Does brain reserve protect older women from vascular depression?

Cognitive reserve types and depressive symptoms development in late-life: A population-based cohort study

INTRODUCTION

Cognitive reserve (CR) describes individual differences in susceptibility to brain damage that translates into varying dementia onsets and may also influence the occurrence of depressive symptoms. Within a population-based cohort of older people, we investigated two operationalizations of CR, residual- and activity-based approaches, in their association with the development of depressive symptoms.

METHODS

We analyzed longitudinal data on 402 dementia- and depression-free adults aged 60+ from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) who underwent brain MRI at baseline. Residual-based reserve was derived by regressing episodic memory on a brain-integrity index incorporating six structural MRI markers. Activity-based reserve factored lifelong CR-enhancing experiences, including education, work complexity, social network, and leisure activities. Clinically relevant depressive symptoms were defined as a Montgomery-Åsberg Depression Rating Scale score >6. Cox hazard models were used to explore the association between both residual- and activity-based CR measures (categorized in tertiles) and incidence of depressive symptoms over a 15-year follow-up, while accounting for sociodemographic, clinical, behavioral factors, and brain integrity. Analyses for the activity-based measure were replicated in the full SNAC-K sample (N = 2709), further exploring depression diagnosis as additional outcome.

RESULTS

Compared to low levels, higher levels of residual-based CR were associated with a lower hazard of depressive symptom onset in fully adjusted models (HR: .43, 95%CI .22, .84). While activity-based CR was not significantly associated with developing depressive symptoms in the MRI subsample (HRhigh .47, 95%CI .21, 1.04), it was in the full sample (HRhigh .52, 95%CI .39, .71). Activity-based CR was further associated with depression diagnoses in the full sample (HRhigh: .45, 95%CI .31, .65).

DISCUSSION

Largely independent of its measurement, CR appears to influence depressive symptomatology in late life. Reserve-enhancing initiatives may be beneficial not only for cognitive but also for mental health in older people.

The role of cognitive and brain reserve in late-life depressive events: The Rotterdam Study

BACKGROUND

Cognitive and brain reserve aim to explain individual differences in susceptibility to dementia and may also affect the risk of late-life depressive events. We assessed whether higher cognitive and brain reserve are associated with lower risk of a late-life depressive event.

METHODS

This study included 4509 participants from the population-based Rotterdam Study (mean age: 63.4 ± 10.2 years, 55 % women) between 2005 and 2019. Participants completed cognitive testing and brain-MRI at baseline. Cognitive reserve was defined as the common variance across cognitive tests, while adjusting for demographic factors and brain MRI-markers. Brain reserve was defined as total brain volume divided by intracranial volume. Depressive events (depressive symptoms/depressive syndrome/major depressive disorder) were repeatedly measured (follow-up: 6.6 ± 3.9 years) with validated questionnaires, clinical interviews, and follow-up of medical records. Hazard ratios (HR) with 95 % confidence intervals (CI) were estimated using Cox-regressions.

RESULTS

Higher cognitive (HR: 0.91/SD, 95%CI: 0.84; 1.00) and brain reserve (HR: 0.88/SD, 95%CI: 0.77; 1.00) were associated with a lower risk of a depressive event after adjustment for baseline depressive symptoms. These associations attenuated when participants with clinically relevant depressive symptoms at baseline were excluded (HR: 0.95/SD, 95%CI: 0.86; 1.05, HR: 0.89/SD, 95%CI: 0.76; 1.03, respectively).

LIMITATIONS

No data was available on depression in early-life and the number of participants with major depressive disorder was relatively low (n = 105).

CONCLUSIONS

Higher cognitive and brain reserve may be protective factors for late-life depressive events, particularly in those who have experienced clinical relevant depressive symptoms before. Further research is needed to determine whether cognitive and brain reserve could be used as targets for the prevention of late-life depression.

The Role of Physical Exercise and Omega-3 Fatty Acids in Depressive Illness in the Elderly

Background:

In adulthood, depression is the most common type of mental illness and will be the second leading cause of disease by 2020. Major depression dramatically affects the function of the central nervous system and degrades the quality of life, especially in old age.

Several mechanisms underlie the pathophysiology of depressive illness, since it has a multifactorial etiology. Human and an-imal studies have demonstrated that depression is mainly associated with imbalances in neurotransmitters and neurotrophins, hypothalamic-pituitary-adrenal axis alterations, brain volume changes, neurogenesis dysfunction, and dysregulation of in-flammatory pathways. Also the gut microbiota may influence mental health outcomes.

Although depression is not a consequence of normal aging, depressive disorders are common in later life, even if often undi-agnosed or mis-diagnosed in old age. When untreated, depression reduces life expectancy, worsens medical illnesses, en-hances health care costs and is the primary cause of suicide among older people. To date, the underpinnings of depression in the elderly are still to be understood, and the pharmacological treatment is the most commonly used therapy.

Objective:

Since a sedentary lifestyle and poor eating habits have recently emerged as crucial contributors to the genesis and course of depression, in the present review, we have focused on the effects of physical activity and omega-3 fatty acids on depressive illness in the elderly.

Results:

A growing literature indicates that both exercise and dietary interventions can promote mental health throughout one’s lifespan.

Conclusion:

There thus emerges the awareness that an active lifestyle and a balanced diet may constitute valid low-cost pre-vention strategies to counteract depressive illness in the elderly.

The relationship between moderate alcohol consumption, depressive symptomatology, and C-reactive protein: the Health and Retirement Study

OBJECTIVE

Moderate alcohol use has been broadly associated with health benefits among older adults, including improved mood. Aims of this study were to evaluate the relationship of moderate alcohol use and depressive symptomatology over a period of eight years, and to examine inflammation, indicated by C-reactive protein (CRP), as one mechanism by which this relationship functions.

METHODS

The study included 3177 community-dwelling participants over the age of 65 in 2008 drawn from the Health and Retirement Study. Data from the 2006, 2008, 2012, and 2014 waves were used. Alcohol use was measured via self-report and was dichotomized as abstinent (0 drinks per week) and moderate (1-14 drinks per week). Inflammation was measured using CRP, which was collected using an enzyme-linked immunosorbent assay and provided in units of μg/mL. Control variables included gender, age, body mass index (BMI), and medical burden.

RESULTS

A latent growth curve model with full information maximum likelihood was used, with results revealing that moderate drinkers endorsed fewer depressive symptoms at baseline and a steeper rate of change over time. Abstinent respondents' depressive symptomatology was characterized by a more linear change rate. Further, moderate drinkers had lower CRP levels suggesting that inflammation partially mediates the relationship between moderate alcohol use and depressive symptomatology.

CONCLUSIONS

Moderate alcohol use predicts fewer depressive symptoms among older adults. This relationship is partially moderated by CRP and is eroded by the passage of time. Future research should identify additional mechanisms relating alcohol to positive health outcomes and less depressive symptomatology. Copyright © 2017 John Wiley & Sons, Ltd.

Cognitive reserve as a moderator of the negative association between mood and cognition: evidence from a population-representative cohort

BACKGROUND

Cognitive reserve (CR) has been associated with better cognitive function and lower risk of depression in older people, yet it remains unclear whether CR moderates the association between mood and cognition. This study aimed to investigate whether a comprehensive indicator of CR, including education, occupation and engagement in cognitive and social activities, acts as a moderator of this association.

METHODS

This was a cross-sectional study utilising baseline data from the Cognitive Function and Ageing Study II (CFAS II), a large population-based cohort of people aged 65+ in England. Complete data on the measures of CR, mood and cognition were available for 6565 dementia-free individuals. Linear regression models were used to investigate the potential modifying effect of CR on the association between cognition and mood with adjustment for age, sex and missing data.

RESULTS

Levels of CR did moderate the negative association between mood and cognition; the difference in cognition between those with and without a clinical level mood disorder was significantly smaller in the middle (-2.28; 95% confidence interval (CI) -3.65 to -0.90) and higher (-1.30; 95% CI -2.46 to -0.15) CR groups compared with the lower CR group (-4.01; 95% CI -5.53 to -2.49). The individual components of CR did not significantly moderate the negative association between mood and cognition.

CONCLUSION

These results demonstrate that CR, indexed by a composite score based on multiple indicators, can moderate the negative association between lowered mood and cognition, emphasising the importance of continuing to build CR across the lifespan in order to maintain cognitive health.

Cognitive reserve is associated with quality of life: A population-based study

OBJECTIVES

To assess the association between cognitive reserve (CR) and quality of life (QoL), as well as the role of depression, cognitive functioning, and disability in this association.

METHODS

Nationally-representative cross-sectional population-based data on 1973 individuals aged ≥50years from the Spanish sample of the Collaborative Research on Ageing in Europe (COURAGE) study were analysed. CR was a composite score ranging from 0 to 25 obtained from the Cognitive Reserve Questionnaire, which is composed of items on training courses, occupation, musical training, languages, reading activities, intellectual games, and level of education of the participants and their parents. QoL, ranging from 0 to 100, was assessed with the WHOQOL-AGE. Multiple linear regression and mediation analyses were performed.

RESULTS

Higher levels of CR were associated with higher QoL, after controlling for potential confounders (Coef. 0.53; 95% CI=0.36, 0.70). The strongest mediator in this association was disability, which explained about half of the association, while depression and cognition explained 6-10% of this association.

DISCUSSION

CR is associated with higher QoL in older adults. Interventions targeting determinants of CR that can be modified or trained across the lifespan may lead to successful ageing by prolonging autonomous functioning and enhancing QoL.

Vascular depression consensus report - a critical update

BACKGROUND

Vascular depression is regarded as a subtype of late-life depression characterized by a distinct clinical presentation and an association with cerebrovascular damage. Although the term is commonly used in research settings, widely accepted diagnostic criteria are lacking and vascular depression is absent from formal psychiatric manuals such as the Diagnostic and Statistical Manual of Mental Disorders, 5^th edition - a fact that limits its use in clinical settings. Magnetic resonance imaging (MRI) techniques, showing a variety of cerebrovascular lesions, including extensive white matter hyperintensities, subcortical microvascular lesions, lacunes, and microinfarcts, in patients with late life depression, led to the introduction of the term "MRI-defined vascular depression".

DISCUSSION

This diagnosis, based on clinical and MRI findings, suggests that vascular lesions lead to depression by disruption of frontal-subcortical-limbic networks involved in mood regulation. However, despite multiple MRI approaches to shed light on the spatiotemporal structural changes associated with late life depression, the causal relationship between brain changes, related lesions, and late life depression remains controversial. While postmortem studies of elderly persons who died from suicide revealed lacunes, small vessel, and Alzheimer-related pathologies, recent autopsy data challenged the role of these lesions in the pathogenesis of vascular depression. Current data propose that the vascular depression connotation should be reserved for depressed older patients with vascular pathology and evident cerebral involvement. Based on current knowledge, the correlations between intra vitam neuroimaging findings and their postmortem validity as well as the role of peripheral markers of vascular disease in late life depression are discussed.

CONCLUSION

The multifold pathogenesis of vascular depression as a possible subtype of late life depression needs further elucidation. There is a need for correlative clinical, intra vitam structural and functional MRI as well as postmortem MRI and neuropathological studies in order to confirm the relationship between clinical symptomatology and changes in specific brain regions related to depression. To elucidate the causal relationship between regional vascular brain changes and vascular depression, animal models could be helpful. Current treatment options include a combination of vasoactive drugs and antidepressants, but the outcomes are still unsatisfying.

Is cognitive lifestyle associated with depressive thoughts and self-reported depressive symptoms in later life?

Key components of cognitive lifestyle are educational attainment, occupational complexity and engagement in cognitively stimulating leisure activities. Each of these factors is associated with experiencing fewer depressive symptoms in later life, but no study to date has examined the relationship between overall cognitive lifestyle and depressive symptoms. This task is made more complex because relatively few older participants in cross-sectional studies will be currently experiencing depression. However, many more will show evidence of a depressive thinking style that predisposes them towards depression. This study aimed to investigate the extent to which cognitive lifestyle and its individual components are associated with depressive thoughts and symptoms. Two hundred and six community-dwelling participants aged 65+ completed the depressive cognitions scale, the geriatric depression scale and the lifetime of experiences questionnaire, which assesses cognitive lifestyle. Correlational analysis indicated that each of the individual lifestyle factors—education, occupational complexity and activities in young adulthood, mid-life and later life—and the combined cognitive lifestyle score was positively associated with each other and negatively with depressive symptoms, while all except education were negatively associated with depressive thoughts. Depressive thoughts and symptoms were strongly correlated. Cognitive lifestyle score explained 4.6 % of the variance in depressive thoughts and 10.2 % of the variance in depressive symptoms. The association of greater participation in cognitive activities, especially in later life, with fewer depressive symptoms and thoughts suggests that preventive interventions aimed at increasing participation in cognitively stimulating leisure activity could be beneficial in decreasing the risk of experiencing depressive thoughts and symptoms in later life.

Current understanding of the neurobiology and longitudinal course of geriatric depression

Late life depression is a complex disease associated with a number of contributing neurobiological factors, including cerebrovascular disease, neurodegeneration, and inflammation, which also contribute to its longitudinal prognosis and course. These factors create a context in which the brain is more vulnerable to the impact of stress, and thus, to depression. At the same time, some individuals are protected from late life depression and its consequences, even in the face of neurobiological vulnerability, through benefitting from one or more attributes associated with resilience, including social support, engagement in physical and cognitive activities, and brain reserve. Enhanced understanding of how neurobiological and environmental factors interact in predicting vulnerability and resilience is needed to predict onset and course of depression in late life and develop more effective interventions.

Vascular depression and frailty: a compound threat to longevity among older-old women

OBJECTIVES

The vascular depression hypothesis posits that cerebrovascular burden contributes to the development of depression symptoms in late life. Building on work that suggests that vascular depression is a prodrome for frailty, this paper tests a theoretical framework that vascular depression symptoms are an early marker of a broader pattern of decline characterized by more frailty symptoms and shortened lifespan, and that vascular depression symptoms predict mortality through frailty.

METHODS

The sample was drawn from the Health and Retirement Study and included 1361 stroke-free women over the age of 80. Data were included from six biannual waves from 1998 to 2008 (waves 4-9). A vascular depression symptomatology variable was based on Center for Epidemiological Studies Depression Scale (CES-D) scores and number of cerebrovascular risk factors (hypertension, diabetes, cardiac disease, and smoking). Frailty was measured based on wasting, slowness, weakness, fatigue, and falls. Vascular depression and frailty symptoms were modeled using slope and intercept terms. Mortality was modeled using a discrete-time survival term.

RESULTS

The data supported the proposed model (RMSEA = 0.051; CFI = 0.971; X² = 234.84, p < 0.001). Higher vascular depression symptom slope and intercept scores significantly predicted higher frailty slope and intercept scores, respectively. Frailty intercept scores significantly predicted mortality. The vascular depression symptoms indirectly predicted mortality through frailty symptoms. A second model testing the competing hypothesis - that frailty symptoms lead to vascular depression symptoms and indirectly to mortality - was not supported by the data.

CONCLUSIONS

Results suggest that vascular depression symptoms are associated with a clinical trajectory that includes greater frailty and shortened remaining lifespan.

Vascular depression: an early warning sign of frailty

OBJECTIVES

Frailty is a common geriatric disorder associated with activities of daily living (ADL) impairment, hospitalization, and death. Phenomenological evidence suggests that late-life depression (Katz, 2004 ), particularly vascular depression, may be a risk factor for frailty. This study tests that hypothesis.

METHODS

We identified a sample of stroke-free women over the age of 80 from the Health and Retirement Survey. The sample included 984 respondents in 2000 (incidence sample). Of these, 459 were non-frail at baseline and still alive in 2004 (prevalence sample). Frail respondents experienced at least three of the following: wasting, exhaustion, weakness, slowness, and falls. Vascular depression was represented using two dummy variables. The first represented respondents with either high cerebrovascular burden (CVB; at least two cerebrovascular risk factors) or probable depression (score ≥3 on the 8-item Center for Epidemiological Studies Depression Scale (CES-D)), and the second represented respondents with both high CVB and probable depression.

RESULTS

At baseline, the prevalence of frailty was 31.5%. Over four years the incidence of frailty was 31.8%. After controlling for age, education, ADL and IADL disability, arthritis, pulmonary disorders, cancer, and self-rated health, respondents with either high CVB or probable depression were more likely to be frail at baseline, and those with both were at even higher risk. Of those who were not frail at the 2000 wave, respondents who reported both high CVB and probable depression were more likely to become frail by 2004.

DISCUSSION

These findings suggest that vascular depression is a prodrome for frailty.