usage of Histamine Type 1 Receptor Antagonist and Risk of Dementia in the Elderly: A Nationwide Cohort Study

Background

The histamine type 1 receptor antagonist (H1RA) has been commonly used. This study aimed to examine the association between the usage of H1RA and the risk of dementia.

Methods

A total of 8,986 H1RA users aged ≥50 and 26,958 controls matched a ratio of 1:3 for age, sex, and comorbidity, were selected between January 1, and December 31, 2000, from Taiwan’s National Health Insurance Research Database. Fine and Gray’s survival analysis (competing with mortality) was used to compare the risk of developing dementia during a 15-year follow-up period (2000–2015).

Results

In general, the H1RA usage was not significantly associated with dementia (adjusted subdistribution hazard ratio [SHR] = 1.025, 95% confidence interval [CI] = 0.883–1.297, p = 0.274) for the H1RA cohort. However, a differential risk was found among the groups at risk. The patients with the usage of H1RA aged ≥65 years (adjusted SHR: 1.782, 95% CI = 1.368–2.168, p &lt; 0.001) were associated with a higher risk of dementia, in comparison to the control groups. Furthermore, the patients with the usage of H1RA that were male, or had more comorbidities, were also associated with an increased risk of dementia.

Conclusion

The usage of H1RA was associated with the risk of developing dementia in the patients aged ≥ 65 years.

2022 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on family caregivers, the dementia workforce and society. The Special Report discusses consumers' and primary care physicians' perspectives on awareness, diagnosis and treatment of mild cognitive impairment (MCI), including MCI due to Alzheimer's disease. An estimated 6.5 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, the latest year for which data are available. Alzheimer's disease was officially listed as the sixth-leading cause of death in the United States in 2019 and the seventh-leading cause of death in 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. More than 11 million family members and other unpaid caregivers provided an estimated 16 billion hours of care to people with Alzheimer's or other dementias in 2021. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $271.6 billion in 2021. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Members of the dementia care workforce have also been affected by COVID-19. As essential care workers, some have opted to change jobs to protect their own health and the health of their families. However, this occurs at a time when more members of the dementia care workforce are needed. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2022 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $321 billion. A recent survey commissioned by the Alzheimer's Association revealed several barriers to consumers' understanding of MCI. The survey showed low awareness of MCI among Americans, a reluctance among Americans to see their doctor after noticing MCI symptoms, and persistent challenges for primary care physicians in diagnosing MCI. Survey results indicate the need to improve MCI awareness and diagnosis, especially in underserved communities, and to encourage greater participation in MCI-related clinical trials.

Endogenous and Exogenous Estrogen Exposures: How Women's Reproductive Health Can Drive Brain Aging and Inform Alzheimer's Prevention

After advanced age, female sex is the major risk factor for late-onset Alzheimer's disease (AD), the most common cause of dementia affecting over 24 million people worldwide. The prevalence of AD is higher in women than in men, with postmenopausal women accounting for over 60% of all those affected. While most research has focused on gender-combined risk, emerging data indicate sex and gender differences in AD pathophysiology, onset, and progression, which may help account for the higher prevalence in women. Notably, AD-related brain changes develop during a 10-20 year prodromal phase originating in midlife, thus proximate with the hormonal transitions of endocrine aging characteristic of the menopause transition in women. Preclinical evidence for neuroprotective effects of gonadal sex steroid hormones, especially 17β-estradiol, strongly argue for associations between female fertility, reproductive history, and AD risk. The level of gonadal hormones to which the female brain is exposed changes considerably across the lifespan, with relevance to AD risk. However, the neurobiological consequences of hormonal fluctuations, as well as that of hormone therapies, are yet to be fully understood. Epidemiological studies have yielded contrasting results of protective, deleterious and null effects of estrogen exposure on dementia risk. In contrast, brain imaging studies provide encouraging evidence for positive associations between greater cumulative lifetime estrogen exposure and lower AD risk in women, whereas estrogen deprivation is associated with negative consequences on brain structure, function, and biochemistry. Herein, we review the existing literature and evaluate the strength of observed associations between female-specific reproductive health factors and AD risk in women, with a focus on the role of endogenous and exogenous estrogen exposures as a key underlying mechanism. Chief among these variables are reproductive lifespan, menopause status, type of menopause (spontaneous vs. induced), number of pregnancies, and exposure to hormonal therapy, including hormonal contraceptives, hormonal therapy for menopause, and anti-estrogen treatment. As aging is the greatest risk factor for AD followed by female sex, understanding sex-specific biological pathways through which reproductive history modulates brain aging is crucial to inform preventative and therapeutic strategies for AD.

Heterogeneity in Alzheimer's Disease Diagnosis and Progression Rates: Implications for Therapeutic Trials

The clinical presentation and the pathological processes underlying Alzheimer's disease (AD) can be very heterogeneous in severity, location, and composition including the amount and distribution of AB deposition and spread of neurofibrillary tangles in different brain regions resulting in atypical clinical patterns and the existence of distinct AD variants. Heterogeneity in AD may be related to demographic factors (such as age, sex, educational and socioeconomic level) and genetic factors, which influence underlying pathology, the cognitive and behavioral phenotype, rate of progression, the occurrence of neuropsychiatric features, and the presence of comorbidities (e.g., vascular disease, neuroinflammation). Heterogeneity is also manifest in the individual resilience to the development of neuropathology (brain reserve) and the ability to compensate for its cognitive and functional impact (cognitive and functional reserve). The variability in specific cognitive profiles and types of functional impairment may be associated with different progression rates, and standard measures assessing progression may not be equivalent for individual cognitive and functional profiles. Other factors, which may govern the presence, rate, and type of progression of AD, include the individuals' general medical health, the presence of specific systemic conditions, and lifestyle factors, including physical exercise, cognitive and social stimulation, amount of leisure activities, environmental stressors, such as toxins and pollution, and the effects of medications used to treat medical and behavioral conditions. These factors that affect progression are important to consider while designing a clinical trial to ensure, as far as possible, well-balanced treatment and control groups.

Female specific risk factors for the development of Alzheimer's disease neuropathology and cognitive impairment: Call for a precision medicine approach

Alzheimer's disease (AD) includes a long asymptomatic stage, which precedes the formal diagnosis of dementia. AD biomarker models provide a framework for precision medicine approaches during this stage. However, such approaches have ignored the possible influence of sex on cognition and brain health, despite female sex noted as a major risk factor. Since AD-related changes may emerge in midlife, intervention efforts are being redirected around this period. Midlife coincides with several endocrinological changes, such as the menopausal transition experienced by women. In this narrative review, we discuss evidence for sex-differences in AD neuropathological burden and outline key endocrinological mechanisms for both sexes, focussing on hormonal events throughout the lifespan that may influence female susceptibility to AD neuropathology and dementia onset. We further consider common non-modifiable (genetic) and modifiable (lifestyle and health) risk factors, highlighting possible sex-dependent differential effects for the AD disease course. Finally, we evaluate the studies selected for this review demonstrating sex-differences in cognitive, pathological and health factors, summarising the state of sex differences in AD risk factors. We further provide recommendations for targeted research on female-specific risk factors, to inform personalised strategies for AD-prevention and the promotion of female brain health.

Body mass index in early adulthood and dementia in late life: Findings from a pooled cohort

INTRODUCTION

To examine the independent association of body mass index (BMI) in early adulthood with dementia incidence among men and women.

METHODS

We studied 5104 older adults from the Cardiovascular Health Study (CHS) and the Health, Aging, and Body Composition (Health ABC) study. We imputed early adulthood and midlife BMI using a pooled parent cohort with complete adult lifespan coverage and previously established methods. Dementia was ascertained using criteria such as neuropsychological test battery, medical records, and dementia-related drug use. Pooled logistic regression (PLR) models were used.

RESULTS

Compared to women with normal BMI in early adulthood, the odds of dementia were higher among both overweight (odds ratio [OR] = 1.8; 95% confidence interval [CI] = 1.31 to 2.54) and obese (OR = 2.45; 95% CI = 1.47 to 4.06) women, independent of mid- and late-life BMI. Similar relationship was observed in men.

CONCLUSIONS

With the growing obesity epidemic among US adults, efforts aimed at reducing dementia may need to begin obesity prevention and treatment early in the life course.

A study of dementia in old age homes

BACKGROUND

By 2040, dementia is projected to rise exponentially by 300% in India. Studies addressing the need for psychiatric care in the community being few and those focusing in old age homes even fewer, a study was undertaken to study the prevalence of dementia and the association with sociodemographic factors and psychiatric morbidity.

MATERIALS AND METHODS

A total of 558 elderly aged 60 years and above, residing in old age homes in Pune were studied. 179 inmates were included based on the inclusion and exclusion criteria. Those who scored a predetermined cut-off score on the screening tool were included to undergo a detailed physical and neurological examination, cognitive profile using subtests from the cognitive test (community screening instrument for Dementia of 10/66 group).

RESULTS

Mean age of the sample was 75.02 years majority (39.7%) was in the 60-70 years group. Males 25.7% versus females 74.3%. The sample consisted of the following socioeconomic groups: 40.2% middle, 26.3% low middle, 24% high middle, 8.4% high income, and 1.1% in low income. 60.3% widow/widower category, 36.3% never married, 4.5% had family history of dementia. Mean scores of mini mental state examination in the overall sample was 26.02 compared to 18.02 in those cut-off point of 23. The prevalence of dementia in the sample was 22.9%. There was the high prevalence of psychiatric symptoms and psychiatric morbidity in the dementia group than the rest. Frontal lobe dysfunction and impairment of orientation with increasing severity of dementia were observed.

CONCLUSIONS

Sociodemographic factors, which were considered protective against the prevalence of dementia, identified were less restriction in physical activity and having fish in the diet regularly.

Alzheimer's pathogenic mechanisms and underlying sex difference

AD is a neurodegenerative disease, and its frequency is often reported to be higher for women than men: almost two-thirds of patients with AD are women. One prevailing view is that women live longer than men on average of 4.5 years, plus there are more women aged 85 years or older than men in most global subpopulations; and older age is the greatest risk factor for AD. However, the differences in the actual risk of developing AD for men and women of the same age is difficult to assess, and the findings have been mixed. An increasing body of evidence from preclinical and clinical studies as well as the complications in estimating incidence support the sex-specific biological mechanisms in diverging AD risk as an important adjunct explanation to the epidemiologic perspective. Although some of the sex differences in AD prevalence are due to differences in longevity, other distinct biological mechanisms increase the risk and progression of AD in women. These risk factors include (1) deviations in brain structure and biomarkers, (2) psychosocial stress responses, (3) pregnancy, menopause, and sex hormones, (4) genetic background (i.e., APOE), (5) inflammation, gliosis, and immune module (i.e., TREM2), and (6) vascular disorders. More studies focusing on the underlying biological mechanisms for this phenomenon are needed to better understand AD. This review presents the most recent data in sex differences in AD-the gateway to precision medicine, therefore, shaping expert perspectives, inspiring researchers to go in new directions, and driving development of future diagnostic tools and treatments for AD in a more customized way.

Smoking is associated with impaired verbal learning and memory performance in women more than men

Vascular contributions to cognitive impairment and dementia (VCID) include structural and functional blood vessel injuries linked to poor neurocognitive outcomes. Smoking might indirectly increase the likelihood of cognitive impairment by exacerbating vascular disease risks. Sex disparities in VCID have been reported, however, few studies have assessed the sex-specific relationships between smoking and memory performance and with contradictory results. We investigated the associations between sex, smoking, and cardiovascular disease with verbal learning and memory function. Using MindCrowd, an observational web-based cohort of ~ 70,000 people aged 18-85, we investigated whether sex modifies the relationship between smoking and cardiovascular disease with verbal memory performance. We found significant interactions in that smoking is associated with verbal learning performance more in women and cardiovascular disease more in men across a wide age range. These results suggest that smoking and cardiovascular disease may impact verbal learning and memory throughout adulthood differently for men and women.

Consideration of Sex Differences in the Measurement and Interpretation of Alzheimer Disease-Related Biofluid-Based Biomarkers

BACKGROUND

The development of cerebrospinal fluid and blood-based biomarkers for Alzheimer disease (AD) and related disorders is rapidly progressing. Such biomarkers may be used clinically to screen the population, to enhance diagnosis, or to help determine prognosis. Although the use of precision medicine methods has contributed to enhanced understanding of the AD pathophysiological changes and development of assays, one aspect not commonly considered is sex differences.

CONTENT

There are several ways in which sex can affect the concentration or interpretation of biofluid biomarkers. For some markers, concentrations will vary by sex. For others, the concentrations might not vary by sex, but the impact or interpretation may vary by sex depending on the context of use (e.g., diagnostic vs prognostic). Finally, for others, there will be no sex differences in concentrations or their interpretation. This review will first provide a basis for sex differences, including differences in brain structure and function, and the means by which these differences could contribute to sex differences in biomarker concentrations. Next, the current state of sex differences in AD-related biofluid markers (i.e., amyloid-β, phosphorylated τ, total τ, neurofilament light chain, and neurogranin) will be reviewed. Lastly, factors that can lead to the misinterpretation of observed sex differences in biomarkers (either providing evidence for or against) will be considered.

SUMMARY

This review is intended to provide an impetus to consider sex differences in the measurement and interpretation of AD-related biofluid-based biomarkers.

2021 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including incidence and prevalence, mortality and morbidity, use and costs of care, and the overall impact on caregivers and society. The Special Report discusses the challenges of providing equitable health care for people with dementia in the United States. An estimated 6.2 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060 barring the development of medical breakthroughs to prevent, slow or cure AD. Official death certificates recorded 121,499 deaths from AD in 2019, the latest year for which data are available, making Alzheimer's the sixth-leading cause of death in the United States and the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2019, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 145%. This trajectory of deaths from AD was likely exacerbated in 2020 by the COVID-19 pandemic. More than 11 million family members and other unpaid caregivers provided an estimated 15.3 billion hours of care to people with Alzheimer's or other dementias in 2020. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $256.7 billion in 2020. Its costs, however, extend to family caregivers' increased risk for emotional distress and negative mental and physical health outcomes - costs that have been aggravated by COVID-19. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are more than three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 23 times as great. Total payments in 2021 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $355 billion. Despite years of efforts to make health care more equitable in the United States, racial and ethnic disparities remain - both in terms of health disparities, which involve differences in the burden of illness, and health care disparities, which involve differences in the ability to use health care services. Blacks, Hispanics, Asian Americans and Native Americans continue to have a higher burden of illness and lower access to health care compared with Whites. Such disparities, which have become more apparent during COVID-19, extend to dementia care. Surveys commissioned by the Alzheimer's Association recently shed new light on the role of discrimination in dementia care, the varying levels of trust between racial and ethnic groups in medical research, and the differences between groups in their levels of concern about and awareness of Alzheimer's disease. These findings emphasize the need to increase racial and ethnic diversity in both the dementia care workforce and in Alzheimer's clinical trials.

Cognitive decline among European retirees: impact of early retirement, nation-related and personal characteristics

Our study aimed to enhance understanding of memory decline (MD) in old age by evaluating longitudinal effects of personal and national contributing factors. We used data collected by the Survey of Health, Ageing and Retirement in Europe (SHARE) from 12 European countries and Israel. Our sample included 11,930 retirees aged 50+, interviewed at baseline and four years later. MD was evaluated by the change in the number of recalled words from first to second interview. Except for gender, all of our explanatory variables had a significant unique effect on MD – age, education, type of occupation, European geographical region, early retirement, time elapsed from retirement, reason for retirement, active lifestyle, re-employment, health/function status, depressive symptoms, and decline in physical and mental health – over the four years of the study. Our findings indicate that MD can be postponed by national policies such as those which prolong years of education and participation in the workforce, and by social interventions directed to promote active lifestyles in late life, especially in Mediterranean and Eastern European nations.

Trends in the prevalence of cognitive impairment in Chinese older adults: based on the Chinese Longitudinal Healthy Longevity Survey cohorts from 1998 to 2014

In the context of a rapidly ageing Chinese population, this study aims to examine trends in the prevalence of cognitive impairment among people ≥65 y of age in China. Our sample is 72 821 adults aged 65–105 y from the seven waves of the Chinese Longitudinal Healthy Longevity Survey, a national mixed longitudinal cohort. The Chinese version of the Mini-Mental State Examination was used to measure CI. Risk factor-adjusted prevalence trend was examined using multilevel regression models. Age-standardized prevalence of cognitive impairment increased from 11.00% in 1998 to 11.84% in 2008 and decreased to 8.88% in 2014. Older age, female gender, less education, rural residence, not married, lack of physical and cognitive activities, suffering from stroke, vision and hearing impairment, and activities of daily living disability were negatively associated with cognitive impairment. Our study suggests a decreasing trend of cognitive impairment prevalence in China. However, whether decreasing prevalence will contribute to a reduced burden of cognitive impairment given the ageing of the population is unknown.

Dissecting Sex-Related Cognition between Alzheimer's Disease and Diabetes: From Molecular Mechanisms to Potential Therapeutic Strategies

The brain is a sexually dimorphic organ that implies different functions and structures depending on sex. Current pharmacological approaches against different neurological diseases act distinctly in male and female brains. In all neurodegenerative diseases, including Alzheimer's disease (AD), sex-related outcomes regarding pathogenesis, prevalence, and response to treatments indicate that sex differences are important for precise diagnosis and therapeutic strategy. Pathogenesis of AD includes vascular dementia, and in most cases, this is accompanied by metabolic complications with similar features as those assembled in diabetes. This review discusses how AD-associated dementia and diabetes affect cognition in relation to sex difference, as both diseases share similar pathological mechanisms. We highlight potential protective strategies to mitigate amyloid-beta (Aβ) pathogenesis, emphasizing how these drugs act in the male and female brains.

Sex differences in the blood-brain barrier and neurodegenerative diseases

The number of people diagnosed with neurodegenerative diseases is on the rise. Many of these diseases, including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and motor neuron disease, demonstrate clear sexual dimorphisms. While sex as a biological variable must now be included in animal studies, sex is rarely included in in vitro models of human neurodegenerative disease. In this Review, we describe these sex-related differences in neurodegenerative diseases and the blood-brain barrier (BBB), whose dysfunction is linked to neurodegenerative disease development and progression. We explain potential mechanisms by which sex and sex hormones affect BBB integrity. Finally, we summarize current in vitro BBB bioengineered models and highlight their potential to study sex differences in BBB integrity and neurodegenerative disease.

Sex Differences in Cognitive Decline Among US Adults

Importance

Sex differences in dementia risk are unclear, but some studies have found greater risk for women.

Objective

To determine associations between sex and cognitive decline in order to better understand sex differences in dementia risk.

Design, Setting, and Participants

This cohort study used pooled analysis of individual participant data from 5 cohort studies for years 1971 to 2017: Atherosclerosis Risk in Communities Study, Coronary Artery Risk Development in Young Adults Study, Cardiovascular Health Study, Framingham Offspring Study, and Northern Manhattan Study. Linear mixed-effects models were used to estimate changes in each continuous cognitive outcome over time by sex. Data analysis was completed from March 2019 to October 2020.

Exposure

Sex.

Main Outcomes and Measures

The primary outcome was change in global cognition. Secondary outcomes were change in memory and executive function. Outcomes were standardized as t scores (mean [SD], 50 [10]); a 1-point difference represents a 0.1-SD difference in cognition.

Results

Among 34 349 participants, 26 088 who self-reported Black or White race, were free of stroke and dementia, and had covariate data at or before the first cognitive assessment were included for analysis. Median (interquartile range) follow-up was 7.9 (5.3-20.5) years. There were 11 775 (44.7%) men (median [interquartile range] age, 58 [51-66] years at first cognitive assessment; 2229 [18.9%] Black) and 14 313 women (median [interquartile range] age, 58 [51-67] years at first cognitive assessment; 3636 [25.4%] Black). Women had significantly higher baseline performance than men in global cognition (2.20 points higher; 95% CI, 2.04 to 2.35 points; P < .001), executive function (2.13 points higher; 95% CI, 1.98 to 2.29 points; P < .001), and memory (1.89 points higher; 95% CI, 1.72 to 2.06 points; P < .001). Compared with men, women had significantly faster declines in global cognition (-0.07 points/y faster; 95% CI, -0.08 to -0.05 points/y; P < .001) and executive function (-0.06 points/y faster; 95% CI, -0.07 to -0.05 points/y; P < .001). Men and women had similar declines in memory (-0.004 points/y faster; 95% CI, -0.023 to 0.014; P = .61).

Conclusions and Relevance

The results of this cohort study suggest that women may have greater cognitive reserve but faster cognitive decline than men, which could contribute to sex differences in late-life dementia.

Testing the Cognitive Reserve Index Questionnaire in an Alzheimer's Disease Population

Background

Alzheimer's disease (AD) is the 6th leading cause of death in the United States and has no cure or progression prevention. The Cognitive Reserve (CR) theory poses that constant brain activity earlier in life later helps to deter pathological changes in the brain, delaying the onset of disease symptoms.

Objective

To determine the reliability and validity of the Cognitive Reserve Index questionnaire (CRIq) in AD patients.

Methods

Primary data collection was done using the CRIq to quantify CR in 90 participants. Correlations and multivariable linear regressions were used to assess reliability and validity.

Results

Reliability was tested in 34 participants. A Pearson correlation coefficient of 0.89 (p < 0.001) indicated a strong positive correlation. Validity was tested in 33 participants. A Pearson correlation coefficient of 0.30 (p = 0.10) indicated an insignificant weak positive correlation.

Conclusion

The CRIq was found reliable. Gaining a better understanding of how CR tools can be used in various cognitive populations will help with the establishment of a research tool that is universally accepted as a true CR measure.

AAV delivery of shRNA against IRS1 in GABAergic neurons in rat hippocampus impairs spatial memory in females and male rats

Brain insulin resistance is a major factor leading to impaired cognitive function and it is considered as the onset of Alzheimer´s disease. Insulin resistance is intimately linked to inflammatory conditions, many studies have revealed how pro-inflammatory cytokines lead to insulin resistance, by inhibiting IRS1 function. Thus, the dysfunction of insulin signaling is concomitant with inflammatory biomarkers. However, the specific effect of IRS1 impaired function in otherwise healthy brain has not been dissected out. So, we decided in our study, to study the specific role of IRS1 in the hippocampus, in the absence of comorbidities. To that end, shRNA against rat and human IRS1 was designed and tested in cultured HEK cells to evaluate mRNA levels and specificity. The best candidate sequence was encapsulated in an AAV vector (strain DJ8) under the control of the cytomegalovirus promoter and together with the green fluorescent protein gene as a reporter. AAV-CMV-shIRS1-EGFP and control AAV-CMV-EGFP were inoculated into the dorsal hippocampus of female and male Wistar rats. One month later, animals undertook a battery of behavioral paradigms evaluating spatial and social memory and anxiety. Our results suggest that females displayed increased susceptibility to AAV-shIRS1 in the novel recognition object paradigm; whereas both females and males show impaired performance in the T maze when infected with AAV-shIRS1 compared to control. Anxiety parameters were not affected by AAV-shIRS1 infection. We observed specific fluorescence within the hilum of the dentate gyrus, in immuno-characterized parvalbumin and somatostatin neurons. AAV DJ8 did not enter astrocytes. Intense green fibers were found in the fornix, mammillary bodies, and in the medial septum indicating that hippocampal efferent had been efficiently targeted by the AAV DJ8 infection. We observed that AAV-shIRS1 reduced significantly synaptophysin labeling in hippocampal-septal projections compared to controls. These results support that, small alterations in the insulin/IGF1 pathway in specific hippocampal circuitries can underlie alterations in synaptic plasticity and affect behavior, in the absence of inflammatory conditions.

APOEɛ4 Gene Dose and Sex Effects on Alzheimer's Disease MRI Biomarkers in Older Adults with Mild Cognitive Impairment

Background:

APOEɛ4 and sex have been linked to increased risk for conversion to Alzheimer’s disease (AD). However, the relationship between APOEɛ4 gene dose, sex, and AD biomarkers remains understudied.

Objective:

To investigate the effect of APOEɛ4 dose on AD biomarkers in a sample of older adults with mild cognitive impairment (MCI), and to examine whether APOEɛ4 dose modifies AD risk differently in MCI women and men.

Methods:

We examined cross-sectional AD biomarkers for participants with MCI (n = 930, 55–96 years old) from three large aging cohorts. Region of interest MRI volumes, global cognition, and episodic memory were analyzed by number of APOEɛ4 alleles and stratified by sex.

Results:

Across all participants, number of APOEɛ4 alleles was associated with smaller hippocampal and amygdala volumes and poorer cognition. When stratified by sex, women showed an APOEɛ4 dose effect for bilateral hippocampal and left amygdala volumes and cognition. In contrast, men showed an APOEɛ4 dose effect for hippocampal volumes with a trend in amygdala, but cognition did not differ between men with 1 and 2 APOEɛ4 alleles. Women with 2 APOEɛ4 alleles had poorer memory between 65–69 and poorer global cognition between 70–74 compared to men with 2 APOEɛ4 alleles.

Conclusion:

APOEɛ4 confers a dose effect on AD biomarkers in patients with MCI, and the number of APOEɛ4 alleles has a greater detrimental impact in women than men, which may be specific to a critical time window.