A 9-year prospective population-based study on the association between the APOE*E4 allele and late-life depression in Sweden

Differences in the Prevalence and Clinical Correlates Between Early-Onset and Late-Onset Major Depressive Disorder Patients with Comorbid Abnormal Lipid Metabolism

BACKGROUND AND OBJECTIVES

Growing evidence suggested that abnormal lipid metabolism (ALM) was associated with an increased severity of depressive symptoms, but no previous studies have examined the differences in comorbid ALM in major depressive disorder (MDD) patients of different ages of onset. We aim to compare the differences in the prevalence and clinical correlates of ALM between early-onset and late-onset patients with first-episode and drug-naive (FEDN) MDD patients.

METHODS

Using a cross-sectional design, we recruited a total of 1718 FEDN MDD outpatients in this study. We used the 17-item Hamilton Rating Scale for Depression (HAMD-17), The Hamilton Anxiety Rating Scale (HAMA), the Positive and Negative Syndrome Scale (PANSS) positive subscale, and Clinical Global Impression-Severity Scale (CGI-S) to assess their depression, anxiety, and psychotic symptoms and clinical severity, respectively.

RESULTS

There were 349 patients (20.3%) in the early-onset subgroup and 1369 (79.7%) in the late-onset subgroup. In this study, 65.1% (1188/1718) of patients were diagnosed with ALM. The prevalence of ALM in the late-onset group (81.5%, 1116/1369) was significantly higher than that in the early-onset group (20.6%, 72/349) (p = 0.36, OR = 1.147, 95%CI = 0.855-1.537). The HAMD total score (OR = 1.34, 95% CI = 1.18-1.53, p < 0.001) was the only risk factor for ALM in early-onset MDD patients. In late-onset MDD patients, the HAMD total score (OR = 1.19, 95% CI = 1.11-1.28, p < 0.001), TSH (OR = 1.25, 95% CI = 1.16-1.36, p < 0.001), CGI (OR = 1.7, 95% CI = 1.31-2.19, p < 0.001), and anxiety (OR = 2.22, 95% CI = 1.23-4.02, p = 0.008) were risk factors for ALM.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Our results suggest that there are significant differences in the prevalence and clinical factors of comorbid ALM between early-onset and late-onset FEND MDD patients.

Sex differences in cognition, anxiety-phenotype and therapeutic effect of metformin in the aged apoE-TR mice

BACKGROUND

Apolipoprotein E4 (ApoE4) is associated with an increased risk of Alzheimer's disease (AD), depression, and anxiety, which were reported to improve after the administration of metformin. However, sex influence on the effect of ApoE4 and metformin on cognition and mental health is poorly understood.

METHODS

ApoE3-TR and apoE4-TR mice of both sexes were randomly assigned to the normal saline and metformin groups from 13 months to 18 months of age. Behavior tests (MWM, EPM, OFT, TST, FST) were conducted to assess cognition, anxiety, and depression-like behaviors. The mice's blood glucose was also recorded.

RESULTS

Male aged apoE4-TR mice are more vulnerable to cognitive decline than females. Metformin improves the spatial memory of female, but not male apoE3-TR mice and female apoE4-TR mice while aggravating the cognitive impairment of male apoE4-TR mice. The anxiety-like phenotypes in male apoE4-TR mice are more severe than in male apoE3-TR mice, while metformin ameliorates the anxiety-like behaviors in the male apoE4-TR mice but not in male apoE3-TR mice. In addition, metformin alleviates depression-like behaviors in male and female apoE4-TR mice. The hypoglycemic effect of metformin is insignificant in both male and female apoE4-TR mice.

CONCLUSIONS

Male sex exacerbates APOE4-related cognitive impairment and anxiety in aged mice and is insensitive to the cognition improvement effect of metformin in the aged apoE3 mice. Male sex with APOE4 may experience more severe cognitive impairment after treatment with metformin while sensitive to the anti-anxiety effects of metformin. These findings identify sex-specific effects on ApoE4-based dementia, anxiety prevention, and therapy, emphasizing the importance of further sex dimension analyses in vivo and clinical studies.

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.

Prevalence and clinical correlates of abnormal lipid metabolism in older Chinese patients with first-episode drug-naïve major depressive disorder

BACKGROUND

Older major depressive disorder (MDD) patients have more complex clinical symptoms and higher abnormal lipid metabolism (ALM) rates. This study aimed to compare clinical differences between those with and without ALM in a sample of older first-episode drug naïve (FEDN) patients.

METHODS

We recruited 266 older MDD patients. Socio-demographic variables, clinical data, and lipid parameters were obtained. The Hamilton Depression Rating Scale (HAMD), Hamilton Anxiety Rating Scale (HAMA), and the positive subscale of the Positive and Negative Syndrome Scale (PANSS-P) were conducted to evaluate patients' depression, anxiety and psychotic symptoms, respectively.

RESULTS

In this study, we found that the prevalence of comorbid ALM was 86.1% in older MDD patients. Compared with the non-abnormal lipid metabolism (NALM) group, the ALM group had a higher duration of illness, higher clinical global impression of severity scale (CGI-S) and HAMD scores, higher thyroid stimulating hormone (TSH) and glucose levels. Logistic regression analysis indicated that duration of illness (OR = 1.11, P = 0.023, 95%CI = 1.015-1.216) and CGI-S score (OR = 2.28, P = 0.014, 95%CI = 1.18-4.39) were associated with ALM in older MDD patients.

CONCLUSION

The importance of regular lipid assessment in older MDD patients needs to be taken into account.

Redox-associated changes in healthy individuals at risk of Alzheimer's disease. A ten-year follow-up study

Carrying an allele 4 of the apolipoprotein E (ApoE) is the best-established genetic risk factor to develop Alzheimer's disease (AD). Fifty percent of ApoE4/4 individuals develop the disease at 70 years of age. ApoE3/4 carriers have a lower risk of developing the disease, still 50% of them suffer AD at around 80 years. In a previous study we showed that healthy young individuals, who had a parent with AD and were carriers of at least one ApoE4 allele displayed reductive stress. This was evidenced as a decrease in oxidative markers, such as oxidized glutathione, p-p38, and NADP+/NADPH ratio, and an increase of antioxidant enzymes, such as glutathione peroxidase (Gpx1) and both the catalytic and regulatory subunits of glutamyl-cysteinyl (GCLM and GCLC). Moreover, we found an increase in stress-related proteins involved in tau physiopathology. Now, 10 years later, we have conducted a follow-up study measuring the same parameters in the same cohort. Our results show that reductive stress has reversed, as we could now observe an increase in lipid peroxidation and in the oxidation of glutathione along with a decrease in the expression of Gpx1 and SOD1 antioxidant enzymes in ApoE4 carriers. Furthermore, we found an increase in plasma levels of IL1β levels and in PKR (eukaryotic translation initiation factor 2 alpha kinase 2) gene expression in isolated lymphocytes. Altogether, our results suggest that, in the continuum of Alzheimer's disease, people at risk of developing the disease go through different redox phases, from stablished reductive stress to oxidative stress.

Exploring the Genetic Landscape of Mild Behavioral Impairment as an Early Marker of Cognitive Decline: An Updated Review Focusing on Alzheimer's Disease

The clinical features and pathophysiology of neuropsychiatric symptoms (NPSs) in dementia have been extensively studied. However, the genetic architecture and underlying neurobiological mechanisms of NPSs at preclinical stages of cognitive decline and Alzheimer's disease (AD) remain largely unknown. Mild behavioral impairment (MBI) represents an at-risk state for incident cognitive impairment and is defined by the emergence of persistent NPSs among non-demented individuals in later life. These NPSs include affective dysregulation, decreased motivation, impulse dyscontrol, abnormal perception and thought content, and social inappropriateness. Accumulating evidence has recently begun to shed more light on the genetic background of MBI, focusing on its potential association with genetic factors related to AD. The Apolipoprotein E (APOE) genotype and the MS4A locus have been associated with affective dysregulation, ZCWPW1 with social inappropriateness and psychosis, BIN1 and EPHA1 with psychosis, and NME8 with apathy. The association between MBI and polygenic risk scores (PRSs) in terms of AD dementia has been also explored. Potential implicated mechanisms include neuroinflammation, synaptic dysfunction, epigenetic modifications, oxidative stress responses, proteosomal impairment, and abnormal immune responses. In this review, we summarize and critically discuss the available evidence on the genetic background of MBI with an emphasis on AD, aiming to gain insights into the potential underlying neurobiological mechanisms, which till now remain largely unexplored. In addition, we propose future areas of research in this emerging field, with the aim to better understand the molecular pathophysiology of MBI and its genetic links with cognitive decline.

Dose-response effects of exercise on mental health in community-dwelling older adults: Exploration of genetic moderators

Background/Objective

(1) Examine the role of exercise intensity on mental health symptoms in a community-based sample of older adults. (2) Explore the moderating role of genetic variation in brain-derived neurotrophic factor (BDNF) and apolipoprotein E (APOE) on the effects of exercise on mental health symptoms.

Method

This study is a secondary analysis of a three-arm randomized controlled trial, comparing the effects of 6 months of high-intensity aerobic training vs. moderate-intensity aerobic training vs. a no-contact control group on mental health symptoms assessed using the Depression, Anxiety, and Stress Scale (DASS). The BDNF Val66Met polymorphism and APOE ε4 carrier status were explored as genetic moderators of exercise effects on mental health symptoms.

Results

The exercise intervention did not influence mental health symptoms. The BDNF Val66Met polymorphism did not moderate intervention effects on mental health symptoms. APOE ε4 carrier status moderated the effect of intervention group on perceived stress over 6 months, such that APOE ε4 carriers, but not non-carriers, in the high-intensity aerobic training group showed a decline in perceived stress over 6 months.

Conclusions

APOE ε4 carrier status may modify the benefits of high-intensity exercise on perceived stress such that APOE ε4 carriers show a greater decline in stress as a result of exercise relative to non-APOE ε4 carriers.

Plasma and cerebrospinal fluid concentrations of neurofilament light protein correlate in patients with idiopathic normal pressure hydrocephalus

BACKGROUND

Neurofilament light chain protein (NFL), a marker of neuronal axonal degeneration, is increased in cerebrospinal fluid (CSF) of patients with idiopathic normal pressure hydrocephalus (iNPH). Assays for analysis of NFL in plasma are now widely available but plasma NFL has not been reported in iNPH patients. Our aim was to examine plasma NFL in iNPH patients and to evaluate the correlation between plasma and CSF levels, and whether NFL levels are associated with clinical symptoms and outcome after shunt surgery.

METHODS

Fifty iNPH patients with median age 73 who had their symptoms assessed with the iNPH scale and plasma and CSF NFL sampled pre- and median 9 months post-operatively. CSF plasma was compared with 50 healthy controls (HC) matched for age and gender. Concentrations of NFL were determined in plasma using an in-house Simoa method and in CSF using a commercially available ELISA method.

RESULTS

Plasma NFL was elevated in patients with iNPH compared to HC (iNPH: 45 (30-64) pg/mL; HC: 33 (26-50) (median; Q1-Q3), p = 0.029). Plasma and CSF NFL concentrations correlated in iNPH patients both pre- and postoperatively (r = 0.67 and 0.72, p < 0.001). We found only weak correlations between plasma or CSF NFL and clinical symptoms and no associations with outcome. A postoperative NFL increase was seen in CSF but not in plasma.

CONCLUSIONS

Plasma NFL is increased in iNPH patients and concentrations correlate with CSF NFL implying that plasma NFL can be used to assess evidence of axonal degeneration in iNPH. This finding opens a window for plasma samples to be used in future studies of other biomarkers in iNPH. NFL is probably not a very useful marker of symptomatology or for prediction of outcome in iNPH.

Prevalence and clinical correlates of abnormal lipid metabolism in first-episode and drug-naïve patients with major depressive disorder: A large-scale cross-sectional study

OBJECTIVE

Studies have shown an association between abnormal lipid profiles and MDD, but there are few studies on the clinical correlates of lipid abnormalities in patients with major depressive disorder (MDD). The purpose of this study was to investigate the prevalence of abnormal lipid metabolism and its correlates in Chinese first-episode and drug-naïve MDD patients, which has not yet been reported.

METHODS

A total of 1718 outpatients with first-episode and drug-naïve MDD were included. Demographic data were collected by a standardized questionnaire and blood lipid levels were measured, including total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C). The Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), Positive and Negative Syndrome Scale (PANSS) positive subscale, and Clinical Global Impression of Severity Scale (CGI-S) were assessed for each patient.

RESULTS

The prevalence of abnormal lipid metabolism was 72.73% (1301/1718), and the rates of high TC, high TG, high LDL-C and low HDL-C were 51.05% (877/1718), 61.18% (1051/1718), 30.09% (517/1718), 23.40% (402/1718), respectively. Logistic regression showed the risk factors for abnormal lipid metabolism were severe anxiety, HAMD score, CGI-S score, BMI and systolic blood pressure (SBP). Multiple linear regression analysis showed that age at onset, SBP, HAMD score, HAMA score, PANSS positive subscale score, and CGI-S were independently associated with TC levels. BMI, HAMD score, PANSS positive subscale score and CGI-S score were independently associated with TG levels. SBP, HAMD score, PANSS positive subscale score and CGI-S score were independently associated with LDL-C levels. Age of onset, SBP and CGI-S score were independently associated with HDL-C levels.

CONCLUSIONS

The prevalence of abnormal lipid metabolism in first-episode and drug-naïve MDD patients is quite high. The severity of psychiatric symptoms may be closely associated with the presence of abnormal lipid metabolism in patients with MDD.

Attrition in the Gothenburg H70 birth cohort studies, an 18-year follow-up of the 1930 cohort

Background

Longitudinal studies are essential to understand the ageing process, and risk factors and consequences for disorders, but attrition may cause selection bias and impact generalizability. We describe the 1930 cohort of the Gothenburg H70 Birth Cohort Studies, followed from age 70 to 88, and compare baseline characteristics for those who continue participation with those who die, refuse, and drop out for any reason during follow-up.

Methods

A population-based sample born 1930 was examined with comprehensive assessments at age 70 (N = 524). The sample was followed up and extended to increase sample size at age 75 (N = 767). Subsequent follow-ups were conducted at ages 79, 85, and 88. Logistic regression was used to analyze baseline characteristics in relation to participation status at follow-up.

Results

Refusal to participate in subsequent examinations was related to lower educational level, higher blood pressure, and lower scores on cognitive tests. Both attrition due to death and total attrition were associated with male sex, lower educational level, smoking, ADL dependency, several diseases, poorer lung function, slower gait speed, lower scores on cognitive tests, depressive symptoms, and a larger number of medications. Attrition due to death was also associated with not having a partner.

Conclusions

It is important to consider different types of attrition when interpreting results from longitudinal studies, as representativeness and results may be differently affected by different types of attrition. Besides reducing barriers to participation, methods such as imputation and weighted analyses can be used to handle selection bias.

A genetic correlation and bivariate genome-wide association study of grip strength and depression

Grip strength is an important biomarker reflecting muscle strength, and depression is a psychiatric disorder all over the world. Several studies found a significant inverse association between grip strength and depression, and there is also evidence for common physiological mechanisms between them. We used twin data from Qingdao, China to calculate genetic correlations, and we performed a bivariate GWAS to explore potential SNPs, genes, and pathways in common between grip strength and depression. 139 pairs of Dizygotic twins were used for bivariate GWAS. VEAGSE2 and PASCAL software were used for gene-based analysis and pathway enrichment analysis, respectively. And the resulting SNPs were subjected to eQTL analysis and pleiotropy analysis. The genetic correlation coefficient between grip strength and depression was -0.41 (-0.96, -0.15). In SNP-based analysis, 7 SNPs exceeded the genome-wide significance level (P<5×10-8) and a total of 336 SNPs reached the level of suggestive significance (P<1×10-5). Gene-based analysis and pathway-based analysis identified genes and pathways related to muscle strength and the nervous system. The results of eQTL analysis were mainly enriched in tissues such as the brain, thyroid, and skeletal muscle. Pleiotropy analysis shows that 9 of the 15 top SNPs were associated with both grip strength and depression. In conclusion, this bivariate GWAS identified potentially common pleiotropic SNPs, genes, and pathways in grip strength and depression.

Sini powder with paroxetine ameliorates major depressive disorder by modulating circadian rhythm: A randomized, double-blind, placebo-controlled trial

Circadian rhythm disorder is a significant risk factor for mental diseases, and the recovery of circadian rhythm function has gradually become a signal of effective antidepressant therapy. Sini powder (SNP) is a classical, traditional Chinese formula for depression treatment. However, few clinical reports have been recorded. This randomized, double-blinded, controlled trial (ChiCTR1900022700) aimed to explore the efficacy of SNP on depression via regulating circadian rhythm. In total, 36 patients with major depressive disorder (MDD) were enrolled for 4-weeks medication and 6-weeks follow-up. HAMD-24 score and circadian rhythm index, including dim light melatonin onset (DLMO) and phase angle difference (PAD), were included in the assessment. DLMO and PAD were statistically significant in the SNP group after 4 weeks of treatment (p < .05) and with greater improvement in DLMO (p = .03). In addition, DLMO and the HAMD-24 score showed a positive correlation (p < .05); the HAMD-24 score degree decreased significantly over time (p < .001). Similarly, interaction effects were shown significantly between group and time (p = .049). The duration of SNP supplementation was relatively short, and the sample size was relatively small. SNP granules combined with paroxetine tablets have definite efficacy in improving the circadian rhythms of MDD patients, reflecting the therapeutic advantages of traditional Chinese medicine as antidepressants.

Metformin alleviates the depression-like behaviors of elderly apoE4 mice via improving glucose metabolism and mitochondrial biogenesis

Apolipoprotein E4 (apoE4) is closely related to late-onset depression (LOD). In addition, the benefits of metformin treatment of depression have been documented in a range of rodent studies and human trials, but few studies have probed into the effect of metformin on and the related mechanism in depressed elderly mice, especially in those APOE4 carriers. Here, we treated 13-month-old apoE3-targeted replacement (TR) and apoE4-TR mice with an intragastric administration of metformin (300 mg/kg/d) or normal saline for 5 months. We found that metformin exerted antidepressant effects on apoE4 mice, including reduced immobility time in TST and FST, and increased ratios of time and distance in the central area of OFT. Importantly, compared with apoE3 mice, apoE4 mice showed a higher expression of lactate dehydrogenase (LDH) and pyruvate dehydrogenase kinase (PDK1 and PDK4) in the hippocampus. The increased LDH level was rescued by metformin treatment. Moreover, the metformin administration increased the levels of transcriptional factor NRF-1 and TFAM, mtDNA, and most mitochondrial complex subunits in apoE-TR mice. Furthermore, it upregulated the expressions of antioxidant enzymes, such as MnSOD, GPX1, and GSR1/2. Interestingly, apoE4 blunted the hypoglycemic effect of metformin in aged mice. These data suggest that metformin ameliorates the depression-like behaviors probably by improving glucose metabolism and mitochondria biogenesis in the hippocampus of aged apoE4 mice. These findings imply that chronic metformin treatment can improve apoE4-mediated LOD, providing mechanistic insights for apoE4- and age-based depression prevention and therapy.

Evaluation of High Cholesterol and Risk of Dementia and Cognitive Decline in Older Adults Using Individual Patient Meta-Analysis

INTRODUCTION

Although increased cholesterol level has been acknowledged as a risk factor for dementia, evidence synthesis based on published data has yielded mixed results. This is especially relevant in older adults where individual studies report non-linear relationships between cholesterol and cognition and, in some cases, find higher cholesterol associated with a lower risk of subsequent cognitive decline or dementia. Prior evidence synthesis based on published results has not allowed us to focus on older adults or to standardize analyses across studies. Given our ageing population, an increased risk of dementia in older adults, and the need for proportionate treatment in this age group, an individual participant data (IPD) meta-analysis is timely.

METHOD

We combined data from 8 studies and over 21,000 participants aged 60 years and over in a 2-stage IPD to examine the relationship between total, high-density, and low-density lipoprotein (HDL and LDL) cholesterol and subsequent incident dementia or cognitive decline, with the latter categorized using a reliable change index method.

RESULTS

Meta-analyses found no relationship between total, HDL, or LDL cholesterol (per millimoles per litre increase) and risk of cognitive decline in this older adult group averaging 76 years of age. For total cholesterol and cognitive decline: odds ratio (OR) 0.93 (95% confidence interval [CI] 0.86: 1.01) and for incident dementia: OR 1.01 [95% CI 0.89: 1.13]. This was not altered by rerunning the analyses separately for statin users and non-users or by the presence of an APOE e4 allele.

CONCLUSION

There were no clear consistent relationships between cholesterol and cognitive decline or dementia in this older adult group, nor was there evidence of effect modification by statin use. Further work is needed in younger populations to understand the role of cholesterol across the life-course and to identify any relevant intervention points. This is especially important if modification of cholesterol is to be further evaluated for its potential influence on risk of cognitive decline or dementia.

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.

ApoE4 increases susceptibility to stress-induced age-dependent depression-like behavior and cognitive impairment

Though apolipoprotein E ε4 (APOE ε4) is a major genetic risk factor for late-onset Alzheimer's disease, its association with depression remains controversial. In present study, 3-month-old and 8-month-old apoE-targeted replacement (TR) mice were both subjected to chronic unpredictable mild stress (CUMS) for six weeks. The results showed that 8-month apoE4-TR mice were more susceptible to the CUMS-induced depression-like behaviors and cognitive impairment than age-matched apoE3-TR mice. Stress induced a loss of GABAergic neurons and decline of Reelin level in the prefrontal cortex (PFC) and in the dentate gyrus (DG) of the hippocampus in both 3-month-old and 8-month-old apoE-TR mice, which were more pronounced in the 8-month-old apoE4-TR mice. Of note, stress decreased the level of PSD95 in the hippocampal synaptosome and increased the phosphorylation of N-methyl-D-aspartate receptor subunit GluN2B in the hippocampus of 8-month-old apoE4-TR mice. However, the expressions of apoE and apoE receptor 2 (apoER2) were not affected by stress. The study provides rodent evidence that APOE ε4 may increase the risk of depression and dementia in the elderly population by impairing the GABAergic signaling pathway and enhancing the GluN2B phosphorylation, which signifies that GluN2B inhibitors in clinical settings may be effective for elderly depression patients with APOE4 carriers.

APOE4 genotype exacerbates the depression-like behavior of mice during aging through ATP decline

Population-based studies reveal that apolipoprotein E (APOE) ε4 gene allele is closely associated with late-life depression (LLD). However, its exact role and underlying mechanism remain obscure. The current study found that aged apoE4-targeted replacement (TR) mice displayed obvious depression-like behavior when compared with age-matched apoE3-TR mice. Furthermore, apoE4 increased stress-induced depression-like behaviors, accompanied by declines in the hippocampal 5-HT (1A) radioligand [18F] MPPF uptake evidenced by positron emission tomography (PET). In [18F]-fluorodeoxyglucose PET ([18F]-FDG PET) analyses, the FDG uptake in the prefrontal cortex, temporal cortex and hippocampus of apoE4-TR mice significantly declined when compared with that of apoE3-TR mice after acute stress. Further biochemical analysis revealed that ATP levels in the prefrontal cortex of apoE4-TR mice decreased during aging or stress process and ATP supplementation effectively rescued the depression-like behaviors of elderly apoE4-TR mice. In primary cultured astrocytes from the cortex of apoE-TR mice, apoE4, when compared with apoE3, obviously decreased the mitochondrial membrane potential, mitochondrial respiration, and glycolysis in a culture time-dependent manner. Our findings highlight that apoE4 is a potential risk factor of depression in elderly population by impairing the glucose metabolism, reducing ATP level, and damaging mitochondrial functions in astrocytes, which indicates that in clinical settings ATP supplementation may be effective for elderly depression patients with apoE4 carrier.

Trajectories of depression symptoms over time differ by APOE4 genotype in older adults with type 2 diabetes

OBJECTIVES

The APOE-ε4 genotype has been associated with old-age depression, but this relationship has been rarely investigated in type 2 diabetes (T2D) older adults, who are at significantly increased risk for depression, a major contributor to T2D complications. We examined whether trajectories of depression symptoms over time differ by APOE-ε4 genotype in older adults with T2D.

METHODS

Participants (n = 754 [13.1% APOE-ε4 carrier]s) were from the longitudinal Israel Diabetes and Cognitive Decline (IDCD) study. They were initially cognitively normal and underwent evaluations of depression approximately every 18 months using the 15-item version of the Geriatric Depression Scale (GDS) and the depression subscale of the Neuropsychiatric Inventory (NPI). APOE was defined as a dichotomy of ε4 carriers and non-carriers. We used Hierarchical Linear Mixed Models (HLMM) that modeled the effects of APOE status on repeated GDS and NPI-depression scores in an unadjusted model (Model 1), adjusting for demographic factors (Model 2) and additionally adjusting for cardiovascular factors and global cognition (Model 3).

RESULTS

Participants' mean age was 71.37 (SD = 4.5); 38.2% female. In comparison to non-carriers, APOE-ε4 carriers had lower mean GDS scores (β = -0.46, p = 0.018) and lower NPI-depression scores (β = -0.170, p = 0.038) throughout all study follow period. The groups did not differ in the slope of change over time in GDS (β = -0.005, p = 0.252) or NPI-depression (β = -0.001, p = 0.994) scores. Additional adjustment for cardiovascular factors and global cognition did not alter these results.

CONCLUSIONS

In older adults with T2D, APOE-ε4 carriers have less depressive symptoms in successive measurements suggesting they may be less susceptible to depression.

Late-Life Depression: A Narrative Review on Risk Factors and Prevention

After participating in this activity, learners should be better able to:• Identify risk factors for late-life depression• Evaluate strategies to prevent late-life depression ABSTRACT: Late-life depression (LLD) is one of the major sources of morbidity and mortality in the world. Because LLD is related to increased public health burden, excess health care costs and utilization, reduced quality of life, and increased mortality, prevention is a priority. Older adults differ from younger adults with respect to key features, such as their chronicity and lifetime burden of depression and their constellation of comorbidities and risk factors. LLD likely arises from a complex interplay of risk factors, including medical, physiologic, psychosocial, behavioral, and environmental factors. Thus, a comprehensive understanding of LLD risk factors is necessary to inform prevention strategies. In this narrative literature review, we address both the risk architecture of LLD and several potential strategies for prevention. Our description of LLD risk factors and prevention approaches is informed by the framework developed by the National Academy of Medicine (formerly, Institute of Medicine), which includes indicated, selective, and universal approaches to prevention.

Apolipoprotein E homozygous ε4 allele status: Effects on cortical structure and white matter integrity in a young to mid-age sample

Apolipoprotein E (APOE) genotype is the strongest single gene predictor of Alzheimer's disease (AD) and has been frequently associated with AD-related brain structural alterations before the onset of dementia. While previous research has primarily focused on hippocampal morphometry in relation to APOE, sporadic recent findings have questioned the specificity of the hippocampus and instead suggested more global effects on the brain. With the present study we aimed to investigate associations between homozygous APOE ε4 status and cortical gray matter structure as well as white matter microstructure. In our study, we contrasted n = 31 homozygous APOE ε4 carriers (age=34.47 years, including a subsample of n = 12 subjects with depression) with a demographically matched sample without an ε4 allele (resulting total sample: N = 62). Morphometry analyses included a) Freesurfer based cortical segmentations of thickness and surface area measures and b) tract based spatial statistics of DTI measures. We found pronounced and widespread reductions in cortical surface area of ε4 homozygotes in 57 out of 68 cortical brain regions. In contrast, no differences in cortical thickness were observed. Furthermore, APOE ε4 homozygous carriers showed significantly lower fractional anisotropy in the corpus callosum, the right internal and external capsule, the left corona radiata and the right fornix. The present findings support a global rather than regionally specific effect of homozygous APOE ε4 allele status on cortical surface area and white matter microstructure. Future studies should aim to delineate the clinical implications of these findings.

Apolipoprotein E e4 allele status and later-life depression in the Lothian Birth Cohort 1936

BACKGROUND

Previous results have been mixed regarding the role of the apolipoprotein E e4 (APOE e4) allele in later-life depression: some studies note that carriers experience greater symptoms and increased risk while others find no such association. However, there are few prospective, population-based studies of the APOE e4-depression association and fewer that examine depressive symptom trajectory and depression risk longitudinally. We examined the association between APOE e4 allele status and longitudinal change in depressive symptoms and depression risk in later-life, over a 12-year follow-up period.

METHODS

We used data from 690 participants of the Lothian Birth Cohort 1936 who took part in the Scottish Mental Survey 1947 (aged 11) and were followed-up in later-life over five waves from 2004 to 2019 (aged 70-82). We used APOE e4 allele status to predict longitudinal change in depressive symptom scores and risk of depression (defined by a symptom score threshold or use of depression-related medication). Models were adjusted for sex, childhood cognitive ability, childhood social class, education, adult social class, smoking status and functional limitations at baseline.

RESULTS

Depressive symptom scores increased with age. Once adjusted for covariates, APOE e4 allele status did not significantly predict symptom score trajectories or depression risk. Greater functional limitations at baseline significantly predicted poorer symptom score trajectories and increased depression risk (defined by medications). APOE e4 allele status did not significantly moderate the contribution of sex, education or functional limitations.

CONCLUSIONS

There was no evidence that APOE e4 carriers experience an increased risk for later-life depression.

The National Health and Resilience in Veterans Study: A Narrative Review and Future Directions

United States (U.S.) veterans are substantially older than their non-veteran counterparts. However, nationally representative, population-based data on the unique health needs of this population are lacking. Such data are critical to informing the design of large-scale outreach initiatives, and to ensure the effectiveness of service care delivery both within and outside of the Veterans Affairs healthcare system. The National Health and Resilience in Veterans Study (NHRVS) is a contemporary, nationally representative, prospective study of two independent cohorts (n = 3,157 and n = 1,484) of U.S. veterans, which is examining longitudinal changes, and key risk and protective factors for several health outcomes. In this narrative review, we summarize the main findings of all NHRVS studies (n = 82) published as of June 2020, and discuss the clinical implications, limitations, and future directions of this study. Review of these articles was organized into six major topic areas: post-traumatic stress disorder, suicidality, aging, resilience and post-traumatic growth, special topics relevant to veterans, and genetics and epigenetics. Collectively, results of these studies suggest that while a significant minority of veterans screen positive for mental disorders, the majority are psychologically resilient. They further suggest that prevention and treatment efforts designed to promote protective psychosocial characteristics (i.e., resilience, gratitude, purpose in life), and social connectedness (i.e., secure attachment, community integration, social engagement) help mitigate risk for mental disorders, and promote psychological resilience and post-traumatic growth in this population.

Sex differences in dementia: on the potentially mediating effects of educational attainment and experiences of psychological distress

BACKGROUND

Old-age dementias are known to disproportionally affect women as well as individuals with low educational attainment. The higher lifetime risk of dementia among women is usually attributed to their longer life expectancy. However, the impact of sex, and subsequent gender inequity, is likely to be more multifaceted than this explanation implies. Not least because of historical inequities in access to education between the sexes and the gender and socio-economic gradients in risk factors such as stress, depression and social isolation. Consequently, the present study sought to test whether differences in educational attainment and experiences of general psychological distress mediate the association between female sex and dementia.

METHODS

The study utilizes data obtained through the Gothenburg H70 Birth Cohort Study and the Prospective Populations Study on Women (n = 892). Data were analysed using Confirmatory Factor Analysis (CFA) and Structural Equation Modelling (SEM) with Weighted Least Squares Means and Variance adjusted (WLSMV) estimation. General psychological distress was indicated by a latent variable and constructed from five manifest items (previous depression, stress, self-esteem, chronic loneliness and satisfaction with social situation) that were all measured at baseline.

RESULTS

While the results could not corroborate that education directly mediates the effect of sex on dementia, level of distress was predicted by both female sex (0.607, p < .001) and education (- 0.166, p < .01) and, in turn, shown to be significantly associated with dementia (0.167, p < .05), also after controlling for confounders. When time from baseline to diagnosis was increased through sequential exclusion of dementia cases, the effect of distress on dementia was no longer significant.

CONCLUSION

The overall findings suggest that social (dis) advantage predicts general psychological distress, which thereby constitutes a potential, and rarely acknowledged, pathway between female sex, education, and dementia. They further underline the importance of attending to both education and distress as 'gendered' phenomena when considering the nature of their associations with dementia. However, the possibility of reverse causality bias must be acknowledged and the need for longitudinal studies with longer follow-up stressed.

Depression and APOEε4 Status in Individuals with Subjective Cognitive Decline: A Meta-Analysis

OBJECTIVE

To evaluate the associative role of depression and apolipoprotein E epsilon 4 allele (APOEε4) in subjective cognitive decline (SCD) and its progression to objective cognitive decline.

METHODS

After literature search in electronic databases, studies were selected by following precise eligibility criteria. Meta-analyses were performed to examine the role of APOEε4 and depression in SCD or its progression to mild cognitive impairment (MCI) or dementia.

RESULTS

APOEε4 positivity was not different between SCD and normal individuals but was significantly higher in individuals with SCD plus than in normal individuals [odds ratio: 2.39 (95% CI: 1.87, 3.05); p<0.00001] and in SCD converters than in non-converters [odds ratio: 5.19 (95% CI: 2.36, 11.42); p<0.00001]. Depression was significantly higher in individuals with SCD [standardized mean difference: 0.63 (0.45, 0.82); p<0.00001] and SCD plus [standardized mean difference: 0.83 (0.43, 1.22); p<0.0001] than in normal individuals. However, depression was not different between SCD and MCI or between SCD converters and non-converters. Age of SCD converters was higher than non-converters [mean difference: 2.95 years (0.58, 5.31)].

CONCLUSION

Whereas APOEε4 positivity was higher in SCD plus and SCD converters, depression was higher in SCD and SCD plus but was not different between SCD and MCI.

Subjective Cognitive Decline Below and Above the Age of 60: A Multivariate Study on Neuroimaging, Cognitive, Clinical, and Demographic Measures

Subjective cognitive complaints in cognitively normal individuals are a relevant predictor of Alzheimer's disease (AD), cerebrovascular disease, and age-related tauopathy. Complaints starting after the age of 60 increase the likelihood of preclinical AD. However, this criterion is arbitrary and current data show that neurodegenerative disorders likely start before that age. Further, data on the role of subjective complaints below the age of 60 in individuals qualifying for subjective cognitive decline (SCD) are lacking. We investigated the association of subjective cognitive complaints with an extensive number of neuroimaging, demographic, clinical, and cognitive measures in individuals fulfilling criteria for SCD below and above the age of 60. Nine complaints were scored in 416 individuals. Complaints were related to a higher load of white matter signal abnormalities, and this association was stronger the more subclinical changes in personality, interest, and drive were reported. In individuals <60 years, complaints were associated with lower global cognitive performance. In individuals ≥60 years, complaints were related to greater global brain atrophy and smaller total intracranial volume, and this association was stronger the more subclinical difficulties in activities of daily living were reported. Also, complaints were associated with increased depressive symptomatology irrespective of age. We conclude that complaints below the age of 60 may be associated with subtle signs of brain pathology. In the community, screening for risk of future cognitive decline should include subjective cognitive complaints, depressive symptomatology, and subclinical reduced cognition (<60 years)/activities of daily living (≥60 years), supported by basic neuroimaging examinations.

Predicting self-reported depression after the onset of multiple sclerosis using genetic and non-genetic factors

BACKGROUND

Persons with multiple sclerosis (PwMS) are disproportionately burdened by depression compared to the general population. While several factors associated with depression and depression severity in PwMS have been identified, a prediction model for depression risk has not been developed. In addition, it is unknown if depression-related genetic variants, including Apolipoprotein E (APOE), would be informative for predicting depression in PwMS.

OBJECTIVE

To develop a depression prediction model for PwMS who did not have a history of depression prior MS onset.

METHODS

The study population included 917 non-Hispanic white PwMS. An optimized multivariable Cox proportional hazards model for time to depression was generated using non-genetic variables, to which APOE and a depression-related genetic risk score were included.

RESULTS

Having a mother who had a history of depression, having obstructive pulmonary disease, obesity and other physical disorders at MS onset, and affect-related symptoms at MS onset predicted depression risk (hazards ratios (HRs): 1.6-2.3). Genetic variables improved the prediction model's performance. APOE ε4/ε4 and ε2/x conferred increased (HR = 2.5, p = 0.026) and decreased (HR = 0.65, p = 0.046) depression risk, respectively.

CONCLUSION

We present a prediction model aligned with The Precision Medicine Initiative, which integrates genetic and non-genetic predictors to inform depression risk stratification after MS onset.

Role of apolipoprotein E epsilon 4 (APOE*ε4) as an independent risk factor for incident depression over a 12-year period in cognitively intact adults across the lifespan

BACKGROUND

The apolipoprotein E ε4 allele (APOE*ε4) is indicated as a risk for Alzheimer's disease and other age-related diseases. The risk attributable to APOE*ε4 for depression is less clear and may be because of confounding of the relationship between dementia and depression.

AIMS

We examined the risk of APOE* ε4 for incident depression and depressive symptomology over a 12-year period across the adult lifespan.

METHOD

Participants were from the Personality and Total Health Through Life study, aged 20 to 24 (n = 1420), 40 to 44 (n = 1592) or 60-64 (n = 1768) at baseline, and interviewed every 4 years since 1999. Ethnicities other than White, those without genotyping and those with depression at baseline, or who reported strokes and scores on the Mini-Mental State Examination <27 at any observation, were excluded.

RESULTS

Over the study period, there was no evidence that APOE*ε4+ was a risk factor for depression, including any depression (odds ratio (OR) = 0.94, 95% CI 0.77-1.16, P = 0.573), major depression (OR = 0.96, 95% CI 0.60-1.53, P = 0.860), minor depression (OR = 0.94, 95% CI 0.67-1.30, P = 0.695) or depressive symptomology (incidence rate ratio (IRR) = 1.02, 95% CI 0.97-1.08, P = 0.451). APOE*ε4 was unrelated to incident depression. Findings were consistent for all age cohorts.

CONCLUSIONS

Among cognitively intact Australian adults who were free of depression at baseline, there was little evidence that APOE*ε4+ carriers are at increased risk for depression over a 12-year period among those who are cognitively intact.

The impact of social networks and APOE ε4 on dementia among older adults: tests of possible interactions

Objectives: Emerging evidence suggests that social networks may protect against the development of dementia among older adults. In this study we analysed the association between social networks, the apolipoprotein E (APOE) ε4 allele, and dementia. We also investigated whether there were gender-specific patterns in this respect.Method: The analyses used population-based longitudinal data from Gothenburg, Sweden: the H70 Birth Cohort Study and the Prospective Population Study on Women (PPSW). A total of 580 individuals born in 1930 underwent semi-structured neuropsychiatric examinations in 2000-2001. Follow-up examinations were carried out in 2005-2006 and 2009-2010. The timing of dementia onset was analysed using Cox proportional hazards regression.Results: The presence of the APOE ε4 allele affected the risk of developing dementia in both genders. Among women, distant social networks had a protective effect on dementia, while among men the significant associations between close social networks and dementia did not remain after controlling for covariates. Significant interactions between social networks and the APOE ε4 allele were not found.Conclusion: Strong social networks do not seem to moderate the increased risk of dementia implied by the APOE ε4 allele. Nevertheless, our results underline the importance of strong social networks in postponing dementia onset and indicate that their impact may differ among men and women.

Polyunsaturated Fatty Acid Composition of Cerebrospinal Fluid Fractions Shows Their Contribution to Cognitive Resilience of a Pre-symptomatic Alzheimer's Disease Cohort

Alzheimer’s disease (AD) pathology is characterized by an early and prolonged decrease in the amyloid peptide (Aβ) levels concomitant with a later increase in phospho-tau concentrations in cerebrospinal fluid (CSF). We propose that changes in lipid metabolism can contribute to the abnormal processing of Aβ₄₂ in AD. Our aim was to determine if polyunsaturated fatty acid (PUFA) metabolism can differentiate pre-symptomatic AD from normal aging and symptomatic AD. Using neuropsychology measures and Aβ₄₂/T-tau in cerebrospinal fluid (CSF), we classify three groups of elderly study participants: cognitively healthy with normal Aβ₄₂/T-tau (CH-NAT), cognitively healthy with pathological Aβ₄₂/T-tau (CH-PAT), and AD individuals. We determined the size distribution and the concentration of CSF particles using light scattering and quantified PUFA composition in the nanoparticulate (NP) fraction, supernatant fluid (SF), and unesterified PUFA levels using gas chromatography combined with mass spectrometry. Four PUFAs (C20:2n-6, C20:3n-3, C22:4n-6, C22:5n-3) were enriched in NP of AD compared with CH-NAT. C20:3n-3 levels were higher in the NP fraction from AD compared with CH-PAT. When normalized to the number of NPs in CSF, PUFA levels were significantly higher in CH-NAT and CH-PAT compared with AD. In the SF fractions, only the levels of docosahexaenoic acid (DHA, C22:6n-3) differentiated all three clinical groups. Unesterified DHA was also higher in CH-NAT compared with the other clinical groups. Our studies also show that NP PUFAs in CH participants negatively correlate with CSF Aβ₄₂ while C20:4n-6, DHA, and n-3 PUFAs in the SF fraction positively correlate with T-tau. The profile of PUFAs in different CSF fractions that correlate with Aβ₄₂ or with T-tau are different for CH-NAT compared with CH-PAT. These studies show that PUFA metabolism is associated with amyloid and tau processing. Importantly, higher PUFA levels in the cognitively healthy study participants with abnormal Aβ₄₂/T-tau suggest that PUFA enhances the cognitive resilience of the pre-symptomatic AD population. We propose that interventions that prevent PUFA depletion in the brain may prevent AD pathology by stabilizing Aβ₄₂ and tau metabolism. Further studies to determine changes in PUFA composition during the progression from pre-symptomatic to AD should reveal novel biomarkers and potential preventive approaches.

Investigation of antihypertensive class, dementia, and cognitive decline: A meta-analysis

OBJECTIVE

High blood pressure is one of the main modifiable risk factors for dementia. However, there is conflicting evidence regarding the best antihypertensive class for optimizing cognition. Our objective was to determine whether any particular antihypertensive class was associated with a reduced risk of cognitive decline or dementia using comprehensive meta-analysis including reanalysis of original participant data.

METHODS

To identify suitable studies, MEDLINE, Embase, and PsycINFO and preexisting study consortia were searched from inception to December 2017. Authors of prospective longitudinal human studies or trials of antihypertensives were contacted for data sharing and collaboration. Outcome measures were incident dementia or incident cognitive decline (classified using the reliable change index method). Data were separated into mid and late-life (>65 years) and each antihypertensive class was compared to no treatment and to treatment with other antihypertensives. Meta-analysis was used to synthesize data.

RESULTS

Over 50,000 participants from 27 studies were included. Among those aged >65 years, with the exception of diuretics, we found no relationship by class with incident cognitive decline or dementia. Diuretic use was suggestive of benefit in some analyses but results were not consistent across follow-up time, comparator group, and outcome. Limited data precluded meaningful analyses in those ≤65 years of age.

CONCLUSION

Our findings, drawn from the current evidence base, support clinical freedom in the selection of antihypertensive regimens to achieve blood pressure goals.

CLINICAL TRIALS REGISTRATION

The review was registered with the international prospective register of systematic reviews (PROSPERO), registration number CRD42016045454.

Homozygosity in the APOE 3 Polymorphism Is Associated With Less Depression and Higher Serum Low-Density Lipoprotein in Chinese Elderly Schizophrenics

Background: Depressive symptoms are common comorbidities in schizophrenia. However, the effect of APOE E3 on depressive symptoms has never been investigated in an aging Chinese population with schizophrenia. This cross-sectional study aimed to investigate the effects of APOE E3 on blood lipid metabolism and depressive symptoms in elderly schizophrenics in China. Methods: Three Hundred and one elderly schizophrenics (161 males, age ranges from 60 to 92 years, with an average age of 67.31 ± 6.667) were included in the study. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS). APOE gene polymorphism was determined by polymerase chain reaction (PCR). We assessed the correlations of GDS and serum low-density lipoprotein (LDL) with APOE genotypes. Results: The concentration of LDL in the Homozygous APOE E3 group was significantly higher than that in the non-homozygous APOE E3 group, while the scores of GDS of the Homozygous APOE E3 group were lower than that in the non-homozygous APOE E3 group. Using partial correlation analysis and controlling age, gender, duration of disease, and hyperlipidemia, we found that the scores of GDS were significantly correlated with LDL (r = -0.194, p = 0.016). Conclusions: APOE E3 is associated with less depressive symptoms and higher serum LDL in Chinese elderly patients with schizophrenia, and there is a negative correlation between depressive symptoms and LDL.

Genetic Variation in FOXO3 is Associated with Self-Rated Health in a Population-Based Sample of Older Individuals

Self-rated health (SRH) strongly predicts mortality. Twin studies estimate that genetic factors account for a substantial part of the variability in SRH. Variations in the gene FOXO3 (forkhead box O3), and in genes located at the APOE (apoplipoprotein E) locus, are associated with longevity. This study explores the relationship between SRH and genetic variation related to longevity, in a population-based cohort of older individuals. SRH was assessed among 1,520 individuals aged 75–87, and five single nucleotide polymorphisms (SNPs), in APOE, TOMM40 (translocase of outer mitochondrial membrane 40 homolog), and FOXO3 were genotyped. Two SNPs (rs10457180 and rs2802292) in FOXO3 were associated with SRH (OR = 2.18 [CI: 1.27–3.76], p = .005 and OR = 1.63 [CI: 1.11–2.40], p = .013), while no associations were found with SNPs in APOE and TOMM40. Several factors, such as depression, cardiovascular disease (CVD), and diabetes, were related to SRH, but the only factor that had any influence on the association with FOXO3 was CVD. Still, after including CVD as a covariate, the associations between FOXO3 SNPs and SRH remained significant. Our results suggest that FOXO3 is related to SRH in older individuals. This relationship seems to be influenced by CVD, but not by mental and cognitive status.

Neurobiological substrates underlying the effect of genomic risk for depression on the conversion of amnestic mild cognitive impairment

Depression increases the conversion risk from amnestic mild cognitive impairment to Alzheimer's disease with unknown mechanisms. We hypothesize that the cumulative genomic risk for major depressive disorder may be a candidate cause for the increased conversion risk. Here, we aimed to investigate the predictive effect of the polygenic risk scores of major depressive disorder-specific genetic variants (PRSsMDD) on the conversion from non-depressed amnestic mild cognitive impairment to Alzheimer's disease, and its underlying neurobiological mechanisms. The PRSsMDD could predict the conversion from amnestic mild cognitive impairment to Alzheimer's disease, and amnestic mild cognitive impairment patients with high risk scores showed 16.25% higher conversion rate than those with low risk. The PRSsMDD was correlated with the left hippocampal volume, which was found to mediate the predictive effect of the PRSsMDD on the conversion of amnestic mild cognitive impairment. The major depressive disorder-specific genetic variants were mapped into genes using different strategies, and then enrichment analyses and protein-protein interaction network analysis revealed that these genes were involved in developmental process and amyloid-beta binding. They showed temporal-specific expression in the hippocampus in middle and late foetal developmental periods. Cell type-specific expression analysis of these genes demonstrated significant over-representation in the pyramidal neurons and interneurons in the hippocampus. These cross-scale neurobiological analyses and functional annotations indicate that major depressive disorder-specific genetic variants may increase the conversion from amnestic mild cognitive impairment to Alzheimer's disease by modulating the early hippocampal development and amyloid-beta binding. The PRSsMDD could be used as a complementary measure to select patients with amnestic mild cognitive impairment with high conversion risk to Alzheimer's disease.

Shared genetic risk factors for depression and stroke

BACKGROUND

The comorbidity of major depressive disorder (MDD) and stroke are common in clinic. There is a growing body of evidence suggesting a bi-directional relationship between stroke and depression. However, the mechanisms underlying the relationship between MDD and stroke are poorly investigated. Considering that both MDD and stroke can be heritable and are influenced by multiple risk genes, shared genetic risk factors between MDD and stroke may exist.

OBJECTIVE

The objective is to review the existing evidence for common genetic risk factors for both MDD and stroke and to outline the possible pathophysiological mechanisms mediating this association.

METHODS

A systematic review and meta-analysis was performed. Gene association studies regarding stroke and depression were searched in the database PubMed, CNKI, and Chinese Biomedical Literature Database before December 2018. Statistical analysis was performed using the software Revman 5.3.

RESULTS

Genetic polymorphisms of 4 genes, methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein E (ApoE) have been demonstrated to associate with the increased risk for both MDD and stroke, while the association between identified polymorphisms in angiotensin converting enzyme (ACE) and serum paraoxonase (PON1) with depression is still under debate, for the existing studies are insufficient in sample size. These results suggest the possible pathophysiological mechanisms that are common to these two disorders, including immune-inflammatory imbalance, increased oxidative and nitrative stress, dysregulation of lipoprotein and lipid metabolism, and changes of cerebrovascular morphology and function. Other associated genes with few or conflicting results have also been included, and a few studies have investigated the effects of the described polymorphisms on MDD and stroke comorbidity, such as post stroke depression.

CONCLUSION

These findings suggest that shared genetic pathways may contribute to the comorbidity of MDD and stroke. Studies to evaluate the shared genetic variations between MDD and stroke may provide insights into the molecular mechanisms that trigger disease progression.

Epidemiology of suicidal feelings in an ageing Swedish population: from old to very old age in the Gothenburg H70 Birth Cohort Studies

AIMS

The first aim of this study was to provide prevalence suicidal feelings over time (past week, past month, past year and lifetime) in a population-based sample of old to very old adults without dementia. Does prevalence change with rising age? The second aim was to examine the fluctuation of suicidal feelings over time. How does this coincide with depression status?

METHODS

Data were derived from the Gothenburg H70 Birth Cohort Studies (the H70 studies) which are multidisciplinary longitudinal studies on ageing. A representative sample of adults in Gothenburg, Sweden with birth years 1901-1944 were invited to take part in a longitudinal health study on ageing and participated at one or more occasions during 1986-2014. The sample consisted of 6668 observations originating from 3972 participants without dementia between the ages of 70 and 108, including 1604 participants with multiple examination times. Suicidal feelings were examined during a psychiatric interview using the Paykel questions (life not worth living, death wishes, thoughts of taking own life, seriously considered taking life, attempted suicide).

RESULTS

Prevalence figures for suicidal feelings of any severity were as follows: past week 4.8%, past month 6.7%, past year 11.2% and lifetime 25.2%. Prevalence rates increased with age in the total group and in women but not in men. Suicidal feelings were common in participants with concurrent major or minor depression, but over a third of the participants who reported suicidal feelings did not fulfil criteria for these diagnoses nor did they present elevated mean depressive symptom scores. The majority of participants consistently reported no experience of suicidal feelings over multiple examination times, but fluctuation was more common in women compared with men.

CONCLUSION

Suicidal feelings in late-life are uncommon in individuals without depression indicating that such behaviour is not a widespread, normative phenomenon. However, such feelings may occur outside the context of depression.

Lifestyle multidomain intervention, omega-3 supplementation, or both for reducing the risk of developing clinically relevant depressive symptoms in older adults with memory complaints? Secondary analysis from the MAPT trial

BACKGROUND

We tested the associations of a lifestyle multidomain intervention (MI), omega-3 supplementation (O3) or their combination with the change of clinically meaningful depressive symptoms in older adults.

METHODS

Secondary analysis of the 3-year Multidomain Alzheimer Preventive Trial (MAPT), in which 1679 people, ≥70 years with memory complaints were randomized into: MI, O3, MI + O3, or placebo. MI was composed of nutritional and physical activity counselling and cognitive training. O3 supplementation corresponded to a daily dose of 1000 mg of omega-3. Discrete-time cox regressions were performed for each outcome. Three binary variables of incidence of depressive symptoms were created from the 15-item geriatric depression scale (GDS-15): minimum clinically meaningful depressive symptoms (≥2-point increase in GDS-15), moderate depressive symptoms (GDS-15 ≥ 5), and severe depressive symptoms (GDS-15 ≥ 10) DS.

RESULTS

Discrete-time cox proportional hazards have found no associations for all of the analysis. The incidence of severe depressive symptoms across groups were, respectively: 1.1, 2.4, 2.3 and 2.5 per 100 person year for MI + O3, for O3, for MI, for placebo. There was a trend for a decreased risk of developing severe DS compared to placebo in the MI + O3 group (p = 0.085 after adjustment).

CONCLUSIONS

To conclude, we did not find any association of a lifestyle multidomain intervention with the onset of clinically depressive symptoms in older adults with memory complaints. A study with a more intensive multidomain intervention might bring further insights on this topic.

Associations between ApoE gene and psychological consequences post stroke in a Bahraini cohort

BACKGROUND

The contribution of genetic factors such as the presence of ApoE allele e4 and its association with psychological consequences post stroke remains unknown within Middle-Eastern regions. This study examined the association of ApoE genotype with cognitive impairment and mood in stroke patients and compare with healthy older adults in Bahrain.

METHOD

A prospective sample of n = 62 stroke patients (case group) and n = 53 healthy ageing individuals (control group) were eligible to participate in the study. A neuropsychological battery of cognitive assessments were conducted on all participants, and then stratified by cognitive function: no cognitive impairment, mild cognitive impairment and moderate to severe cognitive impairment. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS).

RESULTS

Most frequent ApoE genotype was e2/e3 in case (44%) and control groups (63%). ApoE allele e3 had the highest frequency for both groups with all stroke patients presenting with this allele and 86% for the control group (χ²  = 12.14, p < .0001). Stroke patients' non-carriers for ApoE allele e4 performed better on all cognitive measures but differences were not statistically significant (ns). Carriers of ApoE allele e2 in both groups had less mood symptoms compared to non-carriers.

DISCUSSION

ApoE genotype e3/e4 and e4/e4 was low in this Bahraini cohort explaining why there may been no significant associations found for this genotype variant with cognitive impairment. Further investigation of cognitive impairment and mood dysregulation with the different variants of the ApoE gene in general ageing and stroke populations is required from different ethno-cultural groups and geographical regions globally.

Association of Alzheimer's genetic loci with mild behavioral impairment

Mild behavioral impairment (MBI) describes the emergence of later-life neuropsychiatric symptoms (NPS) as an at-risk state for incident cognitive decline and dementia, and for some as a potential manifestation of prodromal dementia. How NPS mechanistically link to the development of mild cognitive impairment and Alzheimer's disease (AD) is not fully understood, with potential mechanisms including shared risk factors related to both NPS and cognitive impairment, or AD pathology promoting NPS. This is the first exploratory study to examine whether AD genetic loci as a genetic risk score (GRS), or individually, are a shared risk factor with MBI. Participants were 1,226 older adults (aged 72-79; 738 males; 763 normal cognition) from the Personality and Total Health Through Life project. MBI was approximated in accordance with Criterion 1 of the ISTAART-AA diagnostic criteria using a transformation algorithm for the neuropsychiatric inventory. A GRS was constructed from 25 AD risk loci. Binomial logistic regression adjusting for age, gender, and education examined the association between GRS and MBI. A higher GRS and APOE*ε4 were associated with increased likelihood of affective dysregulation. Nominally significant associations were observed between MS4A4A-rs4938933*C and MS4A6A-rs610932*G with a reduced likelihood of affective dysregulation; ZCWPW1-rs1476679*C with a reduced likelihood of social inappropriateness and abnormal perception/thought content; BIN1-rs744373*G and EPHA1-rs11767557*C with higher likelihood of abnormal perception/thought content; NME8-rs2718058*G with a reduced likelihood of decreased motivation. These preliminary findings suggest a common genetic etiology between MBI and traditionally recognized cognitive problems observed in AD and improve our understanding of the pathophysiological features underlying MBI.

The Gothenburg H70 Birth cohort study 2014-16: design, methods and study population

To improve health care for older persons, we need to learn more about ageing, e.g. identify protective factors and early markers for diseases. The Gothenburg H70 Birth Cohort Studies (the H70 studies) are multidisciplinary epidemiological studies examining representative birth cohorts of older populations in Gothenburg, Sweden. So far, six birth cohorts of 70-year-olds have been examined over time, and examinations have been virtually identical between studies. This paper describes the study procedures for the baseline examination of the Birth cohort 1944, conducted in 2014–16. In this study, all men and women born 1944 on specific dates, and registered as residents in Gothenburg, were eligible for participation (n = 1839). A total of 1203 (response rate 72.2%; 559 men and 644 women; mean age 70.5 years) agreed to participate in the study. The study comprised sampling of blood and cerebrospinal fluid, psychiatric, cognitive, and physical health examinations, examinations of genetics and family history, use of medications, social factors, functional ability and disability, physical fitness and activity, body composition, lung function, audiological and ophthalmological examinations, diet, brain imaging, as well as a close informant interview, and qualitative studies. As in previous examinations, data collection serves as a basis for future longitudinal follow-up examinations. The research gained from the H70 studies has clinical relevance in relation to prevention, early diagnosis, clinical course, experience of illness, understanding pathogenesis and prognosis. Results will increase our understanding of ageing and inform service development, which may lead to enhanced quality of care for older persons.

Chronic depressive symptomatology and CSF amyloid beta and tau levels in mild cognitive impairment

OBJECTIVES

To investigate the association between chronic subsyndromal symptoms of depression (SSD), cerebrospinal fluid (CSF) biomarkers, and neuropsychological performance in individuals with mild cognitive impairment (MCI).

METHODS

Participants included 238 older adults diagnosed with MCI from the Alzheimer's Disease Neuroimaging Initiative repository with cognitive and CSF amyloid beta (Aβ_1-42 ), total tau (t-tau), and phosphorylated tau (p-tau) data. The Neuropsychiatric Inventory identified individuals with chronic endorsement (SSD group N = 80) or no endorsement (non-SSD group N = 158) of depressive symptoms across timepoints. CSF biomarker and cognitive performance were evaluated with linear regression models adjusting for age, education, gender, APOE genotype, global cognitive status, and SSD group.

RESULTS

As compared to the non-SSD group, the SSD group displayed lower CSF Aβ_1-42 levels (β = -24.293, S.E. = 6.345, P < 0.001). No group differences were observed for CSF t-tau (P = 0.497) or p-tau levels (P = 0.392). Lower CSF Aβ_1-42 levels were associated with poorer performance on learning (β = 0.041, S.E. = 0.018, P = 0.021) and memory (β = -0.012, S.E. = 0.005, P = 0.031) measures, whereas higher CSF t-tau levels were associated with poorer performance on measures of global cognition (β = 0.022, S.E = 0.008, P = 0.007) and language (β = -0.010, S.E = 0.004, P = 0.019). SSD was independently associated with diminished global cognition, learning and memory, language, and executive function performance over and above the effects of CSF biomarkers (all P < 0.05).

CONCLUSIONS

MCI participants with SSD displayed diminished CSF Aβ_1-42 levels but did not differ from non-SSD controls in CSF tau levels. Additionally, CSF biomarkers and SSD independently accounted for variance in cognitive performance, suggesting that these factors may uniquely confer cognitive risk in MCI.

Low fasting serum insulin and dementia in nondiabetic women followed for 34 years

Objective

In a representative population of women followed over 34 years, we investigated the prospective association between fasting serum insulin and dementia, taking into account the incidence of diabetes mellitus.

Methods

Fasting values for serum insulin and blood glucose were obtained in 1,212 nondiabetic women 38 to 60 years of age at the 1968 baseline. Risk of dementia was assessed by Cox proportional hazard regression with adjustment for insulin, glucose, and other covariates and, in a second model, after censoring for incident cases of diabetes mellitus. Incident diabetes mellitus was considered as a third endpoint for comparison with dementia.

Results

Over 34 years, we observed 142 incident cases of dementia. The low tertile of insulin displayed excess risk for dementia (hazard ratio [HR] 2.34, 95% confidence interval [CI] 1.52–3.58) compared to the medium tertile, but the high tertile of insulin did not (HR 1.28, 95% CI 0.81–2.03). These associations were also seen for dementia without diabetes comorbidity. In contrast, high but not low insulin predicted incident diabetes mellitus (115 cases) (HR 1.70, 95% CI 1.08–2.68 and HR 0.76, 95% CI 0.43–1.37, respectively).

Conclusion

A previous study reported a U-shaped association between fasting insulin and dementia in a 5-year follow-up of elderly men. Our results confirmed a nonlinear association in a female population, with high risk at low insulin values that was not attributable to preclinical dementia or impaired insulin secretion. This condition suggests a new pathway to dementia, which differs from the metabolic pathway involving diabetes mellitus.

Socioeconomic status, gender and dementia: The influence of work environment exposures and their interactions with APOE ɛ4

It is a well-established fact that unfavourable social and economic conditions have a negative impact on health and longevity. Recent findings suggest that this is also true of age-related dementias. Yet most common indicators of socioeconomic status (SES) say very little about the actual mechanisms at play in disease development. The present paper explores five work exposure characteristics, all of which have a clear social gradient, that could potentially shed further light on the relationship between SES and dementia. Specifically, it investigates whether these exposures could moderate the impact of a well-known genetic risk factor: the APOE ɛ4 allele. The empirical analyses are based on data from a Swedish population study (n = 1019). Main occupation was linked to The Job Exposure Matrix to estimate the individuals’ exposure to the following work environment factors: work control, support, psychological demands, physical demands and job hazards. All analyses were conducted using binary logistic regression and focused specifically on gene-work exposure interactions. A significant main effect of work control on dementia risk was detected for males (OR = 0.68; p< 0.05), but not for females. However, control was found to significantly moderate the effect of APOE ɛ4 in both genders, albeit in different ways. These findings do not only underscore the importance of considering interactions between social and genetic risk factors to better understanding multifactorial diseases such as dementia. They also propose that gender- and class-based inequities interact, and hence must be considered simultaneously, also in relation to this particular disease.

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There are steep social gradients in exposure to various work environment conditions.

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Work control alters the effect of APOE ɛ4 in both genders, albeit in different ways.

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High work control protects male, but not female, APOE ɛ4-carriers.

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‘Male’ high control jobs differ greatly from ‘female’ high control jobs.

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Gender- and class-based inequities interact also in the development of dementia.

Interactions Among Polymorphisms of Susceptibility Loci for Alzheimer's Disease or Depressive Disorder

Background

Several genetic susceptibility loci for major depressive disorder (MDD) or Alzheimer’s disease (AD) have been described. Interactions among polymorphisms are thought to explain the differences between low- and high-risk groups. We tested for the contribution of interactions between multiple functional polymorphisms in the risk of MDD or AD.

Material/Methods

A genetic association case-control study was performed in 68 MDD cases, 84 AD cases (35 of them with comorbid depression), and 90 controls. The contribution of 7 polymorphisms from 5 genes (APOE, HSPA1A, SLC6A4, HTR2A, and BDNF) related to risk of MDD or AD development was analyzed.

Results

Significant associations were found between MDD and interactions among polymorphisms in HSPA1A, SLC6A4, and BDNF or HSPA1A, BDNF, and APOE genes. For polymorphisms in the APOE gene in AD, significant differences were confirmed on the distributions of alleles and genotype rates compared to the control or MDD. Increased probability of comorbid depression was found in patients with AD who do not carry the ɛ4 allele of APOE.

Conclusions

Assessment of the interactions among polymorphisms of susceptibility loci in both MDD and AD confirmed a synergistic effect of genetic factors influencing inflammatory, serotonergic, and neurotrophic pathways at these heterogenous complex diseases. The effect of interactions was greater in MDD than in AD. A presence of the ɛ4 allele was confirmed as a genetic susceptibility factor in AD. Our findings indicate a role of APOE genotype in onset of comorbid depression in a subgroup of patients with AD who are not carriers of the APOE ɛ4 allele.

APOEε4 and the long arm of social inequity: estimated effects of socio-economic status and sex on the timing of dementia onset

It is well established that carriers of the apolipoprotein E (APOE) ε4 allele run a greater risk of developing Alzheimer's disease, the most common form of dementia and a strongly age-related condition known to disproportionally affect women. Low educational attainment also stands out as a prominent risk factor, and it has been suggested that occupational class plays a similar role in disease susceptibility. Not yet fully explored, however, is the question of whether socio-economic status (SES) could moderate the effect ofAPOEε4. In the present paper, we address this issue. As substantial inequities in workforce participation and educational opportunities have existed between men and women in previous generations, we further examine whether SES-related moderations of the relationship between dementia andAPOEε4 are sex-specific. Our analyses are based on a sample of 580 individuals from the H70 Birth Cohort Study and the Prospective Population Study on Women in Gothenburg, Sweden. Data were analysed using Cox proportional hazards regression, and the results suggest that while high SES postpones dementia onset among maleAPOEε4 carriers, this is not the case for women. These findings underscore the long-term impact of social inequity on health as well as the importance of considering potential interactions between social and genetic risk factors if we are to understand better the complex aetiology of dementia.

Apolipoprotein E gene polymorphism, trauma burden, and posttraumatic stress symptoms in U.S. military veterans: Results from the National Health and Resilience in Veterans Study

BACKGROUND

Previous research examining the association between apolipoprotein E (APOE) gene polymorphism and risk for posttraumatic stress disorder (PTSD) has been inconsistent due to the use of small and select samples. This study examined the relation between APOE genotype and PTSD symptoms in two nationally representative samples of U.S. military veterans. The potential effect of cumulative trauma burden and social support in moderating this association was also evaluated.

METHODS

The main sample consisted of 1,386 trauma-exposed European American (EA) veterans (mean age: 62-63 years) who participated in the National Health and Resilience in Veterans Study (NHRVS) in 2011. The independent replication sample consisted of 509 trauma-exposed EA veterans from the 2013 NHRVS.

RESULTS

APOE ε4 allele carriers reported significantly greater severity of PTSD symptoms than noncarriers in the main, but not the replication, sample. In both samples, the interaction of APOE ε4 carrier status and cumulative trauma burden was associated with greater severity of PTSD symptoms (F range = 2.53-8.09, all P's < .01), particularly re-experiencing/intrusion symptoms (F range = 3.59-4.24, P's < .001). Greater social support was associated with lower severity of PTSD symptoms among APOE ε4 allele carriers with greater cumulative trauma burden (β range -.27 to -.60, P's < .05).

CONCLUSION

U.S. military veterans who are APOE ε4 allele carriers and exposed to a high number of traumas may be at increased risk for developing PTSD symptoms than ε4 noncarriers. Greater social support may moderate this association, thereby highlighting the potential importance of social support promoting interventions in mitigating the effect of ε4 × cumulative trauma burden on PTSD risk.

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.

Decreasing hazards of Alzheimer's disease with the use of antidepressants: mitigating the risk of depression and apolipoprotein E

OBJECTIVE

Alzheimer's disease (AD) is a neurodegenerative disease, manifesting in clinically observable deficits in memory, thinking, and behavior that disproportionately affects older adults. Susceptibility genes, such as apolipoprotein ε4, have long been associated with an increased risk of AD diagnosis. Studies have shown associations between depression and increased risk of AD development. Furthermore, findings from previous investigations suggest mixed effects in the use of psychotropic medication in older adults. The hypothesis for this study is that antidepressant use modifies the increased hazard of depression or such that a non-significant hazard will result with respect to eventual AD development.

METHODS

Utilizing data from the National Alzheimer's Coordinating Center, we examined evaluations of 11,443 cognitively intact participants. Survival analysis was used to explore relationships between depression, apolipoprotein E, AD diagnosis, and antidepressant use.

RESULTS

An analytical sample of 8732 participants with normal cognition was examined. Among users of antidepressant medication, the hazard, in most cases, was no longer statistically significant. One generic medication showed protective benefits for users (p < 0.001). In addition, there was a statistically significant relationship between recent depression (n = 2083; p < 0.001), lifetime depression (n = 2068; p < 0.05), and ε4 carrier status (n = 2470; p < 0.001) and AD development.

CONCLUSIONS

The findings suggest that a mechanism related to antidepressant use may reduce the hazard of eventual AD. Furthermore, the findings reinforce the association between depression, apolipoprotein E (APOE) ε4, and AD diagnosis. This study contributes to the emerging literature exploring interventions aimed at decreasing the risk of AD by targeting potentially modifiable psychosocial risk factors such as depression. Copyright © 2017 John Wiley & Sons, Ltd.