Depressive symptoms and incidence of mild cognitive impairment and probable dementia in elderly women: the Women's Health Initiative Memory Study

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.

Neuroprotective effect of hormone replacement therapy: a review of the literature

OBJECTIVE

Menopause is a physiological period characterized by the cessation of ovarian activity. Sequential changes during this transition affect multiple systems, including the brain. Sixty percent of women experience cognitive impairment. The objective of this review is to show the neuroprotective effect of hormone replacement therapy (HRT) through the different scales and whether there is a benefit of this in women.

METHOD

A search was conducted in six databases. Eligibility criteria included women within 10 years of menopause, receiving HRT controlled with placebo, studies lasting more than 6 months and women without a history of chronic underlying pathology.

RESULTS

A total of nine randomized controlled trials met the inclusion criteria. Regarding memory, two studies reported better performance of HRT with a significant odds ratio (OR) of 0.67; regarding attention, one study reported potential improvement in women receiving HRT with a significant OR of 0.87; and neuroimaging assessment found an increase in ventricular volume compared to placebo over a 3-year period.

CONCLUSIONS

The early initiation of menopausal HRT in healthy women appears to yield a positive effect on certain cognitive aspects, such as attention and cortical volume in the central nervous system. These findings should be confirmed through future prospective studies.

Association between depression and young-onset dementia in middle-aged women

BACKGROUND

Dementia is associated with older adults; however, it can also affect younger individuals, known as young-onset dementia (YOD), when diagnosed before the age of 65 years. We aimed to conduct a retrospective cohort study involving middle-aged women to investigate the association between premorbid depression and YOD development.

METHODS

We included 1.6 million women aged 40-60 years who underwent health checkups under the Korean National Health Insurance Service and investigated the association between depression and YOD.

RESULTS

Women with depression had a significantly higher risk of developing YOD than women without depression. Among premenopausal women, those with depression had a 2.67-fold increased risk, whereas postmenopausal women with depression had a 2.50-fold increased risk. Late age at menarche (> 16 years) and young age at menopause (< 40 years) was associated with an increased risk of YOD.

CONCLUSIONS

Depression in middle-aged women is a significant risk factor for the development of YOD. Understanding the role of reproductive factors can aid in the development of targeted therapeutic interventions to prevent or delay YOD.

Mental Health and Cognition in Women Veterans Enrolled in the Health of Vietnam Era Veteran Women's Study (HealthViEWS)

Objective: This analysis explored relationships between mental health symptoms and conditions and cognitive function in a cohort of Vietnam-era women veterans from the Health of Vietnam Era Veteran Women's Study (HealthViEWS). Methods: Vietnam-era women veterans completed a mail survey assessing self-reported symptom severity of posttraumatic stress disorder (PTSD) and depression. A telephone-based structured interview assessed mental health conditions and cognitive function (telephone interview for cognitive status [TICS]). Participants were categorized using a TICS threshold of ≤29 to designate possible cognitive impairment versus nonimpaired. Separate logistic regression models were used to determine associations between possible cognitive impairment and each self-reported and interviewer-rated assessment of PTSD and depression while adjusting for age, education, race, marital status, and wartime service location. Results: The sample consisted of 4,077 women veterans who were ≥60 years old and completed the TICS. Of these women, 7.20% were categorized with possible cognitive impairment. Logistic regression models indicated that self-reported PTSD and depression symptom severity were each significantly associated with higher odds of possible cognitive impairment (adjusted odds ratios [aOR]: 1.03 [95% confidence interval [CI]: 1.02-1.04] and 1.07 [95% CI: 1.04-1.09], respectively). Women veterans with a probable diagnosis of depression had higher odds of possible cognitive impairment compared to those without depression (aOR: 1.61 [95% CI: 1.07-2.42]). No association was found for probable diagnosis of PTSD. Conclusions: Although further examination remains necessary, results suggest that Vietnam-era women veterans with self-reported PTSD and depression symptom severity or a probable diagnosis of depression may benefit from screening of cognitive function to inform clinical care.

Relationships of depression and antidepressant use with epigenetic age acceleration and all-cause mortality among postmenopausal women

We investigated relations of depressive symptoms, antidepressant use, and epigenetic age acceleration with all-cause mortality risk among postmenopausal women. Data were analyzed from ≤1,900 participants in the Women's Health Initiative study testing four-way decomposition models. After a median 20.4y follow-up, 1,161 deaths occurred. Approximately 11% had elevated depressive symptoms (EDS+), 7% were taking antidepressant medication at baseline (ANTIDEP+), while 16.5% fell into either category (EDS_ANTIDEP+). Baseline ANTIDEP+, longitudinal transition into ANTIDEP+ and accelerated epigenetic aging directly predicted increased mortality risk. GrimAge DNA methylation age acceleration (AgeAccelGrim) partially mediated total effects of baseline ANTIDEP+ and EDS_ANTIDEP+ on all-cause mortality risk in socio-demographic factors-adjusted models (Pure Indirect Effect >0, P < 0.05; Total Effect >0, P < 0.05). Thus, higher AgeAccelGrim partially explained the relationship between antidepressant use and increased all-cause mortality risk, though only prior to controlling for lifestyle and health-related factors. Antidepressant use and epigenetic age acceleration independently predicted increased all-cause mortality risk. Further studies are needed in varying populations.

20-year depressive symptoms, dementia, and structural neuropathology in older women

INTRODUCTION

The course of depressive symptoms and dementia risk is unclear, as are potential structural neuropathological common causes.

METHODS

Utilizing joint latent class mixture models, we identified longitudinal trajectories of annually assessed depressive symptoms and dementia risk over 21 years in 957 older women (baseline age 72.7 years old) from the Women's Health Initiative Memory Study. In a subsample of 569 women who underwent structural magnetic resonance imaging, we examined whether estimates of cerebrovascular disease and Alzheimer's disease (AD)-related neurodegeneration were associated with identified trajectories.

RESULTS

Five trajectories of depressive symptoms and dementia risk were identified. Compared to women with minimal symptoms, women who reported mild and stable and emerging depressive symptoms were at the highest risk of developing dementia and had more cerebrovascular disease and AD-related neurodegeneration.

DISCUSSION

There are heterogeneous profiles of depressive symptoms and dementia risk. Common neuropathological factors may contribute to both depression and dementia. Highlights The progression of depressive symptoms and concurrent dementia risk is heterogeneous. Emerging depressive symptoms may be a prodromal symptom of dementia. Cerebrovascular disease and AD are potentially shared neuropathological factors.

Loneliness, social isolation, and cardiovascular disease among nonveteran and veteran women

We examined the prospective associations of social isolation and loneliness with incident cardiovascular disease (CVD) among aging nonveteran and veteran women, and effect modification by veteran status. Participants with no history of myocardial infarction (MI), stroke, coronary heart disease (CHD), or coronary heart failure from the Women's Health Initiative Extension Study II self-reported social isolation, loneliness, health behaviors, health status, and veteran status. CVD and CVD subevents were physician adjudicated. Hazard ratios (HR) and 95% confidence intervals (CI) for the Interquartile Range (IQR) in social isolation (IQR = 1) and loneliness (IQR=.33) were calculated using Cox proportional hazard models adjusting for sociodemographic, health behavior, and health status characteristics. Veteran status was tested as an effect modifier. Among 52,442 women (Mean age = 79 ± 6.1; veterans n = 1023; 89.2% non-Hispanic White), 3579 major CVD events occurred over an average 5.8 follow-up years. Compared to nonveterans, veteran women reported higher levels of social isolation (p < .01) and loneliness (p < .01). The CVD HR was 1.07 (95% CI, 1.04-1.10) for the IQR in social isolation and 1.03 (95% CI, 1.10-1.06) for the IQR in loneliness. The HR for the IQR in both social isolation and loneliness was 1.10 (95% CI, 1.05-1.15). Social isolation was associated with CHD (HR = 1.12; 95% CI, 1.03-1.21). The CHD HR for the IQR in social isolation was 1.12 (95% CI, 1.03-1.21). Associations did not differ by veteran status (all p-interactions > 0.08). Findings suggest that the adverse associations of social isolation and loneliness with CVD are similar among veteran and nonveteran women.

Combining artificial neural networks and a marginal structural model to predict the progression from depression to Alzheimer's disease

Introduction

Decades of research in population health have established depression as a likely precursor to Alzheimer's disease. A combination of causal estimates and machine learning methods in artificial intelligence could identify internal and external mediating mechanisms that contribute to the likelihood of progression from depression to Alzheimer's disease.

Methods

We developed an integrated predictive model, combining the marginal structural model and an artificial intelligence predictive model, distinguishing between patients likely to progress from depressive states to Alzheimer's disease better than each model alone.

Results

The integrated predictive model achieved substantial clinical relevance when using the area under the curve measure. It performed better than the traditional statistical method or a single artificial intelligence method alone.

Discussion

The integrated predictive model could form a part of a clinical screening tool that identifies patients who are likely to progress from depression to Alzheimer's disease for early behavioral health interventions. Given the high costs of treating Alzheimer's disease, our model could serve as a cost-effective intervention for the early detection of depression before it progresses to Alzheimer's disease.

Depressive symptoms and antidepressant use in relation to white blood cell count among postmenopausal women from the Women's Health Initiative

Inflammation can play a role in the pathophysiology of depression, and specific types of antidepressants may have inflammatory or anti-inflammatory properties. Furthermore, depression and antidepressant use has been linked to white blood cell (WBC) count, a routinely measured inflammatory marker. We examined the cross-sectional and longitudinal relationships of depressive symptoms and/or antidepressant use with WBC count among postmenopausal women. Analyses of cross-sectional data at enrollment were performed on 125,307 participants, 50-79 years of age, from the Women's Health Initiative Clinical Trials and Observational Studies who met eligibility criteria, and a subset of those with 3-year follow-up data were examined for longitudinal relationships. Depressive symptoms were defined using the Burnam Algorithm whereas antidepressant use was defined using therapeutic class codes. WBC count (Kcell/ml) was obtained through laboratory evaluations of fasting blood samples. Multivariable regression modeling was performed taking sociodemographic, lifestyle and health characteristics into consideration. At enrollment, nearly 85% were non-users of antidepressants with no depressive symptoms, 5% were antidepressant users with no depressive symptoms, 9% were non-users of antidepressants with depressive symptoms, and 2% were users of antidepressants with depressive symptoms. In fully-adjusted models, cross-sectional relationships were observed whereby women in the 2nd (OR = 1.06, 95% CI: 1.01, 1.13), 3rd (OR = 1.06, 95% CI: 1.00, 1.12) or 4th (OR = 1.10, 95% CI: 1.05, 1.17) quartiles of WBC count were more likely to exhibit depressive symptoms, and women in the 4th quartile were more likely to be users of antidepressants (OR = 1.07, 95% CI: 1.00, 1.15), compared to women in the 1st quartile. Compared to women who exhibited no depressive symptoms at either visit, those with consistent depressive symptoms at enrollment and at 3-year follow-up had faster decline in WBC count (β = -0.73, 95% CI: -1.33, -0.14) over time. No significant bidirectional relationships were observed between changes in depressive symptoms score and WBC count over time. In conclusion, depressive symptoms and/or antidepressant use were cross-sectionally related to higher WBC counts among postmenopausal women. Further evaluation of observed relationships is needed in the context of prospective cohort studies involving older adult men and women, with repeated measures of depression, antidepressant use, and WBC count.

Leveraging electronic health records and knowledge networks for Alzheimer's disease prediction and sex-specific biological insights

Identification of Alzheimer's disease (AD) onset risk can facilitate interventions before irreversible disease progression. We demonstrate that electronic health records from the University of California, San Francisco, followed by knowledge networks (for example, SPOKE) allow for (1) prediction of AD onset and (2) prioritization of biological hypotheses, and (3) contextualization of sex dimorphism. We trained random forest models and predicted AD onset on a cohort of 749 individuals with AD and 250,545 controls with a mean area under the receiver operating characteristic of 0.72 (7 years prior) to 0.81 (1 day prior). We further harnessed matched cohort models to identify conditions with predictive power before AD onset. Knowledge networks highlight shared genes between multiple top predictors and AD (for example, APOE, ACTB, IL6 and INS). Genetic colocalization analysis supports AD association with hyperlipidemia at the APOE locus, as well as a stronger female AD association with osteoporosis at a locus near MS4A6A. We therefore show how clinical data can be utilized for early AD prediction and identification of personalized biological hypotheses.

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.

Depression as a Risk Factor for Dementia: A Meta-Analysis

Dementia is a syndrome characterized by the deterioration of cognitive function beyond what is expected. The increased risk of developing this syndrome resulting from established modifiable risk factors, such as depressive episodes, is currently a subject of interest. The aim of this study was to review the scientific evidence that addresses the relationship between depression and dementia. A bibliographic search of the PubMed and PsycInfo databases for articles published over the past 20 years was conducted with the following medical subject heading terms: depression or depressive, dementia, and incidence or cohort studies. After articles meeting the inclusion criteria were selected, relevant moderating variables were grouped as sample characteristics, methodological characteristics, extrinsic characteristics, and outcome variables. The 26 selected studies resulted in a sample comprising 1,760,262 individuals. Statistical analysis revealed a pooled relative risk for the development of dementia of 1.82 (95% CI=1.62-2.06). The primary variables evaluated were the diagnostic methods for depression and dementia and the presence of depression. Other variables, such as mean age, methodological quality of each study, follow-up time, and publication year, were also evaluated. Age was statistically but not clinically significant. No relevant publication bias or alterations in the results were found when accounting for the quality of the studies. It is recommended that new moderating variables be evaluated or that existing variables be reformulated in future studies.

Temporal relationship between depression and cognitive decline in the elderly: a two-wave cross-lagged study in a Chinese sample

Objectives: Less information is available about the temporal relationship between depression in the elderly and cognitive decline. In the current study, we (1) evaluated the temporal association between depression and cognitive decline in older adults over a 4-year period; (2) indicated which cognitive domains have a strong temporal relationship with depression.Methods: Using data from China Family Panel Studies, we examined the relationship between depression and cognition among adults aged 65 and older with a cross-lagged design.Results: The results showed that initial depression affected subsequent cognitive function, especially immediate and delayed recall, but that cognition decline did not predict depression over time.Conclusion: The findings suggest that depression precedes cognitive decline in older adults, which is of great significance for the future research of mild cognitive impairment and dementia in the elderly.

Risk assessment and stratification of mild cognitive impairment among the Chinese elderly: attention to modifiable risk factors

BACKGROUND

The early identification of individuals at risk of mild cognitive impairment (MCI) has major public health implications for Alzheimer's disease prevention.

OBJECTIVE

This study aims to develop and validate a risk assessment tool for MCI with a focus on modifiable factors and a suggested risk stratification strategy.

METHODS

Modifiable risk factors were selected from recent reviews, and risk scores were obtained from the literature or calculated based on the Rothman-Keller model. Simulated data of 10 000 subjects with the exposure rates of the selected factors were generated, and the risk stratifications were determined by the theoretical incidences of MCI. The performance of the tool was verified using cross-sectional and longitudinal datasets from a population-based Chinese elderly cohort.

RESULTS

Nine modifiable risk factors (social isolation, less education, hypertension, hyperlipidaemia, diabetes, smoking, drinking, physical inactivity and depression) were selected for the predictive model. The area under the curve (AUC) was 0.71 in the training set and 0.72 in the validation set for the cross-sectional dataset. The AUCs were 0.70 and 0.64 in the training and validation sets, respectively, for the longitudinal dataset. A combined risk score of 0.95 and 1.86 was used as the threshold to categorise MCI risk as 'low', 'moderate' and 'high'.

CONCLUSION

A risk assessment tool for MCI with appropriate accuracy was developed in this study, and risk stratification thresholds were also suggested. The tool might have significant public health implications for the primary prevention of MCI in elderly individuals in China.

Putative pathological mechanisms of late-life depression and Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder that is characterized by progressive impairment in cognition and memory. AD is accompanied by several neuropsychiatric symptoms, with depression being the most prominent. Although depression has long been known to be associated with AD, controversial findings from preclinical and clinical studies have obscured the precise nature of this association. However recent evidence suggests that depression could be a prodrome or harbinger of AD. Evidence indicates that the major central serotonergic nucleus-the dorsal raphe nucleus (DRN)-shows very early AD pathology: neurofibrillary tangles made of hyperphosphorylated tau protein and degenerated neurites. AD and depression share common pathophysiologies, including functional deficits of the serotonin (5-HT) system. 5-HT receptors have modulatory effects on the progression of AD pathology i.e., reduction in Aβ load, increased hyper-phosphorylation of tau, decreased oxidative stress etc. Moreover, preclinical models show a role for specific channelopathies that result in abnormal regional activational and neuroplasticity patterns. One of these concerns the pathological upregulation of the small conductance calcium-activated potassium (SK) channel in corticolimbic structure. This has also been observed in the DRN in both diseases. The SKC is a key regulator of cell excitability and long-term potentiation (LTP). SKC over-expression is positively correlated with aging and cognitive decline, and is evident in AD. Pharmacological blockade of SKCs has been reported to reverse symptoms of depression and AD. Thus, aberrant SKC functioning could be related to depression pathophysiology and diverts its late-life progression towards the development of AD. We summarize findings from preclinical and clinical studies suggesting a molecular linkage between depression and AD pathology. We also provide a rationale for considering SKCs as a novel pharmacological target for the treatment of AD-associated symptoms.

Sex Differences in Alzheimer's Disease

Reviewing the research presented in this article, it is evident that from an epidemiological perspective, it is important to evaluate the extent to which findings of sex and gender differences in Alzheimer's dementia (AD) are due to differences in longevity, survival bias, and comorbidities. Medical, genetic, psychosocial, and behavioral factors, in addition to hormonal factors, can differentially affect the risk and progression of AD in women versus men. Further, evaluation of sex differences in AD progression and the trajectory of change in cognitive function, neuroimaging, cerebrospinal fluid (CSF), and blood-based biomarkers of AD is needed. Finally, identifying sex differences in AD biomarkers and change across the lifespan is critical for the planning of prevention trials to reduce the risk of developing AD.

A Cross-sectional Assessment of Depression, Anxiety, and Cognition in Perimenopausal and Menopausal Women

Introduction

Menopausal transition involves failure of ovarian function followed by cessation of menstruation. This has been said to lead to psychiatric comorbidities such as depression and anxiety. Estrogen also has beneficial effects on cognition and thus fluctuation in the same can lead to cognitive decline. Given the number of women undergoing menopause, timely screening of the comorbidities is of importance.

Aims and Objectives

Our study aimed at assessment of anxiety, depression, and cognitive impairment in perimenopausal and postmenopausal women presenting in the medicine and gynecology units of a tertiary care hospital. The objectives were to screen the peri- and postmenopausal women presenting with medical and gynecological complaints for the presence of depression and anxiety and assess their cognitive function. To find association of their symptoms with psychosocial and menopausal factors with the psychiatric parameters.

Settings and Design

Our study was conducted among the perimenopausal and postmenopausal women visiting gynecology and medicine units in a tertiary care hospital. One hundred and five women in the age group of 45-55 were assessed using a specialized pro forma, Beck's Anxiety Inventory, Beck's Depression Inventory, and Addenbrooke's Cognitive Examination III.

Statistical Analysis Used

The results were analyzed using SPSS software (version 20.0).

Results

21.9% of females had moderate levels of anxiety, 24.76% had clinical depression, and 13.33% had mild cognitive impairment. The presence of psychosocial stressors had a significant impact on the anxiety, depression, and cognitive impairment. There was no significant association found between psychiatric parameters and peri- and postmenopausal stage as well between natural or surgical menopause.

Associations Between Changes in Loneliness and Social Connections, and Mental Health During the COVID-19 Pandemic: The Women's Health Initiative

BACKGROUND

Older women have faced significant disruptions in social connections during the coronavirus disease 2019 pandemic. Whether loneliness increased or whether a change in loneliness from pre- to intrapandemic period was associated with mental health during the pandemic is unknown.

METHODS

Older women (n = 27 479; mean age 83.2 [SD: 5.4] years) completed surveys in mid-2020, including questions about loneliness, living arrangements, changes in social connections, and mental health. Loneliness was also previously assessed in 2014-2016. We examined whether loneliness changed from the pre- to intrapandemic period and explored factors associated with this change. In multivariable models, we investigated the association of changes in loneliness and social connections with mental health.

RESULTS

Loneliness increased from pre- to intrapandemic levels. Factors associated with worsening loneliness included older age, experiencing stressful life events, bereavement, histories of vascular disease and depression, and social connection disruptions. Factors associated with a decrease in loneliness included identifying as Black, engaging in more frequent physical activity, being optimistic, and having a higher purpose in life. A 3-point increase in loneliness scores was associated with higher perceived stress, higher depressive, and higher anxiety symptoms. Social connection disruptions showed modest or no associations with mental health.

CONCLUSIONS

Loneliness increased during the pandemic in older women and was associated with higher stress, depressive, and anxiety symptoms. Our findings point to opportunities for interventions targeting lifestyle behaviors, well-being, disrupted social connections, and paying closer attention to those with specific medical and mental health histories that may reduce loneliness and improve mental health.

Association of Global Cognitive Function With Psychological Distress and Adherence to Public Health Recommendations During the Coronavirus Disease 2019 Pandemic: The Women's Health Initiative

BACKGROUND

The association of cognitive function with symptoms of psychological distress during the coronavirus disease 2019 (COVID-19) pandemic or adherence to COVID-19 protective health behaviors is not well-understood.

METHODS

We examined 2 890 older women from the Women's Health Initiative cohort. Prepandemic (ie, within 12 months prior to pandemic onset) and peripandemic global cognitive function scores were assessed with the modified Telephone Interview for Cognitive Status (TICS-m). Anxiety, stress, and depressive symptom severity during the pandemic were assessed using validated questionnaires. We examined adherence to protective behaviors that included safe hygiene, social distancing, mask wearing, and staying home. Multivariable models were adjusted for age, race, ethnicity, education, region of residence, alcohol intake, and comorbidities.

RESULTS

Every 5-point lower prepandemic TICS-m score was associated with 0.33-point mean higher (95% confidence interval [CI], 0.20, 0.45) perceived stress and 0.20-point mean higher (95% CI, 0.07, 0.32) depressive symptom severity during the pandemic. Higher depressive symptom severity, but not anxiety or perceived stress, was associated with a 0.69-point (95% CI, -1.13, -0.25) mean decline in TICS-m from the prepandemic to peripandemic period. Every 5-point lower peripandemic TICS-m score was associated with 12% lower odds ratio (OR, 0.88; 95% CI, 0.80, 0.97) of practicing safe hygiene.

CONCLUSIONS

Among older women, we observed that: (a) lower prepandemic global cognitive function was associated with higher stress and depressive symptom severity during the pandemic; (b) higher depressive symptom severity during the pandemic was associated with cognitive decline; and (c) lower global cognitive function during the pandemic was associated with lower odds of practicing safe hygiene.

Hormone therapy and the decreased risk of dementia in women with depression: a population-based cohort study

Background

The literature has shown depression to be associated with an increased risk of dementia. In addition, hormone therapy can be a responsive treatment option for a certain type of depression. In this study, we examined the association between hormone therapy, including lifetime oral contraceptive (OC) use, and hormone replacement therapy (HRT) after menopause with the occurrence of dementia among female patients with depression.

Methods

The South Korean national claims data from January 1, 2005, to December 31, 2018, was used. Female subjects aged 40 years or older with depression were included in the analyses. Information on hormone therapy was identified from health examination data and followed up for the occurrence of dementia during the average follow-up period of 7.72 years.

Results

Among 209,588 subjects, 23,555 were diagnosed with Alzheimer’s disease (AD) and 3023 with vascular dementia (VD). Lifetime OC usage was associated with a decreased risk of AD (OC use for < 1 year: HR, 0.92 [95% CI, 0.88–0.97]; OC use for ≥ 1 year: HR, 0.89 [95% CI, 0.84–0.94]), and HRT after menopause was associated with a decreased risk of AD (HRT for < 2 years: HR, 0.84 [95% CI, 0.79–0.89]; HRT for 2–5 years: HR, 0.80 [95% CI, 0.74–0.88]; and HRT for ≥ 5 years : HR, 0.78 [95% CI, 0.71–0.85]) and VD (HRT < 2 years: HR, 0.82 [95% CI, 0.71–0.96]; HRT for 2–5 years: HR, 0.81 [95% CI, 0.64–1.02]; and HRT for ≥ 5 years: HR, 0.61 [95% CI, 0.47–0.79]).

Conclusions

In this nationwide cohort study, lifetime OC use was associated with a decreased risk of AD, and HRT after menopause was associated with a decreased risk of AD and VD among female patients with depression. However, further studies are needed to establish causality.

B vitamin intakes modify the association between particulate air pollutants and incidence of all-cause dementia: Findings from the Women's Health Initiative Memory Study

INTRODUCTION

Particulate air pollutants may induce neurotoxicity by increasing homocysteine levels, which can be lowered by high B vitamin intakes. Therefore, we examined whether intakes of three B vitamins (folate, B12 , and B6 ) modified the association between PM2.5 exposure and incidence of all-cause dementia.

METHODS

This study included 7183 women aged 65 to 80 years at baseline. B vitamin intakes from diet and supplements were estimated by food frequency questionnaires at baseline. The 3-year average PM2.5 exposure was estimated using a spatiotemporal model.

RESULTS

During a mean follow-up of 9 years, 342 participants developed all-cause dementia. We found that residing in locations with PM2.5 exposure above the regulatory standard (12 μg/m3 ) was associated with a higher risk of dementia only among participants with lower intakes of these B vitamins.

DISCUSSION

This is the first study suggesting that the putative neurotoxicity of PM2.5 exposure may be attenuated by high B vitamin intakes.

Fluctuation of depressive symptoms in cognitively unimpaired participants and the risk of mild cognitive impairment 5 years later: Results of the Heinz Nixdorf Recall study

BACKGROUND

Depression might be an independent risk factor for cognitive decline, a prodromal dementia symptom or a reaction to cognitive/functional impairment.

OBJECTIVE

To investigate the association between (1) depressive symptoms and (2) depressive symptom patterns over 13 years with incident mild cognitive impairment (MCI) 5 years later.

MATERIALS AND METHODS

We included 724/823 cognitively unimpaired men/women who participated in the population-based Heinz Nixdorf Recall study (t1: 2005-2008, ø62.9 years; t2: 2010-2015, ø68.1 years). Depressive symptoms were assessed in the study center and during six postal follow-ups using the short form of the Center for Epidemiologic Studies Depression Scale (CES-D). Relative risks (RR; 95% confidence intervals) for MCI at t2 (men/women: 71/76) were estimated for CES-D at t1 (linear and dichotomized at ≥17, cut-off for clinically relevant depressive symptoms) and CES-D fluctuations over 13 years (stable low, large fluctuations, stable high/stable around cut-off) using log-linear regression models with Poisson working likelihood adjusted for age, sex, education, diabetes mellitus, coronary heart disease, and stroke.

RESULTS

Fully adjusted risk for MCI at t2 (per CES-D point increase at t1) was elevated for the total cohort (1.053, 1.031-1.076), men (1.046, 1.012-1.081), and women (1.059, 1.029-1.090). Applying the dichotomized CES-D, risk for MCI was substantially increased for the total cohort [2.22 (1.38-3.58)] and in women [2.59 (1.46-4.58)]. Large CES-D fluctuations and stable high/stable around cut-off were associated with increased RR for MCI in the total cohort and in women compared to stable low symptoms.

CONCLUSION

Depressive symptoms predicted MCI in cognitively unimpaired participants of our population-based study. Adequate treatment of depression may therefore contribute to the maintenance of normal cognition and delay dementia onset.

Reduced Hippocampal and Anterior Cingulate Expression of Antioxidant Enzymes and Membrane Progesterone Receptors in Alzheimer's Disease with Depression

BACKGROUND

Major depressive disorder (MDD) is a risk factor for dementia including that caused by Alzheimer's disease (AD). Both MDD and AD have a higher prevalence in women than men, and estrogen-related processes have been implicated in this sex difference.

OBJECTIVE

To identify if enhanced oxidative stress and decreased expression of the memory enhancer insulin-like growth factor 2 (IGF2), each implicated separately in MDD and AD, are exaggerated in individuals with both AD and MDD compared to those with AD.

METHODS

Expression of target genes are determined by qPCR in postmortem hippocampus (Hip) and anterior cingulate cortex (ACC) of individuals with dementia and autopsy confirmed AD and those of AD+MDD.

RESULTS

Transcript levels of the antioxidant enzymes catalase (CAT) and superoxide dismutase 1 (SOD1), as well as IGF2 and its receptor (IGF2R) were significantly lower in the Hip and ACC of individuals with both AD and MDD compared to those with AD and no MDD. Expressions of Progestin and AdipoQ Receptor Family Member 7 (PAQR7, alias progesterone receptor alpha, mPRa) and PAQR8 (mPRβ), receptors that bind neurosteroids, were also lower in the Hip and ACC of AD+MDD samples compared to those of AD without MDD. Correlations among these transcripts revealed that estrogen receptor 2 (ESR2) and mPR β are direct or indirect regulators of the expression of the antioxidant enzymes and IGF2R.

CONCLUSION

Reduced levels of antioxidant enzymes, decreased IGF2 expression, and diminished estrogen or membrane progesterone receptor-dependent processes might be more pronounced in the subpopulation of individuals with AD and MDD than without MDD.

Deep phenotyping of Alzheimer's disease leveraging electronic medical records identifies sex-specific clinical associations

Alzheimer's Disease (AD) is a neurodegenerative disorder that is still not fully understood. Sex modifies AD vulnerability, but the reasons for this are largely unknown. We utilize two independent electronic medical record (EMR) systems across 44,288 patients to perform deep clinical phenotyping and network analysis to gain insight into clinical characteristics and sex-specific clinical associations in AD. Embeddings and network representation of patient diagnoses demonstrate greater comorbidity interactions in AD in comparison to matched controls. Enrichment analysis identifies multiple known and new diagnostic, medication, and lab result associations across the whole cohort and in a sex-stratified analysis. With this data-driven method of phenotyping, we can represent AD complexity and generate hypotheses of clinical factors that can be followed-up for further diagnostic and predictive analyses, mechanistic understanding, or drug repurposing and therapeutic approaches.

Menopause and cognitive impairment: A narrative review of current knowledge

A severe impairment of cognitive function characterizes dementia. Mild cognitive impairment represents a transition between normal cognition and dementia. The frequency of cognitive changes is higher in women than in men. Based on this fact, hormonal factors likely contribute to cognitive decline. In this sense, cognitive complaints are more common near menopause, a phase marked by a decrease in hormone levels, especially estrogen. Additionally, a tendency toward worsened cognitive performance has been reported in women during menopause. Vasomotor symptoms (hot flashes, sweating, and dizziness), vaginal dryness, irritability and forgetfulness are common and associated with a progressive decrease in ovarian function and a subsequent reduction in the serum estrogen concentration. Hormone therapy (HT), based on estrogen with or without progestogen, is the treatment of choice to relieve menopausal symptoms. The studies conducted to date have reported conflicting results regarding the effects of HT on cognition. This article reviews the main aspects of menopause and cognition, including the neuroprotective role of estrogen and the relationship between menopausal symptoms and cognitive function. We present and discuss the findings of the central observational and interventional studies on HT and cognition.

Geriatric Depression and Cognitive Impairment-An Update

BACKGROUND

Depression and cognitive impairment often coexist in older adults. The relation between depression and cognitive impairment is complex. The objective of this article is to review recent literature on cognitive impairment in older adults with depression and provide clinicians an update.

METHODS

We searched PubMed, Google Scholar, Science Direct, and Psych Info for the articles published in the English language related to late-life depression (LLD)/geriatric depression and cognitive impairment. We considered original research articles, relevant systematic reviews, chapters, and important conceptual articles published in the last 9 years (2011-2019). We selected relevant articles for this narrative review.

CONCLUSION

The concept pseudodementia, indicating depression with cognitive impairment mimicking dementia, is now seen only as a historical concept. The current literature strongly agrees with fact that cognitive deficits often exist in LLD. The cognitive deficits in depression were initially seen as trait marker; however, some recent studies suggest that cognitive deficits persist even in the remission phase. There is heterogeneity among the studies in terms of the nature of the cognitive deficits, but higher number of studies reported impairment in attention and executive function. LLD with cognitive deficits is at a higher risk of progression to dementia. In older adults, depression with cognitive impairments requires a comprehensive evaluation. Electroencephalography, event-related potentials, fluorodeoxyglucose-positron emission tomography, amyloid positron emission tomography, and CSF amyloid will supplement clinical evaluation in differentiating functional depressive disorder with cognitive impairment from depression with an underlying degenerative condition.

The mediating and moderating effects of depression on the relationship between cognitive function and difficulty in activities of daily living among postmenopausal women

OBJECTIVE

Cognitive function and depression impact critically the daily functioning of menopausal women. This study aimed to explore the mediating and moderating effects of depressive symptoms on the association between cognitive function and activities of daily living (ADL) difficulty in postmenopausal women.

METHODS

A total of 2,596 postmenopausal women from the China Health and Retirement Longitudinal Study completed the Chinese version of the Mini-Mental State Examination, basic ADL (BADL) and instrumental ADL (IADL) scales, and 10-item Short-Form Center for Epidemiological Studies Depression. We constructed structural equation modeling to examine the association between cognitive function, depressive symptoms, and BADL/IADL difficulty.

RESULTS

The prevalence of BADL/IADL difficulty in postmenopausal women was 22.5% and 31.5%, respectively. After adjustments for demographic and health-related covariates, cognitive decline (contributed by four cognitive dimensions with different weights) was significantly associated with BADL/IADL difficulty (contributed by six-item daily activities with different weights). Depressive symptoms mediated and explained 28.8% and 23.2% of cognitive function associations with BADL and IADL difficulty, respectively. The Johnson-Neyman technique identified a threshold of eight and four for depressive symptoms, beyond which the protective effect of cognitive function on BADL and IADL emerged.

CONCLUSIONS

Depressive symptoms mediated and moderated the association between cognition and BADL/IADL difficulty in postmenopausal women. Compared with BADL, IADL may be more sensitive to changes in cognitive function. More strength should be put on developing comprehensive intervention techniques focusing on simultaneous intervention of multidimensional cognitive function and depression to maintain and improve the quality of life of postmenopausal women.

Risk of Dementia in persons who have previously experienced clinically-significant Depression, Anxiety, or PTSD: A Systematic Review and Meta-Analysis

BACKGROUND

Depression, anxiety and PTSD appear to be linked to dementia, but it is unclear whether they are risk factors (causal or prodromal) for, comorbid with, or sequelae to (secondary effect of) dementia. Existing meta-analyses have examined depression or anxiety in all-cause dementia, Alzheimer's disease (AD) and vascular dementia (VaD), but have not considered post-traumatic stress disorder (PTSD), dementia with Lewy bodies (DLB), or frontotemporal dementia (FTD). The current meta-analysis examined the risk of developing dementia (AD, VaD, DLB, FTD, all-cause) in people with and without a history of clinically-significant depression, anxiety or PTSD in order to better understand the link between mental illness and dementia (PROSPERO number: CRD42018099872).

METHODS

PubMed, EMBASE, PsycINFO and CINAHL searches identified 36 eligible studies.

RESULTS

There is a higher risk of developing all-cause dementia and AD in people with previous depression, and a higher risk of all-cause dementia in people with prior anxiety, than in persons without this history. Prior PTSD was not associated with a higher risk of later being diagnosed with dementia.

LIMITATIONS

The data for anxiety, PTSD, DLB and FTD were limited.

CONCLUSIONS

Depression and anxiety appear to be risk factors for dementia, but longitudinal studies across adulthood (young adult/mid-life/older adult) are needed to evaluate the likely causal or prodromal nature of this risk. The link between PTSD and dementia remains unclear. Regular screening for new onset mental illness and for cognitive changes in older adults with a history of mental illness may assist with earlier identification of dementia.

Treatment-Resistant depression enhances risks of dementia and alzheimer's disease: A nationwide longitudinal study

BACKGROUND

Previous evidence indicates late-onset depression or depression with greater severity are associated with subsequent risk of dementia or Alzheimer's disease (AD). However, whether treatment-resistant depression is associated with such risks remain elusive.

METHODS

Using the Taiwan Nationwide Health Insurance Research Database, 3,345 patients with newly-diagnosed major depressive disorder (MDD) and 13,380 well-matched controls were enrolled between 2002 and 2004. MDD patients were stratified according to their treatment response to adequate antidepressant trials, and all participants were followed up until the end of 2013. Those who developed dementia and AD were identified.

RESULTS

MDD patients were more likely to develop dementia and AD than controls. Difficult-to-treat patients (i.e., DTT; those who failed to respond to at least two adequate antidepressant trials) had the highest risk of developing dementia (hazard ratio [HR] = 5.19) and AD (HR 4.44), whereas easy-to-treat patients (i.e., ETT-1; those who had no prescription of antidepressants) had the lowest risk of developing dementia (HR 2.37) and AD (HR 2.59) compared with controls. Subsequent analysis demonstrated that only among patients with late-onset depression (age > 65 years), DTT patients consistently showed higher risks and faster development of dementia (HR 6.64, mean: 1.45 yr) and AD (HR 4.97, mean: 1.67 yr) than did ETT-1 patients and controls.

LIMITATIONS

Subjects who have not received medical examination were not included as diagnosis were determined by ICD codes. Also, longer follow-up period might be needed for the younger group.

CONCLUSIONS

Late-onset treatment-resistant depression is associated with an elevated risk of dementia and AD.

Neuropsychiatric symptoms as prognostic makers for the elderly with mild cognitive impairment: a meta-analysis

BACKGROUND

Although several neuropsychiatric symptoms (NPSs) have been demonstrated to have value in the prediction of the progression of mild cognitive impairment (MCI) to dementia, these symptoms are less studied for the prediction of the transition from normal cognition (NC) to MCI.

METHODS

Prospective cohort studies were included if they reported on at least one NPS at baseline and had MCI as the outcome.

RESULTS

We obtained 13 cohort studies with a total population of 33,066. Depression was the most common neuropsychiatric symptom and could significantly predict transition to MCI (RR = 1.49, 95% CI: 1.13-1.86). However, depression was more capable of predicting amnestic MCI (RR=1.43, 95% CI: 1.04-1.83) than non-aMCI (RR= 0.96, 95% CI 95% CI: 0.60-1.33). Subgroup analysis suggested that the association between depression and MCI changed with depression severity, depression criteria, apolipoprotein-E-adjusted status, age, the percentage of females, and follow-up times, but some data were too sparse for a reliable estimate. Regarding other NPSs, there were insufficient data to assess their effect on the development of MCI. However, apathy, anxiety, sleep disturbances, irritability, and agitation might be risk factors for the prediction of NC-MCI transition with strong predictive value.

CONCLUSIONS

Depression was associated with an approximately 1.5-fold sincreased risk of the progression to MCI in the population with normal cognition. Other NPSs with underlying predictive value deserve more attention.

Depression-an underrecognized target for prevention of dementia in Alzheimer's disease

It is broadly acknowledged that the onset of dementia in Alzheimer's disease (AD) may be modifiable by the management of risk factors. While several recent guidelines and multidomain intervention trials on prevention of cognitive decline address lifestyle factors and risk diseases, such as hypertension and diabetes, a special reference to the established risk factor of depression or depressive symptoms is systematically lacking. In this article we review epidemiological studies and biological mechanisms linking depression with AD and cognitive decline. We also emphasize the effects of antidepressive treatment on AD pathology including the molecular effects of antidepressants on neurogenesis, amyloid burden, tau pathology, and inflammation. We advocate moving depression and depressive symptoms into the focus of prevention of cognitive decline and dementia. We constitute that early treatment of depressive symptoms may impact on the disease course of AD and affect the risk of developing dementia and we propose the need for clinical trials.

Depressive symptoms as predictors of visual memory deficits in middle-age

BACKGROUND

Depression has been known to affect memory and other cognitive domains. The objective of this longitudinal cohort study was to investigate longitudinal associations between depressive symptoms at age 31 years and visual memory and new learning at the age of 46 years. We investigated whether depressive symptoms at age 31 predicted visual memory deficits at age 46 years, and whether changes in depressive symptoms between 31 and 46 years predicted visual memory at age 46.

METHODS

Participants were members of the Northern Finland Birth Cohort 1966. Depressive symptoms were assessed with the Symptom Checklist-25 (SCL-25) on both occasions. Visual memory and new learning were assessed using Paired Associative Learning (PAL) test at the age 46 follow-up. PAL total errors adjusted and first trial memory score were used as outcomes and basic educational level, relationship status, physical activity and diet at baseline were considered as confounding factors in linear regression analysis.

RESULTS

A total of 5029 (57% female) participants were included in the main analysis. No associations were found between depressive symptoms or change in depressive symptoms and visual memory and new learning scores. The result did not change following cut-offs 1.55 and 1.75 for depression.

LIMITATIONS

SCL-25 only measures symptoms during the past week. Only one cognitive domain was assessed.

CONCLUSIONS

Contrary to our hypothesis, neither baseline depressive symptoms nor change in depressive symptoms predicted visual memory scores 15 years later. It appears that sub-clinical depressive symptoms do not effect this cognitive domain in the middle-aged population.

Dementia in Women

Despite the progress made in the understanding of the etiology, neuropathophysiology, and treatment of different types of dementia, such disorders continue to pose huge health problems worldwide. The differential effect of the burden of disease on women is just being realized. These effects range from direct effects of the disease processes themselves, the way women experience the disease, and the caregiver burden. This article provides a brief overview of the available information on this topic.

A 'Framingham-like' Algorithm for Predicting 4-Year Risk of Progression to Amnestic Mild Cognitive Impairment or Alzheimer's Disease Using Multidomain Information

BACKGROUND

There are no agreed-upon variables for predicting progression from unimpaired cognition to amnestic mild cognitive impairment (aMCI), or from aMCI to Alzheimer's disease (AD).

OBJECTIVE

Use ADNI data to develop a 'Framingham-like' prediction model for a 4-year period.

METHODS

We developed models using the strongest baseline predictors from six domains (demographics, neuroimaging, CSF biomarkers, genetics, cognitive tests, and functional ability). We chose the best predictor from each domain, which was dichotomized into more versus less harmful.

RESULTS

There were 224 unimpaired individuals and 424 aMCI subjects with baseline data on all predictors, of whom 37 (17% ) and 150 (35% ) converted to aMCI and AD, respectively, during 4 years of follow-up. For the unimpaired, CSF tau/Aβ ratio, hippocampal volume, and a memory score predicted progression. For those aMCI at baseline, the same predictors plus APOE4 status and functional ability predicted progression. Demographics and family history were not important predictors for progression for either group. The fit statistic was good for the unimpaired-aMCI model (C-statistic 0.80) and very good for the aMCI-AD model (C-statistic 0.91). Among the unimpaired, those with no harmful risk factors had a 4-year predicted 2% risk of progression, while those with the most harmful risk factors had a predicted 35% risk. The aMCI subjects with no harmful risk factors had a predicted 1% risk of progression those with all six harmful risk factors had a predicted 90% risk.

CONCLUSION

Our parsimonious model accurately predicted progression from unimpaired to aMCI with three variables, and from aMCI to AD with five variables.

Sex differences in Alzheimer's disease: Understanding the molecular impact

Alzheimer's disease (AD) is a common neurodegenerative disorder that presents with cognitive impairment and behavioral disturbance. Approximately 5.5 million people in the United States live with AD, most of whom are over the age of 65 with two-thirds being woman. There have been major advancements over the last decade or so in the understanding of AD neuropathological changes and genetic involvement. However, studies of sex impact in AD have not been adequately integrated into the investigation of disease development and progression. It becomes indispensable to acknowledge in both basic science and clinical research studies the importance of understanding sex-specific differences in AD pathophysiology and pathogenesis, which could guide future effort in the discovery of novel targets for AD. Here, we review the latest and most relevant literature on this topic, highlighting the importance of understanding sex dimorphism from a molecular perspective and its association to clinical trial design and development in AD research field.

Depressive symptoms in relation to clinical symptom onset of mild cognitive impairment

ABSTRACTObjective:There is increasing evidence of an association between depressive symptoms and mild cognitive impairment (MCI) in cross-sectional studies, but the longitudinal association between depressive symptoms and risk of MCI onset is less clear. The authors investigated whether baseline symptom severity of depression was predictive of time to onset of symptoms of MCI.

METHOD

These analyses included 300 participants from the BIOCARD study, a cohort of individuals who were cognitively normal at baseline (mean age = 57.4 years) and followed for up to 20 years (mean follow-up = 2.5 years). Depression symptom severity was measured using the Hamilton Depression Scale (HAM-D). The authors assessed the association between dichotomous and continuous HAM-D and time to onset of MCI within 7 years versus after 7 years from baseline (reflecting the mean time from baseline to onset of clinical symptoms in the cohort) using Cox regression models adjusted for gender, age, and education.

RESULTS

At baseline, subjects had a mean HAM-D score of 2.2 (SD = 2.8). Higher baseline HAM-D scores were associated with an increased risk of progression from normal cognition to clinical symptom onset ≤ 7 years from baseline (p = 0.043), but not with progression > 7 years from baseline (p = 0.194). These findings remained significant after adjustment for baseline cognition.

CONCLUSIONS

These results suggest that low levels of depressive symptoms may be predictive of clinical symptom onset within approximately 7 years among cognitively normal individuals and may be useful in identifying persons at risk for MCI due to Alzheimer's disease.

Negative Affect Is Associated With Higher Risk of Incident Cognitive Impairment in Nondepressed Postmenopausal Women

Background

Positive affect (PA) and negative affect (NA) reflect subjective emotional experiences. Although related to depression and anxiety, these dimensions are distinct constructs representing affective states and patterns. Prior studies suggest that elevated depressive symptoms are associated with risk of mild cognitive impairment (MCI) and probable dementia, but whether affective states are associated with cognitive impairment is still unknown. The present study examined relationships between baseline affective states and cognitive impairment (MCI, probable dementia) in nondepressed women.

Method

Baseline PA and NA were assessed in postmenopausal women (N = 2,137; mean age = 73.8 years) from the Women's Health Initiative Study of Cognitive Aging (WHISCA) using the Positive and Negative Affect Schedule (PANAS). Women were followed annually for an average of 11.3 years; those with elevated depressive symptoms at baseline were excluded.

Results

Higher NA was associated with a higher risk of MCI and probable dementia, even after adjusting for important covariates including age, education, sociodemographic, lifestyle, and cardiovascular risk factors, global cognition, and hormone therapy assignment at baseline. PA was not significantly associated with either outcome.

Conclusions

We present the first evidence to date that greater NA, even in the absence of elevated depressive symptoms, is associated with higher risk of MCI and dementia. This suggests that NA may be an important, measureable and potentially modifiable risk factor for age-related cognitive decline.

The effect of hormone replacement therapy on cognitive function in postmenopausal women: An RCT

Background

During the reproductive age, the human brain becomes a target for gonadal steroid hormones. Estrogens influence neural function through effects on neurons and affects indirectly the oxidative stress, inflammation, the cerebral vascular and the immune system.

Objective

To evaluate the effect of the traditional hormone replacement therapy (HRT) on the cognitive function in postmenopausal women.

Materials and Methods

In this randomized clinical trial, 140 postmenopausal women, from November 2014 to February 2015, were included. Women were randomly divided into two groups. Each woman in the case group took traditional HRT (0.625mg conjugated equine estrogens+2.5mg medroxyprogesterone acetate daily) plus one Cal+D tablet (500 mg calcium+200 IU vitamin D) daily for four months. Women in the control group received only one Cal+D tablet (500 mg calcium+200 IU vitamin D) daily for four months period. The Montreal Cognitive Assessment (MoCA) and Green Climacteric Scale (GCS) questionnaires filled out after the intervention and compared between the two groups.

Results

The mean points of the MoCA after the intervention indicate that all MoCA domains except for the orientation improved in the case group. There was a significant difference in the memory domain after the treatment between the two groups. MoCA domains and GCS were negatively correlated after the intervention (r=-0.235,p=0.006).

Conclusion

The HRT has affected some of the MoCA factors. The effects of HRT on cognitive function should be studied in a large prospective study in a group of women in their early and late menopausal ages with periodic assessment of their cognitive function during these follow-up years.

Military-related risk factors in female veterans and risk of dementia

OBJECTIVE

To determine whether diagnoses of traumatic brain injury (TBI), posttraumatic stress disorder (PTSD), and depression, alone or in combination, increase dementia risk among older female veterans.

METHODS

This cohort study included data from 109,140 female veterans ≥55 years of age receiving care from Veterans Health Administration medical centers in the United States between October 2004 and September 2015 with at least 1 follow-up visit. TBI, PTSD, depression, and medical conditions at study baseline and incident dementia were determined according to ICD-9-CM codes. Fine-Gray proportional hazards models were used to determine the association between military-related risk factors and dementia diagnosis, accounting for the competing risk of death.

RESULTS

During follow-up (mean 4.0 years, SD 2.3), 4% of female veterans (n = 4,125) developed dementia. After adjustment for demographics and medical conditions, women with TBI, PTSD, and depression had a significant increase in risk of developing dementia compared to women without these diagnoses (TBI-adjusted subdistribution hazard ratio [adjusted sHR] 1.49, 95% confidence interval [CI] 1.01-2.20; PTSD adjusted sHR 1.78, 95% CI 1.34-2.36; and depression-adjusted sHR 1.67, 95% CI 1.55-1.80), while women with >1 diagnosis had the highest risk for dementia (adjusted sHR 2.15, 95% CI 1.84-2.51).

CONCLUSIONS

We found that women with military-related risk factors had an ≈50% to 80% increase in developing dementia relative to women without these diagnoses, while female veterans with multiple risk factors had a >2-fold risk of developing dementia. These findings highlight the need for increased screening of TBI, PTSD, and depression in older women, especially female veterans.

Cognition and its association with the factors of the EURO-D: Suffering and Motivation. Findings from SHARE Wave 6

The aims of this study were (1) to analyse the relationship between cognition and clinical and sociodemographic variables, (2) to explore the relationship between cognitive tests and factors of EURO-D depression scale (Suffering and Motivation), and (3) to determine the relevance of cognition with respect to clinical and sociodemographic variables in the scores of the EURO-D factors.

METHOD

About 63 755 participants in the Survey of Health, Ageing and Retirement in Europe (SHARE) Wave 6 (2015) were included. Instruments are as follows: the SHARE study, the EURO-D scale, and cognitive tests. Bivariate, correlation, and multiple linear regression analyses were performed.

RESULTS

In the regression analysis with cognition, the variables associated with poor cognition were higher age (β = .29), lower educational level (β = -.26), economic difficulties (β = .17), and depression (β = .10). The correlation between cognition and EURO-D factors was weak in Suffering (r = -0.139) and moderate in Motivation (r = -0.382). In the regression analysis with the EURO-D, loneliness, poor self-perceived physical health, female gender, and low cognition were associated with higher depression levels. The main differences in the predictor variables of each factor were cognition (Motivation = -0.248, P < .001; Suffering = 0.002, P = .648) and the female sex (Motivation = 0.015, P < .001, Suffering = 0.175, P < .001).

CONCLUSIONS

In the EURO-D depression scale, poor cognition was associated with higher scores in the Motivation factor only, while the female gender presented higher scores in the Suffering factor.

Understanding the impact of sex and gender in Alzheimer's disease: A call to action

INTRODUCTION

Precision medicine methodologies and approaches have advanced our understanding of the clinical presentation, development, progression, and management of Alzheimer's disease (AD) dementia. However, sex and gender have not yet been adequately integrated into many of these approaches.

METHODS

The Society for Women's Health Research Interdisciplinary Network on AD, comprised of an expert panel of scientists and clinicians, reviewed ongoing and published research related to sex and gender differences in AD.

RESULTS

The current review is a result of this Network's efforts and aims to: (1) highlight the current state-of-the-science in the AD field on sex and gender differences; (2) address knowledge gaps in assessing sex and gender differences; and (3) discuss 12 priority areas that merit further research.

DISCUSSION

The exclusion of sex and gender has impeded faster advancement in the detection, treatment, and care of AD across the clinical spectrum. Greater attention to these differences will improve outcomes for both sexes.

The Impact of Depression on the Development of Mild Cognitive Impairment over 3 Years of Follow-Up: A Population-Based Study

BACKGROUND/AIMS

In the absence of effective treatments for dementia, major efforts are being directed towards identifying the risk factors of the prodromal phase of the disease. We report the incidence rates of mild cognitive impairment (MCI) in a Spanish population sample and assess the effect of depression at baseline on incident MCI (or MCI subtypes) at a 3-year follow-up.

METHODS

A total of 1,642 participants (age ≥50 years) were examined as part of a Spanish nationally representative longitudinal study. MCI was defined as the presence of cognitive concerns, objective evidence of impairment in one or more cognitive domains, preservation of independence in functional abilities, and no dementia. Depression was assessed through an adaptation of the Composite International Diagnostic Interview (CIDI 3.0). Binary and multinomial logistic regression analyses were carried out to assess the associations.

RESULTS

The overall MCI incidence rate was 33.19 (95% CI = 26.02, 43.04) per 1,000 person-years. Depression at baseline predicted the onset of MCI at follow-up after controlling for sociodemographics, cognitive functioning, and other physical health conditions (OR = 2.79; 95% CI = 1.70, 4.59). The effect of baseline depression on incident MCI subtypes was as follows: amnestic MCI, OR = 3.81 (95% CI = 1.96, 7.43); nonamnestic MCI, OR = 2.03 (95% CI = 0.98, 4.21).

CONCLUSION

Depression significantly increases the risk for MCI. Targeting depression among those at risk for dementia may help delay or even prevent the onset of dementia.

Premature hippocampus-dependent memory decline in middle-aged females of a genetic rat model of depression

Aging and major depressive disorder are risk factors for dementia, including Alzheimer's Disease (AD), but the mechanism(s) linking depression and dementia are not known. Both AD and depression show greater prevalence in women. We began to investigate this connection using females of the genetic model of depression, the inbred Wistar Kyoto More Immobile (WMI) rat. These rats consistently display depression-like behavior compared to the genetically close control, the Wistar Kyoto Less Immobile (WLI) strain. Hippocampus-dependent contextual fear memory did not differ between young WLI and WMI females, but, by middle-age, female WMIs showed memory deficits compared to same age WLIs. This deficit, measured as duration of freezing in the fear provoking-context was not related to activity differences between the strains prior to fear conditioning. Hippocampal expression of AD-related genes, such as amyloid precursor protein, amyloid beta 42, beta secretase, synucleins, total and dephosphorylated tau, and synaptophysin, did not differ between WLIs and WMIs in either age group. However, hippocampal transcript levels of catalase (Cat) and hippocampal and frontal cortex expression of insulin-like growth factor 2 (Igf2) and Igf2 receptor (Igf2r) paralleled fear memory differences between middle-aged WLIs and WMIs. This data suggests that chronic depression-like behavior that is present in this genetic model is a risk factor for early spatial memory decline in females. The molecular mechanisms of this early memory decline likely involve the interaction of aging processes with the genetic components responsible for the depression-like behavior in this model.

Optimism predicts sustained vigorous physical activity in postmenopausal women

Optimism and cynical hostility are associated with health behaviors and health outcomes, including morbidity and mortality. This analysis assesses their association with longitudinal vigorous physical activity (PA) in postmenopausal women of the Women's Health Initiative (WHI). Subjects include 73,485 women nationwide without history of cancer or cardiovascular disease (CVD), and no missing baseline optimism, cynical hostility, or PA data. The Life Orientation Test-Revised Scale measured optimism. A Cook Medley questionnaire subscale measured cynical hostility. Scale scores were divided into quartiles. Vigorous PA three times or more per week was assessed via self-report at study baseline (1994–1998) and through follow-up year 6. Descriptive analysis mapped lifetime trajectories of vigorous PA (recalled at ages 18, 25, 50; prospectively assessed at baseline, and 3 and 6 years later). Hierarchical generalized linear mixed models examined the prospective association between optimism, cynical hostility, and vigorous PA over 6 years. Models adjusted for baseline sociodemographic variables, psychosocial characteristics, and health conditions and behaviors. Vigorous PA rates were highest for most optimistic women, but fell for all women by approximately 60% between age 50 and study baseline. In adjusted models from baseline through year 6, most vs. least optimistic women were 15% more likely to exercise vigorously (p < 0.001). Cynical hostility was not associated with lower odds of longitudinal vigorous PA after adjustment. Results did not differ by race/ethnicity or socioeconomic status. Higher optimism is associated with maintaining vigorous PA over time in post-menopausal women, and may protect women's health over the lifespan.

Particulate Air Pollutants, Brain Structure, and Neurocognitive Disorders in Older Women

Introduction

An increasing number of studies have suggested that exposure to particulate matter (PM) may represent a novel - and potentially amendable - environmental determinant of brain aging. The current longitudinal environmental epidemiological study addressed some important knowledge gaps in this emerging field, which combines the study of air pollution and neuroepidemiology. The investigators hypothesized that long-term PM exposure adversely influences global brain volume and brain regions (e.g., frontal lobe or hippocampus) that are critical to memory and complex cognitive processing or that are affected by neuropathological changes in dementia. It was also hypothesized that long-term PM exposure results in neurovascular damage and may increase the risk of mild cognitive impairment (MCI) and -dementia.

Methods

The investigators selected a well-characterized and geographically diverse population of older women (N = 7,479; average age = 71.0 ± 3.8 years at baseline) in the Women's Health Initiative (WHI) Memory Study (WHIMS) cohort (1996-2007), which included a subcohort (n = 1,403) enrolled in the WHIMS-Magnetic Resonance Imaging (WHIMS-MRI) study (2005-2006). Residence-specific yearly exposures to PM ≤ 2.5 µm in aerodynamic diameter (PM₂.₅) were estimated using a Bayesian maximum entropy spatiotemporal model of annual monitoring data (1999-2007) recorded in the U.S. Environmental Protection Agency (U.S. EPA) Air Quality System (AQS). Annual exposures (1996-2005) to diesel PM (DPM) were assigned to each residential census tract in a nationwide spatiotemporal mapping, based on a generalized additive model (GAM), to conduct census tract-specific temporal interpolation of DPM on-road estimates given by the U.S. EPA National-Scale Air Toxics Assessment Program. Multiple linear regression and multicovariate-adjusted Cox models were used to examine the associations, with statistical adjustment for multiple potential confounders.

Results

The investigators found that participants had smaller brain volumes, especially in the normal-appearing white matter (WM), if they lived in locations with higher levels of cumulative exposure (1999-2006) to PM ₂.₅ before the brain MRI scans were performed. The associations were not explained by sociodemographic factors, socioeconomic status, lifestyle factors, or other clinical characteristics. Analyses showed that the adverse effect on brain structure in the participants was driven primarily by the smaller WM volumes associated with cumulative PM₂.₅ exposures, which were present in the WM divisions of the association brain area (frontal, parietal, and temporal lobes) and corpus callosum. Increased DPM exposures were associated with larger ventricular volume, suggesting an overall atrophic effect on the aging brains. The participants tended to have smaller gray matter (GM) volumes if they lived in areas with the highest (i.e., fourth quartile) estimated cumulative DPM exposure in the 10 years before the brain MRI scans, compared with women in the first to third quartiles. This observed association was present in the total brain GM and in the association brain cortices. The associations with normal-appearing WM varied by DPM exposure range. For women with estimated cumulative exposure below that of the fourth quartile, increased DPM estimates were associated with smaller WM volumes. However, for women with increased cumulative DPM exposures estimates in the fourth quartile, WM volumes were larger. This pattern of association was found consistently in the association brain area; no measurable difference was found in the volume of the corpus callosum. These observed adverse effects of cumulative exposure to PM₂.₅ (linking exposure with smaller WM volumes) and to DPM (linking exposure in the highest quartile with smaller GM volumes) were not significantly modified by existing cardiovascular diseases, diabetes mellitus, obesity, or measured white blood cell (WBC) count. MRI measurements of the structural brain showed no differences in small-vessel ischemic diseases (SVID) in participants with varying levels of cumulative exposure to PM₂.₅ (1999-2006) or DPM (1996-2005), and no associations between PM exposures and SVID volumes were noted for total brain, association brain area, GM, or WM. For neurocognitive outcomes followed until 2007, the investigators found no evidence for increased risk of MCI/dementia associated with long-term PM exposures. Although exploratory secondary analyses showed different patterns of associations linking PM exposures separately with MCI and dementia, none of the -results was statistically significant. A similar lack of associations between PM exposures and MCI/dementia was found across the subgroups, with no strong indications for effect modification by cardiovascular diseases, diabetes mellitus, obesity, or WBC count.

Conclusions

The investigators concluded that their study findings support the hypothesized brain-structure neurotoxicity associated with PM exposures, a result that is in line with emerging neurotoxicological data. However, the investigators found no evidence of increased risk of MCI/dementia associated with long-term PM exposures.

To better test the neurovascular effect hypothesis in PM-associated neurotoxic effects on the aging brain, the investigators recommend that future studies pay greater attention to selecting optimal populations with repeated measurements of cerebrovascular damage and address the possibility of selection biases accordingly. To further investigate the long-term consequence of brain-structure neurotoxicity on pathological brain aging, future researchers should take the pathobiologically heterogeneous neurocognitive outcomes into account and design adequately powered prospective cohort studies with improved exposure estimation and valid outcome ascertainment to assess whether PM-associated neurotoxicity increases the risks of pathological brain aging, including MCI and dementia.

Genetic Analysis of Mitochondrial Ribosomal Proteins and Cognitive Aging in Postmenopausal Women

Genes encoding mitochondrial ribosomal proteins (MRPs) have been linked to aging and longevity in model organisms (i.e., mice, Caenorhabditis elegans). Here we evaluated if the MRPs have conserved effects on aging traits in humans. We utilized data from 4,504 participants of the Women's Health Initiative Memory Study (WHIMS) who had both longitudinal cognitive data and genetic data. Two aging phenotypes were considered: (1) gross lifespan (time to all-cause mortality), and (2) cognitive aging (longitudinal rate of change in modified mini-mental state scores). We tested genetic association with variants in 78 members of the MRP gene family. Genetic association tests were done at the single nucleotide polymorphism (SNP) level, and at gene-set level using two distinct procedures (GATES and MAGMA). We included SNPs in APOE and adjusted the tests for the APOE-ε4 allele, a known risk factor for dementia. The strongest association signal is for the known cognitive aging SNP, rs429358, in APOE (p-value = 5 × 10-28 for cognitive aging; p-value = 0.03 for survival). We found no significant association between the MRPs and survival time. For cognitive aging, we detected SNP level association for rs189661478 in MRPL23 (p-value < 9 × 10-6). Furthermore, the gene-set analysis showed modest but significant association between the MRP family and cognitive aging. In conclusion, our results indicate a potential pathway-level association between the MRPs and cognitive aging that is independent of the APOE locus. We however did not detect association between the MRPs and lifespan.