Association between Stressful Life Events and Cognitive Disorders in Central Africa: Results from the EPIDEMCA Program

Gender differences in the associations of psychosocial trauma and acute medical stressors with immune system activation and dementia risk

Objective: The purpose of this article is to provide a narrative review synthesizing the literature on differences between women and men in relationships among certain stressors associated with immune system activation and their relationship to cognitive dysfunction and dementia. Method: We review the cycle of stress leading to neuroinflammation via cortisol and neurochemical alterations, cell-mediated immune system activation, and pro-inflammatory cytokines, and how this is implicated in the development of dementia. We follow this by discussing sex differences in stress physiology and immune function. We then review the work on early life adversity (ELA) and adverse childhood experiences (ACEs), post-traumatic stress disorder, acute medical stressors, and their associations with cognitive dysfunction and dementia. Throughout, we emphasize women's presentations and issues unique to women (e.g. trauma disorder prevalence). Conclusions: There is a need for more mechanistic and longitudinal studies that consider trauma accumulation, both physical and emotional, as well as a greater focus on traumas more likely to occur in women (e.g. sexual abuse), and their relationship to early cognitive decline and dementia.

The Association Between Adverse Childhood Experiences and Late-Life Cognition: A Systematic Review of Cross-Sectional and Case-Control Studies

BACKGROUND AND OBJECTIVES

Adverse childhood experiences (ACEs) are a recognized risk factor for unfavorable health outcomes. No prior systematic review has explored the association between ACEs and cognition in late life, a critical period for cognitive fluctuation. The objective of this review is to address the following research question: What is the association between ACEs and late-life cognition?

RESEARCH DESIGN AND METHODS

Articles were obtained from PubMed, PsycINFO, and Scopus. The last search was performed in May 2021. Eligible articles examined the association between exposure to at least 1 ACE and the outcome of late-life cognition, measured either by cognitive testing or the presence/absence of a neurocognitive disorder. Data were synthesized narratively using the synthesis without meta-analysis guidelines, and the risk of bias was assessed using the Newcastle-Ottawa Scale (NOS) and Adapted NOS.

RESULTS

Twenty articles representing 18 unique studies were included in the narrative synthesis. Associations with lower late-life cognition were reported for: childhood maternal death, parental divorce, physical neglect, emotional neglect, physical abuse, and combinations of ACEs. However, most results were statistically nonsignificant, and many were unlikely to be clinically important.

DISCUSSION AND IMPLICATIONS

We found an association between ACEs and late-life cognition. However, the direction and magnitude of association varied between and within types of ACEs and measures of cognitive function. Most included articles had a moderate risk of bias. This review is the first attempt to synthesize the literature on this topic and it outlines the next steps to improve the evidence base in the area.

Is Stress an Overlooked Risk Factor for Dementia? A Systematic Review from a Lifespan Developmental Perspective

Stress exposure and stress reactivity may be potent factors associated with increased risk of dementia. The 2017 Lancet Commission on Dementia and its 2020 update reviewed modifiable risk factors associated with dementia, but stress was not addressed directly. The present study provides a focused review of the association between stress and dementia across the lifespan, with measures of stress including stress exposure, psychological stress, posttraumatic stress disorder (PTSD), and biological markers of stress. Published research articles were identified in the American Psychological Association PsycINFO database (1887-2021), Web of Science database, and Google Scholar. A total of 53 samples from 40 studies published from 1985 to 2020 met inclusion criteria. Results suggest that stressful life events that occur earlier in the lifespan, such as loss of a parent, psychological stress experienced in midlife, and extreme stress responses, i.e., PTSD, correlate with higher risk of dementia. Although results generally are mixed, a consistent theme is that stress experienced earlier in the lifespan and chronic stress portend the greatest risk of dementia. Reducing stress exposure and improving stress management when stress exposure cannot be changed are thus relevant strategies in dementia risk reduction.

Lifecourse Traumatic Events and Cognitive Aging in the Health and Retirement Study

INTRODUCTION

Much of the heterogeneity in the rate of cognitive decline and the age of dementia onset remains unexplained, and there is compelling data supporting psychosocial stressors as important risk factors. However, the literature has yet to come to a consensus on whether there is a causal relationship and, if there is, its direction and strength. This study estimates the relationship between lifecourse traumatic events and cognitive trajectories and predicted dementia incidence.

METHODS

Using data on 7,785 participants aged ≥65 years from the Health and Retirement Study, this study estimated the association between lifecourse experience of 10 traumatic events (e.g., losing a child) and trajectories of Telephone Interview for Cognitive Status from 2006 to 2016 using linear mixed-effects models and predicted incident dementia from 2006 to 2014 using cumulative incidence functions (data analysis was in 2020-2022). Inverse probability weights accounted for loss to follow-up and confounding by sex, education, race/ethnicity, and age.

RESULTS

Experiencing 1 or more traumatic events over the lifecourse was associated with accelerated decline compared with experiencing no events (e.g., β= -0.05 [95% CI= -0.07, -0.02] Health and Retirement Study-Telephone Interview for Cognitive Status units/year; 1 vs 0 events). In contrast, experiencing traumatic events was associated with better cognitive function cross-sectionally. Furthermore, the impact of trauma on cognitive decline was of greater magnitude when it occurred after the age of 64 years. However, the magnitude and direction of association varied by the specific traumatic event. There were no associations with predicted incident dementia.

CONCLUSIONS

These results suggest that researchers and clinicians should not aggregate traumatic events for understanding the risk of accelerated cognitive decline.

Heterogeneous adverse childhood experiences and cognitive function in an elderly Chinese population: a cohort study

OBJECTIVE

To identify the heterogeneity of adverse childhood experiences (ACEs) as well as their association with cognitive function in an elderly Chinese population.

DESIGN

A retrospective cohort study.

PARTICIPANTS

The data were from the latest wave of the China Health and Retirement Longitudinal Study and a total of 7222 participants aged ≥60 were included.

PRIMARY AND SECONDARY OUTCOME MEASURES

Latent class analysis was used to identify the classes characterised by 11 types of ACEs. Cognitive function was measured by the Mini-Mental State Examination (MMSE) and cognitive impairment was defined by education-specific threshold MMSE scores. Logistic models were constructed to examine the relationship between ACE classes and cognitive impairment. Several childhood and adulthood confounding factors were considered.

RESULTS

Three ACE latent classes were identified. Of them, 76.09% were in the 'Low ACEs' class, 15.43% were in the 'Household dysfunction' class and 8.49% were in the 'Child maltreatment' class. The people in the 'Low ACEs' class seemed to have better childhood family financial situations and higher education levels. The population in the 'Household dysfunction' class tended to live in rural areas and have a higher proportion of men, whereas people in the 'Child maltreatment' class showed a significantly higher proportion of women and higher levels of chronic diseases. 'Child maltreatment' was related to a higher risk of cognitive impairment (OR=1.37, 95% CI: 1.12 to 1.68), while the risk of 'Household dysfunction' was not significantly different from that of the 'Low ACEs' participants (OR=1.06, 95% CI: 0.90 to 1.26).

CONCLUSIONS

The findings supported differences in cognitive function in elderly Chinese people exposed to different types of ACEs.

Vision Impairment and Adverse Health Conditions in Congolese Older People: A Population-Based Study

INTRODUCTION

In sub-Saharan Africa, many older people experience vision impairment (VI) and its adverse health outcomes. In this study, we examined separately the association between VI and each adverse health conditions (cognitive disorders, vision-related quality of life [VRQoL], and daily functioning interference [DFI]) among Congolese older people. We also explored whether VI had a significant effect on VRQoL components in our population.

METHOD

We performed cross-sectional analyses on data from 660 Congolese people aged ≥65 years who participated in the 2013 survey of the EPIDEMCA population-based cohort study. VI was defined as having a near visual acuity <20/40 (assessed at 30 cm using a Parinaud chart). Cognitive disorders were assessed using neuropsychological tests and neurological examinations. VRQoL was assessed using a reduced version of the National Eye Institute Visual Function Questionnaire (VFQ-22) and DFI using 11 items of participation restrictions and activity limitations. Regarding our main objective, each association was explored separately using multivariable logistic and linear regression models. Additionally, the effects of VI on each VRQoL components were explored using univariable linear regression models.

RESULTS

VI was not associated with cognitive disorders after adjustment for residence area (adjusted odds ratio = 1.7; 95% confidence interval [CI]: 0.6; 4.7), but it was associated with a low VRQoL score (adjusted β = -12.4; 95% CI: -17.5; -7.3) even after controlling for several covariates. An interaction between VI and age (p = 0.007) was identified, and VI was associated with DFI only among people aged >73 years (adjusted β = 0.5; 95% CI: 0.2; 0.8). Our exploratory analysis showed that all components of VRQoL decreased with a decrease in visual acuity (corrected p ≤ 0.05).

CONCLUSION

VI was associated with poor VRQoL and high DFI. Residence area seems to play a confounding role in the association between VI and cognitive disorders. Our findings suggest that targeting interventions on vision could reduce DFI among older people and improve their well-being.

Association between sexual orientation and subjective cognitive complaints in the general population in England

There is a scarcity of literature investigating the association between minority sexual orientations and subjective cognitive complaints (SCC). Therefore, the aim of this study was to investigate the association between identifying as a sexual minority and SCC in a large sample of adults from England. The study further aimed to identify the extent to which the association could be explained by several behavioral, psychological and clinical factors. Cross-sectional data from the 2007 Adult Psychiatric Morbidity Survey (APMS) were analyzed. Sexual orientation was dichotomized into heterosexual and sexual minority orientation. SCC referred to subjective concentration and memory complaints. Control variables included sex, age, ethnicity, marital status, education, employment, and income. Influential factors included smoking status, alcohol dependence, perceived stress, the number of stressful life events, depression, any anxiety disorder, sleep problems, and obesity. This study included 7,400 participants (51.4% women; mean [standard deviation] age 46.3 [18.6] years). After adjusting for control variables, sexual minority orientation was positively and significantly associated with subjective concentration (OR = 1.40, 95% CI = 1.12-1.76) but not memory complaints (OR = 1.19, 95% CI = 0.96-1.47). The number of stressful life events, sleep problems and any anxiety disorder explained 13.4%, 11.0% and 10.9% of the association between sexual orientation and subjective concentration complaints, respectively. In this large sample of English adults, identifying as a sexual minority was significantly associated with subjective concentration complaints, while stressful life events, sleep problems, and anxiety explained a large proportion of the association. Targeted interventions towards sexual minority groups to reduce SCC may be warranted.

Factors Associated with the High Prevalence of Dementia in Older Aboriginal Australians

Dementia prevalence in Aboriginal and Torres Strait Islander Australians is three to five times higher than the general Australian population. A better understanding of the underlying biomedical and social risk factors is needed to guide dementia prevention in Aboriginal Australians. The current study is the first to examine potential risk factors for dementia in the majority urban and regional population, with a representative sample of 336 Aboriginal Australians aged 60 years and older. Participants included 45 people with a dementia diagnosis (n = 27 probable/possible Alzheimer's disease); and 286 people without dementia. Univariate logistic regression analyses (controlling for age) identified childhood trauma, mid-life factors (history of unskilled work, past high-risk alcohol use), and medical factors (history of stroke, head injury with loss of consciousness, epilepsy) as risk factors for dementia. Multivariable analysis revealed age, childhood trauma, unskilled work, stroke, and head injury as independent predictors of all-cause dementia. A range of comorbid factors related to dementia was also identified (i.e., functional impairment, incontinence, recent hospital admission, low body mass index, living in residential care, depression, current high-risk alcohol use, social isolation, low physical activity levels). These findings extend previous outcomes in a remote Aboriginal population by highlighting that life-course social determinants of health, in addition to neurological disorders, likely play an important role in elevating dementia risk. Certain psychosocial and medical exposures are highly prevalent in Aboriginal Australians, similar to other indigenous populations, and should be considered when designing targeted and culturally appropriate prevention initiatives to reduce the burden of dementia.

Adverse life events and late-life cognitive decline in a Chinese cohort: The Shanghai Aging Study

OBJECTIVE

This study aimed to demonstrate the association between adverse life events (ALEs) and the risk of late-life cognitive decline in older community-dwelling individuals in China.

METHODS

We prospectively followed up 1657 dementia-free participants with ALE data at baseline in the Shanghai Aging Study. The cohort was categorized into four subgroups (depression with ALEs, depression without ALEs, no depression with ALEs, and no depression without ALEs). Cox regressions were conducted to estimate the hazard ratio (HR) for incident dementia stratified by all participants and depressed and nondepressed participants.

RESULTS

We identified 168 incident dementia cases over a mean period of 5.2 years. The cumulative dementia incidence in nondepressed participants with ALEs was the lowest among the four subgroups. Nondepressed participants with ALEs had a lower risk of incident dementia (HR [95% CI]: 0.50 [0.27-0.92], P = .0267) than those without ALEs, adjusted for age, sex, education, apolipoprotein E ε4 (APOE ε4), body mass index, cigarette smoking, heart disease, hypertension, diabetes, stroke, Mini-Mental State Examination (MMSE) at baseline, and anxiety.

CONCLUSIONS

This study explored a significant inverse association between ALEs and the risk of incident cognitive decline among older adults without depression in China. Interventions for depression prevention immediately after ALEs may reduce the risk of cognitive decline later in life.

Cognitive Function and Impairment in Older, Rural South African Adults: Evidence from "Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in Rural South Africa"

BACKGROUND/AIMS

We aimed to estimate the prevalence of cognitive impairment, and the sociodemographic and comorbid predictors of cognitive function among older, rural South African adults.

METHODS

Data were from a population-based study of 5,059 adults aged ≥40 years in rural South Africa in 2015. Cognitive impairment was defined as scoring ≤1.5 SDs below the mean composite time orientation and memory score, or requiring a proxy interview with "fair" or "poor" proxy-reported memory. Multiple linear regression estimated the sociodemographic and comorbid predictors of cognitive score, with multiplicative statistical interactions between each of age and sex with education.

RESULTS

Cognitive impairment increased with age, from 2% of those aged 40-44 (11/516) to 24% of those aged ≥75 years (214/899). The independent predictors of lower cognitive score were being older, female, unmarried, not working, having low education, low household wealth, and a history of cardiovascular conditions. Education modified the negative associations between female sex, older age, and cognitive function score.

CONCLUSIONS

The prevalence of cognitive impairment increased with age and is comparable to rates of dementia reported in other sub-Saharan African countries. Age and sex differences in cognitive function scores were minimized as education increased, potentially reflecting the power of even poor-quality education to improve cognitive reserve.

Childhood Stress and Adversity is Associated with Late-Life Dementia in Aboriginal Australians

OBJECTIVES

High rates of dementia have been observed in Aboriginal Australians. This study aimed to describe childhood stress in older Aboriginal Australians and to examine associations with late-life health and dementia.

DESIGN

A cross-sectional study with a representative sample of community-dwelling older Aboriginal Australians.

SETTING

Urban and regional communities in New South Wales, Australia.

PARTICIPANTS

336 Aboriginal and/or Torres Strait Islander Australians aged 60-92 years, of whom 296 were included in the current analyses.

MEASUREMENTS

Participants completed a life course survey of health, well-being, cognition, and social history including the Childhood Trauma Questionnaire (CTQ), with consensus diagnosis of dementia and Alzheimer disease.

RESULTS

CTQ scores ranged from 25-117 (median: 29) and were associated with several adverse childhood indicators including separation from family, poor childhood health, frequent relocation, and growing up in a major city. Controlling for age, higher CTQ scores were associated with depression, anxiety, suicide attempt, dementia diagnosis, and, specifically, Alzheimer disease. The association between CTQ scores and dementia remained significant after controlling for depression and anxiety variables (OR: 1.61, 95% CI: 1.05-2.45). In contrast, there were no significant associations between CTQ scores and smoking, alcohol abuse, diabetes, or cardiovascular risk factors.

CONCLUSIONS

Childhood stress appears to have a significant impact on emotional health and dementia for older Aboriginal Australians. The ongoing effects of childhood stress need to be recognized as people grow older, particularly in terms of dementia prevention and care, as well as in populations with greater exposure to childhood adversity, such as Aboriginal Australians.