Sex Differences in Cognition Across Aging

Association between cognitive impairment and cardiovascular mortality in mature and older adults: A meta-analysis

BACKGROUND

Cognitive impairment contributes significantly to negative health outcomes. This meta-analysis aimed to investigate the association between cognitive impairment and cardiovascular mortality in mature and older adults.

METHODS

PubMed, Web of Science, and Embase databases were searched until February 10, 2024, to identify the association between cognitive impairment and cardiovascular mortality in mature and older adults (aged 50 years and older) from the general population. The adjusted risk estimates from the included studies were extracted and pooled using a random effects model.

RESULTS

Ten studies were included in the meta-analysis, involving 16,765 participants. The pooled hazard ratio (HR) of cardiovascular mortality was 1.75 (95 % confidence interval [CI] 1.44-2.14; I2 = 48.2 %) for individuals with cognitive impairment compared to those without, even after adjusting for common confounding factors. Subgroup analysis revealed that the prognostic value of cognitive impairment may be influenced by the assessment tools used for measuring cognition. Additionally, cognitive impairment significantly predicted cardiovascular mortality in women (HR 2.40; 95 % CI 1.54-3.74; I2 = 45.4 %) but not in men (HR 1.49; 95 % CI 0.99-2.24; I2 = 44.8 %).

CONCLUSIONS

Cognitive impairment is a significant predictor of cardiovascular mortality in mature and older adults from the general population. However, future studies are needed to evaluate the specific impact of cognitive impairment on different genders.

Relationship between sex, APOE genotype, endocannabinoids and cognitive change in older adults with metabolic syndrome during a 3-year Mediterranean diet intervention

BACKGROUND

The Mediterranean diet (MedDiet) has demonstrated efficacy in preventing age-related cognitive decline and modulating plasma concentrations of endocannabinoids (eCBs) and N-acylethanolamines (NAEs, or eCB-like compounds), which are lipid mediators involved in multiple neurological disorders and metabolic processes. Hypothesizing that eCBs and NAEs will be biomarkers of a MedDiet intervention and will be related to the cognitive response, we investigated this relationship according to sex and apolipoprotein E (APOE) genotype, which may affect eCBs and cognitive performance.

METHODS

This was a prospective cohort study of 102 participants (53.9% women, 18.8% APOE-ɛ4 carriers, aged 65.6 ± 4.5 years) from the PREDIMED-Plus-Cognition substudy, who were recruited at the Hospital del Mar Research Institute (Barcelona). All of them presented metabolic syndrome plus overweight/obesity (inclusion criteria of the PREDIMED-Plus) and normal cognitive performance at baseline (inclusion criteria of this substudy). A comprehensive battery of neuropsychological tests was administered at baseline and after 1 and 3 years. Plasma concentrations of eCBs and NAEs, including 2-arachidonoylglycerol (2-AG), anandamide (AEA), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and N-docosahexaenoylethanolamine (DHEA), were also monitored. Baseline cognition, cognitive changes, and the association between eCBs/NAEs and cognition were evaluated according to gender (crude models), sex (adjusted models), and APOE genotype.

RESULTS

At baseline, men had better executive function and global cognition than women (the effect size of gender differences was - 0.49, p = 0.015; and - 0.42, p = 0.036); however, these differences became nonsignificant in models of sex differences. After 3 years of MedDiet intervention, participants exhibited modest improvements in memory and global cognition. However, greater memory changes were observed in men than in women (Cohen's d of 0.40 vs. 0.25; p = 0.017). In men and APOE-ε4 carriers, 2-AG concentrations were inversely associated with baseline cognition and cognitive changes, while in women, cognitive changes were positively linked to changes in DHEA and the DHEA/AEA ratio. In men, changes in the OEA/AEA and OEA/PEA ratios were positively associated with cognitive changes.

CONCLUSIONS

The MedDiet improved participants' cognitive performance but the effect size was small and negatively influenced by female sex. Changes in 2-AG, DHEA, the OEA/AEA, the OEA/PEA and the DHEA/AEA ratios were associated with cognitive changes in a sex- and APOE-dependent fashion. These results support the modulation of the endocannabinoid system as a potential therapeutic approach to prevent cognitive decline in at-risk populations.

TRIAL REGISTRATION

ISRCTN89898870.

Age-related differences in network controllability are mitigated by redundancy in large-scale brain networks

The aging brain undergoes major changes in its topology. The mechanisms by which the brain mitigates age-associated changes in topology to maintain robust control of brain networks are unknown. Here we use diffusion MRI data from cognitively intact participants (n = 480, ages 40-90) to study age-associated differences in the average controllability of structural brain networks, topological features that could mitigate these differences, and the overall effect on cognitive function. We find age-associated declines in average controllability in control hubs and large-scale networks, particularly within the frontoparietal control and default mode networks. Further, we find that redundancy, a hypothesized mechanism of reserve, quantified via the assessment of multi-step paths within networks, mitigates the effects of topological differences on average network controllability. Lastly, we discover that average network controllability, redundancy, and grey matter volume, each uniquely contribute to predictive models of cognitive function. In sum, our results highlight the importance of redundancy for robust control of brain networks and in cognitive function in healthy-aging.

Hippocampal astrocytes induce sex-dimorphic effects on memory

Astrocytic receptors influence cognitive function and can promote behavioral deficits in disease. These effects may vary based on variables such as biological sex, but it is not known if the effects of astrocytic receptors are dependent on sex. We leveraged in vivo gene editing and chemogenetics to examine the roles of astrocytic receptors in spatial memory and other processes. We show that reductions in metabotropic glutamate receptor 3 (mGluR3), the main astrocytic glutamate receptor in adults, impair memory in females but enhance memory in males. Similarly, increases in astrocytic mGluR3 levels have sex-dependent effects and enhance memory in females. mGluR3 manipulations also alter spatial search strategies during recall in a sex-specific manner. In addition, acute chemogenetic stimulation of Gi/o-coupled or Gs-coupled receptors in hippocampal astrocytes induces bidirectional and sex-dimorphic effects on memory. Thus, astrocytes are sex-dependent modulators of cognitive function and may promote sex differences in aging and disease.

Integration of sex/gender and utilization of ecological Momentary assessment of cognition in clinical populations: a scoping review

Objectives: We aimed to describe the methods of smartphone-based cognitive ecological momentary assessment designs in clinical populations, with an intention to evaluate how the role of sex and/or gender has been considered in the design and analyses, particularly including female-specific physiology. Methods: This scoping review was conducted based on JBI scoping review methodology. On March 2nd, 2023, we searched for literature across four databases. Screening of the results and data extraction were conducted in duplicate according to the a priori methods in the pre-registered protocol. Results: 31 articles were included in this review. Participants ranged in age from 15-85 years old with various clinical disorders. Prompts were given between 1-7 times per day for 7-84 days. Executive function was the most frequently assessed cognitive domain. Over half the studies (n = 17, 55%) did not investigate the effects of sex and/or gender, and only one study considered the impact of hormonal therapy. Many studies (n = 14, 45%) used sex and gender interchangeably or incorrectly. Conclusions: Studies varied in design, with heterogeneity in the reporting of methodological information. The lack of attention to sex/gender on neuropsychological outcomes can lead to confusion and contradiction regarding its potential impact on cognition in clinical populations. This may hinder the identification of effective interventions for those assigned female at birth who have been overlooked or considered indistinguishable from their male counterparts. Given the well-documented impact of sex/gender on cognition, it is essential that future neuropsychological research, especially EMA-based studies, prioritize investigating sex/gender to ensure better outcomes for all.

Mechanisms underlying the association between adverse childhood experiences and racial disparities in later-life cognition

OBJECTIVE

Adverse childhood experiences (ACEs) may be a risk factor for later-life cognitive disorders such as dementia; however, few studies have investigated underlying mechanisms, such as cardiovascular health and depressive symptoms, in a health disparities framework.

METHOD

418 community-dwelling adults (50% nonHispanic Black, 50% nonHispanic White) aged 55+ from the Michigan Cognitive Aging Project retrospectively reported on nine ACEs. Baseline global cognition was a z-score composite of five factor scores from a comprehensive neuropsychological battery. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale. Cardiovascular health was operationalized through systolic blood pressure. A mediation model controlling for sociodemographics, childhood health, and childhood socioeconomic status estimated indirect effects of ACEs on global cognition via depressive symptoms and blood pressure. Racial differences were probed via t-tests and stratified models.

RESULTS

A negative indirect effect of ACEs on cognition was observed through depressive symptoms [β = -.040, 95% CI (-.067, -.017)], but not blood pressure, for the whole sample. Black participants reported more ACEs (Cohen's d = .21), reported more depressive symptoms (Cohen's d = .35), higher blood pressure (Cohen's d = .41), and lower cognitive scores (Cohen's d = 1.35) compared to White participants. In stratified models, there was a negative indirect effect through depressive symptoms for Black participants [β = -.074, 95% CI (-.128, -.029)] but not for White participants.

CONCLUSIONS

These results highlight the need to consider racially patterned contextual factors across the life course. Such factors could exacerbate the negative impact of ACEs and related mental health consequences and contribute to racial disparities in cognitive aging.

Increased Stress Is Associated With Severe Pain and Decrements in Cognitive Function in Patients Receiving Chemotherapy

OBJECTIVES

Purposes were to identify subgroups of adult oncology patients (n = 1342) with distinct joint profiles of worst pain and cognitive function (CF) and evaluate for differences in demographic and clinical characteristics, as well as the severity of three distinct types of stress, resilience, and coping.

DATA SOURCES

Measures of pain and CF were evaluated six times over two cycles of chemotherapy. The other measures of demographic and clinical characteristics, stress, resilience, and coping were completed at enrollment (ie, prior to the second or third cycle of chemotherapy).

RESULTS

Using latent profile analysis, four distinct profiles were identified (ie, no pain + moderate CF [27.6%], moderate pain + high CF [22.4%] moderate pain and moderate CF [32.4%, both moderate], severe pain and low CF [17.5%, both severe]). Both moderate and both severe classes reported higher global, cancer-specific, and cumulative life stress, lower levels of resilience, and greater use of disengagement coping strategies. The Both severe class had higher occurrence rates for a number of adverse childhood experiences (ie, family violence in childhood, physical abuse at <16 years, forced sex at <16 years). Risk factors associated with membership in the two worst profiles included: being female, having a lower annual income, having a higher comorbidity burden, and having a poorer functional status.

CONCLUSION

Findings suggest that 72.4% of the patients reported pain scores in the moderate to severe range and 77.6% reported low to moderate levels of CF. Clinicians need to assess for both symptoms and various types of stress on a routine basis.

Gender differences in prevalence and associations between cognitive symptoms and suicidal ideation in patients with recurrent major depressive disorder: findings from the Chinese NSSD study

BACKGROUND

This study aimed to explore gender differences in associations between cognitive symptoms and suicidal ideation (SI) among patients with recurrent major depressive disorder (MDD).

METHODS

We recruited 1222 patients with recurrent MDD from the National Survey on Symptomatology of Depression (NSSD), a survey designed to investigate the symptoms experienced during current major depressive episodes in China. A four-point Likert questionnaire was used to assess the frequency of cognitive symptoms and SI in the past two weeks.

RESULTS

Gender differences in clinical features and cognitive symptoms of participants with recurrent MDD were found. Specifically, male patients had a higher prevalence of memory loss, decreased verbal output, indecisiveness, and impaired interpersonal relationships, while female patients exhibited a higher prevalence of impaired social and occupational functioning (all P < 0.05). No significant difference in SI prevalence was found between male and female patients. The logistic regression analysis revealed that in male patients, SI was associated with indecisiveness and impaired interpersonal relationships. In female patients, reduced verbal output and impaired social and professional functions were also associated with SI in addition to the above-mentioned variables.

CONCLUSION

The findings of gender differences in associations between cognitive symptoms and SI highlight the need to carefully assess gender-specific cognitive predictors of SI in patients with recurrent MDD. This has further implications for more targeted prevention and treatment strategies for SI based on gender.

Estrogen receptor beta in astrocytes modulates cognitive function in mid-age female mice

Menopause is associated with cognitive deficits and brain atrophy, but the brain region and cell-specific mechanisms are not fully understood. Here, we identify a sex hormone by age interaction whereby loss of ovarian hormones in female mice at midlife, but not young age, induced hippocampal-dependent cognitive impairment, dorsal hippocampal atrophy, and astrocyte and microglia activation with synaptic loss. Selective deletion of estrogen receptor beta (ERβ) in astrocytes, but not neurons, in gonadally intact female mice induced the same brain effects. RNA sequencing and pathway analyses of gene expression in hippocampal astrocytes from midlife female astrocyte-ERβ conditional knock out (cKO) mice revealed Gluconeogenesis I and Glycolysis I as the most differentially expressed pathways. Enolase 1 gene expression was increased in hippocampi from both astrocyte-ERβ cKO female mice at midlife and from postmenopausal women. Gain of function studies showed that ERβ ligand treatment of midlife female mice reversed dorsal hippocampal neuropathology.