Depressive symptoms, vascular risk factors and mild cognitive impairment. The Italian longitudinal study on aging

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Depression and bone loss as risk factors for cognitive decline: A systematic review and meta-analysis

BACKGROUND

Depression is linked to Alzheimer's disease (AD) but it is unclear whether depression is also associated with cognitive decline in the preclinical phase and mild cognitive impairment (MCI). Previous meta-analyses have only investigated AD as an outcome without accounting for individuals showing cognitive decline that does not meet the diagnostic criteria for AD. Other potentially modifiable risk factors such as bone loss have also been less explored and there remains uncertainty around their temporal relationship with cognitive decline.

AIMS

To conduct a systematic review and meta-analysis investigating depression and bone loss as risk factors for subsequent cognitive decline.

METHODS

A comprehensive search strategy was developed and applied using four databases; MEDLINE Complete, Embase, PsycINFO and CINAHL Complete. The pooled summary effects were estimated as odds ratios with 95% confidence intervals using a random-effects model. The study protocol was registered with PROSPERO (ID: CRD42020159369).

RESULTS

A total of 75 longitudinal cohort studies were identified for meta-analysis, of which 70 examined the impact of depression on cognitive decline and five examined the impact of bone loss. Prior exposure to depression was found to be associated with cognitive score reduction (OR 1.33 95% CI 1.17, 1.51), MCI incidence (OR 1.52 95% CI 1.28, 1.79) and AD incidence (OR 1.79 95% CI 1.46, 2.2). Bone loss was also associated with the incidence of AD (OR=1.81 95% CI 1.28, 2.55).

CONCLUSIONS

Overall, the results support the hypothesis that depression is associated with subsequent cognitive decline. Bone loss was also found to be associated with AD incidence; however, due to the small number of studies, the results should be viewed with caution.

Is cognitive performance of women sensitive to the severity of menopausal symptoms?

OBJECTIVE

Menopause is a natural phenomenon among women during their midlife, which is accompanied by unfavorable physical, physiological, and psychological consequences. Therefore, the major aim of the present cross-sectional study was to examine whether the cognitive performance of women is sensitive to the severity of menopausal symptoms.

METHODS

A total number of 404 rural women aged between 40 and 65 years were included in the present study. The menopausal symptoms and cognitive performance of the women were assessed using the Greene Climacteric Scale and Hindi Mini-Mental State Examination scale respectively.

RESULTS

The results of the present study demonstrated that women experiencing severe menopausal symptoms (higher Total Greene climacteric score) presented significantly lower mean values for orientation (8.11 vs 8.90, P < 0.001), registration (2.77 vs 2.91, P < 0.001), attention (4.31 vs 4.48, P < 0.01), recall (2.26 vs 2.53, P < 0.05), and language/visuo-spatial skills (7.13 vs 7.91, P < 0.001) as compared with their counterparts with mild menopausal symptoms. The multivariate linear regression model (after adjustment for age, marital status, and educational status) recorded severe depression and greater sexual dysfunction as the factors significantly associated with lower Mini-Mental State Examination scores.

CONCLUSION

Hence, the findings of the present study indicated that the cognitive performance of women was sensitive to severe depression and sexual dysfunction.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Directional associations between memory impairment and depressive symptoms: data from a longitudinal sample and meta-analysis

BACKGROUND

Previous cross-lagged studies on depression and memory impairment among the elderly have revealed conflicting findings relating to the direction of influence between depression and memory impairment. The current study aims to clarify this direction of influence by examining the cross-lagged relationships between memory impairment and depression in an Asian sample of elderly community dwellers, as well as synthesizing previous relevant cross-lagged findings via a meta-analysis.

METHODS

A total of 160 participants (Mage = 68.14, s.d. = 5.34) were assessed across two time points (average of 1.9 years apart) on measures of memory and depressive symptoms. The data were then fitted to a structural equation model to examine two cross-lagged effects (i.e. depressive symptoms→memory; memory→depressive symptoms). A total of 14 effect-sizes for each of the two cross-lagged directions were extracted from six studies (including the present; total N = 8324). These effects were then meta-analyzed using a three-level mixed effects model.

RESULTS

In the current sample, lower memory ability at baseline was associated with worse depressive symptoms levels at follow-up, after controlling for baseline depressive symptoms. However, the reverse effect was not significant; baseline depressive symptoms did not predict subsequent memory ability after controlling for baseline memory. The results of the meta-analysis revealed the same pattern of relationship between memory and depressive symptoms.

CONCLUSIONS

These results provide robust evidence that the relationship between memory impairment and depressive symptoms is unidirectional; memory impairment predicts subsequent depressive symptoms but not vice-versa. The implications of these findings are discussed.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical characteristics and quality of life of older adults with cognitive impairment in Macao

BACKGROUND

Little is known about the characteristics of older adults with cognitive impairment in Macao. This study aimed to determine the prevalence of cognitive impairment and the quality of life (QOL) of older adults living in the community and nursing homes.

METHODS

A consecutive sample of 413 subjects (199 from the community; 214 from nursing homes) was recruited and interviewed using standardized instruments. Cognition was measured with the Repeatable Battery for the Assessment of Neuropsychological Status and QOL with the brief version of the World Health Organization Quality of Life instrument.

RESULTS

Altogether 87 subjects (21.0%) had cognitive impairment. On multivariate analyses, advanced age (P < 0.001, OR = 1.06, 95%CI: 1.03-1.1) and depressive symptoms (P = 0.03, OR = 1.07, 95%CI: 0.005-1.1) were positively associated with cognitive impairment. Married marital status (P = 0.01, OR = 0.3, 95%CI: 0.1-0.7) and higher education level (P < 0.001, OR = 0.1, 95%CI: 0.06-0.3) were negatively associated with cognitive impairment. After the confounders were controlled for, cognitive impairment was significantly associated with the lower psychological (F _(11,412) = 6.3, P = 0.01) and social relationship domains of QOL (F _(11,412) = 4.0, P = 0.04).

CONCLUSION

Cognitive impairment was found to be common in community-dwelling and nursing home resident older adults in Macao. Given cognitive impairment's negative impact on QOL, appropriate strategies should be implemented to improve access to treatment in this population.

"You've got a friend in me": can social networks mediate the relationship between mood and MCI?

Background

Social networks can change with age, for reasons that are adaptive or unwanted. Social engagement is beneficial to both mental health and cognition, and represents a potentially modifiable factor. Consequently this study explored this association and assessed whether the relationship between mild cognitive impairment (MCI) and mood problems was mediated by social networks.

Methods

This study includes an analysis of data from the Cognitive Function and Ageing Study Wales (CFAS Wales). CFAS Wales Phase 1 data were collected from 2010 to 2013 by conducting structured interviews with older people aged over 65 years of age living in urban and rural areas of Wales, and included questions that assessed cognitive functioning, mood, and social networks. Regression analyses were used to investigate the associations between individual variables and the mediating role of social networks.

Results

Having richer social networks was beneficial to both mood and cognition. Participants in the MCI category had weaker social networks than participants without cognitive impairment, whereas stronger social networks were associated with a decrease in the odds of experiencing mood problems, suggesting that they may offer a protective effect against anxiety and depression. Regression analyses revealed that social networks are a significant mediator of the relationship between MCI and mood problems.

Conclusions

These findings are important, as mood problems are a risk factor for progression from MCI to dementia, so interventions that increase and strengthen social networks may have beneficial effects on slowing the progression of cognitive decline.

Depressive Symptoms Increase the Risk of Mild Neurocognitive Disorders among Elderly Chinese

BACKGROUND

Depression is prevalent among patients with late life neurocognitive disorders but its role as an independent risk factor is not established. We aimed to examine the longitudinal relationship between depression and the incidence of mild neurocognitive disorders (NCD) in a Chinese population.

METHODS

We analyzed data from 889 community-living Chinese elderly in the Singapore Longitudinal Aging Study (SLAS) cohort. All subjects were cognitively normal at baseline based on their performance on the Mini-Mental State Examination (MMSE). Depression was defined as total score of 5 or more on the 15-item Geriatric Depression Scale. Incident cases of mild NCD were ascertained at follow up after an average of 45 moths (range: 10-62). Odds ratios (OR) of associations were calculated in logistic regression models that adjusted for potential confounders.

RESULTS

A total of 59 mild NCD cases were identified. Increased risk of mild NCD was observed for subjects who had depressive symptom at baseline (OR=2.56, 95%CI 1.17-5.60) after controlling for age, gender, education, hypertension, diabetes mellitus, heart disease, APOE genotype and length of follow-up. The interaction between depression and APOE genotype was not statistically significant.

CONCLUSION

Depressive symptom was independently associated with increased risk of mild NCD among Chinese elderly. Effective management of late life depression may potentially reduce incident cases of NCD in the population.

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.

A study of mild cognitive impairment in veterans: role of hypertension and other confounding factors

INTRODUCTION

Hypertension has shown to be an important risk factor for the decline in cognitive function. Aim of our study is to investigate the presence of cognitive impairment of the elders with hypertension and other confounding factors.

METHODS

This study was conducted on 400 veterans who were matched one-to-one with the confounding factors for assessing the presence of mild cognitive impairment using both MMSE and Montreal Cognitive Assessment (MoCA). The 13 related factors of patient data were studied.

RESULTS

The prevalence rate of cognitive impairment was 29.25%. Age (OR 2.679, 95%CI 1.663-6.875), sleep impairment (OR 1.117, 95%CI 1.754-7.422), uncontrolled hypertension (OR 1.522, 95%CI 1.968-4.454), type 2 diabetes (OR 2.464, 95%CI 1.232-4.931), and hyperlipidaemia (OR 1.411, 95%CI 1.221-8.988) are the risk factors for the cognitive deterioration, while the protective factors are high level of education (OR 0.032, 95%CI 0.007-0.149) and regular exercise (OR 0.307, 95%CI 0.115-0.818).

DISCUSSION

Because some vascular disease risk factors, such as hypertension, can be treated effectively, cognitive decline related to these risk factors, and vascular disease per se, may be prevented or its course modified through more aggressive treatment and improved compliance.

The effectiveness of the correction of cognitive impairment using computer-based stimulation programs for patients with coronary heart disease after coronary bypass surgery

We evaluated effectiveness of using copyrighted computer-based stimulation programs in the correction of cognitive function in patients with coronary heart disease after coronary bypass surgery.A total of 74 patients were examined, all the patients underwent a course of drug therapy, 37 patients underwent a course of rehabilitation in addition to medical therapy using computer-based stimulation programs (1 time per day for 20 min within 10 days). A course of rehabilitation using computer-based stimulation programs in patients with coronary heart disease after coronary bypass surgery was proved to be an effective way of correcting cognitive function.

Incidence of and risk factors for Alzheimer's disease and mild cognitive impairment in Korean elderly

BACKGROUND/AIMS

Knowledge of incidence rates and risk factors is essential for the development of strategies to treat patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI).

METHODS

A subpopulation of the Nationwide Survey on Dementia Epidemiology (460 Korean subjects aged ≥65 years from 2 rural and 2 urban districts) was followed up for 3.5 years. The age-specific incidence was estimated and risk factors were identified.

RESULTS

The age-standardized incidence of AD and MCI was 7.9 and 28.1 cases per 1,000 person-years, respectively. MCI was associated with a 6-fold increased risk of AD. Depression was a risk factor for AD with MCI. Age, lack of formal education, illiteracy, rural residence, and marital status were associated with the risk of AD.

CONCLUSION

Strategies to control modifiable risk factors should be implemented to decrease the incidence of AD.

Dietary antioxidant intake and its association with cognitive function in an ethnically diverse sample of US adults

BACKGROUND

Dietary antioxidants can inhibit reactions accompanying neurodegeneration and thus prevent cognitive impairment. We describe associations of dietary antioxidants with cognitive function in a large biracial population, while testing moderation by sex, race, and age and mediation by depressive symptoms.

METHODS

This was a cross-sectional analysis of 1274 adults (541 men and 733 women) aged 30 to 64 years at baseline (mean [standard deviation] = 47.5 [9.3]) in the Healthy Aging in Neighborhoods of Diversity Across the Lifespan Study, Baltimore city, MD. Cognitive performance in the domains of memory, language/verbal, attention, spatial, psychomotor speed, executive function, and global mental status were assessed. The 20-item Center for Epidemiologic Studies Depression Scale was used to measure depressive symptoms. Dietary intake was assessed with two 24-hour recalls, estimating daily consumption of total carotenoids and vitamins A, C, and E per 1000 kcal.

RESULTS

Among key findings, 1 standard deviation (∼ 2.02 mg/1000 kcal) higher vitamin E was associated with a higher score on verbal memory, immediate recall (β = +0.64 [0.19], p = .001), and better language/verbal fluency performance (β = +0.53 [0.16], p = .001), particularly among the younger age group. Women with higher vitamin E intake (β = +0.68 [0.21], p = .001) had better performance on a psychomotor speed test. The vitamin E-verbal memory association was partially mediated by depressive symptoms (proportion mediated = 13%-16%).

CONCLUSIONS

In sum, future cohort studies and dietary interventions should focus on associations of dietary vitamin E with cognitive decline, specifically for domains of verbal memory, verbal fluency, and psychomotor speed.

Role of depression in predicting time to conversion to mild cognitive impairment

OBJECTIVE

To establish whether, in a cohort with normal cognition, severity of depressive symptoms at baseline was related to the time taken for conversion to mild cognitive impairment (MCI) and whether this interacted with other potential risk factors, including APOE ε4 status and demographic and cognitive variables.

METHODS

In a population-based cohort study, 126 cognitively normal subjects were assessed for depressive symptoms at baseline using the Geriatric Depression Scale (GDS) and were then followed over 20 years with regular cognitive assessments. The interval-censored accelerated failure time model was used to establish whether GDS and other factors, including APOE ε4 status, predicted the median time to development of MCI.

RESULTS

Fifty subjects developed MCI. In APOE ε4 noncarriers, the degree of depressive symptoms at baseline predicted the time to development of MCI: An increase in GDS of 1 standard deviation (3.85) was associated with shortening of the median time to conversion to MCI by 25.4% (p = 0.0024, z = -5.6). This relationship remained statistically significant after controlling for cognitive and other confounding variables. The relationship was not significant in APOE ε4 carriers.

CONCLUSION

Depressive symptoms (measured by GDS) predict time to conversion to MCI in cognitively normal people who do not carry the APOE ε4 allele. This may explain conflicting results of previous studies where APOE ε4 status was not taken into account when exploring the relationship between depression and MCI. It may also have a clinical application in helping to identify people at greater risk of developing MCI.

Cognitive and emotional dysfunction in mild cognitive impairment

Although mild cognitive impairment (MCI) is a widely accepted construct both clinically and in the research literature, it remains a heterogeneous condition that varies in presentation and prognosis. This article first reviews the evolution of the diagnosis of MCI, followed by examination of pros and cons of cognitive assessments commonly used to assess for MCI. Emotional changes commonly seen in MCI are also reviewed. Finally, the relation between cognitive and emotional dysfunction is examined, including a discussion of specific psychological symptoms seen in subtypes of MCI, and how the presence of neuropsychiatric symptoms may affect the risk for progression to dementia.

Depressive symptoms in healthy apolipoprotein E ε4 carriers and noncarriers: a longitudinal study

OBJECTIVE

To determine if symptoms of depression accelerate in cognitively normal apolipoprotein E (APOE) ε4 carriers as compared to noncarriers.

METHOD

Six hundred thirty-three cognitively and functionally normal members of the Arizona APOE Cohort aged 21-86 years underwent neuropsychological testing every 1 to 2 years that included the Hamilton Depression Rating Scale, the Beck Depression Inventory, the Geriatric Depression Scale, and the Personality Assessment Inventory. We estimated the longitudinal change on these measures using mixed models that simultaneously modeled cross-sectional and longitudinal effects of age on depression scores by APOE status and the interaction between the two. We also estimated incident depression on the basis of accepted clinical cut-scores on depression measures and use of depression medications.

RESULTS

The mean length of follow-up was 7.7 years. Comparing APOE ε4 carriers with noncarriers revealed no significant longitudinal difference in the rate of change or slope of change on any depression scale or subscale. There was also no difference in incident depression or antidepressant drug use between the carrier and noncarrier groups.

CONCLUSIONS

These data fail to support a relationship between APOE genotype and longitudinal change in depression symptoms, suggesting that depression symptoms may not be intrinsic to the early preclinical phase of Alzheimer's disease.

Mild cognitive impairment and mood: a systematic review

This systematic review, with meta-analyses conducted where data were available, aimed to investigate the prevalence of symptoms of depression and anxiety in mild cognitive impairment (MCI), and to establish how symptoms of depression and anxiety relate to the progression from no cognitive impairment to MCI, and from MCI to dementia. Sixty studies were included in the review. Meta-analyses indicated that symptoms of depression and anxiety were more prevalent in people with MCI than in people with normal cognitive function, and increased the risk of progression from no cognitive impairment to MCI. There were mixed results regarding the effect of such symptoms on progression from MCI to dementia. The findings highlight the need for more research in this area, which can inform attempts to slow or halt the progression of cognitive impairment in later life, with resulting benefits for quality of life.

Late-life depression as a risk factor for mild cognitive impairment or Alzheimer's disease in 30 US Alzheimer's disease centers

Identification of potentially modifiable risk factors for cognitive deterioration is important. We conducted a prospective study of 5,607 subjects with normal cognition and 2,500 subjects with mild cognitive impairment (MCI) at 30 Alzheimer's Disease Centers in the Unites States between 2005 and 2011. Cox regression was used to determine whether depression predicted transition from normal to MCI, or MCI to Alzheimer's disease (AD). Over an average of 3.3 visits, 15% of normal subjects transitioned to MCI (62/1000 per year), while 38% of MCI subjects transitioned to AD (146/1000 per year). At baseline, 22% of participants had recent (within the last two years) depression defined by clinician judgment; 9% and 17% were depressed using the Geriatric Depression Scale (GDS score ≥5) and the Neuropsychiatric Inventory Questionnaire (NPI-Q), respectively. At baseline, depressed subjects performed significantly worse on cognitive tests. Those always depressed throughout follow-up had an increased risk for progression from normal to MCI (RR = 2.35; 95% CI 1.93-3.08) versus never depressed. Normal subjects, identified as depressed at first visit but subsequently improved, were found to have lower risk of progression (RR 1.40 (1.01-1.95)). The 'always depressed' had only a modest increased risk of progression from MCI to AD (RR = 1.21 (1.00-1.46). Results were similar using time-dependent variables for depression or when defining depression via the GDS or NPI-Q. We found no effect of earlier depression (>2 years past). The effect of recent depression did not differ by antidepressant treatment, APOE4 allele status, or type of MCI. In conclusion, late-life depression is a strong risk factor for normal subjects progressing to MCI.

Depressive symptoms in oldest-old women: risk of mild cognitive impairment and dementia

OBJECTIVES

Increasing evidence suggests that depression is a risk factor for cognitive impairment, but it is unclear if this is true among the oldest old. We determined whether elevated depressive symptoms predicted 5-year incident mild cognitive impairment (MCI) or dementia, and neuropsychological test performance among oldest-old women.

DESIGN

Prospective.

SETTING

Three study sites.

PARTICIPANTS

302 women ≥85 years (mean, 87 ± 2).

MEASUREMENTS

Depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS); scores of 6 or more indicated elevated symptoms. Five years later, participants completed neuropsychological testing and clinical cognitive status was adjudicated.

RESULTS

In analyses of MCI versus normal cognition, 70% of women with GDS score 6 or more at baseline developed MCI versus 37% with GDS score less than 6. After adjustment for age, education, alcohol, and benzodiazepine use, and study site, GDS score 6 or more remained independently associated with much greater likelihood of developing MCI (multivariable odds ratio [MOR] = 3.71, 95% confidence interval (CI): 1.30-10.59). In analyses of dementia versus normal cognition, 65% of women with GDS score 6 or more developed dementia compared with 37% of those with GDS score less than 6 (MOR = 3.15, 95% CI: 1.03-9.65). Only 19% of women with GDS score 6 or more had normal cognitive status 5 years later, compared with 46% of those with GDS score less than 6 (MOR = 0.28, 95% CI: 0.11-0.73). Women with elevated depressive symptoms had worse scores on tests of global cognition and working memory.

CONCLUSION

Elevated depressive symptoms are an important risk factor for cognitive disorders and lower cognitive performance among women living to their ninth and tenth decades.

Lack of association between prior depressive episodes and cerebral [11C]PiB binding

Depressive symptoms are frequent in Alzheimer's disease (AD), but it is controversial whether depression is a risk factor for AD. This study measured for the first time cortical amyloid-β (Aβ) levels using [(11)C] Pittsburgh Compound B (PiB) positron emission tomography (PET) in a group of nondemented patients with prior depressive episodes. Twenty-eight elderly patients (mean age 61 years, range 51-75, 18 women) with onset of first depressive episode more than 6 years ago but now remitted from depression and 18 healthy subjects (mean age 61 years, range 50-76, 12 women) were included. All subjects were investigated with cognitive testing, 3T magnetic resonance imaging (MRI) and [(11)C]PiB high resolution research tomography (HRRT) positron emission tomography scan. There was no between-groups difference in [(11)C]PiB binding (p = 0.5) and no associations to number of depressive episodes, cognitive performance, or antidepressant treatment. Patients with late onset of depression had increased severity of white matter lesions (p = 0.04). In this study depressive episodes were not associated with increased levels of [(11)C]PiB. Thus, our results do not support the notion that depressive episodes previously in life are a risk factor for developing AD.

Depression, strokes and dementia: new biological insights into an unfortunate pathway

The literature emphasizes the risk of depression after a stroke. Less well known is the fact that depression may be as big a risk factor for strokes as hypertension, particularly in the older age group. This article reviews the risk for stroke and cognitive impairment consequent to depression, and describes the cardiovascular and immunological mechanisms that would appear to link depression to its cerebrovascular consequences. As well, the article refers to the brain imaging signatures that may allow prediction of impending brain injury. Finally, some questions that might be explored by future research are suggested, and some practical means to identify and help those at risk for the development of depression-associated vascular disease of the brain are suggested.

Prevalence of gender disparities and predictors affecting the occurrence of mild cognitive impairment (MCI)

The aims were to investigate the prevalence of mild cognitive impairment (MCI) within gender disparities in Malaysian older adults, and to determine the predictors of MCI according to gender disparities. A community-based sample of urban, multiethnic dwelling elderly aged 60 years of age and above from Cheras, Kuala Lumpur was recruited. Prevalence of all-type MCI, amnestic-type MCI (am-MCI) and non-amnestic-type MCI (nam-MCI) was assessed using comprehensive neuropsychological batteries. The association between demography, socioeconomic status, lifestyle practices, and nutritional status and health risk factors with MCI were examined. Predictors of MCI occurrence between gender disparities were determined. The prevalence of all-type MCI, am-MCI and nam-MCI was 21.1%, 15.4% and 5.7%, respectively. Binary logistic regression indicated that hypercholesterolemia is the significant predictor for MCI in men after adjustment for age, ethnicity and total years of education. While, in women, MCI was best predicted by married status, without exercise practice, overweight and obesity. These results suggest that approximately one-fifth of the studied elderly people had MCI. Predictors for MCI are totally different between men and women. It is critical to identify those at higher risk for MCI in order to implement preventative measures to delay or reverse this abnormal condition.

Explicit and implicit memory in late-life depression

OBJECTIVE

Late-life depression has been associated with memory loss and is frequently assumed to be a risk factor for continued cognitive decline. This study examined cognition in patients with late-life depression with a focus on the assessment of the extent and type of memory loss among elderly depressed patients.

METHODS

Two-year cross-sectional study of elderly depressed (N = 112) and nondepressed (N = 138) individuals at or older than 60 years in an urban area surrounding a major medical center in southern California. Participants had little to moderate stroke risk. Volunteers were screened with the Hamilton Depression Rating Scale and the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) Axis I Disorders. Patients were diagnosed for major depression by a geriatric psychiatrist using DSM-IV criteria. Volunteers completed neuropsychological testing, a standard battery of laboratory tests, and a neurologic and psychiatric evaluation to rule out a medical burden that might contribute to depression or early dementia.

RESULTS

Depressed patients showed deficits in attention and processing, executive function, and immediate explicit recall. Implicit learning and episodic recall of the testing procedure, semantic and phonetic fluency, and retention of newly acquired verbal material after a delay period were comparable with controls.

CONCLUSION

Moderately depressed patients demonstrate a pattern of cognitive deficits suggestive of mild frontal dysfunction during recall tasks. Their retention of material over a delay period and their intact language skills indicate medial hippocampal function similar to controls. Subcortically mediated implicit memory is also at normal levels. These findings support current efforts to identify pathways of frontal and/or striatal compromise during depressive episodes.

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

OBJECTIVES

To examine whether significant depressive symptoms in postmenopausal women increases the risk of subsequent mild cognitive impairment (MCI) and dementia.

DESIGN

Prospective cohort study.

SETTING

Thirty nine of the 40 Women's Health Initiative (WHI) clinical centers that participated in a randomized clinical trial of hormone therapy.

PARTICIPANTS

Six thousand three hundred seventy-six postmenopausal women without cognitive impairment aged 65 to 79 at baseline.

MEASUREMENTS

Depressive disorders were assessed using an eight-item Burnam algorithm and followed annually for a mean period of 5.4 years. A central adjudication committee classified the presence of MCI and probable dementia based on an extensive neuropsychiatric examination.

RESULTS

Eight percent of postmenopausal women in this sample reported depressive symptoms above a 0.06 cut point on the Burnam algorithm. Depressive disorder at baseline was associated with greater risk of incident MCI (hazard ratio (HR)=1.98, 95% confidence interval (CI)=1.33-2.94), probable dementia (HR=2.03, 95% CI=1.15-3.60), and MCI or probable dementia (HR=1.92, 95% CI=1.35-2.73) after controlling for sociodemographic characteristics, lifestyle and vascular risk factors, cardiovascular and cerebrovascular disease, antidepressant use, and current and past hormone therapy status. Assignment to hormone therapy and baseline cognitive function did not affect these relationships. Women without depression who endorsed a remote history of depression had a higher risk of developing dementia.

CONCLUSION

Clinically significant depressive symptoms in women aged 65 and older are independently associated with greater incidence of MCI and probable dementia.

Late-life depression, mild cognitive impairment, and dementia: possible continuum?

Clinical and epidemiologic research has focused on the identification of risk factors that may be modified in predementia syndromes, at a preclinical and early clinical stage of dementing disorders, with specific attention to the role of depression. Our goal was to provide an overview of these studies and more specifically to describe the prevalence and incidence of depression in individuals with mild cognitive impairment (MCI), the possible impact of depressive symptoms on incident MCI, or its progression to dementia and the possible mechanisms behind the observed associations. Prevalence and incidence of depressive symptoms or syndromes in MCI vary as a result of different diagnostic criteria and different sampling and assessment procedures. The prevalence of depression in individuals with MCI was higher in hospital-based studies (median: 44.3%, range: 9%-83%) than in population-based studies (median: 15.7%, range: 3%-63%), reflecting different referral patterns and selection criteria. Incidence of depressive symptoms varied from 11.7 to 26.6/100 person-years in hospital-based and population-based studies. For depressed normal subjects and depressed patients with MCI, the findings on increased risk of incident MCI or its progression to dementia were conflicting. These contrasting findings suggested that the length of the follow-up period, the study design, the sample population, and methodological differences may be central for detecting an association between baseline depression and subsequent development of MCI or its progression to dementia. Assuming that MCI may be the earliest identifiable clinical stage of dementia, depressive symptoms may be an early manifestation rather than a risk factor for dementia and Alzheimer disease, arguing that the underlying neuropathological condition that causes MCI or dementia also causes depressive symptoms. In this scenario, at least in certain subsets of elderly patients, late-life depression, MCI, and dementia could represent a possible clinical continuum.

Psychological distress and risk for dementia

The concept of mild cognitive impairment (MCI) primarily emphasizes changes in individuals' mental abilities, but it has recently been suggested that neuropsychiatric symptoms should also be considered important factors in age-related neurodegeneration. Psychological distress, defined as a reaction of an individual to external and internal stresses, is characterized by a mixture of psychological symptoms. It also may be considered a neuropsychiatric symptom encompassing depression, anxiety, and apathy. This paper reviews and summarizes recent evidence and relevant issues regarding the presence of psychological distress in healthy older adults and MCI patients and its relationship to risk for developing dementia. Results presented in this review show that psychological distress and depressive, anxious, and apathetic symptoms can be present in MCI and may predict progression to dementia. This article also provides suggestions for future research.

Impact of depressive symptoms on the rate of progression to dementia in patients affected by mild cognitive impairment. The Italian Longitudinal Study on Aging

BACKGROUND

Mild cognitive impairment (MCI) is often a prodromal of dementia and depressive symptoms have been suggested as risk factor for dementing disorders. We evaluated the possible impact of depressive symptoms on the rate of progression to dementia in MCI patients after a 3.5-year follow-up; and the interaction between depressive symptoms and vascular risk factors for conversion to dementia.

METHODS

A total of 2,963 individuals from a sample of 5,632 65-84 year old subjects were evaluated at the first (1992-1993), and second survey (1995-1996) of the Italian Longitudinal Study on Aging (ILSA), a prospective cohort study. MCI and dementia were classified using current clinical criteria. Depressive symptoms were measured with the Geriatric Depression Scale.

RESULTS

Among the 2,963 participants, 139 prevalent MCI patients were diagnosed at the first survey. During the 3.5-year follow-up, 14 MCI patients progressed to dementia, and we did not find any significant relationship between depressive symptoms and rate of progression to dementia (RR 1.42, 95% CI, 0.48-4.23, chi2 0.40, p < 0.53). No socio-demographic variables or vascular risk factors modified the association between depressive symptoms and conversion to dementia.

CONCLUSIONS

In our population, depressive symptoms were not associated with the rate of progression to dementia in MCI patients. Our findings did not support a role of socio-demographic variables or vascular risk factors in the association of depressive symptoms and conversion to dementia.