Prevalence and Determinants of Diagnosed Dementia: A Registry Linkage Study Linking Diagnosis of Dementia in the Population-Based HUNT Study to Registry Diagnosis of Dementia in Primary Care and Hospitals in Norway.

Background: A timely diagnosis of dementia can be beneficial for providing good support, treatment, and care, but the diagnostic rate remains unknown and is probably low. Objective: To determine the dementia diagnostic rate and to describe factors associated with diagnosed dementia. Methods: This registry linkage study linked information on research-based study diagnoses of all-cause dementia and subtypes of dementias, Alzheimer's disease, and related dementias, in 1,525 participants from a cross-sectional population-based study (HUNT4 70+) to dementia registry diagnoses in both primary-care and hospital registries. Factors associated with dementia were analyzed with multiple logistic regression. Results: Among those with research-based dementia study diagnoses in HUNT4 70+, 35.6% had a dementia registry diagnosis in the health registries. The diagnostic rate in registry diagnoses was 19.8% among home-dwellers and 66.0% among nursing home residents. Of those with a study diagnosis of Alzheimer's disease, 35.8% (95% confidence interval (CI) 32.6-39.0) had a registry diagnosis; for those with a study diagnosis of vascular dementia, the rate was 25.8% (95% CI 19.2-33.3) and for Lewy body dementias and frontotemporal dementia, the diagnosis rate was 63.0% (95% CI 48.7-75.7) and 60.0% (95% CI 43.3-75.1), respectively. Factors associated with having a registry diagnosis included dementia in the family, not being in the youngest or oldest age group, higher education, more severe cognitive decline, and greater need for help with activities of daily living. Conclusions: Undiagnosed dementia is common, as only one-third of those with dementia are diagnosed. Diagnoses appear to be made at a late stage of dementia.

Constructing personalized characterizations of structural brain aberrations in patients with dementia using explainable artificial intelligence.

Deep learning approaches for clinical predictions based on magnetic resonance imaging data have shown great promise as a translational technology for diagnosis and prognosis in neurological disorders, but its clinical impact has been limited. This is partially attributed to the opaqueness of deep learning models, causing insufficient understanding of what underlies their decisions. To overcome this, we trained convolutional neural networks on structural brain scans to differentiate dementia patients from healthy controls, and applied layerwise relevance propagation to procure individual-level explanations of the model predictions. Through extensive validations we demonstrate that deviations recognized by the model corroborate existing knowledge of structural brain aberrations in dementia. By employing the explainable dementia classifier in a longitudinal dataset of patients with mild cognitive impairment, we show that the spatially rich explanations complement the model prediction when forecasting transition to dementia and help characterize the biological manifestation of disease in the individual brain. Overall, our work exemplifies the clinical potential of explainable artificial intelligence in precision medicine.

A longitudinal cohort study on the use of health and care services by older adults living at home with/without dementia before and during the COVID-19 pandemic: the HUNT study.

BACKGROUND: Older adults and people with dementia were anticipated to be particularly unable to use health and care services during the lockdown period following the COVID-19 pandemic. To better prepare for future pandemics, we aimed to investigate whether the use of health and care services changed during the pandemic and whether those at older ages and/or dementia experienced a higher degree of change than that observed by their counterparts. METHODS: Data from the Norwegian Trøndelag Health Study (HUNT4 70 + , 2017-2019) were linked to two national health registries that have individual-level data on the use of primary and specialist health and care services. A multilevel mixed-effects linear regression model was used to calculate changes in the use of services from 18 months before the lockdown, (12 March 2020) to 18 months after the lockdown. RESULTS: The study sample included 10,607 participants, 54% were women and 11% had dementia. The mean age was 76 years (SD: 5.7, range: 68-102 years). A decrease in primary health and care service use, except for contact with general practitioners (GPs), was observed during the lockdown period for people with dementia (p < 0.001) and those aged ≥ 80 years without dementia (p = 0.006), compared to the 6-month period before the lockdown. The use of specialist health services decreased during the lockdown period for all groups (p ≤ 0.011), except for those aged < 80 years with dementia. Service use reached levels comparable to pre-pandemic data within one year after the lockdown. CONCLUSION: Older adults experienced an immediate reduction in the use of health and care services, other than GP contacts, during the first wave of the COVID-19 pandemic. Within primary care services, people with dementia demonstrated a more pronounced reduction than that observed in people without dementia; otherwise, the variations related to age and dementia status were small. Both groups returned to services levels similar to those during the pre-pandemic period within one year after the lockdown. The increase in GP contacts may indicate a need to reallocate resources to primary health services during future pandemics. TRIAL REGISTRATION: The study is registered at ClinicalTrials.gov, with the identification number NCT04792086.

Trajectories of Occupational Cognitive Demands and Risk of Mild Cognitive Impairment and Dementia in Later Life: The HUNT4 70+ Study.

BACKGROUND AND OBJECTIVES: The cognitive reserve hypothesis posits that cognitively stimulating work delays the onset of mild cognitive impairment (MCI) and dementia. However, the effect of occupational cognitive demands across midlife on the risk of these conditions is unclear. METHODS: Using a cohort study design, we evaluated the association between registry-based trajectories of occupational cognitive demands from ages 30-65 years and clinically diagnosed MCI and dementia in participants in the HUNT4 70+ Study (2017-19). Group-based trajectory modeling identified trajectories of occupational cognitive demands, measured by the routine task intensity (RTI) index (lower RTI indicates more cognitively demanding occupation) from the Occupational Information Network. Multinomial regression was implemented to estimate the relative risk ratios (RRRs) of MCI and dementia, after adjusting for age, sex, education, income, baseline hypertension, obesity, diabetes, psychiatric impairment, hearing impairment, loneliness, smoking status, and physical inactivity assessed at HUNT1-2 in 1984-1986 and 1995-1997. To handle missing data, we used inverse probability weighting to account for nonparticipation in cognitive testing and multiple imputation. RESULTS: Based on longitudinal RTI scores for 305 unique occupations, 4 RTI trajectory groups were identified (n = 7,003, 49.8% women, age range 69-104 years): low RTI (n = 1,431, 20.4%), intermediate-low RTI (n = 1,578, 22.5%), intermediate-high RTI (n = 2,601, 37.1%), and high RTI (n = 1,393, 19.9%). Participants in the high RTI group had a higher risk of MCI (RRR 1.74, 95% CI 1.41-2.14) and dementia (RRR 1.37, 95% CI 1.01-1.86), after adjusting for age, sex, and education compared with participants in the low RTI group. In a sensitivity analysis, controlling for income and baseline health-related factors, the point estimates were not appreciably changed (RRR 1.66, 95% CI 1.35-2.06 for MCI, and RRR 1.31, 95% CI 0.96-1.78 for dementia). DISCUSSION: People with a history of cognitively stimulating occupations during their 30s, 40s, 50s, and 60s had a lower risk of MCI and dementia older than 70 years, highlighting the importance of occupational cognitive stimulation during midlife for maintaining cognitive function in old age. Further research is required to pinpoint the specific occupational cognitive demands that are most advantageous for maintaining later-life cognitive function.

Regional MRI volumetry using NeuroQuant versus visual rating scales in patients with cognitive impairment and dementia.

BACKGROUND AND PURPOSE: The aims were to compare the novel regional brain volumetric measures derived by the automatic software NeuroQuant (NQ) with clinically used visual rating scales of medial temporal lobe atrophy (MTA), global cortical atrophy-frontal (GCA-f), and posterior atrophy (PA) brain regions, assessing their diagnostic validity, and to explore if combining automatic and visual methods would increase diagnostic prediction accuracy. METHODS: Brain magnetic resonance imaging (MRI) examinations from 86 patients with subjective and mild cognitive impairment (i.e., non-dementia, n = 41) and dementia (n = 45) from the Memory Clinic at Oslo University Hospital were assessed using NQ volumetry and with visual rating scales. Correlations, receiver operating characteristic analyses calculating area under the curves (AUCs) for diagnostic accuracy, and logistic regression analyses were performed. RESULTS: The correlations between NQ volumetrics and visual ratings of corresponding regions were generally high between NQ hippocampi/temporal volumes and MTA (r = -0.72/-0.65) and between NQ frontal volume and GCA-f (r = -0.62) but lower between NQ parietal/occipital volumes and PA (r = -0.49/-0.37). AUCs of each region, separating non-dementia from dementia, were generally comparable between the two methods, except that NQ hippocampi volume did substantially better than visual MTA (AUC = 0.80 vs. 0.69). Combining both MRI methods increased only the explained variance of the diagnostic prediction substantially regarding the posterior brain region. CONCLUSIONS: The findings of this study encourage the use of regional automatic volumetry in locations lacking neuroradiologists with experience in the rating of atrophy typical of neurodegenerative diseases, and in primary care settings.

Exploring the lived experience: impact of dementia diagnosis on individuals with cognitive impairment - a qualitative study.

OBJECTIVE: Although knowledge about the experience of being diagnosed with dementia is limited, with the expected rise in dementia's prevalence in the coming decades, such knowledge is pivotal for the people diagnosed, their families, and healthcare planners. Thus, the aim of our study was to explore the experience of living with cognitive impairment and dementia and the impact of being diagnosed with dementia. METHOD: A qualitative design was applied. Participants were recruited based on age-adjusted values below ​​threshold values on the Montreal Cognitive Assessment Scale (i.e. 70-79 years, < 22; 80-89 years, < 21; 90 + years, < 20), and the sample ultimately included 15 participants: six with and nine without a documented dementia diagnosis. Qualitative content analysis was performed on the transcribed interviews in four steps to identify codes, categories, and the overall theme. RESULTS: Three major categories emerged from the interviews: (1) experiences with changes, (2) experiences with being diagnosed with dementia, and (3) existential experience. All participants with and most participants without a dementia diagnosis experienced changes in cognition. CONCLUSION: Our findings imply that being diagnosed with dementia is a relief because it explains observed cognitive and functional decreases and reduces confusion, shame and stigma. However, it also raises concerns about an unknown future. Most participants not diagnosed with dementia reported having little or no difficulty with everyday living and leading a fulfilling life. Those findings emphasise the significance of timely versus early diagnosis.

Meeting Summary of The NYO3 5th NO-Age/AD Meeting and the 1st Norway-UK Joint Meeting on Aging and Dementia: Recent Progress on the Mechanisms and Interventional Strategies.

Unhealthy aging poses a global challenge with profound healthcare and socioeconomic implications. Slowing down the aging process offers a promising approach to reduce the burden of a number of age-related diseases, such as dementia, and promoting healthy longevity in the old population. In response to the challenge of the aging population and with a view to the future, Norway and the United Kingdom are fostering collaborations, supported by a "Money Follows Cooperation agreement" between the 2 nations. The inaugural Norway-UK joint meeting on aging and dementia gathered leading experts on aging and dementia from the 2 nations to share their latest discoveries in related fields. Since aging is an international challenge, and to foster collaborations, we also invited leading scholars from 11 additional countries to join this event. This report provides a summary of the conference, highlighting recent progress on molecular aging mechanisms, genetic risk factors, DNA damage and repair, mitophagy, autophagy, as well as progress on a series of clinical trials (eg, using NAD+ precursors). The meeting facilitated dialogue among policymakers, administrative leaders, researchers, and clinical experts, aiming to promote international research collaborations and to translate findings into clinical applications and interventions to advance healthy aging.

Oral symptoms in dying nursing home patients. Results from the prospective REDIC study.

BACKGROUND: The mouth is a central organ for communication and fluid intake, also for dying nursing home patients. This study describes the prevalence and severity of oral symptoms from nursing home admission until the day of perceived dying and the day of death. METHODS: A prospective, longitudinal cohort study including 696 patients who were admitted to 47 Norwegian nursing homes in 35 municipalities. During the first year of their stay, 189 died (27%), of whom 82 participants were assessed on the day they were perceived as dying and 134 on the day of death. Mouth care, nutrition, and bedsores were assessed with the Residents' Assessment Instrument for nursing homes (RAI-NH) and palliative care (RAI-PC). Pain intensity was assessed with the Mobilization-Observation-Behaviour-Intensity-Dementia-2 Pain Scale (MOBID-2). RESULTS: The proportion of patients with ≥ 6 oral symptoms increased from 16% when perceived as dying to 20% on the day of death (P = 0.001). On the day of death, xerostomia (66%), dysphagia (59%), and mastication problems (50%) were the most frequently observed oral symptoms. Only 16% received mouth care every hour and 12% were in pain during this procedure. Compared to people without dementia, those with a diagnosis of dementia at admission (N = 112, 86%) had xerostomia and mastication problems more frequently (50% vs. 73%; 32% vs. 56% (P = 0.038), respectively) on the day of death. CONCLUSIONS: The high extent of oral symptoms such as xerostomia, dysphagia, and mastication problems underline the need for systematic assessment and improved oral palliative care for dying nursing home patients with dementia. TRIAL REGISTRATION: Clinicaltrials.gov NCT01920100 08/08/2013. First submission to BMC oral 15/03/2023.

The effect of a music-based caregiving intervention on pain intensity in nursing home patients with dementia. A cluster-randomized controlled study.

ABSTRACT: Treatment of chronic pain in patients with dementia is challenging because they have reduced ability to report pain and are particularly vulnerable to side effects of analgesics. Different types of music-based therapy have been recommended and are used as an alternative to analgesics, but the evidence is lacking. Therefore, we performed a cluster-randomized controlled study (RCT) to reduce pain intensity using music-based caregiving (MBC) over 8 weeks in nursing home patients with dementia and chronic pain. We also investigated if the amount of MBC and different chronic pain syndromes would impact on the effect. Of the 645 patients, 498 patients from 36 wards in 12 nursing homes were screened for dementia and pain. Using the Clinical Dementia Rating Scale and the Mobilization-Observation-Behavior-Intensity-Dementia Pain Scale (range 0-10), 279 (71% females, 42% severe dementia) nursing home patients were randomized to intervention group (n = 134, 18 wards) or control group (n = 145, 18 wards). The main outcome was change in pain intensity before and after the intervention. The study did not reveal any effect of MBC on pain intensity when compared with the control group (B = -0.15, 95% CI [-0.72 to 0.43]). No significant difference was found within the intervention group analyzing the impact of intervention time (B = 0.73, 95% CI [-0.55 to 2.02]) or chronic primary vs secondary pain syndromes (B = 0.45, 95% CI [-0.05 to 0.96]). Our data from this first RCT on music and pain intensity in patients with dementia and chronic pain did not find an effect of MBC on pain.

Proteome Network Analysis Identifies Potential Biomarkers for Brain Aging.

BACKGROUND: Alzheimer's disease and related dementias (ADRD) involve biological processes that begin years to decades before onset of clinical symptoms. The plasma proteome can offer insight into brain aging and risk of incident dementia among cognitively healthy adults. OBJECTIVE: To identify biomarkers and biological pathways associated with neuroimaging measures and incident dementia in two large community-based cohorts by applying a correlation-based network analysis to the plasma proteome. METHODS: Weighted co-expression network analysis of 1,305 plasma proteins identified four modules of co-expressed proteins, which were related to MRI brain volumes and risk of incident dementia over a median 20-year follow-up in Framingham Heart Study (FHS) Offspring cohort participants (n = 1,861). Analyses were replicated in the Cardiovascular Health Study (CHS) (n = 2,117, mean 6-year follow-up). RESULTS: Two proteomic modules, one related to protein clearance and synaptic maintenance (M2) and a second to inflammation (M4), were associated with total brain volume in FHS (M2: p = 0.014; M4: p = 4.2×10-5). These modules were not significantly associated with hippocampal volume, white matter hyperintensities, or incident all-cause or AD dementia. Associations with TCBV did not replicate in CHS, an older cohort with a greater burden of comorbidities. CONCLUSIONS: Proteome networks implicate an early role for biological pathways involving inflammation and synaptic function in preclinical brain atrophy, with implications for clinical dementia.

Trajectories of occupational physical activity and risk of later-life mild cognitive impairment and dementia: the HUNT4 70+ study.

Background: High levels of occupational physical activity (PA) have been linked to an increased risk of dementia. We assessed the association of trajectories of occupational PA at ages 33-65 with risk of dementia and mild cognitive impairment (MCI) at ages 70+. Methods: We included 7005 participants (49.8% were women, 3488/7005) from the HUNT4 70+ Study. Group-based trajectory modelling was used to identify four trajectories of occupational PA based on national registry data from 1960 to 2014: stable low (30.9%, 2162/7005), increasing then decreasing (8.9%, 625/7005), stable intermediate (25.1%, 1755/7005), and stable high (35.2%, 2463/7005). Dementia and MCI were clinically assessed in 2017-2019. We performed adjusted multinomial regression to estimate relative risk ratios (RRR) with 95% confidence intervals (CI) for dementia and MCI. Findings: 902 participants were diagnosed with dementia and 2407 were diagnosed with MCI. Absolute unadjusted risks for dementia and MCI were 8.8% (95% CI: 7.6-10.0) and 27.4% (25.5-29.3), respectively, for those with a stable low PA trajectory, 8.2% (6.0-10.4) and 33.3% (29.6-37.0) for those with increasing, then decreasing PA; while they were 16.0% (14.3-17.7) and 35% (32.8-37.2) for those with stable intermediate, and 15.4% (14.0-16.8) and 40.2% (38.3-42.1) for those with stable high PA trajectories. In the adjusted model, participants with a stable high trajectory had a higher risk of dementia (RRR 1.34, 1.04-1.73) and MCI (1.80, 1.54-2.11), whereas participants with a stable intermediate trajectory had a higher risk of MCI (1.36, 1.15-1.61) compared to the stable low trajectory. While not statistically significant, participants with increasing then decreasing occupational PA had a 24% lower risk of dementia and 18% higher risk of MCI than the stable low PA group. Interpretation: Consistently working in an occupation with intermediate or high occupational PA was linked to an increased risk of cognitive impairment, indicating the importance of developing strategies for individuals in physically demanding occupations to prevent cognitive impairment. Funding: This work was supported by the National Institutes of Health (R01AG069109-01) and the Research Council of Norway (296297, 262700, 288083).

Change in physical activity and systolic blood pressure trajectories throughout mid-life and the development of dementia in older age: the HUNT study.

BACKGROUND: There is lack of research on combinations of possible modifiable risk factors for dementia in a life-time perspective. Dementia has currently no cure, and therefore new knowledge of preventive factors is important. The purpose of this study is to investigate if changes in physical activity (PA) in combinations with systolic blood pressure (SBP) trajectories in mid to late life are related to development of dementia in older age. METHODS: This prospective cohort study uses data from four consecutive surveys of the HUNT Study, Norway. Dementia was assessed in the HUNT4 70 + sub-study (2017-19). Group-based trajectory modelling identified three SBP trajectories from HUNT1 (1984-86) to HUNT3 (2006-2008): low, middle, and high. Change in PA was categorized into four groups based on high or low PA level at HUNT1 and HUNT3 and were combined with the SBP trajectories resulting in 12 distinct categories. Logistic regression was used to estimate odds ratios (ORs) of dementia. RESULTS: A total of 8487 participants (55% women, mean age (SD) 44.8 (6.5) years at HUNT1) were included. At HUNT4 70 + , 15.2% had dementia. We observed an overall decrease in OR of dementia across the PA/SBP categories when ranked from low to high PA (OR, 0.96; 95% CI, 0.93 to 1.00, P = 0.04). Within PA groups, a low SBP trajectory was associated with lower OR for dementia, apart from those with decreasing PA. The strongest association was observed for people with stable high PA and low SBP trajectory (OR, 0.38; 95% confidence interval (CI), 0.13 to 1.10 and adjusted risk difference, -8.34 percentage points; 95% CI, -15.32 to -1.36). CONCLUSION: Our findings illustrate the clinical importance of PA and SBP for dementia prevention and that favorable levels of both are associated with reduced occurrence of dementia.

Prevalence of malnutrition among older adults in a population-based study - the HUNT Study.

BACKGROUND: Malnutrition is common in older adults and is associated with increased morbidity and mortality rates. AIM: The aim of the study is to describe the prevalence of malnutrition based on low BMI, involuntary weight loss, and reduced food intake, in a Norwegian population of community-dwelling older adults and older adults living in nursing homes. METHODS: This population-based study is part of the fourth wave of the Trøndelag Health Study (HUNT4) and includes participants ≥70 years from the HUNT4 70+ cohort. The HUNT4 70+ cohort consist of 9930 (response rate 51.2%) participants. In the current study 8127 older people had complete dataset for inclusion in the analyses. Participants completed a self-report questionnaire and standardised interviews and clinical assessments at field stations, in participants' homes or at nursing homes. Malnutrition was defined using the following criteria: low BMI, involuntary weight loss and severely reduced food intake. The standardised prevalence of malnutrition was estimated using inverse probability weighting (IPW) with weights for sex, age and education of the total population in the catchment area of HUNT. RESULTS: Of the 8127 included participants, 7671 (94.4%) met at field stations, 356 (4.4%) were examined in their home, and 100 (1.2%) in nursing homes. In total, 14.3% of the population were malnourished based on either low BMI, weight loss, or reduced food intake, of which low BMI was the most frequently fulfilled criterion. The prevalence of malnutrition was less common among men than among women (10.1 vs 18.0%, p < 0.001), also after adjustment for age (OR 0.53, 95% confidence interval (CI) 0.46-0.61). The prevalence increased gradually with increasing age and the regression analysis adjusted for sex showed that for each year increase in age the prevalence of malnutrition increased with 4.0% (OR 1.04, 95% CI 1.03-1.05). The prevalence was higher both among older adults examined in their homes (26.4%) and residents in nursing home (23.6%), as compared to community-dwelling older adults who met at field stations (13.5%). CONCLUSION: The prevalence of malnutrition is high in the older population. Special attention on prevention and treatment of malnutrition should be given to older women, the oldest age groups, and care-dependent community-dwelling older adults and nursing home residents.

Diagnostic accuracy of brain age prediction in a memory clinic population and comparison with clinically available volumetric measures.

The aim of this study was to assess the diagnostic validity of a deep learning-based method estimating brain age based on magnetic resonance imaging (MRI) and to compare it with volumetrics obtained using NeuroQuant (NQ) in a clinical cohort. Brain age prediction was performed on minimally processed MRI data using deep convolutional neural networks and an independent training set. The brain age gap (difference between chronological and biological age) was calculated, and volumetrics were performed in 110 patients with dementia (Alzheimer's disease, frontotemporal dementia (FTD), and dementia with Lewy bodies), and 122 with non-dementia (subjective and mild cognitive impairment). Area-under-the-curve (AUC) based on receiver operating characteristics and logistic regression analyses were performed. The mean age was 67.1 (9.5) years and 48.7% (113) were females. The dementia versus non-dementia sensitivity and specificity of the volumetric measures exceeded 80% and yielded higher AUCs compared to BAG. The explained variance of the prediction of diagnostic stage increased when BAG was added to the volumetrics. Further, BAG separated patients with FTD from other dementia etiologies with > 80% sensitivity and specificity. NQ volumetrics outperformed BAG in terms of diagnostic discriminatory power but the two methods provided complementary information, and BAG discriminated FTD from other dementia etiologies.

Time trends in loneliness from 1984 to 2019 among 27,032 older adults in Norway: A HUNT study.

The aging population and increasing evidence of the detrimental health impacts of loneliness emphasize the importance of studying and predicting changes in loneliness prevalence among older adults. To understand and project changes in loneliness over time, we examined 35-year trends in adults aged 70 and older, considering factors such as sex, age, and living situation. Cross-sectional data from 27,032 home-dwelling adults aged 70 years and older who participated in at least one of the four Norwegian HUNT surveys from 1984 to 2019, and Norwegian population data from Statistics Norway were used for the analyses. Loneliness was self-reported, and the prevalence of loneliness was standardized to the Norwegian population at the survey year by age and sex. The results showed that the prevalence of loneliness significantly decreased between each survey. The higher categories of loneliness (a good amount, very much) decreased, from 11.4% (1995-97), 6.7% (2006-08), and 5.8% (2017-19). Across surveys, loneliness was significantly more common among women, the oldest, and those living alone. The prevalence of loneliness among the oldest adults living alone increased from 2006 to 2019. The gradual decline in loneliness observed from 1995 to 2019 coincided with notable societal changes in Norway. We estimated that the number of older adults experiencing loneliness in Norway could rise from 184,000 in 2020 to 286,000 in 2035, and potentially reach 380,000 in 2050.

Delirium, neurofilament light chain, and progressive cognitive impairment: analysis of a prospective Norwegian population-based cohort.

BACKGROUND: Previous population-based, longitudinal studies have shown that delirium is associated with an increased risk of dementia and cognitive decline. However, the underlying biological mechanisms are largely unknown. We aimed to assess the effects of delirium on both cognitive trajectories and any neuronal injury, measured via neurofilament light chain (NfL). METHODS: In this analysis of a prospective, 2-year follow-up, cohort study of participants aged 65 years or older living in Sandefjord municipality, Norway, we included cohort participants who were receiving domiciliary care services at least once per week between May 12, 2015, and July 8, 2016. Individuals with a life expectancy of less than 1 week, with Lewy body dementia, with psychiatric illness (except dementia), or for whom substance misuse was the principal indication for domiciliary services were excluded. Participants had a comprehensive assessment at 6-month intervals for 2 years, which included the Montreal Cognitive Assessment (MoCA) and a blood sample for NfL to measure neuronal injury. All information on clinical diagnoses and medications were cross-referenced with medical records. During any acute change in mental status or hospitalisation (ie, admission to hospital), participants were assessed once per day for delirium with Diagnostic and Statistical Manual of Mental Disorders, fifth edition criteria. We also measured NfL from blood samples taken from participants who were acutely hospitalised. FINDINGS: Between May 12, 2015, and July 8, 2016, 210 participants were eligible for inclusion and assessed at baseline (138 [66%] of whom were female and 72 [34%] of whom were male), 203 completed cognitive assessment, and 141 were followed up for 2 years. 160 (76%) of 210 had moderate or severe frailty and 112 (53%) were living with dementia. During the 2-year follow-up, 89 (42%) of 210 participants were diagnosed with one or more episodes of delirium. Incident delirium was independently associated with a decrease in MoCA score at the next 6-month follow-up, even after adjustment for age, sex, education, previous MoCA score, and frailty (adjusted mean difference -1·5, 95% CI -2·9 to -0·1). We found an interaction between previous MoCA score and delirium (ß -0·254, 95% CI -0·441 to -0·066, p=0·010), with the largest decline being observed in people with better baseline cognition. Participants with delirium and good previous cognitive function and participants with a high peak concentration of NfL during any hospitalisation had increased NfL at the next 6-month follow-up. Mediation analyses showed independent pathways from previous MoCA score to follow-up MoCA score with contributions from incident delirium (-1·7, 95% CI -2·8 to -0·6) and from previous NfL to follow-up MoCA score with contributions from acute NfL concentrations (-1·8, -2·5 to -1·1). Delirium was directly linked with a predicted value of 1·2 pg/mL (95% CI 1·02 to 1·40, p=0·029) increase in NfL. INTERPRETATION: In people aged 65 years or older, an episode of delirium was associated with a decline in MoCA score. Greater neuronal injury during acute illness and delirium, measured by NfL, was associated with greater cognitive decline. For clinicians, our finding of delirium associated with both signs of acute neuronal injury, measured via NfL, and cognitive decline is important regarding the risk of long-term cognitive deterioration and to acknowledge that delirium is harmful for the brain. FUNDING: South-Eastern Norway Health Authorities, Old Age Psychiatry Research Network, Telemark Hospital Trust, Vestfold Hospital Trust, and Norwegian National Centre for Ageing and Health. TRANSLATION: For the Norwegian translation of the abstract see Supplementary Materials section.

Retirement age and disability status as pathways to later-life cognitive impairment: Evidence from the Norwegian HUNT Study linked with Norwegian population registers.

BACKGROUND: Research shows that retirement age is associated with later-life cognition but has not sufficiently distinguished between retirement pathways. We examined how retirement age was associated with later-life dementia and mild cognitive impairment (MCI) for people who retired via the disability pathway (received a disability pension prior to old-age pension eligibility) and those who retired via the standard pathway. METHODS: The study sample comprised 7210 participants from the Norwegian Trøndelag Health Study (HUNT4 70+, 2017-2019) who had worked for at least one year in 1967-2019, worked until age 55+, and retired before HUNT4. Dementia and MCI were clinically assessed in HUNT4 70+ when participants were aged 69-85 years. Historical data on participants' retirement age and pathway were retrieved from population registers. We used multinomial regression to assess the dementia/MCI risk for women and men retiring via the disability pathway, or early (<67 years), on-time (age 67, old-age pension eligibility) or late (age 68+) via the standard pathway. RESULTS: In our study sample, 9.5% had dementia, 35.3% had MCI, and 28.1% retired via the disability pathway. The disability retirement group had an elevated risk of dementia compared to the on-time standard retirement group (relative risk ratio [RRR]: 1.64, 95% CI 1.14-2.37 for women, 1.70, 95% CI 1.17-2.48 for men). MCI risk was lower among men who retired late versus on-time (RRR, 0.76, 95% CI 0.61-0.95). CONCLUSION: Disability retirees should be monitored more closely, and preventive policies should be considered to minimize the dementia risk observed among this group of retirees.

The Association between Coffee and Tea Consumption at Midlife and Risk of Dementia Later in Life: The HUNT Study.

BACKGROUND: Studies exploring the possible protective effect of coffee and tea consumption on dementia have shown inconsistent results so far. We aimed to investigate whether consumption of tea and different types of coffee at midlife are associated with dementia later in life and whether sex or ApoE4 influence such association. METHODS: We included 7381 participants from the Norwegian HUNT Study. Self-reported questionnaires assessed daily consumption of coffee and tea at baseline. After 22 years, individuals 70 years or older were screened for cognitive impairment. RESULTS: General coffee consumption and tea consumption was not associated with dementia risk. Compared to daily consumption of 0-1 cups of coffee, daily consumption of ≥8 cups of boiled coffee was associated with increased dementia risk in women (OR: 1.83, 95% CI: 1.10-3.04, p-value for trend = 0.03) and daily consumption of 4-5 cups of other types of coffee was associated with a decrease in dementia risk in men (OR: 0.48, 95% CI: 0.32-0.72, p-value for trend = 0.05). Furthermore, the association between boiled coffee and increased dementia risk was only found in ApoE4 non-carriers. Differences by sex or ApoE4 carrier status were not supported by strong statistical evidence for interaction. Tea consumption was not associated with dementia risk. CONCLUSION: type of coffee may play a role in the direction of the association between coffee-drinking habits and dementia later in life.

Shared genetic loci between Alzheimer's disease and multiple sclerosis: Crossroads between neurodegeneration and immune system.

BACKGROUND: Neuroinflammation is involved in the pathophysiology of Alzheimer's disease (AD), including immune-linked genetic variants and molecular pathways, microglia and astrocytes. Multiple Sclerosis (MS) is a chronic, immune-mediated disease with genetic and environmental risk factors and neuropathological features. There are clinical and pathobiological similarities between AD and MS. Here, we investigated shared genetic susceptibility between AD and MS to identify putative pathological mechanisms shared between neurodegeneration and the immune system. METHODS: We analysed GWAS data for late-onset AD (N cases = 64,549, N controls = 634,442) and MS (N cases = 14,802, N controls = 26,703). Gaussian causal mixture modelling (MiXeR) was applied to characterise the genetic architecture and overlap between AD and MS. Local genetic correlation was investigated with Local Analysis of [co]Variant Association (LAVA). The conjunctional false discovery rate (conjFDR) framework was used to identify the specific shared genetic loci, for which functional annotation was conducted with FUMA and Open Targets. RESULTS: MiXeR analysis showed comparable polygenicities for AD and MS (approximately 1800 trait-influencing variants) and genetic overlap with 20% of shared trait-influencing variants despite negligible genetic correlation (rg = 0.03), suggesting mixed directions of genetic effects across shared variants. conjFDR analysis identified 16 shared genetic loci, with 8 having concordant direction of effects in AD and MS. Annotated genes in shared loci were enriched in molecular signalling pathways involved in inflammation and the structural organisation of neurons. CONCLUSIONS: Despite low global genetic correlation, the current results provide evidence for polygenic overlap between AD and MS. The shared loci between AD and MS were enriched in pathways involved in inflammation and neurodegeneration, highlighting new opportunities for future investigation.