Traumatic life events and risk for dementia: a systematic review and meta-analysis.

OBJECTIVES: To systematically review the association between traumatic life events (TLE) and dementia risk. DESIGN: Systematic review and meta-analysis. DATA SOURCES: APA, PsychINFO, Embase and MEDLINE from their inception to 29.05.21 and updated on 20.04.22. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Original research articles published in peer reviewed journals examining the association between TLE and all cause dementia in individuals aged 60 and over. Two researchers independently assessed the risk of bias using the Newcastle-Ottawa Scale. We conducted a generic inverse variance random effects meta-analysis to provide an overall estimate of TLE impact on dementia risk. MAIN OUTCOME MEASURES: Risk, odds and hazards ratios relating to dementia risk. RESULTS: Initially, 3,487 studies were retrieved in the search and seven studies were included in the meta-analysis with data being used from 276,570 participants. TLE were associated with increased dementia risk. Trauma in general had a pooled HR of 1.21, (95% CI 1.03, 1.43, P = 0.0001). War/ Holocaust trauma and childhood trauma were also associated with increased dementia risk (HR = 1.28 (95% CI 1.01-1.63, P = 0.02) and HR = 1.76 (95% CI 1.17-2.64, P = 0.007) respectively). CONCLUSIONS: We have found an association between TLE and dementia risk. Future research exploring the dimensions of TLE and individual level factors are needed to better understand the relationship between TLE and dementia. TRIAL REGISTRATION: PROSPERO CRD42021253090.

Repetitive negative thinking is associated with amyloid, tau, and cognitive decline.

INTRODUCTION: The Cognitive Debt hypothesis proposes that repetitive negative thinking (RNT), a modifiable process common to many psychological risk factors for Alzheimer's disease (AD) may itself increase risk. We sought to empirically examine relationships between RNT and markers of AD, compared with anxiety and depression symptoms. METHODS: Two hundred and ninety-two older adults with longitudinal cognitive assessments, including 113 with amyloid-positron emission tomography (PET) and tau-PET scans, from the PREVENT-AD cohort and 68 adults with amyloid-PET scans from the IMAP+ cohort were included. All participants completed RNT, anxiety, and depression questionnaires. RESULTS: RNT was associated with decline in global cognition (P = .02); immediate (P = .03) and delayed memory (P = .04); and global amyloid (PREVENT-AD: P = .01; IMAP+: P = .03) and entorhinal tau (P = .02) deposition. Relationships remained after adjusting for potential confounders. DISCUSSION: RNT was associated with decline in cognitive domains affected early in AD and with neuroimaging AD biomarkers. Future research could investigate whether modifying RNT reduces AD risk.