Studies examining the link between objective measures of total daily physical activity and incident Alzheimer disease (AD) are lacking. We tested the hypothesis that an objective measure of total ...daily physical activity predicts incident AD and cognitive decline.
Total daily exercise and nonexercise physical activity was measured continuously for up to 10 days with actigraphy (Actical®; Philips Healthcare, Bend, OR) from 716 older individuals without dementia participating in the Rush Memory and Aging Project, a prospective, observational cohort study. All participants underwent structured annual clinical examination including a battery of 19 cognitive tests.
During an average follow-up of about 4 years, 71 subjects developed clinical AD. In a Cox proportional hazards model adjusting for age, sex, and education, total daily physical activity was associated with incident AD (hazard ratio = 0.477; 95% confidence interval 0.273-0.832). The association remained after adjusting for self-report physical, social, and cognitive activities, as well as current level of motor function, depressive symptoms, chronic health conditions, and APOE allele status. In a linear mixed-effect model, the level of total daily physical activity was associated with the rate of global cognitive decline (estimate 0.033, SE 0.012, p = 0.007).
A higher level of total daily physical activity is associated with a reduced risk of AD.
The impact of cardiovascular risk burden on cognitive trajectories and brain structure changes remains unclear.
This study aimed to examine whether cardiovascular risk burden assessed by the ...Framingham General Cardiovascular Risk Score (FGCRS) is associated with cognitive decline and structural brain differences.
Within the Rush Memory and Aging Project, 1,588 dementia-free participants (mean age: 79.5 years) were followed for up to 21 years. FGCRS was assessed at baseline and categorized into tertiles (lowest, middle, and highest). Episodic memory, semantic memory, working memory, visuospatial ability, and perceptual speed were assessed annually with a battery of 19 tests, from which composite scores were derived. A subsample (n = 378) of participants underwent magnetic resonance imaging. Structural total and regional brain volumes were estimated. Data were analyzed using linear mixed-effects models and linear regression models.
In all participants, FGCRS ranged from 4 to 28 (mean score: 15.6 ± 3.7). Compared with the lowest tertile of FGCRS, the highest tertile was associated with faster decline in global cognition (β = −0.019; 95% confidence interval CI: −0.035 to −0.003), episodic memory (β = −0.023; 95% CI: −0.041 to −0.004), working memory (β = −0.021; 95% CI: −0.035 to −0.007), and perceptual speed (β = −0.027; 95% CI: −0.042 to −0.011) over the follow-up. In magnetic resonance imaging data analyses, higher FGCRS was related to smaller volumes of the hippocampus (β = −0.021; 95% CI: −0.042 to −0.000), gray matter (β = −1.569; 95% CI: −2.757 to −0.382), and total brain (β = −1.588; 95% CI: −2.832 to −0.344), and greater volume of white matter hyperintensities (β = 0.035; 95% CI: 0.001 to 0.069).
Higher cardiovascular risk burden may predict decline in episodic memory, working memory, and perceptual speed and is associated with neurodegeneration and vascular lesions in the brain.
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We tested the hypothesis that impaired kidney function in the elderly is associated with a more rapid rate of cognitive decline.
Baseline serum was used to calculate estimated glomerular filtration ...rate (eGFR), using the Modification of Diet in Renal Disease formula, for 886 elderly without dementia participating in the Rush Memory and Aging Project, a prospective, observational cohort study. Kidney function was also dichotomized into impairment or no impairment based on eGFR < or >or=60 mL/min/1.73 m(2). Structured cognitive testing was performed at baseline and at annual evaluations, using a battery of 19 cognitive tests summarized into global cognition and 5 cognitive domains.
In mixed-effects models adjusted for age, sex, and education, a lower eGFR at baseline was associated with a more rapid rate of cognitive decline (estimate 0.0008, SE <0.001, p = 0.017). The increased rate of cognitive decline associated with a 15-mL/min/1.73 m(2) lower eGFR at baseline (approximately 1 SD) was similar to the effect of being 3 years older at baseline. Impaired kidney function at baseline was associated with a more rapid rate of cognitive decline (estimate -0.028, SE <0.009, p = 0.003). The increased rate of cognitive decline associated with impaired kidney function at baseline was approximately 75% the effect of ApoE4 allele on the rate of cognitive decline. Baseline kidney function was associated with declines in semantic memory, episodic memory, and working memory but not visuospatial abilities or perceptual speed.
Impaired kidney function is associated with a more rapid rate of cognitive decline in old age.
Background
In old age, motor impairments including parkinsonian signs are common, but treatment is lacking for many older adults. In this study, we examined the association of a diet specifically ...developed to promote brain health, called MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay), to the incidence and progression of parkinsonism in older adults.
Methods
A total of 706 Memory and Aging Project participants aged 59–97 years and without parkinsonism at baseline were assessed annually for the presence of four parkinsonian signs using a 26-item modified version of the United Parkinson’s Disease Rating Scale. Incident parkinsonism was defined as the first occurrence over 4.6 years of follow-up of two or more parkinsonian signs. The progression of parkinsonism was assessed by change in a global parkinsonian score (range: 0-100). MIND, Mediterranean, and DASH diet pattern scores were computed based on a validated food frequency questionnaire including 144 food items. We employed Cox-Proportional Hazard models and linear mixed models, to examine the associations of baseline diet scores with incident parkinsonism and the annual rate of change in global parkinsonian score, respectively.
Results
In models adjusted for age, sex, smoking, total energy intake, BMI and depressive symptoms, higher MIND diet scores were associated with a decreased risk of parkinsonism (HR=0.89, 95% CI 0.83-0.96); and a slower rate of parkinsonism progression (β= -0.008; SE=0.0037; p=0.04). The Mediterranean diet was marginally associated with reduced parkinsonism progression (β= -0.002; SE=0.0014; p=0.06). The DASH diet, by contrast, was not associated with either outcome.
Conclusion
The MIND diet created for brain health may be a associated with decreased risk and slower progression of parkinsonism in older adults.
Gravity Probe B, launched 20 April 2004, is a space experiment testing two fundamental predictions of Einstein's theory of general relativity (GR), the geodetic and frame-dragging effects, by means ...of cryogenic gyroscopes in Earth orbit. Data collection started 28 August 2004 and ended 14 August 2005. Analysis of the data from all four gyroscopes results in a geodetic drift rate of -6601.8±18.3 mas/yr and a frame-dragging drift rate of -37.2±7.2 mas/yr, to be compared with the GR predictions of -6606.1 mas/yr and -39.2 mas/yr, respectively ("mas" is milliarcsecond; 1 mas=4.848×10(-9) rad).
To test the hypothesis that level of hemoglobin is associated with incident Alzheimer disease (AD).
A total of 881 community-dwelling older persons participating in the Rush Memory and Aging Project ...without dementia and a measure of hemoglobin level underwent annual cognitive assessments and clinical evaluations for AD.
During an average of 3.3 years of follow-up, 113 persons developed AD. In a Cox proportional hazards model adjusted for age, sex, and education, there was a nonlinear relationship between baseline level of hemoglobin such that higher and lower levels of hemoglobin were associated with AD risk (hazard ratio HR for the quadratic of hemoglobin 1.06, 95% confidence interval CI 1.01-1.11). Findings were unchanged after controlling for multiple covariates. When compared to participants with clinically normal hemoglobin (n = 717), participants with anemia (n = 154) had a 60% increased hazard for developing AD (95% CI 1.02-2.52), as did participants with clinically high hemoglobin (n = 10, HR 3.39, 95% CI 1.25-9.20). Linear mixed-effects models showed that lower and higher hemoglobin levels were associated with a greater rate of global cognitive decline (parameter estimate for quadratic of hemoglobin = -0.008, SE -0.002, p < 0.001). Compared to participants with clinically normal hemoglobin, participants with anemia had a -0.061 z score unit annual decline in global cognitive function (SE 0.012, p < 0.001), as did participants with clinically high hemoglobin (-0.090 unit/year, SE 0.038, p = 0.018).
In older persons without dementia, both lower and higher hemoglobin levels are associated with an increased hazard for developing AD and more rapid cognitive decline.
To examine the association of change in body mass index (BMI) with risk of Alzheimer disease (AD).
Nine hundred eighteen older Catholic clergy participating in the Religious Orders Study without ...dementia at baseline were studied. Outcome measures were the clinical diagnosis of AD and change in cognitive function.
During a mean follow-up of 5.5 years, 151 persons developed AD. BMI averaged 27.4 at baseline and declined in about half the participants. In a proportional hazards model adjusted for age, sex, and education, each 1-unit less of BMI at baseline was associated with about a 5% increase in the risk of AD (hazard ratio = 0.944; 95% CI = 0.908 to 0.981), and each 1-unit annual decline in BMI (about the 10th percentile) was associated with about a 35% increase in the risk of AD compared with a person experiencing no change in BMI (about the 50th percentile) (hazard ratio = 0.730; 95% CI = 0.625 to 0.852). The results were similar after controlling for chronic diseases and excluding persons who developed AD during the first 4 years of observation. Random effects models showed that the rate of cognitive decline increased by about 8% for each 1-unit less of BMI at baseline and declined an additional 40%/year in persons losing 1 unit of BMI/year compared with those with no change in BMI.
Declining body mass index (BMI) is associated with increased risk of incident Alzheimer disease (AD). Loss of BMI may reflect pathologic processes that contribute to the subsequent development of AD.
To assess the association between purpose in life and all-cause mortality in community-dwelling elderly persons.
We used data from 1238 older persons without dementia from two longitudinal cohort ...studies (Rush Memory and Aging Project and Minority Aging Research Study) with baseline evaluations of purpose in life and up to 5 years of follow-up to test the hypothesis that greater purpose in life is associated with a reduced risk of mortality among community-dwelling older persons.
The mean +/- standard deviation score on the purpose in life measure at baseline was 3.7 +/- 0.5 (range = 2-5), with higher scores indicating greater purpose in life. During the 5-year follow-up (mean = 2.7 years), 151 of 1238 persons (12.2%) died. In a proportional hazards model adjusted for age, sex, education, and race, a higher level of purpose in life was associated with a substantially reduced risk of mortality (hazard ratio = 0.60, 95% Confidence Interval = 0.42, 0.87). Thus, the hazard rate for a person with a high score on the purpose in life measure (score = 4.2, 90th percentile) was about 57% of the hazard rate of a person with a low score (score = 3.1, 10th percentile). The association of purpose in life with mortality did not differ among men and women or whites and blacks. Further, the finding persisted after the addition of terms for several potential confounders, including depressive symptoms, disability, neuroticism, the number of chronic medical conditions, and income.
Greater purpose in life is associated with a reduced risk of all-cause mortality among community-dwelling older persons.
We tested the hypothesis that a higher level of social activity was associated with decreased risk of incident disability in older adults.
Data came from older adults in the Rush Memory and Aging ...Project, an ongoing longitudinal cohort study of aging. Analyses were restricted to persons without clinical dementia and reporting no need for help performing any task in the particular functional domain assessed. Participants were followed for an average of 5.1 years (SD = 2.5). Social activity, based on 6 items (visiting friends or relatives; going to restaurants, sporting events, or playing games; group meetings; church/religious services; day or overnight trips; unpaid community/volunteer work), was assessed at baseline. Disability in basic activities of daily living, mobility disability, and instrumental activities of daily living was assessed annually. Proportional hazard models adjusted for age, sex, and education were used to examine the association between social activity and incident disability. Fully adjusted models included terms for depression, vascular diseases and risk factors, body mass index, social networks, and self-reported physical activity.
In fully adjusted models, among 954 persons without baseline disability, the risk of developing disability in activities of daily living decreased by 43% (hazard ratio = 0.57, 95% confidence interval = 0.46, 0.71) for each additional unit of social activity. Social activity was also associated with decreased risk of developing mobility disability (hazard ratio = 0.69, 95% confidence interval = 0.54, 0.88) and disability in instrumental activities of daily living (hazard ratio = 0.71, 95% confidence interval = 0.55, 0.93).
Social activity is associated with a decreased risk of incident disability in activities of daily living, mobility, and instrumental activities of daily living, among community-dwelling older adults.
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