Perceived Stress, Blood Biomarkers, and Cognitive Functioning in Older Adults.

INTRODUCTION: There is a substantial gap in knowledge regarding how perceived stress may influence the relationship between serum-measured biomarkers for Alzheimer's disease and cognitive decline. METHODS: This study consists of 1,118 older adult participants from the Chicago Health and Aging Project (CHAP) (60% Black participants and 63% female participants). Linear mixed effects regression models were conducted to examine the role of perceived stress in the association between three blood biomarkers: total tau (t-tau), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL) on global cognitive decline. Stratified analysis by stress level was also conducted to evaluate the associations between each blood biomarker and baseline cognitive function and decline. All models adjusted for age, race, sex, education, time, and their interactions with time. RESULTS: The interaction of stress, NfL concentration, and time was statistically significant on global cognition (ß = -0.064 (SE = 0.028), p-value = 0.023) and on episodic memory (ß = -0.097 (SE = 0.036), p-value = 0.007). CONCLUSIONS: Greater stress level worsens the association between high NfL concentration and cognitive decline. Stress management interventions may be helpful to reduce rate of cognitive decline in individuals with high concentrations of NfL.

Dietary fats and the APOE-e4 risk allele in relation to cognitive decline: a longitudinal investigation in a biracial population sample.

BACKGROUND: APOE-e4 is the strongest genetic risk factor for Alzheimer's disease. However, the influence of APOE-e4 on dietary fat intake and cognition has not been investigated. OBJECTIVE: We aim to examine the association of types of dietary fat and their association to cognitive decline among those with and without the APOE-e4 allele. METHODS: The study included 3,360 Chicago Health and Aging Project (CHAP) participants from four Southside Chicago communities. Global cognition was assessed using a composite score of episodic memory, perceptual speed, MMSE, and diet using a 144-item food frequency questionnaire. APOE genotype was assessed by the hME Sequenom mass-array platform. Longitudinal mixed-effect regression models were used to examine the association of dietary fat and the APOE-e4 allele with cognitive decline, adjusted for age, sex, education, smoking status, and calorie intake. RESULTS: The present study involved 3,360 participants with a mean age of 74 at baseline, 62% African Americans, 63% females, and a mean follow-up of 7.8 years. Among participants with the APOE-e4 risk allele, higher intakes of total and saturated fat (SFA) were associated with a faster decline in global cognition. Among individuals with the APOE-e4 risk allele, a 5% increase in calories from SFA was associated with a 21% faster decline (ß = -0.0197, P = 0.0038). In contrast, a higher intake of long-chain n-3 polyunsaturated fatty acids (LC-n3 PUFA) was associated with a slower rate of decline in global cognition among APOE-e4 carriers. Specifically, for every 1% energy increment from LC-n3 PUFA, the annual rate of global cognitive decline was slower by 0.024 standardized unit (SD 0.010, P = 0.023), about 30.4% slower annual cognitive decline. Higher SFA or other types of dietary fat were not associated with cognitive decline among APOE-e4 non-carriers. CONCLUSIONS: Our study found a significant association between SFA and faster cognitive decline, LC-n3 PUFA and slower cognitive decline among those with the APOE-e4 allele. Our findings suggested that higher intake of SFA might contribute faster cognitive decline in combination with APOE-e4 whereas LC-n3 PUFA might compensate the adverse effects of APOE-e4. The interaction between intakes of different types of dietary fat and APOE-e4 on cognitive function warrants further research.

Statin Initiation and Risk of Incident Alzheimer Disease and Cognitive Decline in Genetically Susceptible Older Adults.

BACKGROUND AND OBJECTIVES: The association of statin initiation with incident Alzheimer disease (AD) dementia and cognitive decline by the APOE ε4 allele is unknown. Our objective was to examine whether the association of statin initiation with incident AD dementia and cognitive decline differs by the APOE ε4 allele. METHODS: This population-based longitudinal cohort study was conducted in 4 urban communities in Chicago, IL, United States, consisting of 4,807 participants. Statin initiation is based on the inspection of medications during home assessments. Clinical diagnosis for incident AD used the NINCDS-ADRDA criteria, and longitudinal measurements of global cognition consisted of episodic memory, perceptual speed, and the Mini-Mental State Examination tests. RESULTS: The study participants had a mean age of 72 years, consisting of 63% female individuals and 61% non-Hispanic Black individuals. During the study period, 1,470 (31%) participants reported statin initiation. In a covariate-adjusted competing risk model, statin initiation was associated with a reduced risk of incident clinical AD [hazard ratio (HR) 0.81 (95% CI 0.70-0.94)] compared with nonusers. This association was statistically significantly lower (p interaction = 0.015) among participants with the APOE ε4 allele [HR 0.60 (95% CI 0.49-0.74)] compared with those without the APOE ε4 allele [HR 0.96 (95% CI 0.82-1.12)]. The annual decline in global cognition (ß = 0.021, 95% CI 0.007-0.034) and episodic memory (ß = 0.020, 95% CI 0.007-0.033) was also substantially slower among participants with the APOE ε4 allele after statin initiation compared with nonusers. However, the association of statin initiation with cognitive decline was not significant among those without the APOE ε4 allele. DISCUSSION: Our findings suggest that statins might be associated with a lower risk of incident AD among individuals with the APOE ε4 allele. The benefits of statin therapy need further consideration in randomized clinical trials, especially among those with the APOE ε4 allele. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that among those aged 65 years or older, statin initiation was associated with a reduced risk of Alzheimer disease, especially in the presence of an APOE-e4 allele.

Serum total tau, neurofilament light, and glial fibrillary acidic protein are associated with mortality in a population study.

BACKGROUND: Total tau (t-tau), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP) are neuronal cytoskeletal biomarkers that may indicate greater risk of poor outcomes in age-related conditions, including mortality. Health disparities experienced by some racial minority subgroups may influence biomarker expression and effects on longevity. We aimed to examine (a) associations of serum t-tau, NfL, and GFAP with overall and cardiovascular mortality and (b) differences in associations by racial background. METHODS: Data came from 1327 older participants from the Chicago Health and Aging Project (CHAP), a longitudinal population-based study. Cox proportional hazards regression models were used to examine associations between concentrations of serum t-tau, NfL, and GFAP biomarker(s) and mortality (overall/cardiovascular mortality based on age at death). Interaction terms were used to examine differences between African-American and European-American participants. Models were adjusted for age, sex, education, the APOE-ε4 allele, body mass index, chronic health conditions, and cognitive and physical functioning. RESULTS: Models showed that fivefold higher concentrations of t-tau (HR = 1.46, 95% CI: 1.27, 1.68), NfL (HR = 2.13, 95% CI: 1.76, 2.58), and GFAP (HR = 1.43, 95% CI: 1.08, 1.90) were separately associated with increased risk of overall mortality, with higher risk in African Americans in t-tau or NfL. In models with all biomarkers, NfL (HR = 2.17, 95% CI: 1.65, 2.85) was associated with risk of overall mortality, with racial differences in t-tau. Higher concentrations of t-tau (HR = 1.32, 95% CI: 1.02, 1.70), NfL (HR = 1.95, 95% CI: 1.40, 2.72), and GFAP (HR = 1.87, 95% CI: 1.18, 2.98) were separately associated with risk of cardiovascular mortality, with racial differences in t-tau, NfL, or GFAP. In combined models, NfL (HR = 1.73, 95% CI: 1.08, 2.78) was associated with cardiovascular mortality. CONCLUSIONS: Serum t-tau, NfL, and GFAP may be early indicators for mortality outcomes among older adults, with racial differences among associations.

Depressive Symptoms, Glial Fibrillary Acid Protein Concentrations, and Cognitive Decline in a Cohort Study.

BACKGROUND: Little is known about how depressive symptoms and glial fibrillary acid protein (GFAP) concentrations taken together may influence cognitive functioning. Understanding this relationship may inform strategies for screening and early intervention to decrease the rate of cognitive decline. METHODS: This study sample includes 1 169 participants from the Chicago Health and Aging Project (CHAP), consisting of 60% Black participants and 40% White participants, and 63% female participants and 37% male participants. CHAP is a population-based cohort study of older adults with a mean age of 77 years. Linear mixed-effects regression models tested the main effects of depressive symptoms and GFAP concentrations and their interactions on baseline cognitive function and cognitive decline over time. Models included adjustments for age, race, sex, education, chronic medical conditions, body mass index, smoking status, alcohol use, and their interactions with time. RESULTS: The interaction of depressive symptomology and GFAP (ß = -0.105 [standard error = 0.038], p = .006) on global cognitive function was statistically significant. Participants with depressive symptoms including and above the cutoff and high log of GFAP concentrations had more cognitive decline over time, followed by participants with depressive symptoms below the cutoff and high log of GFAP concentrations, depressive symptom scores including and above the cutoff and low log of GFAP concentrations, and depressive symptom scores below the cutoff and low log of GFAP concentrations. CONCLUSIONS: Depressive symptoms have an additive effect on the association between the log of GFAP and baseline global cognitive function.

Temporal Patterns of Change in Physical and Cognitive Performance.

BACKGROUND: This study examined the relation between declines in physical and cognitive performance in older people. METHODS: A population-based cohort of 7 483 adults (average age 72 years) were interviewed. Physical performance was assessed with 3 standardized tests and a combination of 4 cognitive tests was used to assess cognitive function. Rate of change in physical and cognitive performance was determined for each interval between interviews. In mixed effects linear regression models adjusted for age, sex, race, and study time, and change in each factor was used to predict change in the other factor. We examined time associations by using changes in the predictor measured at 1, 2, or 3 intervals before the outcome change. RESULTS: Decline in cognitive function was most strongly predicted by physical decline in the same 3-year interval. The decline in cognitive function was weaker in the 1-time interval after the decline in physical function and was not significant in later intervals. When a decline in cognitive function was used to predict a decline in physical function, the results were similar. The strongest association occurred in the same time interval so that declines in cognitive and physical performance tend to occur together. CONCLUSIONS: Decline in cognition and physical function seem to occur together in a short timeframe. It is important to investigate the reasons for these changes that are short-term to guide the development of interventions.

Association of Vitamin E and Cognitive Decline in Older Adults with and without the APOEɛ4 Allele: A Biracial Population-Based Community Study.

BACKGROUND: The association of different types of tocopherols (vitamin E) with cognition might vary by the APOEɛ4 allele status. OBJECTIVE: We examined the association of dietary tocopherols with cognitive decline among participants with and without the APOEɛ4 allele over a median of 12 years. METHODS: 2,193 participants from the Chicago Health and Aging Project were included in the analyses. Global cognition was assessed in three-year cycles. We used a 144-item FFQ to assess dietary intakes of tocopherols and hME Sequenom mass-array platform to assess APOE genotype. We used linear mixed effects models to examine the relationship between tocopherol from food sources and global cognitive decline. RESULTS: The mean baseline age was 74.1 (SD = 5.9) years. Among APOEɛ4 carriers, participants in the highest quintile of intakes of dietary vitamin E had a slower cognitive decline of 0.022 SDU (95% CI: 0.000, 0.043) compared to those in the lowest quintile. A higher intake of dietary α-tocopherol from food sources only was associated with slower cognitive decline in APOEɛ4 carriers (p for trend 0.002) but not among the non-carriers (p for trend 0.937). Among APOEɛ4 carriers, those in the highest quintile of intake of α-tocopherol had a 16.4% slower rate of decline of global cognition compared to those in the lowest quintile (ß= 0.034, 95% CI: 0.013, 0.054). CONCLUSIONS: Individuals consuming high α-tocopherol from food sources had slower cognitive decline among APOEɛ4 carriers. In older adults, different forms of vitamin E might moderate the relationship of APOEɛ4 with global cognition.

Association of Whole Grain Consumption and Cognitive Decline: An Investigation From a Community-Based Biracial Cohort of Older Adults.

BACKGROUND AND OBJECTIVES: To examine the association of whole grain consumption and longitudinal change in global cognition, perceptual speed, and episodic memory by different race/ethnicity. METHODS: We included 3,326 participants from the Chicago Health and Aging Project who responded to a Food Frequency Questionnaire (FFQ), with 2 or more cognitive assessments. Global cognition was assessed using a composite score of episodic memory, perceptual speed, and the Mini Mental State Examination (MMSE). Diet was assessed by a 144-item FFQ. Linear mixed-effects models were used to estimate the association of intakes of whole grains and cognitive decline. RESULTS: This study involved 3,326 participants (60.1% African American [AA], 63.7% female) with a mean age of 75 years at baseline and a mean follow-up of 6.1 years. Higher consumption of whole grains was associated with a slower rate of global cognitive decline. Among AA participants, those in the highest quintile of whole grain consumption had a slower rate of decline in global cognition (ß = 0.024, 95% CI [0.008-0.039], p = 0.004), perceptual speed (ß = 0.023, 95% CI [0.007-0.040], p = 0.005), and episodic memory (ß = 0.028, 95% CI [0.005-0.050], p = 0.01) compared with those on the lowest quintile. Regarding the amount consumed, in AA participants, those who consumed >3 servings/d vs those who consumed <1 serving/d had a slower rate of decline in global cognition (ß = 0.021, 95% CI [0.005-0.036], p = 0.0093). In White participants, with >3 servings/d, we found a suggestive association of whole grains with global cognitive decline when compared with those who consumed <1 serving/d (ß = 0.025, 95% CI [-0.003 to 0.053], p = 0.08). DISCUSSION: Among AA participants, individuals with higher consumption of whole grains and more frequent consumption of whole grain had slower decline in global cognition, perceptual speed, and episodic memory. We did not see a similar trend in White adults.

Neuroticism, physical activity, and cognitive functioning in a population-based cohort of older adults.

BACKGROUND: Little is known about how physical activity influences the relationship between neuroticism and cognitive function and cognitive decline. METHODS: Data from the Chicago Health and Aging Project (CHAP) was utilized to conduct this study. CHAP is a population-based cohort study of chronic conditions in older adults. Participants completed in-home interviews cycles of three years from 1993-2012. Mixed effects regression models were conducted to test the associations between physical activity, neuroticism, and the interaction between neuroticism and physical activity on outcomes: global cognitive function, global cognitive decline, episodic memory, decline in episodic memory, perceptual speed, and decline in perceptual speed. Stratified mixed effects regression models by physical activity level were conducted to test the associations between neuroticism and global cognitive function and global cognitive decline. RESULTS: A total of 7,685 participants were eligible for this study. Participants were 62% female and 64% African American. We found statistically significant associations for the interaction of high physical activity and neuroticism on baseline global cognitive function (ß = 0.017 (SE = 0.007), p = .010) and on the interaction of neuroticism and high physical activity on baseline episodic memory (ß = 0.020 (SE = .009), p = .021) and on decline in episodic memory over time (ß = -0.003 (SE = .001), p = .039). CONCLUSION: Higher physical activity lessened the association between higher neuroticism and poor cognitive outcomes.

Dietary Sugar Intake Associated with a Higher Risk of Dementia in Community-Dwelling Older Adults.

BACKGROUND: We have limited evidence for the relationship of high sugar intake with dementia risk. OBJECTIVE: To determine whether high sugar intake is associated with an increased risk of dementia in community-dwelling older adultsMethods:This study included 789 participants of the Rush Memory and Aging Project (community-based longitudinal cohort study of older adults free of known dementia at enrollment), with annual clinical assessments and complete nutrient data (obtained by validated food frequency questionnaire). Clinical diagnosis of dementia is based on the criteria of the joint working group of the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association. We used Cox proportional hazard models. RESULTS: 118 participants developed dementia during 7.3±3.8 years of follow-up. Those in the highest quintile of total sugar intake were twice as likely to develop dementia than those in the lowest quintile (Q5 versus Q1:HR=2.10 (95% CI: 1.05, 4.19) when adjusted for age, sex, education, APOEɛ4 allele, calories from sources other than sugar, physical activity, and diet score. Higher percent calories from sugar were positively associated with dementia risk (ß=0.042, p = 0.0009). In exploratory analyses, the highest versus lowest quintile of fructose and sucrose in the diet had higher dementia risk by 2.8 (95% CI: 1.38, 5.67) and 1.93 (95% CI: 1.05, 3.54) times, respectively. CONCLUSIONS: A higher intake of total sugar or total calories from sugar is associated with increased dementia risk in older adults. Among simple sugars, fructose (e.g., sweetened beverages, snacks, packaged desserts) and sucrose (table sugar in juices, desserts, candies, and commercial cereals) are associated with higher dementia risk.

Cardiovascular health and cognitive outcomes: Findings from a biracial population-based study in the United States.

INTRODUCTION: The aim of this study was to evaluate the association of cardiovascular health (CVH) with cognitive outcomes, including incident Alzheimer's dementia, rate of cognitive decline, and measures of brain injury and structure. METHODS: This study consisted of 1702 Black or African American and White participants living in the south side of Chicago, Illinois, and enrolled in the Chicago Health and Aging Project, a population-based cohort since 1993. CVH was based on seven risk factors, including diet, physical activity, body mass index, smoking, dyslipidemia, hypertension, and diabetes. RESULTS: In a multivariable-adjusted model, CVH was associated with a lower risk of Alzheimer's dementia. The hazard ratio per 1 additional point in CVH score was 0.84 (95% CI 0.76, 0.94). CVH was also associated with a slower rate of cognitive decline and less volume (injury) in white matter hyperintensities. DISCUSSION: Promoting CVH in communities with Black residents may lower the future risk of Alzheimer's dementia.

Prevalence of Alzheimer's disease dementia in the 50 US states and 3142 counties: A population estimate using the 2020 bridged-race postcensal from the National Center for Health Statistics.

INTRODUCTION: This study estimates the prevalence and number of people living with Alzheimer's disease (AD) dementia in 50 US states and 3142 counties. METHODS: We used cognitive data from the Chicago Health and Aging Project, a population-based study, and combined it with the National Center for Health Statistics 2020 bridged-race population estimates to determine the prevalence of AD in adults ≥65 years. RESULTS: A higher prevalence of AD was estimated in the east and southeastern regions of the United States, with the highest in Maryland (12.9%), New York (12.7%), and Mississippi (12.5%). US states with the highest number of people with AD were California, Florida, and Texas. Among larger counties, those with the highest prevalence of AD were Miami-Dade County in Florida, Baltimore city in Maryland, and Bronx County in New York. DISCUSSION: The state- and county-specific estimates could help public health officials develop region-specific strategies for caring for people with AD.

Serum neurofilament light chain, brain infarcts, and the risk of stroke: a prospective population-based cohort study.

Neurofilament light chain (NfL), a neuron-specific protein, has been related to several neurodegenerative diseases. In addition, elevated levels of NfL have also been observed in patients admitted to the hospital for stroke, suggesting that NfL as a biomarker may extend well beyond neurodegenerative diseases. Therefore, using data from the Chicago Health and Aging Project (CHAP), a population-based cohort study, we prospectively investigated the association of serum NfL levels with incident stroke and brain infarcts. During a follow-up of 3603 person-years, 133 (16.3%) individuals developed incident stroke, including ischemic and hemorrhagic. The HR (95%CI) of incident stroke was 1.28 (95%CI 1.10-1.50) per 1 standard deviation (SD) increase of log10 NfL serum levels. Compared to participants in the first tertile of NfL (i.e., lower levels), the risk of stroke was 1.68 times higher (95%CI 1.07-2.65) in those in the second tertile and 2.35 times higher (95%CI 1.45-3.81) in those in the third tertile of NfL. NfL levels were also positively associated with brain infarcts; 1-SD in log10 NfL levels was associated with 1.32 (95%CI 1.06-1.66) higher odds of one or more brain infarcts. These results suggest that NfL may serve as a biomarker of stroke in older adults.

Race and Apolipoprotein E-e4 Allele Status Differences in the Association Between Loneliness and Cognitive Decline.

OBJECTIVE: This study aimed to examine race and apolipoprotein E-e4 allele (APOE-e4) status differences in the longitudinal associations between loneliness and cognitive decline. METHODS: The study sample is composed of participants ( N = 7696, 64% Black participants and 36% White participants) from the Chicago Health and Aging Project, a population-based cohort study. Mixed-effects regression models were conducted to examine the longitudinal associations between loneliness on global cognitive function and individual tests of cognitive function. Models were also stratified by race and APOE-e4. RESULTS: A greater percentage of Black participants (17%) reported loneliness at baseline visit compared with White participants (12%). Black and White participants who were lonely individuals had a similar rate of decline in global cognitive function at 0.075 (95% confidence interval [CI] = -0.082 to -0.068) standard deviation unit (SDU) per year for Black participants and at 0.075 (95% CI = -0.086 to -0.063) SDU per year for White participants. Lonely participants with APOE-e4 had a higher rate of global cognitive decline at -0.102 (95% CI = -0.115 to -0.088) SDU per year than for lonely participants without APOE-e4 at -0.052 (95% CI = -0.059 to -0.045) SDU per year. CONCLUSIONS: The burden of loneliness and its relation to cognitive decline is higher among participants with APOE-e4 compared with those without APOE-e4. Loneliness is associated with cognitive decline in both Black and White participants.

Vitamin D intake and cognitive decline in Blacks and Whites: The role of diet and supplements.

INTRODUCTION: To determine the role of vitamin D intake on cognitive decline among Blacks and Whites. METHODS: Using data from the population-based Chicago Health and Aging Project, we studied 2061 Blacks and 1329 Whites with dietary vitamin D data and cognitive testing over 12 years of follow-up. Multivariable linear mixed-effects models were used to determine the association of vitamin D intake with cognitive decline. RESULTS: Vitamin D intake, particularly dietary vitamin D, was associated with a slower rate of decline in cognitive function among Blacks. In Blacks, comparing individuals in the lowest tertile of dietary intake, those in the highest tertile had a slower cognitive decline of 0.017 units/year (95% confidence interval 0.006, 0.027), independently of supplementation use. In Whites, vitamin D intake was not associated with cognitive decline. DISCUSSION: Dietary vitamin D may help to slow the decline in cognitive abilities among Blacks as they age.

White matter hyperintensity, neurofilament light chain, and cognitive decline.

OBJECTIVE: We aimed to determine whether combining white matter hyperintensity (WMH) with neurofilament light chain (NfL) could provide additional information for cognition in older adults. METHODS: Utilizing data from the population-based Chicago Health and Aging Project, we studied 701 individuals with both biomarkers and cognitive data during the follow-up period. NfL was measured using an ultrasensitive immunoassay, single-molecule array technology. MRI scans of the brain were acquired using 1.5-T systems. Global cognitive function was created as a composite measure of four neuropsychological tests, standardized and averaged to z-scores. Multivariable linear mixed-effects models were used to evaluate the association of WMH and NfL with the rate of cognitive decline. RESULTS: Higher WMH and NfL were associated with a faster rate of cognitive decline during the follow-up; ß -coefficients (95%CIs) were -0.011 (-0.02, -0.001) and -0.010 (-0.017, -0.003), respectively. In individuals with lower concentration of NfL (i.e., bottom tertile), a higher WMH volume was associated with a faster cognitive decline ( ß : -0.030; 95%CI -0.046, -0.014). Similarly, in individuals with lower volumes of WMH (i.e., bottom tertile), a higher concentrations of NfL was associated with a faster cognitive decline ( ß : -0.023; 95%CI -0.042, -0.005). When we combined WMH with NfL, we noted a graded association with increasing volumes of WMH, particularly in people with lower NfL values. INTERPRETATION: While both biomarkers, WMH and NfL, were similarly associated with the annual rate of cognitive decline, our study suggests that they provide different underlying mechanisms affecting cognition.

Longitudinal Changes in Blood Biomarkers of Clinical Alzheimer Disease in a Biracial Population Sample.

BACKGROUND AND OBJECTIVES: Recent studies suggest the utility of blood biomarkers in detecting changes in neurodegenerative disorders. The objective of our research was to test the hypothesis that the longitudinal changes in total tau (t-tau), neurofilament light chain (Nf-L), and glial fibrillary acidic protein (GFAP) are associated with structural MRI and the development of clinical Alzheimer disease (AD) and cognitive decline. METHODS: Data came from a population-based sample with serum concentrations of t-tau, Nf-L, and GFAP and cognitive characteristics measured over 17 years. The inclusion criteria for this investigation were based on participants with blood samples, cognitive function testing, and clinical diagnosis for AD. The longitudinal changes in the serum biomarkers were examined using linear mixed models for log10-transformed concentrations. RESULTS: In 1,327 participants (60% Black participants and 60% women, the concentration of t-tau increased annually by 4.8% (95% CI = 4.0-5.6) and Nf-L by 5.9% (95% CI = 5.4-6.4). The longitudinal change in GFAP was higher among Black participants than among White participants (4.4% vs 3.5% per year, p = 0.028). Baseline MRI characteristics were associated with the longitudinal changes in serum biomarkers of clinical AD. Specifically, a higher baseline third ventricular volume was associated with a higher rate of increase in the concentration of t-tau, and white matter hyperintensities predicted a higher rate of increase in Nf-L. The rate of change in concentrations of t-tau, Nf-L, and GFAP was significantly higher among those who developed clinical AD than in those with no cognitive impairment. For each standard deviation unit decline in global cognition, longitudinal change in t-tau increased by 81% (95% CI = 76-86), Nf-L by 113% (95% CI = 105-120), and GFAP by 66% (95% CI = 62-70). DISCUSSION: Blood biomarkers showed significant longitudinal changes corresponding to cognitive decline, clinical AD, and structural MRI characteristics. Our findings show that longitudinal changes in serum biomarkers were associated with several cognitive endophenotypes. CLASSIFICATION OF EVIDENCE: The study found Class II evidence that longitudinal changes in serum t-tau, Nf-L, and GFAP were associated with cognitive decline and the development of clinical AD in people older than 65 years.

Lifestyle and Cognitive Decline in Community-Dwelling Stroke Survivors.

BACKGROUND: Patients with stroke are at a higher risk of cognitive impairment and Alzheimer's disease dementia. OBJECTIVE: To quantify the role of lifestyle pre-stroke, post-stroke, and changes in lifestyle before and after stroke with cognitive decline in community-dwelling stroke survivors. METHODS: Utilizing data from the Chicago Health and Aging Project, a population-based cohort study, we studied 1,078 individuals with stroke (662 incident and 416 prevalent) who underwent cognitive testing during the study period. A healthy lifestyle score was defined by scoring four behaviors: non-smoking, exercising, being cognitively active, and having a high-quality diet. The global cognitive score was derived from a comprehensive battery of 4 standardized tests. RESULTS: The mean age at incident stroke was 78.2 years, and 60.1% were women. A healthy lifestyle pre-incident stroke was associated with a slower rate of cognitive decline after stroke. Participants with 3-4 healthy lifestyle factors pre-incident stroke had a slower cognitive decline after stroke by 0.046 units/year (95% CI 0.010, 0.083), or 47.7% slower, than participants with 0-1 healthy lifestyle factor. Lifestyle score post-prevalent stroke was not associated with cognitive decline. Changes in lifestyle behaviors from pre- to post-incident stroke were related to cognitive decline after stroke. Individuals who deteriorated their lifestyle quality after stroke had a faster cognitive decline by 0.051 units/year (ß -0.051, 95% CI -0.090, -0.012) than participants with no change in lifestyle score. CONCLUSION: A healthy lifestyle pre-stroke was associated with a slower rate of cognitive decline in stroke survivors, highlighting the importance of primary prevention. After the stroke, changes in lifestyle behaviors may influence the cognitive abilities of older adults as they age.

A healthy plant-based diet was associated with slower cognitive decline in African American older adults: a biracial community-based cohort.

BACKGROUND: African American (AA) adults have about twice the risk of developing dementia compared with white adults. However, evidence on dietary modification in preventing cognitive decline from diverse populations focusing on AA adults is minimal. OBJECTIVES: We aimed to evaluate the association between a plant-based diet and the rate of cognitive decline in a population-based sample of AA and white adults. METHODS: This study consisted of 3337 participants from the Chicago Health and Aging Project (60% AA participants, 64% female). Plant-based diet quality was evaluated by the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI). Global cognition was assessed using a composite score of 4 individual tests of cognition. We used mixed models to examine the associations of PDI, hPDI, and uPDI with the rates of decline in global cognition, perceptual speed, and episodic memory. Models were adjusted for age, sex, presence of apoE e4 allele, lifestyle factors including education, cognitive activities, smoking status, calorie intake, risk factors for cardiovascular disease, time, and the interaction terms of time × each covariate. RESULTS: AA and white participants had various dietary patterns. Higher hPDI was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA participants but not white participants. AA study participants in the highest quintile of hPDI had significantly slower rates of global cognitive decline (ß: 0.0183 ± 0.0086; P = 0.032), perceptual speed (ß: 0.0179 ± 0.0088; P = 0.04), and episodic memory (ß: 0.0163 ± 0.0118; P = 0.04) than individuals in the lowest quintile of hPDI. There were no associations of either PDI or uPDI with the rate of cognitive decline in either racial group. CONCLUSIONS: A healthy plant-based diet was associated with a slower rate of decline in global cognition, perceptual speed, and episodic memory in AA adults.

Association of Subjective Memory Complaints With White Matter Hyperintensities and Cognitive Decline Among Older Adults in Chicago, Illinois.

Importance: Subjective memory complaints (SMCs) are associated with a faster cognitive decline; whether this association is also associated with structural brain alterations, such as white matter hyperintensity (WMH) volumes, requires investigation. Objective: To evaluate the association of SMCs with WMH volumes and cognitive decline and investigate the role of WMH volumes in the association between SMCs and cognitive decline. Design, Setting, and Participants: The Chicago Health and Aging Project, a population-based cohort study, enrolled adults aged 65 years or older. Data collection occurred in 3-year cycles from 1993 until 2012. Our study comprised 975 participants with magnetic resonance imaging assessments, of which 900 participants had data on SMCs and covariates, and 713 participants provided 2 or more cognitive assessments during the follow-up. Statistical analyses were conducted from May to October 2021. Exposures: SMCs were obtained from self-reported questionnaire data during clinical evaluations, and the cycle, when reported, constituted the baseline of our study. Based on the frequency and severity of concerns, we categorized participants into 3 groups, (1) no concerns, (2) moderate concerns, and (3) very worried. Main Outcomes and Measures: Volumetric magnetic resonance imaging measures of WMH volume and neuropsychological testing assessments of global cognition. Linear regression analysis was used to investigate the association between SMCs and WMH volumes in a multivariable model adjusted for age, sex, race and ethnicity, education, APOE4 status, and total intracranial volume. The association of SMCs with cognitive decline was investigated using linear mixed-effects models for age, sex, race and ethnicity, education, APOE4 status, follow-up time, and each variable in interaction with time to estimate the annual longitudinal change in cognitive function. Results: Of the 900 participants with data on SMCs, covariates, and WMH volumes, 553 (61.4%) were women, 539 (59.9%) were African American, and the mean (SD) age was 79.5 (6.2) years. SMCs were associated with a larger WMH volume and faster cognitive decline. Compared with participants with no concerns, participants who were very worried had higher WMH volumes (ß = 0.833; 95% CI, 0.203-1.463) and 174% faster cognitive decline (ß = -0.049; 95% CI, -0.076 to -0.022). The association between SMCs and cognitive decline remained statistically significant among individuals with large WMH volumes (ie, within the fourth quartile). Within the fourth quartile of WMH volumes, participants who were very worried had 428% faster cognitive decline (ß = -0.077; 95% CI, -0.144 to -0.011) compared with participants with no concerns. Conclusions and Relevance: This cohort study suggests that SMCs, frequently reported by older individuals, are an important sign of cognitive impairment, especially among people with abnormalities in brain structure, such as larger WMH volumes.