Association of cognitive reserve with transitions across cognitive states and death in older adults: A 15-year follow-up study.

INTRODUCTION: We investigated the association of cognitive reserve (CR) with transitions across cognitive states and death. METHODS: This population-based cohort study included 2631 participants (age ≥60 years) who were dementia-free at baseline and regularly examined up to 15 years. Data were analyzed using the Markov multistate models. RESULTS: Each 1-point increase in the composite CR score (range: -4.25 to 3.46) was significantly associated with lower risks of transition from normal cognition to cognitive impairment, no dementia (CIND) (multivariable-adjusted hazards ratio = 0.78; 95% confidence interval = 0.72-0.85) and death (0.85; 0.79-0.93), and from CIND to death (0.82; 0.73-0.91), but not from CIND to normal cognition or dementia. A greater composite CR score was associated with a lower risk of transition from CIND to death in people aged 60-72 but not in those aged ≥ 78 years. DISCUSSION: CR contributes to cognitive health by delaying cognitive deterioration in the prodromal phase of dementia. HIGHLIGHTS: We use Markov multistate model to examine the association between cognitive reserve and transitions across cognitive states and death. A great cognitive reserve contributes to cognitive health by delaying cognitive deterioration in the prodromal phase of dementia. A great cognitive reserve is associated with a lower risk of transition from cognitive impairment, no dementia to death in people at the early stage of old age, but not in those at the late stage of old age.

Association of objective sleep duration with cognition and brain aging biomarkers in older adults.

The neuropathological mechanisms underlying the association between sleep duration and mild cognitive impairment remain poorly understood. This population-based study included 2032 dementia-free people (age ≥ 60 years; 55.1% women) derived from participants in the Multimodal Interventions to Delay Dementia and Disability in Rural China; of these, data were available in 841 participants for Alzheimer's plasma biomarkers (e.g. amyloid-ß, total tau and neurofilament light chain), 1044 for serum microvascular biomarkers (e.g. soluble adhesion molecules) and 834 for brain MRI biomarkers (e.g. whiter matter, grey matter, hippocampus, lacunes, enlarged perivascular spaces and white matter hyperintensity WMH). We used electrocardiogram-based cardiopulmonary coupling analysis to measure sleep duration, a neuropsychological test battery to assess cognitive function and the Petersen's criteria to define mild cognitive impairment. Data were analysed with multivariable logistic and general linear models. In the total sample (n = 2032), 510 participants were defined with mild cognitive impairment, including 438 with amnestic mild cognitive impairment and 72 with non-amnestic mild cognitive impairment. Long sleep duration (>8 versus 6-8 h) was significantly associated with increased likelihoods of mild cognitive impairment and non-amnestic mild cognitive impairment and lower scores in global cognition, verbal fluency, attention and executive function (Bonferroni-corrected P < 0.05). In the subsamples, long sleep duration was associated with higher plasma amyloid-ß40 and total tau, a lower amyloid-ß42/amyloid-ß40 ratio and smaller grey matter volume (Bonferroni-corrected P < 0.05). Sleep duration was not significantly associated with serum-soluble adhesion molecules, white matter hyperintensity volume, global enlarged perivascular spaces and lacunes (P > 0.05). Alzheimer's and neurodegenerative pathologies may represent common pathways linking long sleep duration with mild cognitive impairment and low cognition in older adults.

The lifestyle for brain health index, the cluster of differentiation 33 (CD33) gene, and cognitive function among rural Chinese older adults: A population-based study.

BACKGROUND: We sought to examine the associations of the Lifestyle for Brain Health (LIBRA) index with cognitive function among rural Chinese older adults and to explore the potential role of cluster of differentiation 33 gene (CD33) in the associations. METHODS: This population-based cross-sectional study included 4914 dementia-free participants (age ≥60 years; 56.43 % women) in the 2018 baseline examination of MIND-China. The LIBRA index was generated from 11 factors. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, executive function, and global cognition. The CD33(rs3865444) polymorphism was detected using multiple-polymerase chain reaction amplification. Data were analyzed using the general linear regression models. RESULTS: A higher LIBRA index was associated with multivariable-adjusted ß-coefficient (95 %CI) of -0.011(-0.020- -0.001) for global cognitive z-score, -0.020(-0.033- -0.006) for episodic memory, and -0.016(-0.029- -0.004) for verbal fluency. The CD33(rs3865444) was associated with a lower global cognitive z-score in the additive (CA vs. CC: ß-coefficient=0.042; 95 %CI=0.008-0.077), the dominant (CA+AA vs. CC: 0.040; 0.007-0.073), and the over-dominant (CA vs. CC+AA: 0.043; 0.009-0.077) models. Similar results were obtained for verbal fluency and attention. The CD33 gene showed statistical interactions with LIBRA index on cognitive function (Pinteraction<0.05) such that a higher LIBRA index was significantly associated with lower z-scores of global cognition and attention only among CD33 CC carriers (P < 0.05). CONCLUSIONS: This population-based study reveals for the first time that a higher LIBRA index is associated with worse cognitive performance in rural Chinese older adults and that CD33 gene could modify the association.

Strategic Lacunes Associated With Mild Cognitive Impairment in Rural Chinese Older Adults: A Population-Based Study.

BACKGROUND: Lacunes are associated with cognitive impairment. We sought to identify strategic lacune locations associated with mild cognitive impairment (MCI) and subtypes of MCI among older adults, and further to examine the role of white matter hyperintensities and perivascular spaces in the association. METHODS: This population-based cross-sectional study included 1230 dementia-free participants in the brain magnetic resonance imaging substudy (2018-2020) in MIND-China (Multimodal Interventions to Delay Dementia and Disability in Rural China). Lacunes were visually identified in frontal lobe, parieto-occipital lobe, temporal lobe, insula, basal ganglia, thalamus, cerebellum, and brainstem. MCI, amnestic MCI (aMCI), and nonamnestic MCI (naMCI) were defined following the Petersen's criteria. Data were analyzed using logistic regression models. RESULTS: Of the 1230 participants (age, ≥60 years; mean age, 69.40; SD, 4.30 years; 58.5% women), lacunes were detected in 357 people and MCI was defined in 286 individuals, including 243 with aMCI and 43 with naMCI. Lacunes in the supratentorial area, internal capsula, putamen/pallidum, and insula was significantly associated with increased odds ratio of MCI (multivariable-adjusted odds ratio ranged 1.40-3.21; P<0.05) and aMCI (multivariable-adjusted odds ratio ranged 1.46-3.36; P<0.05), whereas lacunes in the infratentorial area and brainstem were significantly associated with naMCI (multivariable-adjusted odds ratio ranged 2.68-3.46; P<0.01). Furthermore, the associations of lacunes in insula and internal capsula with MCI and aMCI, as well as the associations of lacunes in infratentorial area and brainstem with naMCI were present independent of white matter hyperintensities volume and perivascular spaces number. CONCLUSIONS: Lacunes in the internal capsula, putamen/pallidum, insula, and brainstem may represent the strategic lacunes that are independently associated with MCI, aMCI, or naMCI in Chinese older adults. REGISTRATION: URL: https://www.chictr.org.cn; Unique identifier: ChiCTR1800017758.

Change in cardiovascular health and rate of cognitive decline in older adults: a 15-year population-based study.

BACKGROUND: Previous research on associations between cardiovascular health, measured at a single timepoint, and rate of age-related cognitive decline shows divergent findings dependent on the participants' age and the health metric studied. The aim of this study was to add to the knowledge in this field by investigating whether change in cardiovascular health, assessed with Life's Simple 7 (LS7) score, is associated with rate of cognitive change in young-old and old-old adults. METHODS: The study included 1022 participants aged ≥ 60 years from the Swedish National Study on Aging and Care-Kungsholmen (SNAC-K), who underwent repeated neuropsychological testing (episodic memory, semantic memory, verbal fluency, and perceptual speed) across up to 15 years. LS7, composed of seven cardiovascular health metrics (smoking, diet, physical activity, body mass index, plasma glucose, total serum cholesterol, and blood pressure), was assessed at baseline and at the 6-year follow-up. Change in LS7 was calculated as the difference between baseline and 6 years (range - 5 to 8 points) and categorised into worse (-5 to -2 points), stable (-1 to 1 points), and improved (2 to 8 points). Change in cognitive performance as a function of LS7 change categories was estimated using linear mixed-effects models. RESULTS: Participants were classified as stable (67.1%), improved (21.0%), or worse (11.8%) according to changes in LS7 score. Both the worse and improved categories were associated with faster cognitive decline. Age-stratified analyses revealed that worsening of LS7 was clearly associated with faster cognitive decline in the old-old (≥ 78 years), whereas improvement tended be associated with faster cognitive decline in the young-old (< 78 years) group. CONCLUSIONS: Change in cardiovascular health in old age may lead to accelerated cognitive decline, particularly in late senescence. These results suggest that it is important to monitor and maintain cardiovascular health status in very old adults.

Prevalence and associated factors of excessive daytime sleepiness in rural older adults: a population-based study.

OBJECTIVE: To investigate the prevalence and associated factors of excessive daytime sleepiness (EDS) among rural-dwelling Chinese older adults. METHODS: We collected data on demographic, epidemiological, and clinical factors via in-person interviews and clinical examinations following a structured questionnaire. The 15-item Geriatric Depression Scale (GDS-15) was used to assess depressive symptoms, the Berlin questionnaire (BQ) to assess obstructive sleep apnea (OSA) risk; and the Epworth Sleepiness Scale (ESS) to assess sleep characteristics. EDS was defined as the total ESS score > 10. RESULTS: This population-based study engaged 4845 participants (age ≥ 65 years, 57.3% female) in the 2018 examination of the Multimodal Interventions to Delay Dementia and Disability in Rural China. The prevalence of EDS was 9.3% in the total sample, 8.3% in females, and 10.6% in males, and the prevalence decreased with advanced age. Logistic regression analysis revealed that EDS was significantly associated with age (multivariable-adjusted odds ratio [OR] = 0.97; 95% confidence interval [CI] 0.95-0.99), female sex (0.53; 0.36-0.77), hypertension (0.68; 0.54-0.85), depressive symptoms (2.68; 2.07-3.46), high OSA risk (2.11; 1.69-2.63), and poor sleep quality (2.12; 1.60-2.82). CONCLUSION: EDS affects nearly one-tenth of rural older adults in China. Older age, female sex, and hypertension were associated with a decreased likelihood of EDS, while depressive symptoms, high OSA risk, and poor sleep quality were correlated with an elevated likelihood of EDS.

Cardiovascular health and rate of cognitive decline in preclinical dementia: A 12-year population-based study.

OBJECTIVE: We investigated whether vascular risk factors (VRFs), assessed with Life's Simple 7 (LS7), are associated with the rate of cognitive decline in the years preceding a dementia diagnosis. METHOD: This study included 1,449 stroke-free participants aged ≥60 years from the Swedish National Study on Aging and Care in Kungsholmen, who underwent repeated neuropsychological testing (episodic memory, semantic memory, verbal fluency, perceptual speed) across 12 years. The LS7 score, assessed at baseline, included smoking, diet, physical activity, body mass index, plasma glucose, total cholesterol, and blood pressure. Preclinical dementia was defined as being dementia-free at baseline and diagnosed with dementia during follow-up. Level and change in cognitive performance as a function of LS7 category (poor vs. intermediate to optimal) and future dementia status were estimated using linear mixed-effect models. RESULTS: Participants who later developed dementia had, on average, a poorer LS7 score compared to those who remained dementia-free. For individuals aged 60-72 years, poor diet was associated with accelerated decline in perceptual speed (ß = -0.05, 95% CI [-0.08, -0.02]), and a poor glucose score was associated with faster rates of verbal fluency (ß = -0.019, 95% CI [-0.09, -0.01]) and global cognitive (ß = -0.028, 95% CI [-0.06, 0.00]) decline in the preclinical dementia group. CONCLUSIONS: VRFs exacerbate rate of cognitive decline in the years preceding a dementia diagnosis. This effect was most pronounced in young-old age and primarily driven by diet and glucose. The effect of VRFs may be especially detrimental for cognitive decline trajectories of individuals with impending dementia. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Quantitative assessments of retinal macular structure among rural-dwelling older adults in China: a population-based, cross-sectional, optical coherence tomography study.

OBJECTIVES: To quantitatively assess and compare retinal macular structures of rural-dwelling older adults in China using two different optical coherence tomography (OCT) scanners and to examine their associations with demographic, lifestyle, clinical and ocular factors. DESIGN, SETTING AND PARTICIPANTS: This population-based, cross-sectional study included 971 participants (age ≥60 years) derived from the Multimodal Interventions to Delay Dementia and Disability in Rural China study. We collected data on demographics, lifestyle factors, clinical conditions (eg, cardiovascular disease (CVD)) and ocular factors (eg, visual acuity and spherical equivalent). We used two models of spectral-domain OCT to measure macular parameters in nine Early Treatment Diabetic Retinopathy Study subfields. Data were analysed using the multiple general linear models. RESULTS: Spectralis OCT demonstrated higher macular thickness but a lower macular volume than Primus 200 OCT (p<0.05). Nasal quadrant of the inner and outer subfields was the thickest, followed by superior quadrant. Adjusting for multiple potential confounding variables, older age was significantly correlated with lower average inner and outer macular thicknesses and overall macular volume. Men had higher macular parameters than women. The presence of CVD was correlated with lower central macular thickness (ß=-6.83; 95% CI: -13.08 to -0.58; p=0.032). Middle school or above was associated with higher average inner macular thickness (ß=7.85; 95% CI: 1.14 to 14.55; p=0.022) and higher spherical equivalent was correlated with lower average inner macular thickness (ß=-1.78; 95% CI: -3.50 to -0.07; p=0.042). CONCLUSIONS: Macular thickness and volume assessed by Spectralis and Primus 200 OCT scanners differ. Older age and female sex are associated with lower macular thickness and volume. Macular parameters are associated with education, CVD and spherical equivalent. TRIAL REGISTERATION NUMBER: MIND-China study (ChiCTR1800017758).

Association of Metabolic Syndrome with Macular Thickness and Volume in Older Adults: A Population-Based Optical Coherence Tomography Study.

Background: To explore the associations of the metabolic syndrome (MetS) and individual components with macular thickness and volume among rural-dwelling Chinese older adults. Methods: This population-based cross-sectional study included 705 participants (age ≥60 years) derived from the MIND-China study. In 2018-2019, we collected data through face-to-face interview, clinical examination, optical coherence tomography (OCT) examination, and blood test. We measured macular thickness and volume using spectral-domain OCT. MetS was defined following the International Diabetes Federation (IDF) criteria, the IDF/American Heart Association (AHA) criteria, the National Cholesterol Education Program-Adult Treatment Panel III criteria, and the Chinese Diabetes Society (CDS) criteria. Data were analyzed with multivariable general linear models. Results: MetS was significantly associated with thinner macula in central (multivariable-adjusted ß = -5.29; 95% confidence interval: -9.31 to -1.26), parafoveal (-2.85; -5.73 to 0.04) and perifoveal regions (-4.37; -6.79 to -1.95) when using the IDF criteria, in the perifoveal regions (-3.82; -6.18 to -1.47) when using the IDF/AHA criteria, and in the central region (-5.63; -10.25 to -1.02) when using the CDS criteria, and with reduced macular volume when using the IDF (-0.16; -0.26 to -0.07) and IDF/AHA (-0.13; -0.22 to -0.04) criteria. In the parafoveal region, the IDF-defined MetS was significantly associated with thinner retina in men (ß = -6.25; -10.94 to -1.56) but not in women. Abdominal obesity (-2.83; -5.41 to -0.25) and elevated fasting blood glucose (-2.65; -5.08 to -0.21) were associated with thinner macular thickness in the perifoveal region. Conclusion: MetS is associated with macular thinning and reduced macular volume among rural-dwelling older adults, and the associations vary by the defining criteria of MetS.

Associations of Orthostatic Hypotension and Frailty With Dementia and Mortality in Older Adults: A Population-Based Cohort Study.

BACKGROUND: This study aimed to assess the associations of orthostatic hypotension (OH), in the presence or absence of frailty, with dementia and mortality in older adults. METHODS: We conducted a 15-year population-based cohort study including 2 703 baseline dementia-free individuals from the Swedish National Study on Aging and Care in Kungsholmen. At baseline, OH was defined as a decline in systolic/diastolic blood pressure ≥20/10 mm Hg 1 minute after standing up from a supine position. Frailty status was defined following Fried's frailty phenotype. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders-fourth edition criteria. Multistate flexible parametric survival models were used to estimate associations of OH and frailty with dementia and mortality. RESULTS: Robust people with OH (adjusted hazard ratio [HR] = 2.28; 95% confidence interval [CI] = 1.47-3.54) and frail people without OH (HR = 1.98; 95% CI = 1.40-2.82) or with OH (HR = 2.73; 95% CI = 1.82-4.10) had a higher dementia risk than OH-free and robust people. Moreover, frail people, independently of the presence of OH, had higher mortality rate than OH-free and robust people. In individuals who developed dementia during the follow-up period, neither OH nor frailty was significantly associated with mortality. CONCLUSIONS: Older adults with OH, whether robust or frail, may have a higher dementia risk than those without OH. Older adults with OH, when having frailty, may have a higher mortality rate than those without OH. The concurrent assessments of OH and frailty may provide prognostic values in terms of dementia and mortality risk in older adults.

Comparing glycemic traits in defining diabetes among rural Chinese older adults.

BACKGROUND: We sought to identify the optimal cut-off of glycated hemoglobin (HbA1c) for defining diabetes and to assess the agreements of fasting plasma glucose (FPG), fasting serum glucose (FSG), and HbA1c in defining diabetes among rural older adults in China. METHODS: This population-based cross-sectional study included 3547 participants (age ≥61 years, 57.8% women) from the Multidomain Interventions to Delay Dementia and Disability in Rural China from 2018-2019; of these, 3122 had no previously diagnosed diabetes. We identified the optimal cut-off of HbA1c against FPG ≥7.0 mmol/L for defining diabetes by using receiver operating characteristic curve and Youden index. The agreements of FPG, FSG, and HbA1c in defining diabetes were assessed using kappa statistics. RESULTS: Among participants without previously diagnosed diabetes (n = 3122), the optimal HbA1c cut-off for defining diabetes was 6.5% (48 mmol/mol), with the sensitivity of 88.9%, specificity of 93.7%, and Youden index of 0.825. The correlation coefficients were 0.845 between FPG and FSG, 0.574 between FPG and HbA1c, and 0.529 between FSG and HbA1c in the total sample (n = 3547). The kappa statistic for defining diabetes was 0.962 between FSG and FPG, and 0.812 between HbA1c and FPG. CONCLUSIONS: The optimal cut-off of HbA1c for diagnosing diabetes against FPG >7.0 mmol/L is ≥6.5% in Chinese rural-dwelling older adults. The agreement in defining diabetes using FPG, FSG, and HbA1c is nearly perfect. These results have relevant implications for diabetes research and clinical practice among older adults in China. CLINICAL TRIAL REGISTRATION: The protocol of MIND-China was registered in the Chinese Clinical Trial Registry (ChiCTR, www.chictr.org.cn; registration no.: ChiCTR1800017758).

Association of sdLDL-C With Incident Carotid Plaques With Stable and Vulnerable Morphology: A Prospective Cohort Study.

BACKGROUND: Small dense low-density lipoprotein cholesterol (sdLDL-C) particles are more atherogenic than large and intermediate low-density lipoprotein cholesterol (LDL-C) subfractions. We sought to investigate the association of sdLDL-C and the sdLDL-C/LDL-C ratio with incident carotid plaques with stable and vulnerable morphology in rural China. METHODS: This community-based cohort study used data from the RICAS study (Rose Asymptomatic Intracranial Artery Stenosis), which enrolled 887 participants (aged ≥40 years) who were living in Kongcun Town, Pingyin County, Shandong, and free of carotid plaques and had no history of clinical stroke or transient ischemic attack at baseline (2017). Incident carotid plaques and their vulnerability were detected by carotid ultrasound at follow-up (2021). Multivariable logistic regression models were used to explore the association of sdLDL-C or sdLDL-C/LDL-C ratio with incident carotid plaques while adjusting for demographic factors, vascular risk factors, and follow-up time. RESULTS: Of the 887 participants (mean age [SD], 53.89 [8.67%] years; 54.34% women), 179 (20.18%) were detected with incident carotid plaques during an average follow-up of 3.94 years (SD=0.14). Higher sdLDL-C or sdLDL-C/LDL-C ratio, but not LDL-C, was significantly associated with an increased risk of incident carotid plaques. The upper tertile of sdLDL-C (versus lower tertile) was associated with the multivariate-adjusted odds ratio of 2.48 (95% CI, 1.00-6.15; P=0.049; P for linear trend=0.046) for carotid plaques with vulnerable morphology (n=41), and the association remained significant in participants with normal LDL-C (<130 mg/dL; n=693; upper versus lower tertile: odds ratio, 3.38 [95% CI, 1.15-9.90]; P=0.027; P for linear trend=0.025). Moreover, the sdLDL-C/LDL-C ratio was associated with a higher odds ratio of incident carotid plaques in participants without diabetes (P for interaction=0.014). CONCLUSIONS: Higher sdLDL-C was associated with an increased risk of incident carotid plaques, especially carotid plaques with vulnerable morphology, even in participants with normal LDL-C. This suggests the potential of sdLDL-C as a therapeutic target for stroke prevention. REGISTRATION: URL: https://www.chictr.org.cn; Unique identifier: ChiCTR1800017197.

Associations of Blood Absolute Neutrophil Count and Cytokines With Cognitive Function in Dementia-Free Participants: A Population-Based Cohort Study.

BACKGROUND: The relationships of neutrophils and cytokines with cognitive dysfunction are poorly defined. We aimed to investigate the association of peripheral blood absolute neutrophil count (ANC) with cognitive function in older adults and to further explore the mediating role of serum cytokines in this association. METHODS: This population-based cohort study included 1 666 dementia-free participants (age ≥60 years) derived from baseline examinations (March-September 2018) of the Multimodal Intervention to Delay Dementia and Disability in Rural China (MIND-China); of these, 1 087 participants completed follow-up examinations in October-December 2019. We used a neuropsychological test battery to assess episodic memory, verbal fluency, attention, and executive function at the baseline and follow-up examinations. We used Mindray BC-6800 automated hematology analyzer to measure ANC and Meso Scale Discovery to measure serum interleukin-6 (IL-6) and eotaxin-3. RESULTS: The linear regression analysis of cross-sectional data at baseline (n = 1 666) suggested that increased ANC was significantly associated with a lower episodic memory z score (ß coefficient: -0.149, 95% CI: -0.274 to -0.023) and lower long-delayed free recall z score (-0.216, -0.361 to -0.070). Serum IL-6 and eotaxin-3 could mediate 16.16% to 20.21% and 7.55% to 9.35%, respectively, of these associations. The analysis of longitudinal data (n = 1 087) showed a J-shaped relationship of ANC with decline in episodic memory z score (p for nonlinear = .049), and a U-shaped relationship between ANC and decline in long-delayed free recall z score (p for nonlinear = .043). CONCLUSIONS: Increased neutrophils are associated with poor cognitive performance and accelerated decline in episodic memory, and the cross-sectional association is partly mediated by serum cytokines.

Multimorbidity, cognitive phenotypes, and Alzheimer's disease plasma biomarkers in older adults: A population-based study.

INTRODUCTION: To examine the burden and clusters of multimorbidity in association with mild cognitive impairment (MCI), dementia, and Alzheimer's disease (AD)-related plasma biomarkers among older adults. METHODS: This population-based study included 5432 participants (age ≥60 years); of these, plasma amyloid beta (Aß), total tau, and neurofilament light chain (NfL) were measured in a subsample (n = 1412). We used hierarchical clustering to generate five multimorbidity clusters from 23 chronic diseases. We diagnosed dementia and MCI following international criteria. Data were analyzed using logistic and linear regression models. RESULTS: The number of chronic diseases was associated with dementia (multivariable-adjusted odds ratio = 1.22; 95% confidence interval [CI] = 1.11 to 1.33), AD (1.13; 1.01 to 1.26), vascular dementia (VaD) (1.44; 1.25 to 1.64), and non-amnestic MCI (1.25; 1.13 to 1.37). Metabolic cluster was associated with VaD and non-amnestic MCI, whereas degenerative ocular cluster was associated with AD (p < 0.05). The number of chronic diseases was associated with increased plasma Aß and NfL (p < 0.05). DISCUSSION: Multimorbidity burden and clusters are differentially associated with subtypes of dementia and MCI and AD-related plasma biomarkers in older adults. HIGHLIGHTS: We used hierarchical clustering to generate five clusters of multimorbidity. The presence and load of multimorbidity were associated with dementia and mild cognitive impairment. Multimorbidity clusters were differentially associated with subtypes of dementia and Alzheimer's disease plasma biomarkers.

Trends in the prevalence of cognitive impairment at old age in China, 2002-2018.

INTRODUCTION: China has the world's largest number of older adults with cognitive impairment (CI). We aimed to examine secular trends in the prevalence of CI in China from 2002 to 2018. METHODS: Generalized estimating equations (GEE) was used to assess changes in CI trend in 44,154 individuals (72,027 observations) aged 65 to 105 years old. RESULTS: The prevalence of CI increased from 2002 to 2008 and then decreased until 2018. The age-standardized prevalence increased from 25.7% in 2002, 26.1% in 2005, to 28.2% in 2008, then decreased to 26.0% in 2011, 25.3% in 2014, and 24.9% in 2018. Females and those ≥ 80 years old had greater CI prevalence. DISCUSSION: The prevalence of CI showed an inverted U shape from early 2000s to late 2010s with a peak in 2008. Follow-up studies are needed to confirm the decreasing trend after 2008 and examine the contributing factors and underlying mechanisms of this trend. HIGHLIGHTS: Generalized estimating equations (GEE) were used to assess trends of changes in cognitive impairment (CI). CI prevalence in China increased from 2002 to 2008 and then decreased until 2018. Females and those ≥ 80 years old had greater CI prevalence. Stroke, diabetes, and cigarette smoking were risk factors for CI.

Association of Triglyceride-Glucose Index With Cognitive Function and Brain Atrophy: A Population-Based Study.

OBJECTIVE: To investigate the associations of triglyceride-glucose (TyG) index, a reliable surrogate marker for insulin resistance, with the function of various cognitive domains and brain structures among older adults. DESIGN: A population-based cross-sectional study. SETTING: Older adults living in the rural communities in China. PARTICIPANTS: About 4,541 rural-dwelling dementia-free participants (age ≥65 years; 56.37% women) undertook examinations in March-September 2018 for MIND-China. MEASUREMENTS: TyG index was calculated as ln[fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2]. A neuropsychological test battery was used to assess memory, attention, verbal fluency, and executive function. Volumetric brain measures were assessed on magnetic resonance imaging (MRI) in a subsample (n = 1,019). Data were analyzed with restricted cubic spline and multivariable general linear models. RESULTS: An inverted J-shaped association was observed between TyG index and z-scores of multiple cognitive domains, such that among individuals with TyG index ≥8.57 (median), a higher TyG index was significantly associated with lower z-scores of memory, attention, verbal fluency, executive function, and global cognition (all p < 0.05); among people with TyG index <8.57, a higher TyG index was significantly associated with a higher executive function z-score (p < 0.05), but not with any of the other examined cognitive domains. In the MRI subsample, a higher TyG index was significantly associated with lower volumes of total brain tissue, gray matter, and white matter as well as greater cerebrospinal fluid volume (p < 0.05), but not with white matter hyperintensity volume. CONCLUSIONS: Insulin resistance, as indicated by a high TyG index, was associated with poor function in multiple cognitive domains and global brain atrophy.

Accelerometer-Measured Sedentary Behavior Patterns, Brain Structure, and Cognitive Function in Dementia-Free Older Adults: A Population-Based Study.

BACKGROUND: Sedentary behavior is associated with cognitive impairment, but the neuropathological mechanisms underlying their associations are poorly understood. OBJECTIVE: To investigate the associations of accelerometer-measured sedentary behavior patterns with brain structure and cognition, and further to explore the potential mechanisms. METHODS: This community-based study included 2,019 older adults (age≥60 years, 59% women) without dementia derived from participants in the baseline examination of MIND-China (2018-2020). We assessed sedentary parameters using an accelerometer and cognitive function using a neuropsychological test battery. Structural brain markers were assessed on the structural brain MRI scans in a subsample (n = 1,009). Data were analyzed using the general linear, isotemporal substitution, and mediation models. RESULTS: In the total sample (n = 2,019), adjusting for multiple covariates and moderate-to-vigorous-intensity physical activity, longer mean sedentary bout duration was linearly related with lower z-scores of global cognition, verbal fluency, and memory (ptrend < 0.05), whereas greater total sedentary time was linearly associated with lower z-scores of global cognition, verbal fluency, and memory only among individuals with long sedentary time (>10 h/day) (ptrend < 0.05); Breaking up sedentary time with same amount of light-intensity physical activity was significantly associated with higher verbal fluency and memory z-scores (p < 0.05). In the MRI subsample (n = 1,009), separately entering structural brain MRI markers into the mediation models substantially attenuated the associations of mean sedentary bout duration with global cognition, verbal fluency, and memory z-scores. CONCLUSION: Prolonged uninterrupted sedentary time is associated with poor global cognition, memory, and verbal fluency among rural older adults, and structural brain markers could partially mediate the association.

Association of plaque characteristics with long-term stroke recurrence in patients with intracranial atherosclerotic disease: a 3D high-resolution MRI-based cohort study.

OBJECTIVES: To evaluate the predictive ability of plaque characteristics for long-term stroke recurrence among patients with symptomatic intracranial atherosclerotic disease (ICAD). METHODS: This cohort study included 132 patients with acute ischemic stroke (AIS) attributed to ICAD who were recruited between July 2017 and December 2020 and followed until stroke recurrence or December 2021. Plaque surface irregularity, degree of stenosis, plaque burden, remodeling ratio, enhancement ratio, and intraplaque hemorrhage were assessed with 3-dimensional high-resolution magnetic resonance vessel wall imaging (3D HR-MRI). Data were analyzed using Cox models, receiver operating characteristic (ROC) curves, and Kaplan-Meier survival analysis. RESULTS: Of the 132 patients, during a median follow-up of 2.8 years, stroke recurrence occurred in 35 patients. The multivariable-adjusted hazard ratio (95% confidence interval) of stroke recurrence was 3.15 (1.34-7.42) per 10% increase in plaque burden and 2.17 (1.27-3.70) for enhancement ratio. The area under the curve (AUC) to predict stroke recurrence was 0.725 (95% CI 0.629-0.822) for plaque burden, 0.692 (95% CI 0.593-0.792) for enhancement ratio, and only 0.595 (95% CI 0.492-0.699) for the Essen stroke risk score. The Kaplan-Meier survival analysis further demonstrated significant differences in survival of free recurrent stroke between patients with plaque burden or enhancement ratio below and above the optimum cut-offs (both p < 0.001). CONCLUSION: Higher plaque burden and enhancement ratio are independent risk factors for long-term stroke recurrence among patients with symptomatic ICAD, and valuable imaging markers for predicting and stratifying risk of stroke recurrence. CLINICAL RELEVANCE STATEMENT: In patients with symptomatic ICAD, the results of this high-resolution magnetic resonance vessel wall imaging study have potential implications for optimal management of intracranial plaques and secondary prevention of stroke recurrence based on plaque burden and enhancement ratio. KEY POINTS: • Identification of intracranial plaque characteristics responsible for stroke recurrence is essential to preventing stroke recurrence in patients with symptomatic intracranial atherosclerotic disease. • Higher plaque burden and enhancement ratio are independent risk factors for stroke recurrence. • Plaque burden and enhancement ratio are valuable imaging markers in the prediction and stratification of the risk of stroke recurrence.

Resting heart rate, cognitive function, and inflammation in older adults: a population-based study.

BACKGROUND: Emerging evidence has linked elevated resting heart rate (RHR) with poor cognitive function in older adults, but the mechanisms underlying their association are poorly understood. METHODS: This population-based cross-sectional study included 4510 dementia-free participants (age ≥ 65 years; 56.9% females; 38.3% no formal education) in the baseline examination of the Multidomain Interventions to Delay Dementia and Disability in Rural China study. Of these, 1,386 had data on serum proinflammatory cytokines and adhesion molecules. RHR was measured using 12-lead electrocardiograph. We used the Mini-Mental State Examination (MMSE) and a neuropsychological test battery to assess cognitive function. Data were analyzed using the general linear and restricted cubic splines models. RESULTS: People with high RHR were more likely to have cardiometabolic diseases and worse cognitive function (p < 0.05). There was an inverted J-shaped association of RHR with MMSE and attention scores. Having RHR ≥ 80 bpm (vs. 60-69 bpm) was significantly associated with the multivariable-adjusted ß coefficients of - 0.58 [95% confidence interval (CI), - 1.00, - 0.16] for MMSE score and - 0.08 (- 0.15, - 0.01) for attention score. In the serum biomarker subsample, RHR was linearly associated with serum interleukin-6 (IL-6) (ß coefficient = 0.19; 95%CI 0.14, 0.24), IL-8 (0.08; 0.02, 0.13), IL-10 (0.09; 0.04, 0.15), tumor necrosis factor-α (0.06; 0.01, 0.11), monocyte chemotactic protein-1 (0.09; 0.04, 0.15), intercellular adhesion molecule-1 (0.16; 0.11, 0.22), and vascular cell adhesion molecule-1 (0.11; 0.06, 0.16). CONCLUSIONS: There is an inverted J-shaped association of RHR with attention and global cognition. Poor cognitive function and high RHR may be linked through systemic low-grade inflammation and endothelial injury.

Plasma Amyloid-ß, Total Tau, and Neurofilament Light Chain Across the Alzheimer's Disease Clinical Spectrum: A Population-Based Study.

BACKGROUND: Plasma biomarkers have emerged as a promising approach for characterizing pathophysiology in mild cognitive impairment (MCI) and Alzheimer's disease (AD). OBJECTIVE: We aimed to characterize plasma biomarkers for AD and neurodegeneration across the AD clinical continuum, and to assess their ability to differentiate between AD, MCI, and normal cognition. METHODS: This population-based study engaged 1,446 rural-dwelling older adults (age ≥60 years, 61.0% women) derived from MIND-China; of these, 402 were defined with MCI and 142 with AD. Plasma amyloid-ß (Aß), total tau (t-tau), and neurofilament light chain (NfL) concentrations were analyzed using the Simoa platform. Data were analyzed using linear and logistic regression models, and receiver operating characteristic (ROC) analysis. RESULTS: Across the AD clinical spectrum, plasma Aß40 and NfL increased, whereas Aß42/Aß40 ratio decreased. Plasma t-tau was higher in people with AD dementia than those with MCI or normal cognition. Plasma NfL outperformed other biomarkers in differentiating AD from normal cognition (area under the ROC curve [AUC] = 0.75), but all plasma biomarkers performed poorly to distinguish MCI from normal cognition (AUC <0.60). Plasma NfL in combination with age, sex, education, and APOE genotype yielded the AUC of 0.87 for differentiating between AD and normal cognition, 0.79 between AD and MCI, and 0.64 between MCI and normal cognition. CONCLUSIONS: In this Chinese population, AD plasma biomarkers vary by age, sex, and APOE genotype. Plasma Aß, t-tau, and NfL differ across the AD clinical spectrum, and plasma NfL appears to be superior to plasma Aß and t-tau for defining the clinical spectrum.