Depressive symptoms moderate the influence of the apolipoproteine epsilon4 allele on cognitive decline in a sample of community dwelling older adults

Substance use moderates relationships between apolipoprotein E genotype, hepatitis C, cognition, and depression in Miami Adult Studies on HIV (MASH) participants

The impact of APOE on HIV and HCV disease course, cognition, and memory has been understudied in minoritized populations. This study examined whether scores on cognition and depression measures differed by APOE ε4 carrier status while considering HCV and HIV seropositivity and whether these measures were moderated by substance use. A retrospective analysis examined cognitive and psychological data from participants (n = 493) in the Miami Adult Studies on HIV (MASH) cohort. APOE genotyping was performed on banked blood samples. Multiple linear regression was employed to examine differences across participants living with and without HIV and/or HCV and by APOE ε4 genotype. APOE ε4 carriers living with HCV who used cannabis had higher depression scores than non-ε4 carriers, while nonusers had fewer depressive symptoms. APOE ε4 carriers living with HCV had better cognition scores after adjusting for cocaine, opiate, and cannabis use than non-ε4 carriers. Scores on cognitive and depression measures did not differ between APOE ε4 carriers and non-ε4 carriers in participants living with HIV, and substance use did not moderate this relationship. This study was the first of its kind to examine substance use as a moderator for cognition and depression among individuals with HIV and/or HCV stratified by APOE genotype. Findings support further research evaluating the frequency and duration of 1) domains of cognitive functioning impacted by APOE genotype relevant to substance use and 2) the influence of substance use on cognitive and depressive outcomes among adults living with HIV and HCV, HIV, or HCV.

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.

Apolipoprotein E4 increases the risk of depression recurrence

BACKGROUND

Possession of the ε4 allele of apolipoprotein E (APOE4) is related to the incidence of depression in old age. We investigated whether the presence of APOE4 is also associated with subsequent depression recurrence in a wide range of age groups.

METHODS

Altogether, 163 patients with major depressive disorder (MDD) after remission were recruited between August 2004 and March 2016 and followed up prospectively. The patients were divided into two groups: APOE4 carriers and non-carriers. We compared the time to recurrence of depression between the two groups. Kaplan-Meier survival curves, log-rank test for trend for survivor functions, and Cox proportional hazard ratio estimates for a multivariate model were conducted to examine the effect of the APOE4 allele on risk of a depression recurrence.

RESULTS

Cumulative probability of developing a depression recurrence was higher in APOE4 carriers than non-carriers. Presence of an APOE4 allele remained significantly associated with the incidence of depression recurrence.

LIMITATIONS

All patients were treated with one or two different antidepressants, which may have had different effects on patients with MDD. Second, participants in the present study comprised patients with both first and multiple episodes of MDD. Third, we did not have the statistical power to perform a stratified analysis in consideration of heterozygous or homozygous genotypes of APOE4.

CONCLUSION

Possession of an APOE4 allele may increase the risk of depression recurrence.

Association Between Elevated Depressive Symptoms and Cognitive Function Moderated by APOE4 Status: Framingham Offspring Study

BACKGROUND

Depression and Apolipoprotein E4 (APOE4) are associated with decreased cognitive function and differences in brain structure.

OBJECTIVE

This study investigated whether APOE4 status moderates the association between elevated depressive symptoms, cognitive function, and brain structure.

METHODS

Stroke- and dementia-free participants (n = 1,968) underwent neuropsychological evaluation, brain MRI, and depression screening. Linear and logistic regression was used to examine all associations. Secondary analyses were performed using interaction terms to assess effect modification by APOE4 status.

RESULTS

Elevated depressive symptoms were associated with lower cognitive performance in several domains. In stratified analyses, elevated depressive symptoms were associated with poorer visual short- and long-term memory performance for APOE4 + participants. Elevated depressive symptoms were not associated with any brain structure in this study sample.

CONCLUSION

Elevated depressive symptoms impact cognitive function in non-demented individuals. Having the APOE4 allele may exacerbate the deleterious effects of elevated depressive symptoms on visual memory performance. Screening for elevated depressive symptoms in both research studies and clinical practice may be warranted to avoid false positive identification of neurodegeneration, particularly among those who are APOE4 + .

Latent Classes of Cognitive Functioning Among Depressed Older Adults Without Dementia

OBJECTIVE

Use latent class analysis (LCA) to identify patterns of cognitive functioning in a sample of older adults with clinical depression and without dementia and assess demographic, psychiatric, and neurobiological predictors of class membership.

METHOD

Neuropsychological assessment data from 121 participants in the Alzheimer's Disease Neuroimaging Initiative-Depression project (ADNI-D) were analyzed, including measures of executive functioning, verbal and visual memory, visuospatial and language functioning, and processing speed. These data were analyzed using LCA, with predictors of class membership such as depression severity, depression and treatment history, amyloid burden, and APOE e4 allele also assessed.

RESULTS

A two-class model of cognitive functioning best fit the data, with the Lower Cognitive Class (46.1% of the sample) performing approximately one standard deviation below the Higher Cognitive Class (53.9%) on most tests. When predictors of class membership were assessed, carrying an APOE e4 allele was significantly associated with membership in the Lower Cognitive Class. Demographic characteristics, age of depression onset, depression severity, history of psychopharmacological treatment for depression, and amyloid positivity did not predict class membership.

CONCLUSION

LCA allows for identification of subgroups of cognitive functioning in a mostly cognitively intact late life depression (LLD) population. One subgroup, the Lower Cognitive Class, more likely to carry an APOE e4 allele, may be at a greater risk for subsequent cognitive decline, even though current performance on neuropsychological testing is within normal limits. These findings have implications for early identification of those at greatest risk, risk factors, and avenues for preventive intervention.

Social Connectedness, Perceived Isolation, and Dementia: Does the Social Environment Moderate the Relationship Between Genetic Risk and Cognitive Well-Being?

Purpose of the Study

This study examined whether the social environment moderates the relationship between the APOE e4 allele and cognitive functioning.

Design and Methods

The Aging, Demographics, and Memory Study (ADAMS) data and multinomial logistic regression models were used to investigate these relationships for a nationally representative sample of U.S. adults aged 70 and older (n = 779).

Results

Living alone (relative risk ratio [RRR] = 5.814; p = .000) and self-reported loneliness (RRR = 1.928, p = .049) were associated with a greater risk of cognitive difficulty. Living arrangements, perceived social support, and loneliness were found to moderate the relationship between the APOE e4 allele and cognitive function.

Implications

The results support the need to consider the social context when examining cognitive well-being in later life. These findings also indicate a need for the development of policies and services that promote a rich social environment.

Apolipoprotein E genotype does not moderate the associations of depressive symptoms, neuroticism and allostatic load with cognitive ability and cognitive aging in the Lothian Birth Cohort 1936

OBJECTIVES

In this replication-and-extension study, we tested whether depressive symptoms, neuroticism, and allostatic load (multisystem physiological dysregulation) were related to lower baseline cognitive ability and greater subsequent cognitive decline in older adults, and whether these relationships were moderated by the E4 allele of the apolipoprotein E (APOE) gene. We also tested whether allostatic load mediated the relationships between neuroticism and cognitive outcomes.

METHODS

We used data from the Lothian Birth Cohort 1936 (n at Waves 1-3: 1,028 [M age = 69.5 y]; 820 [M duration since Wave 1 = 2.98 y]; 659 [M duration since Wave 1 = 6.74 y]). We fitted latent growth curve models of general cognitive ability (modeled using five cognitive tests) with groups of APOE E4 non-carriers and carriers. In separate models, depressive symptoms, neuroticism, and allostatic load predicted baseline cognitive ability and subsequent cognitive decline. In addition, models tested whether allostatic load mediated relationships between neuroticism and cognitive outcomes.

RESULTS

Baseline cognitive ability had small-to-moderate negative associations with depressive symptoms (β range = -0.20 to -0.17), neuroticism (β range = -0.27 to -0.23), and allostatic load (β range = -0.11 to 0.09). Greater cognitive decline was linked to baseline allostatic load (β range = -0.98 to -0.83) and depressive symptoms (β range = -1.00 to -0.88). However, APOE E4 allele possession did not moderate the relationships of depressive symptoms, neuroticism and allostatic load with cognitive ability and cognitive decline. Additionally, the associations of neuroticism with cognitive ability and cognitive decline were not mediated through allostatic load.

CONCLUSIONS

Our results suggest that APOE E4 status does not moderate the relationships of depressive symptoms, neuroticism, and allostatic load with cognitive ability and cognitive decline in healthy older adults. The most notable positive finding in the current research was the strong association between allostatic load and cognitive decline.

APOE ε4 associated with preserved executive function performance and maintenance of temporal and cingulate brain volumes in younger adults

The APOE ε4 allele is associated with cognitive deficits and brain atrophy in older adults, but studies in younger adults are mixed. We examined APOE genotype effects on cognition and brain structure in younger adults and whether genotype effects differed by age and with presence of depression. 157 adults (32 % ε4 carriers, 46 % depressed) between 20 and 50 years of age completed neuropsychological testing, 131 of which also completed 3 T cranial MRI. We did not observe a direct effect of APOE genotype on cognitive performance or structural MRI measures. A significant genotype by age interaction was observed for executive function, where age had less of an effect on executive function in ε4 carriers. Similar interactions were observed for the entorhinal cortex, rostral and caudal anterior cingulate cortex and parahippocampal gyrus, where the effect of age on regional volumes was reduced in ε4 carriers. There were no significant interactions between APOE genotype and depression diagnosis. The ε4 allele benefits younger adults by allowing them to maintain executive function performance and volumes of cingulate and temporal cortex regions with aging, at least through age fifty years.

Early-life stress leads to impaired spatial learning and memory in middle-aged ApoE4-TR mice

Background

Apolipoprotein E (ApoE) is a major lipid carrier that supports lipid transport and injury repair in the brain. The APOE ε4 allele is associated with depression, mild cognitive impairment (MCI) and dementia; however, the precise molecular mechanism through which ApoE4 influences the risk of disease development remains unknown. To address this gap in knowledge, we investigated the potential effects of chronic unpredictable mild stress (CUMS) on ApoE3 and ApoE4 target replacement (ApoE3-TR and ApoE4-TR) mice.

Results

All ApoE-TR mice exposed to CUMS at 3 months old recovered from a depression-like state by the age of 12 months. Of note, ApoE4-TR mice, unlike age-matched ApoE3-TR mice, displayed impaired spatial cognitive abilities, loss of GABAergic neurons, decreased expression of Reelin, PSD95, SYN and Fyn, and reduced phosphorylation of NMDAR2B and CREB.

Conclusion

These results suggest that early-life stress may mediate cognitive impairment in middle-age ApoE4-TR mice through sustained reduction of GABAergic neurons and Reelin expression, which might further diminish the activation of the Fyn/NMDAR2B signaling pathway.

Association between depressive symptoms, use of antidepressant medication and the metabolic syndrome: the Maine-Syracuse Study

Background

Both depression and the metabolic syndrome (MetS) are two major public health issues. The aim of this study was to examine associations between depressive symptoms, the use of antidepressant medications, and the prevalence of MetS.

Methods

Cross-sectional analyses were undertaken on 970 participants from the Maine-Syracuse Study. Depressive symptoms were measured using two self-reported depression scales, the Center for Epidemiological Studies Depression Scale (CES-D), and the Zung self-rating depression scale. Antidepressant medication use was also self-reported. MetS was defined according to the recent harmonized criteria.

Results

The risk of MetS were approximately 79 and 86 % higher for those in the highest quartile for the CESD and the Zung (CES-D: OR = 1.79, p = 0.003; Zung: OR = 1.71, p = 0.006), compared to those in the lowest quartile. With adjustment for socio-demographic variables, lifestyle factors and C-reactive protein (CRP), risk was attenuated, but remained statistically significant for the CES-D. In those who reported using antidepressant medication, the odds of having MetS were over 2-fold higher (OR = 2.22, p < 0.001, fully adjusted model), compared to those who did not use antidepressants. Both measures of depressed mood were also associated with low high density-lipoprotein (HDL) cholesterol levels. Antidepressant use was associated with elevated fasting plasma glucose concentrations, hypertension, and low HDL-cholesterol.

Conclusion

Depressive symptoms and the use of antidepressant medications are associated with the prevalence of MetS, and with some of the individual components of the syndrome.

DNA methylation and single nucleotide variants in the brain-derived neurotrophic factor (BDNF) and oxytocin receptor (OXTR) genes are associated with anxiety/depression in older women

Background: Environmental effects and personal experiences could be expressed in individuals through epigenetic non-structural changes such as DNA methylation. This methylation could up- regulate or down-regulate corresponding gene expressions and modify related phenotypes. DNA methylation increases with aging and could be related to the late expression of some forms of mental disease. The objective of this study was to evaluate the association between anxiety disorders and/or depression in older women and DNA methylation for four genes related to anxiety or depression.

Methods: Women aged 65 and older with (n = 19) or without (n = 24) anxiety disorders and/or major depressive episode (DSM-IV), were recruited. DNA methylation and single nucleotide variant (SNV) were evaluated from saliva, respectively by pyrosequencing and by PCR, for the following genes: brain-derived neurotrophic factor (BDNF; rs6265), oxytocin receptor (OXTR; rs53576), serotonin transporter (SLC6A4; rs25531), and apolipoprotein E (APOE; rs429358 and rs7412).

Results: A greater BDNF DNA methylation was observed in subjects with anxiety/depression compared to control group subjects (Mean: 2.92 SD ± 0.74 vs. 2.34 ± 0.42; p= 0.0026). This difference was more pronounced in subjects carrying the BDNF rs6265 CT genotype (2.99 ± 0.41 vs. 2.27 ± 0.26; p= 0.0006) than those carrying the CC genotype (p= 0.0332); no subjects with the TT genotype were observed. For OXTR, a greater DNA methylation was observed in subjects with anxiety/depression, but only for those carrying the AA genotype of the OXTR rs53576 SNV, more particularly at one out of the seven CpGs studied (7.01 ± 0.94 vs. 4.44 ± 1.11; p= 0.0063). No significant differences were observed for APOE and SLC6A4.

Conclusion: These results suggest that DNA methylation in interaction with SNV variations in BDNF and OXTR, are associated with the occurrence of anxiety/depression in older women.

Current versus lifetime depression, APOE variation, and their interaction on cognitive performance in younger and older adults

OBJECTIVE

An interaction effect of depressive symptoms and APOE e4 allele status on cognitive decline has been shown in old age: e4 allele carriers with more depressive symptoms have faster cognitive decline than those with either depression or the e4 allele. We test this interaction effect on four cognitive domains, using a clinical depression measure comparing current versus lifetime depression.

METHODS

14,379 individuals aged 18 to 59 years, and 3944 individuals aged 60 to 94 years from the Generation Scotland: Scottish Family Health Study participated. Linear-mixed models-accounting for participant relatedness and demographic and health indices-tested for effects of depression and APOE on cognitive abilities.

RESULTS

There was no interaction between depression and APOE on cognition (p > .05). Current depression was associated with poorer speed (in both groups) and memory (18- to 59-year-olds); differences ranged from 0.01 to 0.03 standard deviation [SD]. For lifetime depression, cognitive performance was lower for digit symbol in younger adults, but higher for vocabulary in both younger (0.03 SD) and older (0.05 SD) adults. A negative effect of the APOE e4 allele on speed and memory was found in the group 60 years and older (effect sizes of 0.04 SD).

CONCLUSIONS

The absence of a depression by APOE interaction on cognitive abilities suggests that these synergistic effects only operate at the level of cognitive decline. This implies that it is those biological pathways especially affected by aging that become compromised further by the combined presence of depression and APOE e4 in an individual.

Imbalanced hippocampal functional networks associated with remitted geriatric depression and apolipoprotein E ε4 allele in nondemented elderly: a preliminary study

BACKGROUND

Apolipoprotein E (APOE) ε4 allele and a history of geriatric depression are confirmed risk factors of Alzheimer׳s disease (AD). Coexistence of both factors could notably enhance the risk of cognitive impairment in nondemented elderly. However, neural basis of the association remains unclear.

METHODS

Thirty-one remitted geriatric depression (RGD) patients and 29 cognitively normal subjects were recruited and underwent resting-state functional MRI scans. They were further divided into four groups according to their APOE genotypes. Hippocampal seed-based network analysis and two-way factorial analysis of covariance were employed to detect the main effects and interactive effects of RGD and APOE ε4 allele on the hippocampal functional connectivity (HFC) networks. Partial correlation analysis was applied to examine the cognitive significance of these altered HFC networks.

RESULTS

The HFC networks of RGD patients were decreased in the dorsal frontal and increased in the right temporal-occipital regions. For APOE ε4 carriers, the HFC networks were reduced primarily in medial prefrontal regions and enhanced in the bilateral insula. Additionally, when both factors coexisted, the left HFC network was significantly disrupted in the dorsal anterior cingulate cortex and increased in somatomotor and occipital regions. Importantly, the extent of network alterations was linked to inferior cognitive performances in RGD patients and APOE ε4 carriers.

LIMITATIONS

The small sample size may limit the generalizability of our findings.

CONCLUSIONS

RGD and APOE ε4 allele, and their interaction, are associated with the imbalanced HFC network, which may contribute to cognitive deterioration for subjects with a high risk of AD.

Structural brain changes associated with depressive symptoms in the elderly with Alzheimer's disease

OBJECTIVE

To examine neuroanatomical changes associated with depressive symptoms in Alzheimer's disease (AD) and the relationship between brain structure and cerebrospinal fluid (CSF) AD biomarkers in depressed and non-depressed patients.

METHODS

Two independent cohorts were used in this study. The first cohort (KI) was collected from the Memory Clinic at Karolinska University Hospital and consisted of 41 AD patients. The second cohort was selected and downloaded from the Alzheimer's Disease Neuroimaging Initiative database (ADNI) and consisted of 148 patient. Patients underwent medical, neuropsychological assessment, laboratory analyses of CSF, including β amyloid 1-42 (Aβ 42), total τ (t-τ), phosphorylated τ 181 (p-τ) and brain MRI examination. In the KI cohort, depression was assessed using the Cornell Scale for Depression in Dementia, and in the ADNI cohort the Geriatric Depression Scale was applied. 3D T1-weighted MRI images were processed using automated steps for segmentation and surface reconstruction implemented in Freesurfer. General linear model analysis was used as a statistical approach.

RESULTS

Cortical thinning in AD patients with depressive symptoms compared with those without was observed in the left parietal and temporal brain regions in both cohorts. Negative correlation between cortical thickness and t-τ was greater in depressed compared with non-depressed AD patients in precuneus and parahippocampal cortex.

CONCLUSIONS

Our findings suggest that depressive symptoms in AD patients are associated with cortical thinning in temporal and parietal regions. In addition, our findings suggest that τ protein pathology in these areas may contribute to the development of depressive symptoms in AD.

Current management decisions in mild cognitive impairment

Efforts toward early detection of Alzheimer disease (AD) have focused on refinement and identification of diagnostic markers, with the goal of preventing or delaying disease progression. Mild cognitive impairment (MCI) has emerged as a potential precursor to dementia. Though not without controversy, MCI has been associated with an increased risk for conversion to AD. In this article, with emphasis on meta-analyses, randomized controlled trials, and extant literature reviews, considerations and recommendations for optimal clinical management of MCI are offered. Given the substantial heterogeneity of this patient population and inconsistent research methodologies, the need for informed, clinical judgment is critical.

Gene-behavior interaction of depressive symptoms and the apolipoprotein E {varepsilon}4 allele on cognitive decline

OBJECTIVE

Depressive symptoms and the apolipoprotein E (APOE) ε4 allele are independent risk factors for cognitive decline. However, it is not clear whether the presence of both depressive symptoms and the APOE ε4 allele increases cognitive decline.

METHODS

A prospective study of a population-based sample of 4150 (70% African American and 63% women) participants 65 years and older who were interviewed at 3-year intervals was conducted. Depressive symptoms were measured using the 10-item version of the Center for Epidemiologic Studies Depression scale, with each item coded as presence or absence of a symptom. The APOE genotype was ascertained by DNA samples collected during follow-up. Cognitive function was assessed at the initial and follow-up interviews (average follow-up of 9.2 years), using a standardized global cognitive score.

RESULTS

There were 1405 (34%) participants with one or more copies of the APOE ε4 allele. In participants with no depressive symptoms, cognitive function decreased by 0.0412 unit per year among those with no copies and 0.0704 unit per year among those with one or more copies of the APOE ε4 allele. For each additional symptom of depression, cognitive decline increased by 0.0021 unit per year among those with no copies and 0.0051 unit per year among those with one or more copies of the APOE ε4 allele. The three-way interaction of depressive symptoms, APOE ε4 allele, and time was significant (p = .021).

CONCLUSIONS

The association of depressive symptoms on cognitive decline was increased among participants with one or more copies of the APOE ε4 allele compared with those without the allele.

Apolipoprotein E and depressive symptoms: shared or independent routes to age-related cognitive decline?

Variation in the apolipoprotein E (APOE) genotype is associated with cognitive decline in normal aging. Increased symptoms of depression are also associated with greater cognitive impairment and risk of dementia in old age. Unlike APOE, where the direction of the effect is from genotype to cognitive decline, the causal relationship between depressed mood and cognitive impairment is not known. Rather than being a reaction to worsening cognitive performance with age, depressive symptoms might be a risk factor for age-related cognitive decline. The study by Rajan and colleagues (published in this issue of Psychosomatic Medicine) speaks to this possibility and, importantly, considers the association between depressive symptoms and age-related cognitive decline in the context of APOE variation. This editorial discusses these findings in relation to causal pathways and highlights how longitudinal studies of this nature will improve our understanding of the biological underpinnings of cognitive decline and classification of its risk in the general population.

Optimizing cognitive development over the life course and preventing cognitive decline: Introducing the Cognitive Health Environment Life Course Model (CHELM)

Optimal cognitive development is defined in this article as the highest level of cognitive function reached in each cognitive domain given a person’s biological and genetic disposition, and the highest possible maintenance of cognitive function over the adult life course. Theoretical perspectives underpinning the development of a framework for understanding optimal cognitive development are described, including differential development, intra-individual dynamics, cascades, biological mechanisms, reserve capacity, and plasticity. The Cognitive Health and Environment Life Course Model (CHELM) is proposed as a means to provide a framework for understanding the socio-demographic, lifestyle, and health factors influencing cognitive development and decline. The CHELM may guide framing of policy and interventions to optimize cognitive development and minimize cognitive decline in late-life.

Personality factors moderate the associations between apolipoprotein genotype and cognitive function as well as late onset Alzheimer disease

OBJECTIVES

We tested the hypothesis that neuroticism moderates the association between APOE (apolipoprotein E) genotype and two major outcomes, cognitive function and Alzheimer disease. We also explored whether other personality dimensions (extraversion, openness to experience, agreeableness, and conscientiousness) moderate the associations of APOE with these outcomes.

DESIGN

Primary analyses of existing randomized clinical trial data.

SAMPLE

Six-hundred two older adults (mean age of 78 years at baseline).

MEASUREMENTS

APOE genotype, the NEO-Five Factor Inventory, the Alzheimer's Disease Assessment Scale-Cognitive: measured every 6 months for 6.5 years) and relevant covariates.

RESULTS

Fully adjusted multivariate analyses showed that the association between the presence of APOE [Latin Small Letter Open E]-4 allele(s) and both outcomes was evident among individuals with high levels of neuroticism and extraversion but not among persons with low levels of these traits.

CONCLUSIONS

Phenotypic personality dimensions, primarily neuroticism and extraversion, moderate the relationship between APOE [Latin Small Letter Open E]-4 genotype and cognitive outcomes among older adults. Future research is needed to elucidate the physiological processes involved in these particular phenotype-genotype interactions.

Presepsis depressive symptoms are associated with incident cognitive impairment in survivors of severe sepsis: a prospective cohort study of older Americans

OBJECTIVES

To test the hypothesis that presepsis depressive symptoms are associated with risk of new cognitive impairment in survivors of severe sepsis.

DESIGN

Prospective longitudinal cohort study.

SETTING

Population-based cohort of older U.S. adults interviewed as part of the Health and Retirement Study (1998-2006).

PARTICIPANTS

Four hundred forty-seven individuals with normal presepsis cognition who survived 540 hospitalizations for severe sepsis and completed at least one follow-up interview.

MEASUREMENTS

Severe sepsis was identified using a validated algorithm in Medicare claims. Depressive symptoms were assessed prospectively using a modified version of the Center for Epidemiologic Studies Depression Scale. Cognitive function was assessed using versions of the Telephone Interview for Cognitive Status (TICS). Logistic regression with robust standard errors was used to examine associations between substantial depressive symptoms at any interview before sepsis and incident cognitive impairment (mild or moderate to severe cognitive impairment) at any interview after sepsis.

RESULTS

The prevalence of substantial depressive symptoms in participants with normal cognition before sepsis was 38% (95% confidence interval (CI) = 34-42%). After severe sepsis, 18% (95% CI = 15-20%) of survivors had incident cognitive impairment. In unadjusted analyses, presepsis substantial depressive symptoms were associated with postsepsis incident cognitive impairment (odds ratio (OR) = 2.56, 95% CI = 1.53-4.27). After adjustment for demographics, health-risk behaviors, clinical characteristics of the sepsis episode, and presepsis TICS scores, substantial presepsis depressive symptoms remained the strongest factor associated with postsepsis incident cognitive impairment (OR = 2.58, 95% CI = 1.45-4.59).

CONCLUSION

Substantial presepsis depressive symptoms are independently associated with incident postsepsis cognitive impairment. Depressed older adults may be particularly at risk of developing cognitive impairment after a serious medical illness.

Increasing depressive symptoms in children of Alzheimer parents

Children of persons with Alzheimer disease (AD) are at increased risk of developing AD themselves, but specific factors that predict AD in this population have yet to be elucidated. Various studies indicate depressive symptoms may predate clinical AD and represent a risk factor and/or prodrome of incipient dementia, but their relevance for AD offspring remains uncertain. As part of a longitudinal family study of AD, we assessed depressive symptomatology in 30 middle aged AD offspring (mean age at baseline: 41.2). Their mean total scores on the Hamilton Depression Rating scale increased from 1.8 to 5.3 (P < .001) across a 20-year interval. Neurocognitive performance remained stable in a subset of this cohort (N = 25) over the same interval. Findings from this small convenience sample suggest emerging depressive symptoms may be among the earliest signs of subsequent dementia in this high-risk population but require confirmation through further longitudinal follow-up and replication in larger populations.

Synergistic associations of depression and apolipoprotein E genotype with incidence of dementia

OBJECTIVES

A cohort study of Japanese-American men suggested interactive effects of depression and apolipoprotein E (APOE) e4 allele on risk of incident dementia. In another sample of East Asian origin, we sought to replicate the findings and to explore individual depressive symptoms where this interaction was most evident.

METHODS

Of 625 Korean community elders without dementia at baseline, 518 (83%) were followed over a 2.4-year period and were clinically assessed for incident dementia. Depression was identified by the Geriatric Mental State Schedule (GMS), and nine individual depressive symptoms relevant to DSM-IV major depressive episode criteria were extracted. APOE genotype was ascertained. Covariates included age, gender, education, and disability.

RESULTS

There were synergistic interactions between depression and APOE e4 on incident dementia independent of covariates. This interaction was particularly strong for four depressive symptoms: depressed mood, worthlessness, concentration difficulty, and suicidal ideation.

CONCLUSIONS

We were able to replicate the previous study, finding that, at least in East Asian origin populations, the APOE e4 allele is a stronger predictor of incident dementia in the presence of depressive syndrome, and particular depressive symptoms.

The moderating effect of the APOE [small element of] 4 allele on the relationship between hippocampal volume and cognitive decline in older depressed patients

OBJECTIVE

the apolipoprotein E epsilon-4 (APOE [small element of] 4) allele and depression are independently associated with increased risk for cognitive decline (CD). The authors have reported that depressed elders with an APOE [small element of]4 allele had greater CD compared with depressed elders without the allele. Depression affects the hippocampus, and reduced hippocampal volume has been associated with CD. This study sought to examine in depressed patients the relationships between hippocampal volume, the APOE [small element of] 4 allele, and their interaction on CD. Analyses were performed to examine the influence of baseline hippocampal volume, the APOE [small element of] 4 allele, and their interactions on change in cognitive functioning overtime.

DESIGN

secondary data analysis using linear regression analyses.

SETTING

clinical Research Center for the Study of Depression in Later Life conducted at Duke University.

PARTICIPANTS

depressed older patients (N = 61) followed up for 4 years.

MEASURES

At baseline, cognitive functioning (assessed by the Mini-Mental State Examination), left and right hippocampal volume (assessed by magnetic resonance imaging), and APOE genotype were obtained. At 4-year follow-up, cognitive functioning was reassessed.

RESULTS

the APOE [small element of] 4 allele and left hippocampal volume, but not right hippocampal volume, were independently associated with CD. Importantly, the authors found the APOE [small element of]4 allele to moderate the effects of left hippocampal volume on CD. The APOE [small element of]4 allele seemed to have little effect among those with larger left hippocampal volumes, whereas the allele influenced CD among those with smaller hippocampal volumes.

CONCLUSION

future studies of cognitive impairment and decline should examine both individual and conjoint effects of putative risk factors.

Apolipoprotein e4 genotype and depressive symptoms as risk factors for dementia in an older korean population

OBJECTIVE

Growing evidence suggests the separate associations of apolipoprotein E e4 allele (apo E4) and depression with incident dementia. This study investigated the separate and combined effects of apo E4 and depression on the incidence of dementia in both men and women.

METHODS

Of 625 elderly without dementia at baseline, 518 (83%) were followed over a 2.4-year period and were assessed clinically for incident dementia. The apo E polymorphism was ascertained, and depression was identified using the Korean version of the Geriatric Depression Scale (KGDS). Covariates included age, gender, education, disability, alcohol history, physical activity, and vascular risk factors.

RESULTS

The incidence of dementia was significantly higher in elderly Koreans with both apo E4 and depression compared to those without both factors [adjusted odds ratio (95% CI)=5.85 (1.77-19.38)]. This interaction was significant in men (p=0.049), but not in women (p=0.354).

CONCLUSION

Depressed elderly people are at great risk for incident dementia in the presence of apo E4. Potential gender differences require further evaluation.

Comorbid depression is associated with an increased risk of dementia diagnosis in patients with diabetes: a prospective cohort study

BACKGROUND

Both depression and diabetes have been found to be risk factors for dementia. This study examined whether comorbid depression in patients with diabetes increases the risk for dementia compared to those with diabetes alone.

METHODS

We conducted a prospective cohort study of 3,837 primary care patients with diabetes (mean age 63.2 +/- 13.2 years) enrolled in an HMO in Washington State. The Patient Health Questionnaire (PHQ-9) was used to assess depression at baseline, and ICD-9 diagnoses for dementia were used to identify cases of dementia. Cohort members with no previous ICD-9 diagnosis of dementia prior to baseline were followed for a 5-year period. The risk of dementia for patients with both major depression and diabetes at baseline relative to patients with diabetes alone was estimated using cause-specific Cox proportional hazard regression models that adjusted for age, gender, education, race/ethnicity, diabetes duration, treatment with insulin, diabetes complications, nondiabetes-related medical comorbidity, hypertension, BMI, physical inactivity, smoking, HbA(1c), and number of primary care visits per month.

RESULTS

Over the 5-year period, 36 of 455 (7.9%) patients with major depression and diabetes (incidence rate of 21.5 per 1,000 person-years) versus 163 of 3,382 (4.8%) patients with diabetes alone (incidence rate of 11.8 per 1,000 person-years) had one or more ICD-9 diagnoses of dementia. Patients with comorbid major depression had an increased risk of dementia (fully adjusted hazard ratio 2.69, 95% CI 1.77, 4.07).

CONCLUSIONS

Patients with major depression and diabetes had an increased risk of development of dementia compared to those with diabetes alone. These data add to recent findings showing that depression was associated with an increased risk of macrovascular and microvascular complications in patients with diabetes.

Effects of hormone therapy on depressive symptoms and cognitive functions in women with Alzheimer disease: a 12 month randomized, double-blind, placebo-controlled study of low-dose estradiol and norethisterone

OBJECTIVE

To elucidate the effects of low-dose 17beta-estradiol and norethisterone (hormone therapy [HT]) versus placebo in women with Alzheimer Disease (AD) on cognition, depressive symptoms, and activities of daily living.

DESIGN

A 12-month randomized, double-blind, placebo-controlled study, stratified by apolipoprotein E (ApoE) genotype (with versus without the epsilon4 allele), duration of education (< or =9 versus >9 years), and age (< or =75 versus >75 years) performed during 2000-2004.

SETTING

Ambulatory memory clinic in a general hospital.

PARTICIPANTS

Sixty-five female outpatients aged 65-89 years who met criteria for probable AD according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition and International Classification of Diseases, tenth edition. Ten patients were excluded, resulting in 55 participants who had at least one posttreatment efficacy evaluation.

INTERVENTION

Randomly assigned to receive either 1-mg estradiol and 0.5-mg norethisterone or placebo once daily.

MEASUREMENTS

Cognitive variables were the Dementia Rating Scale, tests from Consortium to Establish a Registry for AD, Global Deterioration Scale (GDS) and Barthel Index.

RESULTS

When only treatment effects were compared by analysis of variance, there were nonsignificant differences between treatment groups for all efficacy variables. A linear model analysis, including stratifying factors in addition to treatment in the model, revealed a significant main effect on mood. The depressive symptoms were lower in the HT group than in the placebo group. Those treated with HT without the ApoE epsilon4 allele had better mood, Word Learning Memory score, and GDS score. Those in the HT group with a higher level of education obtained a better GDS score. Adverse events did not differ between the groups.

CONCLUSION

HT interacts with ApoE genotype in women with AD. Women without an ApoE epsilon4 allele may get better mood and cognition with HT. HT may reduce depressive mood and give less cognitive decline.

A multiplicity of approaches to characterize geriatric depression and its outcomes

PURPOSE OF REVIEW

Research in geriatric depression has always had a multidisciplinary bent, particularly in methods used to characterize depression. Understanding diagnosis, psychiatric comorbidities, and course continues to be a goal of clinical researchers. Those interested in cognitive neuroscience and basic neuroscience have more recently trained their sights on late-life depression. This review identifies recent progress in the characterization of geriatric depression using a variety of methodologies.

RECENT FINDINGS

Depression in the elderly remains underdetected and underdiagnosed, particularly in nonmental health settings. Studies of the impact of psychiatric comorbidities and of the negative outcomes of depression in older adults demonstrate that geriatric depression is a serious medical condition that not only affects mood but can also lead to functional and cognitive decline. Advances in neuroimaging technology have demonstrated structural and functional changes in the brains of older depressed patients. With the advent of brain banks in neuropsychiatry, we are now seeing postmortem neuroanatomical studies that seek to extend findings from clinical practice and from neuroimaging research.

SUMMARY

Clinicians should become more aware of advances in detection of depression, the effect of psychiatric comorbidities, the poor mood and cognitive outcomes associated with late-life depression and should keep abreast of recent neuroimaging and neuroanatomical findings.