COVID-19 Infection and Dementia: Analyses of time-varying risk, subtypes, and subpopulations from the UK Biobank (preprint)

Background Although COVID-19 patients were suggested to experience worse cognitive outcomes, there is a paucity of evidence on time-varying risk of dementia, especially the subtypes, as well as among critical subpopulations.Methods Out of over 50000 individuals from general population in the UK Biobank, SARS-COV-2 infected patients between March 1, 2020, and July 31, 2021 and maximally 5:1 propensity score matched contemporary non-infected individuals were selected, with baseline dementia excluded. Matching was done on demographic characteristics, lifestyle, and comorbidities. Dementia was captured according to primary care, inpatient records, and death registry, with the follow-up ending at the earliest of outcome occurrence, death, or August 31, 2021. Associations were evaluated using time-varying hazard ratios (HRs) and odds ratios (ORs).Results With a mean age of 64.5 years for 18032 COVID-19 patients and 83,008 controls, participants were followed for a median of 247 (IQR: 204–305) days and 255 dementia cases occurred, including 90 Alzheimer’s disease (AD) cases and 42 vascular dementia (VaD) cases. Compared with matched controls, dementia risk declined drastically after COVID-19 infection and sustained for all-cause dementia, VaD, and other dementia. During the acute phase (first 30 days), COVID-19 infection was associated with increased risks of dementia, with HRs (95% CIs) being 12.77 (6.77, 24.08) for all-cause dementia, 9.21 (2.77, 30.59) for AD, 5.53 (1.69, 18.11) for VaD, and 25.35 (8.74, 73.56) for other dementia. Among those not hospitalized within 30 days of enrollment, elevated dementia risk remained for all-cause dementia, VaD, and other dementia, with ORs being 1.82, 4.55, and 1.64, respectively. Among most of the subpopulations classified by demographic characteristics, APOE genotype, and comorbidities (except for those with chronic obstructive pulmonary diseases at enrollment), COVID-19 infection was associated with an elevated all-cause dementia risk and no modification effect was detected.Conclusions Declined yet sustained elevated dementia risk since COVID-19 infection was found and vascular risk factors may need extra attention during the long-term follow-up. Increased dementia risk from COVID-19 infection also applied for the non-hospitalized during the acute phase and most subpopulations. The potential dementia risk associated with Omicron and newer variants warrants further evaluation.

COVID-19 Infection and Dementia: A Prospective Analysis of Time-Varying Risk, Subtypes, and Subpopulations from the UK Biobank (preprint)

Background: Although COVID-19 patients were suggested to experience worse cognitive outcomes, there is a paucity of evidence on time-varying risk of dementia, especially the subtypes, as well as among critical subpopulations. Methods: Out of over 50000 individuals from general population in the UK Biobank, SARS-COV-2 infected patients between March 1, 2020, and July 31, 2021 and maximally 5:1 propensity score matched contemporary non-infected individuals were selected, with baseline dementia excluded. Matching was done on demographic characteristics, lifestyle, and comorbidities. Dementia was captured according to primary care, inpatient records, and death registry, with the follow-up ending at the earliest of outcome occurrence, death, or August 31, 2021. Associations were evaluated using time-varying hazard ratios (HRs) and odds ratios (ORs). Results: With a mean age of 64.5 years for 18032 COVID-19 patients and 83,008 controls, participants were followed for a median of 247 (IQR: 204–305) days and 255 dementia cases occurred, including 90 Alzheimer’s disease (AD) cases and 42 vascular dementia (VaD) cases. Compared with matched controls, dementia risk declined drastically after COVID-19 infection and sustained for all-cause dementia, VaD, and other dementia. During the acute phase (first 30 days), COVID-19 infection was associated with increased risks of dementia, with HRs (95% CIs) being 12.77 (6.77, 24.08) for all-cause dementia, 9.21 (2.77, 30.59) for AD, 5.53 (1.69, 18.11) for VaD, and 25.35 (8.74, 73.56) for other dementia. Among those not hospitalized within 30 days of enrollment, elevated dementia risk remained for all-cause dementia, VaD, and other dementia, with ORs being 1.82, 4.55, and 1.64, respectively. Among most of the subpopulations classified by demographic characteristics, APOE genotype, and comorbidities (except for those with chronic obstructive pulmonary diseases at enrollment), COVID-19 infection was associated with an elevated all-cause dementia risk and no modification effect was detected. Conclusion: Declined yet sustained elevated dementia risk since COVID-19 infection was found and vascular risk factors may need extra attention during the long-term follow-up. Increased dementia risk from COVID-19 infection also applied for the non-hospitalized during the acute phase and most subpopulations. The potential dementia risk associated with Omicron and newer variants warrants further evaluation.

Risk factors for dementia in the context of cardiovascular disease: A protocol of an overview of reviews.

BACKGROUND: Dementia is a major public health priority. Although there is abundant evidence of an association between dementia and poor cardiovascular health, findings have been inconsistent and uncertain in identifying which factors increase dementia risk in those with cardiovascular disease. Indeed, multiple variables including sociodemographic, economic, health, lifestyle and education may indicate who is at higher vs. lower dementia risk and could be used in prediction modelling. Therefore, the aim of this review is to synthesise evidence on the key risk factors for dementia in those with a history of cardiovascular disease. METHODS: This is an overview of reviews protocol, registered on PROSPERO (CRD42021265363). Four electronic databases including MEDLINE, EMBASE, PsycINFO, and the Cochrane Database of Systematic Reviews will be searched. Studies will be included if they are systematic reviews and/or meta-analyses that have investigated the risk of incident dementia (all-cause and subtypes including Alzheimer's disease and vascular dementia) in people with a history of coronary heart disease, heart failure, atrial fibrillation, hypertension, hyperlipidaemia, and vascular stiffness. Study selection will be completed by two independent researchers according to the eligibility criteria, and conflicts resolved by a third reviewer. References will be exported into Covidence for title and abstract sifting, full-text review, and data extraction. Methodological quality will be assessed using the AMSTAR-2 criteria and confidence of evidence will be assessed using the GRADE classification. This overview of reviews will follow PRISMA guidelines. If there is sufficient homogeneity in the data, the results will be pooled, and a meta-analysis conducted to determine the strength of association between each risk factor and incident all-cause dementia and its subtypes for each cardiovascular diagnoses separately. DISCUSSION: We will create a comprehensive summary of the key risk factors linking cardiovascular diseases to risk of incident dementia. This knowledge is essential for informing risk predictive model development as well as the development of risk reduction and prevention strategies.

Molecular Mechanisms of Cerebrovascular Diseases.

Cerebrovascular disease involves a range of conditions including ischemic and hemorrhagic stroke, vascular malformations, and vascular cognitive impairment and dementia (VCID) [...].

A Phenome Wide Association Study of Severe COVID-19 Genetic Risk Variants (preprint)

Background Genetic loci associated with risk of severe COVID-19 infection have been identified and individuals with complicated COVID-19 infections often have multiple comorbidities. Objective Identify known and unidentified comorbidities associated with genetic loci linked to risk of severe COVID-19 infection. Methods A Phenome Wide Association Study (PheWAS) was conducted in 247,448 unrelated, white individuals from the UK Biobank to test the association of 1,402 unique phenotypes with ten genome-wide significant severe-COVID risk single nucleotide polymorphisms (SNP) identified from prior studies. A validation PheWAS was conducted in 2,247 white individuals from the CATHGEN. Results Four of the ten tested genetic loci showed significant phenotypic associations in UK Biobank after FDR adjustment. Vascular dementia significantly associated with rs7271165 near TMEM65 on 8q24.13 in individuals with the C risk allele (OR 5.66 [95% CI 2.21-11.85], q=0.049). We identified 40 novel phenotype associations with rs657152 on 9q34.2 coinciding with the ABO gene with individuals with the A COVID risk allele having higher odds of heart failure (OR 1.09 [95% CI 1.03-1.14], q=0.004), diabetes mellitus (OR 1.05 [95% CI 1.02-1.07], q=0.004) and hypercholesterolemia (OR 1.04 [95% CI 1.02-1.06], q=6.3×10 −5 ). Eight phenotypes associated with rs1819040 near KANSL1 on 17q21.31 in individuals with the A risk allele including atrial fibrillation and flutter (OR 1.07 [95% CI 1.04-1.10], q=0.0084) and pulmonary fibrosis (OR 0.80 [95% CI 0.71-0.89], q=0.035). Ten novel phenotypic associations were identified in association with rs74956615 on 19p13.2 near the TYK2 gene including individuals with the A COVID risk allele having lower odds of psoriatic arthropathy (OR 0.31 [95% CI 0.20-0.47], q=4.5×10 −5 ), rheumatoid arthritis (OR 0.83 [95% CI 0.64-0.83], p=1.4×10 −6 ) and thyrotoxicosis with or without goiter (OR 0.77 [95% CI 0.68-0.87], p-6.9×10 −5 ). Two associations for rs1819040 ( KANSL1 ) and seven associations for rs74956615 ( TYK2 ) validated in CATHGEN. Conclusions Using a broad PheWAS approach in a large discovery and validation cohort, we have identified novel phenotypic associations with risk alleles for severe COVID-19 infection. Interestingly, the ABO locus was associated with comorbidities that are also risk factors for severe COVID-19 infection, suggesting that this locus has pleiotropic effects and provides a potential mechanism for this association. The 19p13 locus was associated with lower risk of autoimmune disease, these findings may have broad implications for the importance of multiple comorbidities across both infectious and non-infectious diseases and may provide insight in the molecular function of the genes near these genetic risk loci.

COVID-19 Case Fatality and Alzheimer's Disease.

Previous studies have identified dementia as a risk factor for death from coronavirus disease 2019 (COVID-19). However, it is unclear whether Alzheimer's disease (AD) is an independent risk factor for COVID-19 case fatality rate. In a retrospective cohort study, we identified 387,841 COVID-19 patients through TriNetX. After adjusting for demographics and comorbidities, we found that AD patients had higher odds of dying from COVID-19 compared to patients without AD (Odds Ratio: 1.20, 95%confidence interval: 1.09-1.32, p < 0.001). Interestingly, we did not observe increased mortality from COVID-19 among patients with vascular dementia. These data are relevant to the evolving COVID-19 pandemic.

COVID-19 and dementia: Analyses of risk, disparity, and outcomes from electronic health records in the US.

INTRODUCTION: At present, there is limited data on the risks, disparity, and outcomes for COVID-19 in patients with dementia in the United States. METHODS: This is a retrospective case-control analysis of patient electronic health records (EHRs) of 61.9 million adult and senior patients (age ≥ 18 years) in the United States up to August 21, 2020. RESULTS: Patients with dementia were at increased risk for COVID-19 compared to patients without dementia (adjusted odds ratio [AOR]: 2.00 [95% confidence interval (CI), 1.94-2.06], P < .001), with the strongest effect for vascular dementia (AOR: 3.17 [95% CI, 2.97-3.37], P < .001), followed by presenile dementia (AOR: 2.62 [95% CI, 2.28-3.00], P < .001), Alzheimer's disease (AOR: 1.86 [95% CI, 1.77-1.96], P < .001), senile dementia (AOR: 1.99 [95% CI, 1.86-2.13], P < .001) and post-traumatic dementia (AOR: 1.67 [95% CI, 1.51-1.86] P < .001). Blacks with dementia had higher risk of COVID-19 than Whites (AOR: 2.86 [95% CI, 2.67-3.06], P < .001). The 6-month mortality and hospitalization risks in patients with dementia and COVID-19 were 20.99% and 59.26%, respectively. DISCUSSION: These findings highlight the need to protect patients with dementia as part of the strategy to control the COVID-19 pandemic.

COVID-19 in Adults With Dementia: Clinical Features and Predictive Factors of Mortality. A Clinical Cohort Study on 125 Patients (preprint)

BACKGROUNDThere is limited evidence on the characteristics and outcome of patients with dementia hospitalized for novel coronavirus infection (COVID-19).METHODWe conducted a prospective study in 2 gerontologic Covid Units in Paris, France, from March 14th 2020 to May 7th 2020. Patients with dementia hospitalized for confirmed COVID-19 infection were systematically enrolled. A binary logistic regression analysis was performed to identify factors associated with mortality at 21 days.RESULTSWe included 125 patients. Median age was 86 (IQI 82-90); 59.4% were female. Most common causes of dementia were Alzheimer’s disease, mixed dementia and vascular dementia. 67.2% had ≥2 comorbidities; 40.2% lived in a long-term care facility. The most common symptoms at COVID-19 onset were confusion and delirium (82.4%), asthenia (76.8%) and fever (72.8%) before polypnea (51.2%) and desaturation (50.4%). Falls were frequent at the initial phase of the disease (35.2%). The fatality rate at 21 days was 22.4%. Chronic kidney disease and CRP at admission were independent factors of death. Persisting confusion, mood and behavioral disorders were observed in survivors (19.2%).CONCLUSIONCOVID-19 in demented individuals is associated with severe outcome in SARS-CoV-2 infection and is characterized by specific clinical features and complications, with confusion and delirium at the forefront. COVID‐19 testing should be considered in front of any significant change from baseline.

Cellular Mechanisms of Melatonin: Insight from Neurodegenerative Diseases.

Neurodegenerative diseases are the second most common cause of death and characterized by progressive impairments in movement or mental functioning in the central or peripheral nervous system. The prevention of neurodegenerative disorders has become an emerging public health challenge for our society. Melatonin, a pineal hormone, has various physiological functions in the brain, including regulating circadian rhythms, clearing free radicals, inhibiting biomolecular oxidation, and suppressing neuroinflammation. Cumulative evidence indicates that melatonin has a wide range of neuroprotective roles by regulating pathophysiological mechanisms and signaling pathways. Moreover, melatonin levels are decreased in patients with neurodegenerative diseases. In this review, we summarize current knowledge on the regulation, molecular mechanisms and biological functions of melatonin in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, vascular dementia and multiple sclerosis. We also discuss the clinical application of melatonin in neurodegenerative disorders. This information will lead to a better understanding of the regulation of melatonin in the brain and provide therapeutic options for the treatment of various neurodegenerative diseases.