Social axioms and psychological toll: A study of emotional, behavioral, and cognitive responses across 35 cultures during the COVID-19 pandemic.

The COVID-19 pandemic has significantly affected the psychological well-being of individuals worldwide. Previous research has indicated that values and beliefs, particularly social axioms, are associated with psychological responses during crises. However, most of the studies have focused on specific regions; the impact of social axioms on a global scale remains unclear. We conducted a multinational study comprising stratified samples of 18,171 participants from 35 cultures. Using multilevel modeling, we examined the associations between social axioms, personal worry, normative concerns, trust, and individuals' psychological responses to the pandemic. The results showed that greater personal worry and normative concerns predicted more negative psychological responses. Furthermore, the study also identified significant buffering effects at the societal level, as cultures with higher overall levels of fate control, religiosity, or reward for application exhibited weaker associations between personal worry and negative responses. Our findings reveal the influence of social axioms on psychological responses during the pandemic, with varying effects across cultures. The buffering effects of fate control, religiosity, and reward for application underscore the importance of considering cultural differences and individual variability when examining the impact of social axioms on psychological outcomes.

Association of Blood Pressure With Brain Ages: A Cohort Study of Gray and White Matter Aging Discrepancy in Mid-to-Older Adults From UK Biobank.

BACKGROUND: Gray matter (GM) and white matter (WM) impairments are both associated with raised blood pressure (BP), although whether elevated BP is differentially associated with the GM and WM aging process remains inadequately examined. METHODS: We included 37 327 participants with diffusion-weighted imaging (DWI) and 39 630 participants with T1-weighted scans from UK Biobank. BP was classified into 4 categories: normal BP, high-normal BP, grade 1, and grade 2 hypertension. Brain age gaps (BAGs) for GM (BAGGM) and WM (BAGWM) were derived from diffusion-weighted imaging and T1 scans separately using 3-dimensional-convolutional neural network deep learning techniques. RESULTS: There was an increase in both BAGGM and BAGWM with raised BP (P<0.05). BAGWM was significantly larger than BAGGM at high-normal BP (0.195 years older; P=0.006), grade 1 hypertension (0.174 years older; P=0.004), and grade 2 hypertension (0.510 years older; P<0.001), but not for normal BP. Mediation analysis revealed that the association between hypertension and cognitive decline was primarily mediated by WM impairment. Mendelian randomization analysis suggested a causal relationship between hypertension and WM aging acceleration (unstandardized B, 1.780; P=0.016) but not for GM (P>0.05). Sliding-window analysis indicated the association between hypertension and brain aging acceleration was moderated by chronological age, showing stronger correlations in midlife but weaker associations in the older age. CONCLUSIONS: Compared with GM, WM was more vulnerable to raised BP. Our study provided compelling evidence that concerted efforts should be directed towards WM damage in individuals with hypertension in clinical practice.

White matter brain age as a biomarker of cerebrovascular burden in the ageing brain.

As the brain ages, it almost invariably accumulates vascular pathology, which differentially affects the cerebral white matter. A rich body of research has investigated the link between vascular risk factors and the brain. One of the less studied questions is that among various modifiable vascular risk factors, which is the most debilitating one for white matter health? A white matter specific brain age was developed to evaluate the overall white matter health from diffusion weighted imaging, using a three-dimensional convolutional neural network deep learning model in both cross-sectional UK biobank participants (n = 37,327) and a longitudinal subset (n = 1409). White matter brain age gap (WMBAG) was the difference between the white matter age and the chronological age. Participants with one, two, and three or more vascular risk factors, compared to those without any, showed an elevated WMBAG of 0.54, 1.23, and 1.94 years, respectively. Diabetes was most strongly associated with an increased WMBAG (1.39 years, p < 0.001) among all risk factors followed by hypertension (0.87 years, p < 0.001) and smoking (0.69 years, p < 0.001). Baseline WMBAG was associated significantly with processing speed, executive and global cognition. Significant associations of diabetes and hypertension with poor processing speed and executive function were found to be mediated through the WMBAG. White matter specific brain age can be successfully targeted for the examination of the most relevant risk factors and cognition, and for tracking an individual's cerebrovascular ageing process. It also provides clinical basis for the better management of specific risk factors.

Critical periods for cognitive reserve building activities for late life global cognition and cognitive decline: the Sydney memory and aging cohort study.

Cognitive, social, and physical activities, collectively linked to cognitive reserve, are associated with better late-life cognitive outcomes. To better understand the building of cognitive reserve, we investigated which of these activities, during which stages of life, had the strongest associations with late-life cognitive performance. From the Sydney Memory and Aging Study, 546 older Australians, who were community-dwelling and without a dementia diagnosis at recruitment (Mage 80.13 years, 52.2% female), were asked about their engagement in social, physical, and cognitive activities throughout young adulthood (YA), midlife (ML), and late-life (LL). Comprehensive neuropsychological testing administered biennially over 6 years measured baseline global cognition and cognitive decline. In our study, YA, but not ML nor LL, cognitive activity was significantly associated with late-life global cognition (ß = 0.315, p < .001). A follow-up analysis pointed to the formal education component of the YA cognitive activity measure, rather than YA cognitive leisure activities, as a significant predictor of better late-life global cognition (ß = 0.146, p = .003). YA social activity and LL cognitive activity were significantly associated with less cognitive decline (ß = 0.023, p < .001, and ß = 0.016, p = .022, respectively). Physical activity was not found to be associated with global cognition or cognitive decline. Overall, YA cognitive activity was associated with better late-life cognition, and YA social and LL cognitive activities were associated with less cognitive decline. Formal education emerges as the key contributor in the association between YA cognitive activity and late-life global cognition.

The combination of olfactory dysfunction and depression increases the risk of incident dementia in older adults.

OBJECTIVES: Olfactory dysfunction and depression are common in later life, and both have been presented as risk factors for dementia. Our purpose was to investigate the associations between these two risk factors and determine if they had an additive effect on dementia risk. DESIGN: Olfactory function was assessed using the Brief Smell Identification Test (BSIT), and depression was classified using a combination of the 15-item Geriatric Depression Scale (GDS) score and current antidepressant use. Cross-sectional associations between depression and olfactory function were examined using correlations. Cox regression analyses were conducted to examine the longitudinal relationship between olfaction and depression and incident dementia across 12-years of follow-up. PARTICIPANTS: Participants were 780 older adults (aged 70-90 years; 56.5% female) from the Sydney Memory and Ageing Study (MAS) without a diagnosis of dementia at baseline. RESULTS: Partial correlation revealed a nonsignificant association between baseline depression and olfactory function after accounting for covariates (r = -.051, p = .173). Cox regression showed that depression at baseline (hazard ratio = 1.706, 95% CI 1.185-2.456, p = .004) and lower BSIT scores (HR = .845, 95%CI .789-.905, p < .001) were independently associated with a higher risk of incident dementia across 12 years. Entering both predictors together improved the overall predictive power of the model. CONCLUSIONS: Lower olfactory identification scores and depressive symptoms predict incident dementia over 12 years. The use of BSIT scores and depression in conjunction provides a greater ability to predict dementia than either used alone. Assessment of olfactory function and depression screening may provide clinical utility in the early detection of dementia.

Frequency of cognitive "super-aging" in three Australian samples using different diagnostic criteria.

OBJECTIVES: To investigate the frequency of exceptional cognition (cognitive super-aging) in Australian older adults using different published definitions, agreement between definitions, and the relationship of super-aging status with function, brain imaging markers, and incident dementia. DESIGN: Three longitudinal cohort studies. SETTING: Participants recruited from the electoral roll, Australian Twins Registry, and community advertisements. PARTICIPANTS: Older adults (aged 65-106) without dementia from the Sydney Memory and Ageing Study (n = 1037; median age 78), Older Australian Twins Study (n = 361; median age 68), and Sydney Centenarian Study (n = 217; median age 97). MEASUREMENTS: Frequency of super-aging was assessed using nine super-aging definitions based on performance on neuropsychological testing. Levels of agreement between definitions were calculated, and associations between super-aging status for each definition and functioning (Bayer ADL score), structural brain imaging measures, and incident dementia were explored. RESULTS: Frequency of super-aging varied between 2.9 and 43.4 percent with more stringent definitions associated with lower frequency. Agreement between different criteria varied from poor (K = 0.04, AC1 = .24) to very good (K = 0.83, AC1 = .91) with better agreement between definitions using similar tests and cutoffs. Super-aging was associated with better functional performance (4.7-11%) and lower rates of incident dementia (hazard ratios 0.08-0.48) for most definitions. Super-aging status was associated with a lower burden of white matter hyperintensities (3.8-33.2%) for all definitions. CONCLUSIONS: The frequency of super-aging is strongly affected by the demographic and neuropsychological testing parameters used. Greater consistency in defining super-aging would enable better characterization of this exceptional minority.

Does Religious Worldview Benefit Life Satisfaction? Examination of the Incremental Predictive Power, Underlying Mechanism, and Temporal Relationship in Hong Kong and the USA.

The benefits of religion have predominantly focused on personal religious identities and experiences, while the broader context of religious worldviews remains understudied. Across two quantitative studies, we showed the incremental predictive power of religious worldview and its mechanism among young adults in two societies-the USA (N = 179) and Hong Kong (N = 164). The mediation mechanism with social connectedness was further inferred from a 12-month study among Hong Kong Chinese (N = 133). This research has laid important groundwork for a deeper understanding of how religion shapes our perception of the world and its impact on our well-being.

Social media trust predicts lower COVID-19 vaccination rates and higher excess mortality over 2 years.

Trust plays a crucial role in implementing public health interventions against the COVID-19 pandemic. We examined the prospective associations of interpersonal, institutional, and media trust with vaccination rates and excess mortality over time in two multinational studies. In study 1, we investigated the country-level relationships between interpersonal trust, vaccination rates, and excess mortality across 54 countries. Interpersonal trust at the country level was calculated by aggregating data of 80,317 participants from the World Values Survey in 2017-20. Data on vaccination rates and excess mortality were obtained from the World Health Organization. Our findings indicated that higher levels of interpersonal trust were linked to higher vaccination rates and lower excess mortality rates in both 2020 and 2021. In study 2, we collected data from 18,171 adults in 35 countries/societies, stratified by age, gender, and region of residence. At the country/society level, interpersonal trust and trust in local healthcare facilities, local healthcare services, and healthcare professionals were associated with higher vaccination rates and lower excess mortality, whereas social media trust was associated with lower vaccination rates and higher excess mortality across three time points over 2 years. Our findings are robust when controlling for country-level covariates of the government stringency index, population density, and medical resources (i.e. critical care beds) in both studies.

A longitudinal examination of the role of social identity in supporting health and well-being in retirement.

Social factors are major determinants of the success of retirement transitions. However, we do not yet fully understand the nature and basis of this impact, particularly as it relates to social group belonging. To address this issue the present article investigated the role that social group memberships play in supporting people's health and well-being in the early phase of transitioning to retirement. More specifically, we drew on the social identity model of identity change (SIMIC) to examine two pathways in which social group processes are theorized to influence adjustment to life change-social identity continuity and social identity gain. To test these pathways, a sample of Australian workers who had transitioned to retirement in the last 12 months (N = 170) were surveyed about their (a) preretirement multiple group memberships and postretirement maintained and new group memberships and (b) their perceived physical health, mental health, and life satisfaction after retirement. While preretirement group memberships did not affect retirement outcomes directly, they supported them indirectly by enabling people both to maintain some existing group memberships and to gain some new group memberships postretirement; as predicted by SIMIC. These findings confirm the importance of social factors and of social group membership in particular, for retiree health and well-being. Theoretically, they support the generalizability of SIMIC and its capacity to explain adjustment to diverse life changes including retirement. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Global Consciousness Predicts Behavioral Responses to the COVID-19 Pandemic: Empirical Evidence From 35 Cultures.

COVID-19 has drastically changed human behaviors and posed a threat to globalism by spurring a resurgence of nationalism. Promoting prosocial behavior within and across borders is of paramount importance for global cooperation to combat pandemics. To examine both self-report and actual prosocial behavior, we conducted the first empirical test of global consciousness theory in a multinational study of 35 cultures (N = 18,171 community adults stratified by age, gender, and region of residence). Global consciousness encompassed cosmopolitan orientation, identification with all humanity, and multicultural acquisition, whereas national consciousness reflected ethnic protection. Both global consciousness and national consciousness positively predicted perceived risk of coronavirus and concern about coronavirus, after controlling for interdependent self-construal. While global consciousness positively predicted prosocial behavior in response to COVID-19, national consciousness positively predicted defensive behavior. These findings shed light on overcoming national parochialism and provide a theoretical framework for the study of global unity and cooperation.

Longitudinal changes in participant and informant reports of subjective cognitive complaints are associated with dementia risk.

Background: Individuals with subjective cognitive complaints (SCCs) are at an increased risk of dementia. Questions remain about participant-reported versus informant-reported SCCs as indicators of future dementia and about longitudinal changes in participant-and informant-reported SCCs and risk of incident dementia. Method: Participants were 873 older adults (M = 78.65-years; 55% female) and 849 informants from the Sydney Memory and Ageing Study. Comprehensive assessments occurred biennially, and clinical diagnoses were made by expert consensus for 10-years. SCCs were participants' and informants' responses to a single binary question concerning their/the participant's memory decline (Yes/No) over the first 6-years. Categorical latent growth curve analyses, using the logit transformation, were used to model SCC change over time. Associations of initial propensity to report SCCs at baseline, and change in propensity to report SCCs over time, with dementia risk were examined using Cox regression. Results: 70% of participants reported SCCs at baseline, with a proportional increase in the odds of reporting by 11% for each additional year in the study. In contrast, 22% of informants reported SCCs at baseline, with a proportional increase by 30% in the odds of reporting per year. Participants' initial level of (p = 0.007), but not change in SCC reporting (p = 0.179), was associated with risk of dementia controlling for all covariates. Both informants' initial level of (p < 0.001), and change in (p < 0.001), SCCs significantly predicted incident dementia. When modelled together, informants' initial level of, and change in, SCCs were still independently associated with increased dementia risk (p's < 0.001). Conclusion: These data suggest that informants' initial impressions, and increased reporting, of SCCs appear to be uniquely prognostic of future dementia compared to participants', even based on a single SCC question.

Hormonal factors moderate the associations between vascular risk factors and white matter hyperintensities.

To examine the moderation effects of hormonal factors on the associations between vascular risk factors and white matter hyperintensities in men and women, separately. White matter hyperintensities were automatically segmented and quantified in the UK Biobank dataset (N = 18,294). Generalised linear models were applied to examine (1) the main effects of vascular and hormonal factors on white matter hyperintensities, and (2) the moderation effects of hormonal factors on the relationship between vascular risk factors and white matter hyperintensities volumes. In men with testosterone levels one standard deviation higher than the mean value, smoking was associated with 27.8% higher white matter hyperintensities volumes in the whole brain. In women with a shorter post-menopause duration (one standard deviation below the mean), diabetes and higher pulse wave velocity were associated with 28.8% and 2.0% more deep white matter hyperintensities, respectively. These findings highlighted the importance of considering hormonal risk factors in the prevention and management of white matter hyperintensities.

Harmonizing Ethno-Regionally Diverse Datasets to Advance the Global Epidemiology of Dementia.

Understanding dementia and cognitive impairment is a global effort needing data from multiple sources across diverse ethno-regional groups. Methodological heterogeneity means that these data often require harmonization to make them comparable before analysis. We discuss the benefits and challenges of harmonization, both retrospective and prospective, broadly and with a focus on data types that require particular sorts of approaches, including neuropsychological test scores and neuroimaging data. Throughout our discussion, we illustrate general principles and give examples of specific approaches in the context of contemporary research in dementia and cognitive impairment from around the world.

Reliability, Validity, and User-Experience of Remote Unsupervised Computerized Neuropsychological Assessments in Community-Living 55- to 75-Year-Olds.

BACKGROUND: Self-administered computerized neuropsychological assessments (CNAs) provide lower cost, more accessible alternatives to traditional in-person assessments but lack critical information on psychometrics and subjective experience of older adults in remote testing environments. OBJECTIVE: We used an online brief battery of computerized tasks selected from the Cogstate Brief Battery (CBB) and Cambridge Brain Sciences (CBS) to 1) determine test-retest reliability in an unsupervised setting; 2) examine convergent validity with a comprehensive 'gold standard' paper-and-pencil neuropsychological test battery administered in-person; and 3) explore user-experience of remote computerized testing and individual tests. METHODS: Fifty-two participants (mean age 65.8±5.7 years) completed CBB and CBS tests on their own computer, unsupervised from home, on three occasions, and visited a research center for an in-person paper-and-pencil assessment. They also completed a user-experience questionnaire. RESULTS: Test-retest reliabilities varied for individual measures (ICCs = 0.20 to 0.83). Global cognition composites showed excellent reliability (ICCs > 0.8 over 1-month follow-up). A strong relationship between a combination of CNA measures and paper-and-pencil battery was found (canonical correlation R = 0.87, p = 0.04). Most tests were rated as enjoyable with easy-to-understand instructions. Ratings of general experience with online testing were mostly favorable; few had difficulty concentrating (17%) or using the computer for tasks (10%), although over one-third experienced performance anxiety (38%). CONCLUSION: A combined brief online battery selected from two CNAs demonstrated robust psychometric standards for reliability (global composite), and convergent validity with a gold standard battery, and mostly good usability and acceptability in the remote testing environment.

Nonpharmacological approaches reduce symptoms of depression in dementia: A systematic review and meta-analysis.

BACKGROUND: Depression is a common psychological symptom associated with dementia. Pharmacological approaches are often used despite two large negative trials of efficacy. This meta-analysis examines nonpharmacological (i.e., psychosocial) approaches for symptoms of depression in people living with dementia and reports statistical and clinical significance. METHODS: Relevant studies published between 2012 and 2020 were sourced by searching electronic databases: MEDLINE, EMBASE, PsychINFO, Social Work Abstracts and the Cochrane Central Register of Controlled Trials. Studies were assessed for methodological quality. Random-effects meta-analysis was performed to calculate a pooled effect size (ES) and 95% confidence intervals (CI). RESULTS: Overall, 37 nonpharmacological studies were identified including 2,636 participants. The mean quality rating was high (12/14, SD=1.4). Meta-analysis revealed that nonpharmacological approaches were significantly associated with reduced symptoms of depression with a medium effect size (ES=-0.53, 95%CI [-0.72, -0.33], p < 0.0001). There was considerable heterogeneity between studies. Meta-regression revealed this was not driven by intervention type or setting (residential versus community). CONCLUSIONS: Nonpharmacological approaches such as reminiscence, cognitive stimulation/ rehabilitation, therapeutic, music-based approaches and education/ training, have the potential to reduce symptoms of depression in dementia.

Memory decline in older individuals predicts an objective indicator of oral health: findings from the Sydney Memory and Ageing Study.

BACKGROUND: Growing evidence suggests that there is an association between poor oral health and cognitive function in late adulthood. However, most studies to date have relied on cross-sectional research methods that do not permit inferences about the temporality of any association. Moreover, the few longitudinal studies that do exist have typically relied on small samples and quite limited cognitive or oral health assessments. The aim of the present study was therefore designed to provide the first direct evaluation of whether cognitive function is predictive of poor oral health in older adults. METHODS: This longitudinal research included data from 339 participants aged 70 years or older from The Sydney Memory and Ageing Study (MAS), a large cohort of healthy community-dwelling older adults. Cognitive function was assessed using a battery of tests at baseline (Wave 1) in 2005 and six years later (Wave 4) in 2011. In 2015 (Wave 6), participants were assessed for oral health using the Oral Health Assessment Tool (OHAT), number of functional occluding pairs of natural teeth and sublingual resting saliva pH (SRSpH). Ordinal least squares regression analysis was used to model the effect of cognitive function on total OHAT score, and binomial logistic regression used for SRSpH and occluding pairs of functional teeth. RESULTS: Two models were tested. In the partially adjusted model, age, gender and years of education were included. The fully adjusted model additionally included medical conditions, general health, depression, smoking, alcohol consumption, functionality, and dental care utilization. The key finding to emerge was that a six-year change in memory (from Wave 1 to Wave 4) was associated with lower sublingual resting saliva pH at Wave 6 in partially (Odds Ratio (OR) = 0.65) and fully adjusted model (OR = 0.63). CONCLUSIONS: This longitudinal study provides further evidence that a relationship between cognitive function and oral health exists, and also points to this relationship potentially being bi-directional, as previous evidence suggests. The findings from the study also suggest that older adults who present with greater than normal memory decline at an earlier point in life were more likely to experience poor oral health when this was evaluated at a later time-point, four years later.

Surgical Hospitalization Is Not Associated With Cognitive Trajectory Over 6 Years in Healthy Older Australians.

OBJECTIVE: The aim was to investigate the association of cognitive trajectories and overnight surgical hospitalization in older adults, while controlling for and comparing to the association with acute medical hospitalizations. DESIGN: This is a secondary analysis of data from a population-based, longitudinal cohort study of older Australians. SETTING AND PARTICIPANTS: Cognition was assessed with 4 biennial waves of prospective neuropsychological data from 1026 Sydney Memory and Aging Study participants age 70 to 90 years at baseline. Hospitalization exposure was obtained from 10 years of electronically linked data from the New South Wales Admitted Patient Data Collection. METHODS: Latent growth curve modeling estimated global cognition z-score baseline and slope over 6 years, and the effects of contemporaneous surgical and medical hospitalization predictors while controlling for potential demographic and comorbidity confounders. RESULTS: After controlling for confounding variables, this analysis showed that overnight surgical hospitalizations were not associated with worse baseline global cognition or accelerated cognitive decline over 6 years. This was despite this cohort having more surgeries and more complex surgeries compared with Australian data for overnight hospitalizations in over 70-year-olds. Conversely, recent medical hospitalizations were associated with accelerated cognitive decline. CONCLUSIONS AND IMPLICATIONS: This analysis finds that surgery and anesthesia are unlikely to be risk factors for medium to long-term global cognitive decline in healthy older adults, while controlling for contemporaneous medical hospitalizations. These findings are contrary to prior conclusions from several surgical studies that may have been impeded by insufficient comparison groups. They are, however, consistent with recent population-based studies suggesting surgery has minimal association with cognitive decline in the medium to long-term. Future research needs to clarify the association of surgical hospitalization with the full spectrum of cognitive outcomes including subjective cognitive complaints and dementia, and importantly, how these cognitive outcomes correlate with clinically significant functional changes.

The Interaction Between Vascular Risk Factors, Cerebral Small Vessel Disease, and Amyloid Burden in Older Adults.

BACKGROUND: Cerebral small vessel disease (SVD) and Alzheimer's disease pathology, namely amyloid-ß (Aß) deposition, commonly co-occur. Exactly how they interact remains uncertain. OBJECTIVE: Using participants from the Alzheimer's Disease Neuroimaging Initiative (n = 216; mean age 73.29±7.08 years, 91 (42.1%) females), we examined whether the presence of vascular risk factors and/or baseline cerebral SVD was related to a greater burden of Aß cross-sectionally, and at 24 months follow-up. METHOD: Amyloid burden, assessed using 18F-florbetapir PET, was quantified as the global standardized uptake value ratio (SUVR). Multimodal imaging was used to strengthen the quantification of baseline SVD as a composite variable, which included white matter hyperintensity volume using MRI, and peak width of skeletonized mean diffusivity using diffusion tensor imaging. Structural equation modeling was used to analyze the associations between demographic factors, Apolipoprotein E ɛ4 carrier status, vascular risk factors, SVD burden and cerebral amyloid. RESULTS: SVD burden had a direct association with Aß burden cross-sectionally (coeff. = 0.229, p = 0.004), and an indirect effect over time (indirect coeff. = 0.235, p = 0.004). Of the vascular risk factors, a history of hypertension (coeff. = 0.094, p = 0.032) and a lower fasting glucose at baseline (coeff. = -0.027, p = 0.014) had a direct effect on Aß burden at 24 months, but only the direct effect of glucose persisted after regularization. CONCLUSION: While Aß and SVD burden have an association cross-sectionally, SVD does not appear to directly influence the accumulation of Aß longitudinally. Glucose regulation may be an important modifiable risk factor for Aß accrual over time.

Is hospitalization a risk factor for cognitive decline in older age adults?

OBJECTIVES: Many studies document cognitive decline following specific types of acute illness hospitalizations (AIH) such as surgery, critical care, or those complicated by delirium. However, cognitive decline may be a complication following all types of AIH. This systematic review will summarize longitudinal observational studies documenting cognitive changes following AIH in the majority admitted population and conduct meta-analysis (MA) to assess the quantitative effect of AIH on post-hospitalization cognitive decline (PHCD). METHODS: We followed Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Selection criteria were defined to identify studies of older age adults exposed to AIH with cognitive measures. 6566 titles were screened. 46 reports were reviewed qualitatively, of which seven contributed data to the MA. Risk of bias was assessed using the Newcastle-Ottawa Scale. RESULTS: The qualitative review suggested increased cognitive decline following AIH, but several reports were particularly vulnerable to bias. Domain-specific outcomes following AIH included declines in memory and processing speed. Increasing age and the severity of illness were the most consistent risk factors for PHCD. PHCD was supported by MA of seven eligible studies with 41,453 participants (Cohen's d = -0.25, 95% CI [-0.02, -0.49] I2 35%). CONCLUSIONS: There is preliminary evidence that AIH exposure accelerates or triggers cognitive decline in the elderly patient. PHCD reported in specific contexts could be subsets of a larger phenomenon and caused by overlapping mechanisms. Future research must clarify the trajectory, clinical significance, and etiology of PHCD: a priority in the face of an aging population with increasing rates of both cognitive impairment and hospitalization.