While I Still Remember: 30 Years of Alzheimer's Disease Research

Childhood Maltreatment and Dementia Risk Factors in Midlife: A Prospective Investigation

BACKGROUND

Previous studies have linked childhood adversities to dementia risk, yet most studies are cross-sectional in design and utilize retrospective self-reports to assess childhood experiences. These design characteristics make it difficult to establish temporal order and draw firm conclusions.

OBJECTIVES

Using a longitudinal design, we sought to determine whether childhood maltreatment predicts dementia risk factors in middle adulthood.

METHODS

Data have been obtained from a prospective cohort design study of children with documented cases of childhood maltreatment (ages 0-11 years at case identification) and demographically matched controls who were followed up and interviewed in middle adulthood. Outcomes were assessed through a medical examination and interview, and 807 of the cases that included blood collection at mean age 41. Dementia risk were investigated using 11 potentially modifiable risk factors.

RESULTS

Compared to controls, individuals with histories of childhood maltreatment had a higher risk of low educational attainment, low social contact, smoking, and clinical depression, and a higher total number of dementia risk factors. In general, childhood maltreatment predicted a higher risk of dementia for females, males, and Black and White participants. Black maltreated participants had a greater risk for traumatic brain injury compared to Black controls. Physical abuse, sexual abuse, and neglect, each predicted a higher number of dementia risk factors in mid-life.

CONCLUSION

These findings provide evidence that childhood maltreatment increases the risk for dementia in mid-life and has a demonstrable impact lasting over 30 years. Reducing the prevalence of mid-life dementia risk factors could reduce the risk of later-life dementia.

The Relationship Between Adverse Childhood Experiences and Alzheimer's Disease: A Systematic Review

Background

Alzheimer's disease is a global health concern, and with no present cure, prevention is critical. Exposure to adverse childhood experiences may increase the risk of developing Alzheimer's disease. This systematic review was conducted to synthesize the evidence on the associations between adverse childhood experiences (<18 years) and the risk of Alzheimer's disease in adulthood.

Methods

A search strategy was developed and conducted to identify articles investigating the associations between exposure to adverse childhood experiences and the onset of Alzheimer's disease by searching key databases (CINAHL, MEDLINE and PsycInfo). Two reviewers independently determined the eligibility of studies according to pre-determined criteria, and assessed the methodological quality using the US National Heart, Lung and Blood Institute 14-item checklist for observational cohort and cross-sectional studies, respectively. Due to limited studies, a descriptive synthesis was performed. The protocol for this review is published in BMJ Open and registered with PROSPERO (CRD42020191439).

Results

Our search yielded 781 articles, of which three (two separate analyses from the same cohort study and one cross-sectional study) met the predetermined eligibility criteria. The methodological quality assessment yielded an overall mean score of 78.9% (range 66.6 – 84.6%). All studies found adverse childhood experiences were associated with an increased risk of Alzheimer's disease. However, there was a limited number of available studies to inform the synthesis.

Conclusions

Adverse childhood experiences appear to be associated with an increased risk of Alzheimer's disease, although, further research is needed.

Registration and Protocol

The protocol for this review is registered with PROSPERO (CRD42020191439) and published with BMJ Open (Corney et al., 2021).

Relationship between adverse childhood experiences and Alzheimer's disease: a systematic review and meta-analysis protocol

INTRODUCTION

Alzheimer's disease has a high prevalence and a substantial impact on society, as well as the individual. Findings from clinical studies to date, suggest that multiple factors are likely to contribute to the variability seen in the progression of Alzheimer's disease. However, despite this accumulating evidence, current identified factors do not explain the full extent of disease onset. Thus, the role of additional factors needs to be explored further.One such factor is exposure to adverse childhood experiences. However, the degree of this association is unknown. This systematic review will examine the literature investigating the associations between adverse childhood experiences and the risk of Alzheimer's disease.

METHODS AND ANALYSIS

Articles investigating associations between exposure to adverse childhood experiences and the risk of Alzheimer's disease will be identified systematically by searching CINAHL, MEDLINE and PsycInfo using Ebscohost. No restrictions on date of publication will be applied. The search strategy will be built combining the main key elements of the Population, Exposure, Comparator, and Outcomes inclusion criteria. A meta-analysis is planned and statistical methods will be used to identify and control for heterogeneity, if possible. The development of this protocol was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols.

ETHICS AND DISSEMINATION

Only published data will be used for this study, thus, ethical approval will not be required. Findings of the review will be published in a peer-reviewed scientific journal, and presented at national and international conferences.

PROSPERO REGISTRATION NUMBER

CRD42020191439.

Glycation affects fibril formation of Aβ peptides

Increasing evidence shows that β-amyloid (Aβ) peptides, which are associated with Alzheimer disease (AD), are heavily glycated in patients, suggesting a role of this irreversible nonenzymatic post-translational modification in pathology. Previous reports have shown that glycation increases the toxicity of the Aβ peptides, although little is known about the mechanism. Here, we used the natural metabolic by-product methylglyoxal as a glycating agent and exploited various spectroscopic methods and atomic force microscopy to study how glycation affects the structures of the Aβ40 and Aβ42 peptides, the aggregation pathway, and the morphologies of the resulting aggregates. We found that glycation significantly slows down but does not prevent β-conversion to mature fibers. We propose that the previously reported higher toxicity of the glycated Aβ peptides could be explained by a longer persistence in an oligomeric form, usually believed to be the toxic species.