Effects of sleep quality on diurnal variation of brain volume in older adults: A retrospective cross-sectional study.

AIM: Brain volume is influenced by several factors that can change throughout the day. In addition, most of these factors are influenced by sleep quality. This study investigated diurnal variation in brain volume and its relation to overnight sleep quality. METHODS: We enrolled 1,003 healthy Koreans without any psychiatric disorders aged 60 years or older. We assessed sleep quality and average wake time using the Pittsburgh Sleep Quality Index, and divided sleep quality into good, moderate, and poor groups. We estimated the whole and regional brain volumes from three-dimensional T1-weighted brain MRI scans. We divided the interval between average wake-up time and MRI acquisition time (INT) into tertile groups: short (INT1), medium (INT2), and long (INT3). RESULTS: Whole and regional brain volumes showed no significance with respect to INT. However, the `interaction between INT and sleep quality showed significance for whole brain, cerebral gray matter, and cerebrospinal fluid volumes (p < .05). The INT2 group showed significantly lower volumes of whole brain, whole gray matter, cerebral gray matter, cortical gray matter, subcortical gray matter, and cerebrospinal fluid than the INT1 and INT3 groups only in the individuals with good sleep quality. CONCLUSION: Human brain volume changes significantly within a day associated with overnight sleep in the individuals with good sleep quality.

The influence of n-3 polyunsaturated fatty acids on cognitive function in individuals without dementia: a systematic review and dose-response meta-analysis.

BACKGROUND: Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been suggested as a cognitive enhancing agent, though their effect is doubtful. We aimed to examine the effect of n-3 PUFA on the cognitive function of middle-aged or older adults without dementia. METHODS: We reviewed randomized controlled trials of individuals aged 40 years or older. We systematically searched PubMed/MEDLINE, EMBASE, CINAHL, PsycINFO, and Cochrane Library databases. We used the restricted cubic splines model for non-linear dose-response meta-analysis in terms of the standardized mean difference with 95% confidence intervals. RESULTS: The current meta-analysis on 24 studies (n 9660; follow-up 3 to 36 months) found that the beneficial effect on executive function demonstrates an upward trend within the initial 12 months of intervention. This effect is prominently observed with a daily intake surpassing 500 mg of n-3 PUFA and up to 420 mg of eicosapentaenoic acid (EPA). Furthermore, these trends exhibit heightened significance in regions where the levels of blood docosahexaenoic acid (DHA) + EPA are not very low. CONCLUSIONS: Supplementation of n-3 PUFA may confer potential benefits to executive function among the middle-aged and elderly demographic, particularly in individuals whose dietary DHA + EPA level is not substantially diminished.

What is the impact of one's chronic illness on his or her spouse's future chronic illness: a community-based prospective cohort study.

BACKGROUND: Integrating a joint approach to chronic disease management within the context of a couple has immense potential as a valuable strategy for both prevention and treatment. Although spousal concordance has been reported in specific chronic illnesses, the impact they cumulatively exert on a spouse in a longitudinal setting has not been investigated. We aimed to determine whether one's cumulative illness burden has a longitudinal impact on that of their spouse. METHODS: Data was acquired from a community-based prospective cohort that included Koreans aged 60 years and over, randomly sampled from 13 districts nationwide. Data from the baseline assessment (conducted from November 2010 to October 2012) up to the 8-year follow-up assessment was analyzed from October 2021 to November 2022. At the last assessment, partners of the index participants were invited, and we included 814 couples in the analysis after excluding 51 with incomplete variables. Chronic illness burden of the participants was measured by the Cumulative Illness Rating Scale (CIRS). Multivariable linear regression and causal mediation analysis were used to examine the longitudinal effects of index chronic illness burden at baseline and its change during follow-up on future index and spouse CIRS scores. RESULTS: Index participants were divided based on baseline CIRS scores (CIRS < 6 points, n = 555, mean [SD] age 66.3 [4.79] years, 43% women; CIRS ≥ 6 points, n = 259, mean [SD] age 67.7 [4.76] years, 36% women). The baseline index CIRS scores and change in index CIRS scores during follow-up were associated with the spouse CIRS scores (ß = 0.154 [SE: 0.039], p < 0.001 for baseline index CIRS; ß = 0.126 [SE: 0.041], p = 0.002 for change in index CIRS) at the 8-year follow-up assessment. Subgroup analysis found similar results only in the high CIRS group. The baseline index CIRS scores and change in index CIRS scores during follow-up had both direct and indirect effects on the spouse CIRS scores at the 8-year follow-up assessment. CONCLUSIONS: The severity and course of one's chronic illnesses had a significant effect on their spouse's future chronic illness particularly when it was severe. Management strategies for chronic diseases that are centered on couples may be more effective.

The impact of the COVID-19 pandemic on depression in community-dwelling older adults: a prospective cohort study.

BACKGROUND: There are growing concerns about the impact of the COVID-19 pandemic on the mental health of older adults. We examined the effect of the pandemic on the risk of depression in older adults. METHODS: We analyzed data from the prospective cohort study of Korean older adults, which has been followed every 2 years. Among the 2308 participants who completed both the third and the fourth follow-up assessments, 58.4% completed their fourth follow-up before the outbreak of COVID-19 and the rest completed it during the pandemic. We conducted face-to-face diagnostic interviews using Mini International Neuropsychiatric Interview and used Geriatric Depression Scale. We performed generalized estimating equations and logistic regression analyses. RESULTS: The COVID-19 pandemic was associated with increased depressive symptoms in older adults [b (standard error) = 0.42 (0.20), p = 0.040] and a doubling of the risk for incident depressive disorder even in euthymic older adults without a history of depression (odds ratio = 2.44, 95% confidence interval 1.18-5.02, p = 0.016). Less social activities, which was associated with the risk of depressive disorder before the pandemic, was not associated with the risk of depressive disorder during the pandemic. However, less family gatherings, which was not associated with the risk of depressive disorder before the pandemic, was associated with the doubled risk of depressive disorder during the pandemic. CONCLUSIONS: The COVID-19 pandemic significantly influences the risk of late-life depression in the community. Older adults with a lack of family gatherings may be particularly vulnerable.

Mood disorders increase mortality mainly through dementia: A community-based prospective cohort study.

OBJECTIVE: The effects of mood disorders on mortality may be mediated by their effects on the risk of dementia, and interventions to reduce the occurrence of dementia may reduce their overall mortality. This study aimed to investigate the direct effects of depressive and bipolar disorders on the 6-year risk of mortality and also their indirect effects on mortality due to their effect on the risk of dementia. METHODS: A total of 5101 Koreans were selected from a community-based prospective cohort study, and 6-year risks of mortality and dementia in participants with depressive and bipolar disorders were estimated by Cox proportional hazard analysis. The direct and indirect effects of depressive and bipolar disorders on the risk of mortality were estimated using structural equation modeling. RESULTS: The depressive and bipolar disorder groups showed 51% and 85% higher 6-year mortality, and 82% and 127% higher risk of dementia, respectively, compared to euthymic controls. The effects of depressive and bipolar disorders on mortality were mainly mediated by their effects on the risk of dementia in a structural equation model. The direct effects of each mood disorder on mortality were not significant. CONCLUSION: Both depressive and bipolar disorders increased the risks of mortality and dementia, and the effects of mood disorders on mortality were mainly mediated through dementia. As dementia occurs later in life than mood disorders, measures to prevent it may effectively reduce mortality in individuals with a history of mood disorders, as well as being more feasible than attempting to control other causes of death.

Association of the Irregular 3-Dimensional Shape of White Matter Hyperintensities with Cognitive Function.

INTRODUCTION: The irregular shapes of white matter hyperintensities (WMHs) are associated with poor cognitive function, diabetes, or lacunes. However, the association between the WMH shape and dementia remains understudied. We investigated the association between the calculated shape index of WMH and the diagnosis of dementia and cognitive function. METHODS: The inverse sphericity index (ISIWMH) and volume of WMHs (VOLWMH) were compared among 82 participants with normal cognition, 82 with Alzheimer's dementia (AD), and 82 with subcortical vascular dementia (SVD). We examined the associations of ISIWMH and VOLWMH with the modified Hachinski Ischemic Score (mHIS), diagnosis of AD and SVD, and cognitive test scores, using linear, multinomial, or hierarchical linear regression models. RESULTS: The mHIS was associated with both ISIWMH (ß = 0.326, p < 0.001) and VOLWMH (ß = 0.299, p < 0.001). Both ISIWMH and VOLWMH were associated with the SVD diagnosis (odds ratio [OR] = 2.685, p = 0.002, ISIWMH; OR = 2.597, p = 0.005, VOLWMH), but not with AD. The SVD diagnosis was better explained when the multinomial regression model included both ISIWMH and VOLWMH instead of VOLWMH alone (χ2 = 20.768, df = 2, p < 0.001). The Trail Making Test-D (TMT-D) scores of the SVD patients were associated with both ISIWMH (ß = 0.308) and VOLWMH (ß = 0.293). CONCLUSION: An irregular WMH shape may be associated with the high cerebrovascular component of cognitive impairment and the diagnosis and low cognitive flexibility of SVD, which may improve the prediction of SVD diagnosis when used in combination with WMH volume.

Magnetic Resonance Imaging Texture of Medial Pulvinar in Dementia with Lewy Bodies.

INTRODUCTION: Executive dysfunction is common in dementia with Lewy bodies (DLB). The pulvinar nucleus plays a role in executive control and synchronizes with cortical regions in the salience network that are vulnerable to Lewy pathology. OBJECTIVE: We investigated the pulvinar subregions in patients with mild DLB and their associations with executive function. METHODS: The sample consisted of 38 DLB patients and 38 age- and sex-matched normal controls. We evaluated cognitive function using the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet. We obtained four pulvinar nuclei using preprocessed T1-weighted magnetic resonance images. We compared volumes and textures of the DLB patients and the normal controls for each nucleus. We used a linear regression to determine the association of textures and neuropsychological test scores. RESULTS: The DLB patients showed comparable volumes to the normal controls in all pulvinar nuclei. However, the DLB patients showed different texture of the left medial pulvinar (PuM) from the normal controls. The entropy, contrast, and cluster shade were lower but autocorrelation of left PuM was higher in the DLB patients compared to the normal controls. These texture features of the left PuM were associated with the set-shifting performance measured by the Trail Making Test. CONCLUSIONS: In DLB, the left PuM may be altered from early stage, which may contribute to the development of executive dysfunction.

A cross-national study of depression in preclinical dementia: A COSMIC collaboration study.

INTRODUCTION: Depression commonly accompanies Alzheimer's disease, but the nature of this association remains uncertain. METHODS: Longitudinal data from the COSMIC consortium were harmonized for eight population-based cohorts from four continents. Incident dementia was diagnosed in 646 participants, with a median follow-up time of 5.6 years to diagnosis. The association between years to dementia diagnosis and successive depressive states was assessed using a mixed effect logistic regression model. A generic inverse variance method was used to group study results, construct forest plots, and generate heterogeneity statistics. RESULTS: A common trajectory was observed showing an increase in the incidence of depression as the time to dementia diagnosis decreased despite cross-national variability in depression rates. DISCUSSION: The results support the hypothesis that depression occurring in the preclinical phases of dementia is more likely to be attributable to dementia-related brain changes than environment or reverse causality.

Determinants of cognitive performance and decline in 20 diverse ethno-regional groups: A COSMIC collaboration cohort study.

BACKGROUND: With no effective treatments for cognitive decline or dementia, improving the evidence base for modifiable risk factors is a research priority. This study investigated associations between risk factors and late-life cognitive decline on a global scale, including comparisons between ethno-regional groups. METHODS AND FINDINGS: We harmonized longitudinal data from 20 population-based cohorts from 15 countries over 5 continents, including 48,522 individuals (58.4% women) aged 54-105 (mean = 72.7) years and without dementia at baseline. Studies had 2-15 years of follow-up. The risk factors investigated were age, sex, education, alcohol consumption, anxiety, apolipoprotein E ε4 allele (APOE*4) status, atrial fibrillation, blood pressure and pulse pressure, body mass index, cardiovascular disease, depression, diabetes, self-rated health, high cholesterol, hypertension, peripheral vascular disease, physical activity, smoking, and history of stroke. Associations with risk factors were determined for a global cognitive composite outcome (memory, language, processing speed, and executive functioning tests) and Mini-Mental State Examination score. Individual participant data meta-analyses of multivariable linear mixed model results pooled across cohorts revealed that for at least 1 cognitive outcome, age (B = -0.1, SE = 0.01), APOE*4 carriage (B = -0.31, SE = 0.11), depression (B = -0.11, SE = 0.06), diabetes (B = -0.23, SE = 0.10), current smoking (B = -0.20, SE = 0.08), and history of stroke (B = -0.22, SE = 0.09) were independently associated with poorer cognitive performance (p < 0.05 for all), and higher levels of education (B = 0.12, SE = 0.02) and vigorous physical activity (B = 0.17, SE = 0.06) were associated with better performance (p < 0.01 for both). Age (B = -0.07, SE = 0.01), APOE*4 carriage (B = -0.41, SE = 0.18), and diabetes (B = -0.18, SE = 0.10) were independently associated with faster cognitive decline (p < 0.05 for all). Different effects between Asian people and white people included stronger associations for Asian people between ever smoking and poorer cognition (group by risk factor interaction: B = -0.24, SE = 0.12), and between diabetes and cognitive decline (B = -0.66, SE = 0.27; p < 0.05 for both). Limitations of our study include a loss or distortion of risk factor data with harmonization, and not investigating factors at midlife. CONCLUSIONS: These results suggest that education, smoking, physical activity, diabetes, and stroke are all modifiable factors associated with cognitive decline. If these factors are determined to be causal, controlling them could minimize worldwide levels of cognitive decline. However, any global prevention strategy may need to consider ethno-regional differences.

Sleep and cognitive decline: A prospective nondemented elderly cohort study.

OBJECTIVE: To investigate sleep disturbances that induce cognitive changes over 4 years in nondemented elderlies. METHODS: Data were acquired from a nationwide, population-based, prospective cohort of Korean elderlies (2,238 normal cognition [NC] and 655 mild cognitive impairment [MCI]). At baseline and 4-year follow-up assessments, sleep-related parameters (midsleep time, sleep duration, sleep latency, subjective sleep quality, sleep efficiency, and daytime dysfunction) and cognitive status were measured using the Pittsburgh Sleep Quality Index and Consortium to Establish a Registry for Alzheimer's Disease Assessment, respectively. We used logistic regression models adjusted for covariates including age, sex, education, apolipoprotein E genotype, Geriatric Depression Scale, Cumulative Illness Rating Scale, and physical activity. RESULTS: In participants with NC, long sleep latency (>30 minutes), long sleep duration (≥7.95 hours), and late midsleep time (after 3:00 am) at baseline were related to the risk of cognitive decline at 4-year follow-up assessment; odds ratio (OR) was 1.40 for long sleep latency, 1.67 for long sleep duration, and 0.61 for late midsleep time. These relationships remained significant when these variables maintained their status throughout the follow-up period. Newly developed long sleep latency also doubled the risk of cognitive decline. In those with MCI, however, only long sleep latency reduced the chance of reversion to NC (OR = 0.69). INTERPRETATION: As early markers of cognitive decline, long sleep latency can be used for elderlies with NC or MCI, whereas long sleep duration and relatively early sleep time might be used for cognitively normal elderlies only. Ann Neurol 2018;83:472-482.

Delirium and its consequences in the specialized palliative care unit: Validation of the Korean version of Memorial Delirium Assessment Scale.

OBJECTIVES: Delirium is highly prevalent in patients with advanced cancer. This study aimed to investigate delirium rates and potential associated factors such as mortality in patients admitted to an acute palliative care unit (APCU). Our second aim was to validate the Korean version of the Memorial Delirium Assessment Scale (K-MDAS). METHODS: A total of 102 patients with advanced cancer, and who were admitted to the APCU, were assessed. Demographic data were collected alongside clinical diagnosis, Eastern Cooperative Oncology Group (ECOG) performance status, clinical symptoms according to the Edmonton Symptom Assessment System, history of smoking, alcohol use, hypnotic use, and daily dose of morphine were collected. The Confusion Assessment Method, the Delirium Rating Scale-Revised 98, and the K-MDAS were measured at admission and 1 week later. RESULTS: Twenty-four patients (23.52%) were diagnosed with delirium, and associated factors were old age (P = 0.007), higher ECOG (P = 0.011), and drowsiness (P < 0.001). The presence of delirium was an independent predictor of 1-month mortality; male gender, higher body mass index, and hypnotic use were also related to 1-month mortality. The K-MDAS had reliable internal consistency (α = 0.942) and showed sensitivity of 0.958 and specificity of 0.921 at the optimal cutoff score for diagnosing delirium of 9. CONCLUSIONS: Delirium was prevalent in patients admitted to the APCU and was associated with 1-month mortality. The K-MDAS showed acceptable reliability and validity and can be used to screen for delirium in a palliative care setting.

Gait Variability Can Predict the Risk of Cognitive Decline in Cognitively Normal Older People.

BACKGROUND: The aim of this study was to investigate the association of gait speed and gait variability, an index of how much gait parameters, such as step time, fluctuate step-to-step, with risk of cognitive decline in cognitively normal elderly individuals. While high gait variability is emerging as an early indicator of dementing illnesses, there is little research on whether high gait variability predicts cognitive decline in cognitively normal elderly who have no evidence of cognitive impairment. METHODS: In this 4-year prospective cohort study on 91 community-dwelling cognitively normal elderly individuals without cerebral ischemic burden or Parkinsonism, we evaluated gait speed and step time variability using a tri-axial accelerometer placed on the center of body mass, and diagnosed mild cognitive impairment (MCI) according to the International Working Group on MCI. We performed Kaplan-Meier analysis with consecutive log-rank testing for MCI-free survival by cohort-specific tertiles of gait speed; hazard ratios (HR) of incident MCI were estimated using Cox proportional hazards regression analysis adjusted for age, sex, education level, Cumulative Illness Rating Scale score, GDS score, and presence of the apolipoprotein E ε4 allele. RESULTS: Out of the 91 participants in the baseline assessment, 87 completed one or more 2-year follow-up assessments, and the median duration of follow-up was 47.1 months. Kaplan-Meier curves of incident MCI show evident differences in risk by gait variability group (χ2 = 9.64, p = 0.002, log-rank test). Mean MCI-free survival in the high variability group was 12% shorter than in the mid-to-low tertile group (47.4 ± 1.74 [SD] vs. 54.04 ± 0.52 months), while it was comparable between gait speed groups (51.59 ± 0.70 vs. 50.64 ± 1.77 months; χ2 = 1.16, p = 0.281). In multivariate analysis, subjects with high gait variability showed about 12-fold higher risk of MCI (HR = 11.97, 95% CI = 1.29-111.37) than those with mid-to-low variability. However, those with slow gait speed showed comparable MCI risk to those with mid-to-high speed (HR = 5.04, 95% CI = 0.53-48.18). CONCLUSIONS: Gait variability may be a better predictor of cognitive decline than gait speed in cognitively normal elderly individuals without cerebral ischemic burden or Parkinsonism.

Clinical Approaches to Late-Onset Psychosis.

Psychosis can include schizophrenia, mood disorders with psychotic features, delusional disorder, active delirium, and neurodegenerative disorders accompanied by various psychotic symptoms. Late-onset psychosis requires careful intervention due to the greater associated risks of secondary psychosis; higher morbidity and mortality rates than early-onset psychosis; and complicated treatment considerations due to the higher incidence of adverse effects, even with the black box warning against antipsychotics. Pharmacological treatment, including antipsychotics, should be carefully initiated with the lowest dosage for short-term efficacy and monitoring of adverse side effects. Further research involving larger samples, more trials with different countries working in consortia, and unified operational definitions for diagnosis will help elaborate the clinical characteristics of late-onset psychosis and lead to the development of treatment approaches.

Altered resting state brain metabolic connectivity in dementia with Lewy bodies.

Although dementia with Lewy bodies (DLB) have Parkinsonism in common with Parkinson's disease (PD) or PD dementia (PDD), they have different neuropathologies that underlie Parkinsonism. Altered brain functional connectivity that may correspond to neuropathology has been reported in PD while never been studied in DLB. To identify the characteristic brain connectivity of Parkinsonism in DLB, we compared the resting state metabolic connectivity in striato-thalamo-cortical (STC) circuit, nigrostriatal pathway, and cerebello-thalamo-cortical motor (CTC) circuit in 27 patients with drug-naïve DLB and 27 age- and sex-matched normal controls using 18F-fluoro-2-deoxyglucose PET. We derived 118 regions of interest using the Automated Anatomical Labeling templates and the Wake Forest University Pick-Atlas. We applied the sparse inverse covariance estimation method to construct the metabolic connectivity matrix. Patients with DLB, with or without Parkinsonism, showed lower inter-regional connectivity between the areas included in the STC circuit (motor cortex-striatum, midbrain-striatum, striatum-globus pallidus, and globus pallidus-thalamus) than the controls. DLB patients with Parkinsonism showed less reduced inter-regional connectivity between the midbrain and the striatum than those without Parkinsonism, and higher inter-regional connectivity between the areas included in the CTC circuit (motor cortex-pons, pons-cerebellum, and cerebellum-thalamus) than those without Parkinsonism and the controls. The resting state metabolic connectivity in the STC circuit may be reduced in DLB. In DLB with Parkinsonism, the CTC circuit and the nigrostriatal pathway may be activated to mitigate Parkinsonism. This difference in the brain connectivity may be a candidate biomarker for differentiating DLB from PD or PDD.

Optimal flickering light stimulation for entraining gamma waves in the human brain.

Although light flickering at 40 Hz reduced Alzheimer's disease (AD) pathologies in mice by entraining gamma waves, it failed to reduce cerebral amyloid burden in a study on six patients with AD or mild cognitive impairment. We investigated the optimal color, intensity, and frequency of the flickering light stimulus for entraining gamma waves in young adults. We compared the event-related synchronization (ERS) values of entrained gamma waves between four different light colors (white, red, green, and blue) in the first experiment and four different luminance intensities in the second experiment. In both experiments, we compared the ERS values of entrained gamma waves between 10 different flickering frequencies from 32 to 50 Hz. We also examined the severity of six adverse effects in both experiments. We compared the propagation of gamma waves in the visual cortex to other brain regions between different luminance intensities and flickering frequencies. We found that red light entrained gamma waves most effectively, followed by white light. Lights of higher luminance intensities (700 and 400 cd/m2) entrained stronger gamma waves than those of lower luminance intensities (100 and 10 cd/m2). Lights flickering at 34-38 Hz entrained stronger and more widely spread beyond the visual cortex than those flickering at 40-50 Hz. Light of 700 cd/m2 resulted in more moderate-to-severe adverse effects than those of other luminance intensities. In humans, 400 cd/m2 white light flickering at 34-38 Hz was most optimal for gamma entrainment.

Screening major depressive disorder using vocal acoustic features in the elderly by sex.

BACKGROUND: Vocal acoustic features are potential biomarkers of elderly depression. Previous automated diagnostic tests for depression have employed unstandardized speech samples, and few studies have considered differences in voice reactivity. We aimed to develop a voice-based screening test for depression measuring vocal acoustic features of elderly Koreans while they read a series of mood-inducing sentences (MIS). METHODS: In this case-control study, we recruited 61 individuals with major depressive disorder and 143 healthy controls (mean age [SD]: 72 [6]; female, 70%) from the community-dwelling elderly population. Participants were asked to read MIS and their variation pattern of acoustic features represented by the correlation distance between two MIS were analyzed as input features using the univariate feature selection technique and subsequently classified by AdaBoost. RESULTS: Acoustic features showing significant discriminatory performances were spectral and energy-related features for males (sensitivity 0.95, specificity 0.88, and accuracy 0.86) and prosody-related features for females (sensitivity 0.73, specificity 0.86, and accuracy 0.77). The correlation distance between negative and positive MIS was significantly shorter in the depressed group than in the healthy control (F = 18.574, P < 0.001). LIMITATIONS: Small sample size and relatively homogenous clinical profile of depression could limit the generalizability. CONCLUSIONS: While reading MIS, spectral and energy-related acoustic features for males and prosody-related features for females are good discriminators for major depressive disorder. These features may be used as biomarkers of depression in the elderly.

Construction and validation of a cerebral white matter hyperintensity probability map of older Koreans.

BACKGROUND AND PURPOSE: Although two white matter hyperintensity (WMH) probability maps of healthy older adults already exist, they have several limitations in representing the distribution of WMH in healthy older adults, especially Asian older adults. We constructed and validated a WMH probability map (WPM) of healthy older Koreans and examined the age-associated differences of WMH. METHODS: We constructed WPM using development dataset that consisted of high-resolution 3D fluid-attenuated inversion recovery images of 5 age groups (60-64 years, 65-69 years, 70-74 years, 75-79 years, and 80+ years). Each age group included 30 age-matched men and women each. We tested the validity of the WPM by comparing WMH ages estimated by the WPM and the chronological ages of 30 healthy controls, 30 hypertension patients, and 30 S patients. RESULTS: Older age groups showed a higher volume of WMH in both hemispheres (p < 0.001). About 90% of the WMH were periventricular in all age groups. With advancing age, the peak of the distance histogram from the ventricular wall of the periventricular WMH shifted away from the ventricular wall, while that of deep WMH shifted toward the ventricular wall. The estimated WMH ages were comparable to the chronological ages in the healthy controls, while being higher than the chronological ages in hypertension and stroke patients. CONCLUSIONS: This WPM may serve as a standard atlas in research on WMH of older adults, especially Asians.

Disease Burdens of Alzheimer's Disease, Vascular Dementia, and Mild Cognitive Impairment.

OBJECTIVES: Understanding disability-adjusted life-years (DALYs) based on dementia subtypes and mild cognitive impairment (MCI) is essential for optimal resource allocation. This study aimed to investigate disease burdens of various dementias and MCI in a representative South Korean population. DESIGN: Retrospective cohort study. SETTING AND PARTICIPANTS: 6481 Korean older adults. METHODS: We estimated the disease-specific DALYs. RESULTS: DALYs due to MCI and all-cause dementia are estimated to increase from 1295 per 100,000 in 2016 to 9501 per 100,000 in 2065. In 2016, DALYs attributed to Alzheimer's dementia, vascular dementia, and MCI accounted for 33% (423 per 100,000), 20% (316 per 100,000), and 24% (123 per 100,000), respectively, of the total DALYs due to MCI and all-cause dementia. In 2065, DALYs due to Alzheimer's dementia, vascular dementia, and MCI will account for 38% (3654 per 100,000), 17% (1654 per 100,000), and 27% (2585 per 100,000) of total DALYs due to MCI and all-cause dementia, respectively. The years of life lived with disability (YLDs) due to MCI and all-cause dementia are estimated to rise from 479 per 100,000 in 2016 to 2807 per 100,000 in 2065. In 2016, YLDs due to Alzheimer's dementia, vascular dementia, and MCI composed 37% (177 per 100,000), 18% (85 per 100,000), and 15% (70 per 100,000), respectively, of the total YLDs due to MCI and all-cause dementia. In 2065, YLDs due to Alzheimer's dementia, vascular dementia, and MCI will account for 48% (1358 per 100,000), 15% (410 per 100,000), and 10% (290 per 100,000), respectively, of total YLDs due to MCI and all-cause dementia. CONCLUSIONS AND IMPLICATIONS: Considering the rapidly growing disease burden, resources should be allocated to continuously monitor and manage the MCI and dementia burden. Particular attention to Alzheimer's dementia is required considering its significant contribution to current and future disease burden, especially to YLD.

A 9-Year Comparison of Dementia Prevalence in Korea: Results of NaSDEK 2008 and 2017.

BACKGROUND: In many high-income Western countries, the prevalence of dementia had been reduced over the past decades. OBJECTIVE: We investigated whether the prevalence of all-cause dementia, Alzheimer's disease, vascular dementia, and mild cognitive impairment (MCI) had changed in Korea from 2008 to 2017. METHODS: Nationwide Survey on Dementia Epidemiology of Korea (NaSDEK) in 2008 and 2017 was conducted on representative elderly populations that were randomly sampled across South Korea. Both surveys employed a two-stage design (screening and diagnostic phases) and diagnosed dementia and MCI according to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders and the consensus criteria from the International Working Group, respectively. The numbers of participants aged 65 years or older in the screening and diagnostic phases were 6,141 and 1,673 in the NaSDEK 2008 and 2,972 and 474 in the NaSDEK 2017, respectively. RESULTS: The age- and sex-standardized prevalence of all-cause dementia and Alzheimer's disease showed nonsignificant decrease (12.3% to 9.8%, odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.54-1.48 for all-cause dementia; 7.6% to 6.8%, OR [95% CI] = 0.91 [0.58-1.42] for Alzheimer's disease). Vascular dementia decreased in the young-old population aged less than 75 years (2.7% to 0.001%, OR [95% CI] = 0.04 [0.01-0.15]) and in women (1.9% to 0.5%, OR [95% CI] = 0.27 [0.10-0.72]) while MCI remained stable (25.3% to 26.2%, OR [95% CI] = 1.08 [0.67-1.73]). CONCLUSION: We found that the prevalence of dementia in Korea showed a nonsignificant decrease between 2008 and 2017.

Efficacy of Vitamins on Cognitive Function of Non-Demented People: A Systematic Review and Meta-Analysis.

Previous evidence has suggested that vitamins might be beneficial for cognition. This systematic review aimed to investigate the efficacy of B vitamins, antioxidant vitamins, and vitamin D on the cognitive function of non-demented middle-aged or older people. Randomized or quasi-randomized controlled trials of individuals aged 40 years or older were included. PubMed/MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Library databases, and other grey literature sources were searched up to November 2019. Their methodological quality was evaluated using the Cochrane Risk of Bias tool. Twenty-three studies on B vitamins (n = 22-1053; comprising folate, B6, and B12), nine on antioxidant vitamins (n = 185-20,469), and six on vitamin D (n = 55-4122) were included. Taking B vitamins for over 3 months was beneficial for global cognition (standardized mean difference (SMD) -0.18, 95% CI -0.30 to -0.06) and episodic memory (SMD -0.09, 95% CI -0.15 to -0.04). However, antioxidant vitamins (SMD -0.02, 95% CI -0.08 to 0.03) and vitamin D (SMD -0.06, 95% CI -0.36 to 0.23) were not. Antioxidant vitamins were beneficial for global cognition in sensitivity analyses using final measurement data as mean difference estimates (SMD, -0.04, 95% CI -0.08 to -0.01). Taking B vitamins and possibly antioxidant vitamins may be beneficial for the cognitive function of non-demented people.