Apolipoprotein E4 increases the risk of depression recurrence

Changes in dementia risk along with onset age of depression: a longitudinal cohort study of elderly depressed patients

BACKGROUND

Depression in late-life is linked to an increased risk of Alzheimer's dementia (AD), with the risk potentially varying according to the age at onset of depression. Previous studies have typically dichotomized depression onset ages between 55 and 65 years; however, the specific age at which depression onset increases AD risk in older adults remains unclear. In this study, we aimed to investigate the relationship between the age at onset of depression and AD risk, and compare the characteristics between different age groups.

METHODS

A longitudinal cohort of 251 older patients diagnosed with major depressive disorder was followed for up to 22 years. Participants were categorized into four groups based on depression onset age: ≤ 54 years, 55-64, 65-74, and ≥ 75 years. Annual cognitive assessments were conducted using the Korean Mini-Mental State Examination, with further neuropsychological testing when cognitive decline was suspected. Cox proportional hazards models were used to assess AD conversion risk across groups, adjusting for covariates.

RESULTS

During follow-up ranging from 1.0 to 22.9 years, 75 patients (29.88%) converted to AD. Depression onset after age 75 years was significantly associated with a higher risk of AD conversion (hazard ratio [HR], 8.95; 95% confidence interval [CI], 3.41-23.48; p < 0.0001) and a shorter time to conversion compared to onset before age 55 (40.93 vs. 83.40 months). After adjusting for covariates, depression onset after age 75 remained significantly associated with AD conversion (adjusted HR, 5.20; 95% CI, 1.04-25.93; p = 0.0431). This group also had milder depressive symptoms and a higher prevalence of hypertension and cerebrovascular disease than those with depression onset before 55 years of age.

CONCLUSIONS

The onset of depression after the age of 75 years was strongly associated with an increased risk of AD and a shorter time to dementia onset. Individuals with depression onset after age 75 appear more closely linked to vascular comorbidities, while those with depression onset before age 55 are characterized by severe and recurrent depressive episodes. The mechanisms underlying AD in individuals with depression may differ from those in individuals without prior depression.

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.

Relationship of Apolipoprotein E with Alzheimer's Disease and Other Neurological Disorders: An Updated Review

Alzheimer's disease (AD) and other neurodegenerative diseases, for which there is no effective cure, cause great social burden. Apolipoprotein E (APOE) is an important lipid transporter, which has been shown to have a close relationship with AD and other neurological disorders in an increasing number of studies, suggesting its potential as a therapeutic target. In this review, we summarize the recent advances in clinical and basic research on the role of APOE in the pathogenesis of multiple neurological diseases, with an emphasis on the new associations between APOE and AD, and between APOE and depression. The progress of APOE research in Parkinson's disease (PD) and some other neurological diseases is briefly discussed.