Perceived stress and dementia: Results from the Copenhagen city heart study

Convergent effects of synthetic glucocorticoid dexamethasone and amyloid beta in human olfactory neurosphere-derived cells

Stressful life events and glucocorticoid (stress) hormones appear to increase the risk of Alzheimer's disease and hasten its progression, but the reasons for this remain unclear. One potential explanation is that when amyloid β (Aβ) pathology is accumulating in the preclinical disease stage, glucocorticoid receptor signalling during stressful events exacerbates cellular dysfunction caused by Aβ. Alternatively, Aβ may disrupt glucocorticoid receptor signalling. To explore these possibilities, we investigated whether the synthetic glucocorticoid dexamethasone and Aβ have overlapping effects on the cellular proteome and whether Aβ influences canonical glucocorticoid receptor function. Human olfactory neurosphere-derived (ONS) cells, collected from the olfactory mucosa of six adult donors, were treated with soluble Aβ40 or Aβ42 followed by dexamethasone. Proteins were quantified by mass spectrometry. After 32 h treatment, Aβ40 and Aβ42 both induced profound changes in innate immunity-related proteins. After 72 h, Aβ42 formed widespread aggregates and induced few proteomic changes, whereas Aβ40 remained soluble and altered expression of mitochondrial and innate immunity-related proteins. ONS cells revealed overlapping impacts of Aβ40 and dexamethasone, with 23 proteins altered by both treatments. For 16 proteins (including eight mitochondrial proteins) dexamethasone counteracted the effects of Aβ40. For example, caspase 4 and methylmalonate-semialdehyde dehydrogenase were increased by Aβ40 and decreased by dexamethasone. Consistent with this finding, Aβ40 increased, but dexamethasone decreased, ONS cell proliferation. For seven proteins, including superoxide dismutase [Mn] mitochondrial, dexamethasone exacerbated the effects of Aβ40. For some proteins, including complement C3, the effects of dexamethasone differed depending on whether Aβ40 was present or absent. Neither Aβ species influenced glucocorticoid receptor nuclear translocation. Overall, this study revealed that glucocorticoid receptor signalling modifies the intracellular effects of Aß40, counteracting some effects and exacerbating others. It suggests that cellular mechanisms through which glucocorticoid receptor signalling influences Alzheimer's disease risk/progression are complex and determined by the balance of beneficial and detrimental glucocorticoid effects.

Effects of Occupational and Leisure-Time Physical Activity on the Risk of Dementia: Results From the Copenhagen City Heart Study

Leisure-time physical activity (LTPA) decreases the risk of dementia, whereas occupational physical activity (OPA) possibly increases the risk. Yet, previous findings are mixed. We therefore aimed to investigate the effect of LTPA and OPA, respectively, on dementia among men and women. In this observational, longitudinal study, we used data from the second wave of a population-based cohort from the municipality of Copenhagen as baseline. Data were collected in 1981-1983, and 10 343 participants were followed until the end of 2016. LTPA and OPA were self-reported, and information on dementia diagnoses and redemption of dementia medication was obtained at an individual level from national health registers. We used Poisson regression to analyze the association between LTPA/OPA and dementia and adjusted for self-reported age, socioeconomic factors, stress, and cardiovascular risk factors (smoking, alcohol, body mass index, and blood pressure). A higher level of LTPA was associated with a lower dementia risk among men, but we found no clear association among women. OPA and dementia were not associated among men, but occupationally active women who reported OPA in terms of walking, lifting, and heavy work had a higher risk of dementia than women with sedentary jobs. This study supported earlier findings of a protective effect of LTPA on dementia among men. Women in physically demanding jobs possibly have a higher risk of dementia, yet this finding warrants further investigation in future studies.

History of working conditions and the risk of old-age dependency: a nationwide Swedish register-based study

AIMS

There is substantial evidence that previous working conditions influence post-retirement health, yet little is known about previous working conditions' association with old-age dependency. We examined job strain, hazardous and physical demands across working life, in relation to the risk of entering old-age dependency of care.

METHODS

Individually linked nationwide Swedish registers were used to identify people aged 70+ who were not receiving long-term care (residential care or homecare) at baseline (January 2014). Register information on job titles between the years 1970 and 2010 was linked with a job exposure matrix of working conditions. Random effects growth curve models were used to calculate intra-individual trajectories of working conditions. Cox regression models with age as the timescale (adjusted for living situation, educational attainment, country of birth, and sex) were conducted to estimate hazard ratios for entering old-age dependency during the 24 months of follow-up (n = 931,819).

RESULTS

Having initial adverse working conditions followed by an accumulation throughout working life encompassed the highest risk of entering old-age dependency across the categories (job strain: HR 1.23, 95% CI 1.19-1.27; physical demands: HR 1.36, 95% CI 1.31-1.40, and hazardous work: HR 1.35, 95% CI 1.30-1.40). Initially high physical demands or hazardous work followed by a stable trajectory, or initially low-level physical demand or hazardous work followed by an accumulation throughout working life also encompassed a higher risk of dependency.

CONCLUSIONS

A history of adverse working conditions increased the risk of old-age dependency. Reducing the accumulation of adverse working conditions across the working life may contribute to postponing old-age dependency.

Job-related exhaustion risk variant in UST is associated with dementia and DNA methylation

Previous genome-wide association and replication study for job-related exhaustion indicated a risk variant, rs13219957 in the UST gene. Epidemiological studies suggest connection of stress-related conditions and dementia risk. Therefore, we first studied association of rs13219957 and register-based incident dementia using survival models in the Finnish National FINRISK study surveys (N = 26,693). The AA genotype of rs13219957 was significantly associated with 40% increased risk of all-cause dementia. Then we analysed the UST locus association with brain pathology in the Vantaa 85+ cohort and found association with tau pathology (Braak stage) but not with amyloid pathology. Finally, in the functional analyses, rs13219957 showed a highly significant association with two DNA methylation sites of UST, and UST expression. Thus, the results suggest a common risk variant for a stress-related condition and dementia. Mechanisms to mediate the connection may include differential DNA methylation and transcriptional regulation of UST.

Prevalence and risk factors for Alzheimer's disease and related dementias in Ghana: Evidence from a cross-sectional population-based study

Alzheimer's disease and Related Dementia (ADRD) is a growing concern for low- and middle-income countries. Yet, studies on the prevalence and risk factors for dementia in sub-Saharan Africa are limited. This study estimated the prevalence and identified the risk factors for ADRD in Ghana. A cross-sectional design involving 384 participants aged 60 years or more completed the Brief Community Screening Instrument for Dementia (CSID) with an additional set of questions on risk factors. The prevalence of dementia was 16% (62/384). Age (AOR = 1.031 (95% CI 1.002-1.061, p=0.035), education (AOR = 0.689 (95% CI 0.517-0.919, p=0.011), and employment (AOR = 0.320 (95% CI 0.149-0.685, p=0.004) were associated with dementia. Also, "experience of stressful life event from age 16-64" (AOR = 1.325 (95% CI 1.034-1.698, p=0.024), "experience of stressful life event from age 65+" (AOR = 1.258 (95% CI 1.024-1.546, p=0.042), and "activities of daily living" (AOR = 0.925 (95% CI 0.868-0.986, p=0.037) identified as risk factors of dementia. The burden of ADRD was high. Urgent actions are needed to address this problem. There is a possibility that the burden of dementia may have been overestimated because of the study instrument. Findings should be interpreted in light of this limitation.

Experimental laboratory models as tools for understanding modifiable dementia risk

Experimental laboratory research has an important role to play in dementia prevention. Mechanisms underlying modifiable risk factors for dementia are promising targets for dementia prevention but are difficult to investigate in human populations due to technological constraints and confounds. Therefore, controlled laboratory experiments in models such as transgenic rodents, invertebrates and in vitro cultured cells are increasingly used to investigate dementia risk factors and test strategies which target them to prevent dementia. This review provides an overview of experimental research into 15 established and putative modifiable dementia risk factors: less early-life education, hearing loss, depression, social isolation, life stress, hypertension, obesity, diabetes, physical inactivity, heavy alcohol use, smoking, air pollution, anesthetic exposure, traumatic brain injury, and disordered sleep. It explores how experimental models have been, and can be, used to address questions about modifiable dementia risk and prevention that cannot readily be addressed in human studies. HIGHLIGHTS: Modifiable dementia risk factors are promising targets for dementia prevention. Interrogation of mechanisms underlying dementia risk is difficult in human populations. Studies using diverse experimental models are revealing modifiable dementia risk mechanisms. We review experimental research into 15 modifiable dementia risk factors. Laboratory science can contribute uniquely to dementia prevention.

Feelings of tense and risk of incident dementia: A prospective study of 482,360 individuals

BACKGROUND

The relationship between feelings of tense, as a significant emotional distress, and dementia remains unclear. This study aimed to evaluate the association between feelings of tense and dementia.

METHODS

In UK Biobank, feelings of tense were measured with a standard item. The primary outcome was all cause of dementia (ACD) and its subtypes (Alzheimer's disease (AD), vascular dementia (VD), and other dementia). Cox regression models analyzed the association between feelings of tense and dementia risk, while linear regression examined the correlation with neuroimaging outcomes. The potential association and joint effects of AD and tenseness were evaluated based on the established genetic risk score (GRS).

RESULTS

During a median follow-up of 12.7 years among 482,360 participants, 7331 dementia cases were identified. Individuals with feelings of tense had a significantly increased risk of ACD (HR, 1.194; 95 % CI: 1.115-1.278), VD (HR, 1.164; 95 % CI: 1.007-1.346), and other dementia (HR, 1.181; 95 % CI: 1.081-1.289), but not AD in multi-adjusted models. This association persisted across various sensitivity analyses and exhibited some heterogeneity in subgroup analyses. Furthermore, feelings of tense are associated with total brain volume shrinkage, higher white matter hyperintensities, and decreased partial subcortical volume, particularly in the hippocampus. No interaction between tenseness and AD genetic susceptibility was observed (P for interaction =0.346).

LIMITATIONS

Our study only considered feelings of tense measured at a one-time point.

CONCLUSIONS

Our findings demonstrate a significant association between feeling of tense and elevated dementia risk, indicating that tenseness could serve as a modifiable psychological determinant for dementia.

Mapping morbidity 10 years prior to a diagnosis of young onset Alzheimer's disease

INTRODUCTION

Early symptoms in young onset Alzheimer's disease (YOAD) may be misinterpreted, causing delayed diagnosis. This population-based study aimed to map morbidity prior to YOAD diagnosis.

METHODS

In a register-based incidence density matched nested case-control study, we examined hospital-diagnosed morbidity for people diagnosed with YOAD in Danish memory clinics during 2016-2020 compared to controls in a 10-year period. Conditional logistic regression produced incidence rate ratios (IRRs).

RESULTS

The study included 1745 cases and 5235 controls. YOAD patients had a higher morbidity burden in the year immediately before dementia diagnosis, for certain disorders up to 10 years before. This was especially evident for psychiatric morbidity with the highest increased IRRs throughout the entire period and IRR 1.43 (95% confidence interval 1.14-1.79) in the 5-10-years before dementia diagnosis.

DISCUSSION

YOAD patients display a different pattern of morbidity up to 10 years prior to diagnosis. Awareness of specific alterations in morbidity may improve efforts toward a timely diagnosis.

HIGHLIGHTS

Retrospective, nested case-control study of young onset Alzheimer's disease (YOAD). YOAD cases had a higher morbidity burden than controls. YOAD cases had a higher psychiatric morbidity burden up to 10 years before diagnosis. Altered morbidity patterns could serve as an early warning sign of YOAD.

Food insecurity and subjective cognitive complaints among adults aged ≥ 65 years from low- and middle-income countries

PURPOSE

To date, no study has investigated the association between food insecurity and subjective cognitive complaints (SCC). Thus, the aims of the present study were to examine this association among older adults in low- and middle-income countries (LMICs), and to identify the potential mediators in this association, given the importance of SCC in dementia risk among older people, and the projected particularly large increase in dementia in this setting.

METHODS

Cross-sectional, community-based, nationally representative data from the World Health Organization (WHO) Study on global AGEing and Adult Health (SAGE) collected between 2007 and 2010 were analyzed. Two questions on subjective memory and learning complaints in the past 30 days were used to create a SCC scale ranging from 0 (No SCC) to 100 (worse SCC). Past 12 month food insecurity was assessed with two questions on frequency of eating less and hunger due to lack of food. Multivariable linear regression and mediation (Karlson-Holm-Breen method) analyses were conducted to assess associations.

RESULTS

Data on 14,585 individuals aged ≥ 65 years [mean (SD) age 72.6 (11.5) years; 55.0% females] were analyzed. Severe food insecurity (vs. no food insecurity) was associated with 9.16 (95% CI = 6.95-11.37) points higher mean SCC score. Sleep/energy (mediated% 37.9%; P < 0.001), perceived stress (37.2%; P = 0.001), and depression (13.7%; P = 0.008) partially explained the association between severe food insecurity and SCC.

CONCLUSION

Food insecurity was associated with SCC among older adults in LMICs. Future studies should assess whether addressing food insecurity among older adults in LMICs can improve cognitive health.

Association of perceived stress with memory decline in older Chinese: The Guangzhou Biobank Cohort Study

BACKGROUND

Previous studies on associations of perceived stress with poor memory performance in older adults showed inconsistent results. We examined the prospective associations of perceived stress with memory decline using data from Guangzhou Biobank Cohort Study (GBCS).

METHODS

Perceived stress was measured by the Perceived Stress Scale (PSS) at baseline (2003-2006), with greater scores indicating greater stress. Memory function was measured by delayed 10-word recall test (DWRT) and immediate 10-word recall test (IWRT), with greater scores indicating better performance, at baseline and follow-up (2008-2012) examinations, analyzed as mean annual change in scores.

RESULTS

9656 participants (72 % women) with mean age 61.6 (standard deviation = 6.4) years were included. During an average of 4.4 years of follow-up, after adjusting for confounders, each one-point greater PSS score was associated with mean annual decline in DWRT scores (β (95 % CI) = -0.005 (-0.008 to -0.002)). Greater Perceived Helplessness (PH) scores, but not Perceived Self-efficacy scores, was associated with greater mean annual decline in DWRT and IWRT scores (β (95 % CI) = -0.005 (-0.009 to -0.001) and - 0.012 (-0.018 to -0.005), respectively), and similar patterns were observed in five out of seven PH items (βs from -0.02 to -0.07). Interaction analysis showed that the association of greater PSS with greater decline in DWRT scores was observed only in those with low family income (β (95 % CI) = -0.08 (-0.13 to -0.04), P for interaction = 0.03).

CONCLUSIONS

Greater perceived stress was associated with a greater decline in delayed recall memory, especially in those with low family income.

Association between stress-related disorders and the risk of dementia using the Korean National Sample Cohort: a matched cohort study

Post-traumatic stress disorder (PTSD) is associated with the development of dementia; however, the association of dementia risk with overall stress-related disorders is less known. This study investigated the association between stress-related disorders and the risk of dementia in a Korean nationwide sample cohort. The data analyzed in this study were acquired from the Korean National Health Insurance Service National Sample Cohort between 2002 and 2013. Using a 1:3 propensity score matching, 8906 patients with stress-related disorders and 26,718 control participants were included in the analysis. Patients with stress-related disorders had a higher risk of developing dementia after adjusting for covariates (hazard ratio [HR] = 1.15; 95% confidence interval [CI] 1.01-1.30) than control participants. Patients with PTSD showed the highest risk of increase (HR = 1.78) than those with other types of stress-related disorders. Patients with stress-related disorders showed the highest and significantly increased risk for Alzheimer's dementia (HR = 1.22, 95% CI 1.04-1.56). These results indicated an association between a history of stress-related disorders and the risk of dementia in the South Korean population. Further research investigating the causal mechanisms is needed.

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.

Direct and Indirect Effects of Socioeconomic Status and Discrimination on Subjective Cognitive Decline: A Longitudinal Study of African American Women

OBJECTIVES

The present study builds on recent findings suggesting that the stress of institutional and interpersonal racism may contribute to African Americans' elevated risk for dementia. We investigated the extent to which 2 consequences of racism-low socioeconomic status (SES) and discrimination-predict self-reported cognitive decline (SCD) 19 years later. Further, we examined potential mediating pathways that might link SES and discrimination to cognitive decline. Potential mediators included depression, accelerated biological aging, and onset of chronic illnesses.

METHODS

Hypotheses were tested using a sample of 293 African American women. SCD was assessed using the Everyday Cognition Scale. Structural equation modeling was used to assess the effects of SES and racial discrimination, both measured in 2002, on SCD reported in 2021. Turning to the mediators, midlife depression was assessed in 2002, accelerated aging in 2019, and chronic illness in 2019. Age and prodrome depression were included as covariates.

RESULTS

There were direct effects of SES and discrimination on SCD. In addition, these 2 stressors showed a significant indirect effect on SCD through depression. Finally, there was evidence for a more complex pathway where SES and discrimination accelerate biological aging, with accelerated aging, in turn leading to chronic illness, which then predicted SCD.

DISCUSSION

Results of the present study add to a growing literature indicating that living in a racialized society is a central factor in explaining the high risk for dementia among Black Americans. Future research should continue to emphasize the various ways that exposure to racism over the life course effects cognition.

Psychological distress in later life and incident dementia: The Ohsaki Cohort 2006 Study

BACKGROUND

The role of reverse causation in the association between psychological distress and incident dementia remains unclear. We investigated whether psychological distress is a risk factor for, or prodromal symptom of, dementia.

METHODS

A longitudinal analysis of psychological distress with incident dementia was conducted among 12,076 Japanese individuals (age ≥65 years) followed for 5.7 years. Psychological distress was measured using the Kessler 6-item psychological distress scale (0-24 points) at baseline, with participants categorized into four psychological distress groups: no (0-4), mild (5-9), moderate (10-12), and serious (13-24). Dementia cases were retrieved from the public Long-term Care Insurance database. Cox proportional hazards model was used to estimate the multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (95%CIs) for incident dementia. Stratified analysis was conducted by cognitive function (higher or lower) at baseline.

RESULTS

During 60,240 person-years of follow-up, 997 individuals developed dementia. A dose-response association was found between psychological distress and dementia; however, the stratified analysis indicated that this association depended on cognitive function at baseline. Among those with higher cognitive function at baseline, a significantly elevated dementia risk was observed only for serious psychological distress (HR: 2.04, 95%CI: 1.24-3.36). Among those with lower cognitive function, both moderate (HR: 1.30, 95%CI: 1.00-1.68) and serious (HR: 1.79, 95%CI: 1.37-2.34) psychological distress showed an increased dementia risk.

CONCLUSION

The association between late-life psychological distress and incident dementia is partly explained by reserve causation, whereby mild and moderate distress could be a prodromal symptom of dementia.

Changes in Loneliness, BDNF, and Biological Aging Predict Trajectories in a Blood-Based Epigenetic Measure of Cortical Aging: A Study of Older Black Americans

A recent epigenetic measure of aging has developed based on human cortex tissue. This cortical clock (CC) dramatically outperformed extant blood-based epigenetic clocks in predicting brain age and neurological degeneration. Unfortunately, measures that require brain tissue are of limited utility to investigators striving to identify everyday risk factors for dementia. The present study investigated the utility of using the CpG sites included in the CC to formulate a peripheral blood-based cortical measure of brain age (CC-Bd). To establish the utility of CC-Bd, we used growth curves with individually varying time points and longitudinal data from a sample of 694 aging African Americans. We examined whether three risk factors that have been linked to cognitive decline-loneliness, depression, and BDNFm-predicted CC-Bd after controlling for several factors, including three new-generation epigenetic clocks. Our findings showed that two clocks-DunedinPACE and PoAm-predicted CC-BD, but that increases in loneliness and BDNFm continued to be robust predictors of accelerated CC-Bd even after taking these effects into account. This suggests that CC-Bd is assessing something more than the pan-tissue epigenetic clocks but that, at least in part, brain health is also associated with the general aging of the organism.

Stressful life events, general cognitive performance, and financial capacity in healthy older adults and Alzheimer's disease patients

BACKGROUND

The influence of stressful life events on general cognition and for the first time on financial capacity performance of patients with a diagnosis of Alzheimer's disease (AD) and in healthy controls (HC) is assessed.

METHODS

A total of 268 participants (122 patients and 146 HCs with similar demographics) were examined with a number of neuropsychological tests, including Mini Mental State Examination (MMSE), Geriatric Depression Scale (GDS-15), and Legal Capacity for Property Law Transactions Assessment Scale (LCPLTAS) for measuring financial capacity. The life change unit (LCU) method was also used.

RESULTS

HCs reported more stressful events than AD patients before the onset of the disease as the LCU load was higher for them (51.80 vs. 27.50), but in both groups the level of LCU load was far below 100, which is the threshold suggested for the induction of a psychosomatic disorder. The most frequently reported life event for AD patients was increased family arguments (n = 45/122), followed by increase in responsibilities (n = 32/122) and financial difficulties (n = 29/122), while the HC group reported problems within the family (n = 56/146), change in health status (n = 32/146), and a death of a beloved family member (n = 27/146). Regressions indicate no causal role for recent life events in the etiopathogenesis of AD, but an influence only of MMSE and diagnosis on financial capacity.

CONCLUSIONS

Stressful life events do not seem to be important in financial capacity and relevant vulnerability to financial exploitation for either HCs or AD patients; therefore clinicians should not consider them per se as a possible aggravating factor for financial deficits.

Association Between Psychological Distress and Incident Dementia in a Population-Based Cohort in Finland

IMPORTANCE

Symptoms of psychological distress have shown association with subsequent dementia, but the nature of association remains unclear.

OBJECTIVE

To examine the association of psychological distress with etiological risk of dementia and incidence of dementia in presence of competing risk of death.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study consisted of population-based cross-sectional National FINRISK Study surveys collected in 1972, 1977, 1982, 1987, 1992, 1997, 2002, and 2007 in Finland with register-based follow-up; and the cohort was linked to Finnish Health Register data for dementia and mortality for each participant until December 31, 2017. Participants included individuals without dementia who had complete exposure data. Data were analyzed from May 2019 to April 2022.

EXPOSURES

Self-reported symptoms of psychological distress: stress (more than other people), depressive mood, exhaustion, and nervousness (often, sometimes, never).

MAIN OUTCOMES AND MEASURES

Incident all-cause dementia, ascertained through linkage to national health registers. Poisson cause-specific hazard model (emphasizing etiological risk) and Fine-Gray subdistribution hazard model (emphasizing effect on incidence) considering dementia and death without dementia as competing risks. Covariates of age, sex, baseline year, follow-up time, educational level, body mass index, smoking, diabetes, systolic blood pressure, cholesterol, and physical activity. Sensitivity analysis was performed to reduce reverse causation bias by excluding individuals with follow-up less than 10 years.

RESULTS

Among 67 688 participants (34 968 [51.7%] women; age range, 25 to 74 years; mean [SD] age, 45.4 years), 7935 received a diagnosis of dementia over a mean follow-up of 25.4 years (range, 10 to 45 years). Psychological distress was significantly associated with all-cause dementia in a multivariable Poisson model, with incidence rate ratios from 1.17 (95% CI, 1.08-1.26) for exhaustion to 1.24 (95% CI, 1.11-1.38) for stress, and remained significant in sensitivity analyses. A Fine-Gray model showed significant associations (with hazard ratios from 1.08 [95% CI, 1.01-1.17] for exhaustion to 1.12 [95% CI, 1.00-1.25] for stress) for symptoms other than depressive mood (hazard ratio, 1.08 [95% CI, 0.98-1.20]). All the symptoms showed significant associations with competing risk of death in both models.

CONCLUSIONS AND RELEVANCE

In this cohort study, psychological distress symptoms were significantly associated with increased risk of all-cause dementia in the model emphasizing etiological risk. Associations with real incidence of dementia were diminished by the competing risk of death.

Association between food insecurity and perceived stress among older adults (50+) in six low- and middle-income countries

OBJECTIVES

In this study, we assess the relationship between food insecurity andperceived stress among older adults (50+) in six low- and middle-income countries of China, Ghana, India, Mexico, Russia and, South Africa.

METHODS

Cross-sectional comparative analysis was conducted using nationally representative data from the WHO's Study on global AGEing and adult health survey. Bivariate and multivariate regression analyses examine if food insecurity was associated with perceived stress. We also examined the mediating role of health conditions on the association between food insecurity and perceived stress.

RESULTS

Across countries, the mean perceived stress score was higher among the older population with food insecurity. Regression analysis showed significant and positive association between food insecurity and perceived stress. Findings from the pooled data of six countries showed, older adults who experienced severe food insecurity (β = 4.05, p < .001) had higher perceived stress scores. The association was statistically significant in India, Russia, South Africa, and Ghana.

CONCLUSION

Food insecurity showed significant adverse impact on perceived stress among the older population in low- and middle-income countries. Policy measures to reduce household food insecurity are important for improving both mental and physical health conditions of the growing older population in low- and middle-income countries.

Lifetime stress exposure, cognition, and psychiatric wellbeing in women

Objectives:Although life stress has been associated with worse cognitive and psychiatric functioning, few studies on this topic have examined these associations in older adults and no studies to date have assessed lifetime stress exposure in this context.Method:To address this important issue, we investigated associations between lifetime stress exposure, cognition, and psychiatric wellbeing in 44 women aged 60 and older who completed a comprehensive lifetime stress exposure inventory, two memory tasks, and a complete psychiatric assessment.Results:As hypothesized, greater acute and chronic lifetime stress exposure were both related to poorer psychiatric functioning and more somatic health complaints. Greater lifetime stress exposure was also associated with poorer subjective cognition as indicated by memory and thought problems but not objective indices of memory function.Conclusion:Screening for high life stress exposure may therefore help identify older women at increased risk of experiencing negative psychiatric and cognitive outcomes.

Association of Stress with Risk of Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Although many studies have investigated the association between stress and risk of dementia, findings are inconsistent due to the variation in the measures used to assess stress.

OBJECTIVE

We conducted a systematic review and meta-analysis to investigate the association between psychological stress (including neuroticism, stressful life events, and perceived stress) and the risk of incident dementia and mild cognitive impairment in adults.

METHODS

PsycINFO, Embase, and MEDLINE were searched to October 2020 for eligible observational, prospective studies. Of the 1,607 studies screened, 26 (24 unique cohorts) were included in the qualitative analysis and 16 (15 unique cohorts) were included in the quantitative analysis.

RESULTS

Across studies, higher perceived stress was significantly associated with an increased risk of mild cognitive impairment (Cases/Total N = 207/860: hazard ratio [HR] = 1.19, 95% confidence interval [CI] = 1.03-1.38) and all-cause dementia (Cases/Total N = 203/1,882: HR = 1.44, 95% CI = 1.07-1.95). Exposure to two or more stressful life events (versus none) was significantly associated with an increased risk of all-cause dementia (Cases/Total N = 3,354/11,597: HR = 1.72, 95% CI = 1.14-2.60), while one or more stressful life events was not. Higher neuroticism was significantly associated with an increased risk of Alzheimer's disease dementia (Cases/Total N = 497/4,771: HR = 1.07, 95% CI = 1.01-1.12), but not all-cause dementia.

CONCLUSION

This review suggests that psychological stress in adulthood is associated with an increased risk of dementia. Further research is needed to clarify the mechanisms underlying these associations.

Stress diagnoses in midlife and risk of dementia: a register-based follow-up study

OBJECTIVES

Previous studies indicated that stress diagnoses increase the risk of dementia. However, previous results may be biased by confounding, reverse causation and misclassification. Therefore, the main aim of this study was to investigate the association between clinically diagnosed stress in midlife and later dementia risk, while addressing limitations of previous studies.

METHODS

The study population was selected from all individuals in Denmark born 1935-1956. Individuals diagnosed with stress in midlife (aged 37-58 years) were matched (1:5) with individuals without stress diagnoses based on sex and birthdate (N = 103,484). Data were retrieved from national registers. Cox regression models were adjusted for socio-demographic factors and different morbidities.

RESULTS

We found a 2.20 (95% CI: 1.93-2.50) times higher rate of dementia among individuals with any stress diagnosis registered in midlife compared with no stress diagnosis. Hazard rate ratios of dementia were 1.73 (95% CI: 1.13-2.65) among individuals with acute stress reactions, 2.37 (95% CI: 2.05-2.74) among individuals with adjustment disorders, and 2.20 (95% CI: 1.73-2.80) among individuals with unspecified stress reactions. Individuals with PTSD and other stress reactions had non-significantly elevated rates of dementia. Adjustment for confounding only slightly attenuated the association, and reverse causation did not appear to bias the results substantially.

CONCLUSION

Our results support the hypothesis that severe stress in midlife is an important risk factor for dementia. This finding emphasizes the importance of identifying and treating severe stress in midlife to reduce potential detrimental consequences for brain health in later life.

The association between sociodemographic characteristics and dementia in patients with atrial fibrillation

Objectives

Association between socio-demographic factors and dementia risk is studied in general but not for atrial fibrillation (AF) patients.

Methods

We studied AF patients ≥ 45 years in Sweden 1998–2012 (n = 537,513) using the Total Population Register for socio-demographic factors, the Swedish Cause of Death Register, and the National Patient Register (NPR) for incident dementia. Cox regression with hazard ratios (HR) and 95% confidence intervals (CI) was used for the association between exposure and outcome, adjusting for age and comorbidities.

Results

Totally 30,332 patients (5.6%) were diagnosed with dementia during the follow-up (mean 5.4 years). Of these, 14,097 were men (4.9%) and 16,235 were women (6.5%). Lower educational levels (reference: highest level) were associated with increased dementia, HRs (95% CI) for basic school for men 1.23 (1.18–1.29) and women 1.36 (1.30–1.42), and middle-level school for men 1.17 (1.11–1.22) and women 1.28 (1.22–1.34). Divorced men and women (reference: married) showed increased risk of dementia, HR 1.07 (1.01–1.13) and 1.12 (1.06–1.18), respectively, while widowed men showed lower risk, HR 0.84 (0.80–0.88). High deprivation neighborhood socio-economic status (NSES; reference: medium level) was associated with increased dementia in men, HR 1.11 (1.05–1.17), and low deprivation neighborhood socio-economic status (NSES) with increased dementia in men and women, HR 1.12 (1.06–1.18) and 1.18 (1.12–1.24), respectively.

Conclusions

Some results were expected, i.e. association between lower educational level and dementia. The higher risk of dementia in low deprivation NSES-areas could be due to a higher awareness about dementia, and subsequent earlier diagnosis and treatment of dementia.

Electronic supplementary material

The online version of this article (10.1007/s40520-019-01449-3) contains supplementary material, which is available to authorized users.

Stress and neurodegeneration

Neurodegenerative diseases are a great concern because of aging worldwide population. Despite substantial effort to advance our understanding of the etiology and potential treatment of neurodegeneration, there remains a paucity of information with respect to this complex disease process. Interestingly, stress has been implicated among the potential mechanisms implicated in neurodegenerative pathology. Given the increase in chronic stress in modern society, this premise warrants further investigation. The aim of this review is to evaluate the influence of stress on neurodegeneration, the effect of neurodegenerative diseases diagnosis on stress, and therapeutic strategies for neurodegenerative diseases with a special focus on stress reduction. Neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's Disease showed an acceleration in disease progression and a worsening of symptoms under stress. Some therapies (e.g., yoga, meditation) focused on reducing stress showed beneficial effects against neurodegeneration. Nevertheless, more studies are necessary in order to completely understand the implications of stress in neurodegeneration and the usefulness of stress reduction in the treatment thereof.