Examination of a Composite Walking Measure on Cognitive Functioning Among Participants in the Chicago Health and Aging Project.

This study examined the relationship between walking and cognitive function among Chicago Health and Aging Project participants. Data collection occurred during six 3-year cycles, of which Cycles 4-6 were used for this specific analysis. Information was obtained regarding walking frequency and duration, demographics, chronic conditions, cognitive activities, apolipoprotein E4, physical function, and cognitive function (global and domains). A composite walking measure was developed and categorized as follows: no walking, ≤105 min/week, and >105 min/week. Mixed-effects regression analyses tested associations between walking and global cognitive function, episodic memory, and perceptual speed. The sample consisted of 4,320 participants (African American/Black: 65%; female: 65%; mean education: 13 years; mean age: 75 years). Composite or total walking had a statistically significant association with global cognitive function and perceptual speed, after adjustments were made.

Dietary antioxidants associated with slower progression of parkinsonian signs in older adults.

Background and Objective: Progressive loss of motor function including parkinsonian signs is common in older adults. As diet may contribute to the motor decline, we tested the hypothesis that dietary intake of antioxidant nutrients (carotenoids, vitamin E and vitamin C) is related to the progression of parkinsonian signs in older adults.Research Design and Methods: A total of 682 participants without a clinical diagnosis of Parkinson's Disease from the Rush Memory and Aging Project, were assessed annually over an average of 5.7 (±3.0) years using a 26-item modified version of the United Parkinson's Disease Rating Scale. The scale assesses the severity of four parkinsonian signs (bradykinesia, gait, tremors, and rigidity) that were averaged to construct a global parkinsonian sign score. Nutrient intakes were assessed at baseline using a validated food frequency questionnaire. The associations between quintiles of antioxidant nutrient intakes and progression of parkinsonian signs were assessed using mixed effects models adjusted for age, sex, education, smoking.Results: In separate adjusted models, a slower rate of progressive parkinsonian signs was observed among those in the highest intake quintiles of total carotenoids (ß= -0.06, 95%CI: -0.10 to -0.02,), beta-carotene from foods (ß= -0.04, 95% CI:-0.08 to -0.0021), lutein-zeaxanthin (ß= -0.05, 95%CI:-0.09 to -0.02), vitamin E from foods (ß= -0.04, 95%CI:-0.08 to -0.01,) and vitamin C from foods (ß= -0.06, 95%CI:-0.10 to -0.02), when compared to those in the lowest quintiles of intake.Conclusion: A higher level of dietary antioxidant nutrients may slow the rate of parkinsonian sign progression in older adults.

Impact of the Apolipoprotein E ε4 Allele on the Relationship Between Healthy Lifestyle and Cognitive Decline: A Population-Based Study.

Adherence to a healthy lifestyle-characterized by abstaining from smoking, being physically and cognitively active, having a high-quality diet, and limiting alcohol use-is associated with slower cognitive decline in older adults, but whether this relationship extends to persons with a genetic predisposition (e.g., carriers of the ε4 allele of the apolipoprotein E gene (APOE*E4)) remains uncertain. Using data from a population-based study, the Chicago Health and Aging Project (Chicago, Illinois), we followed 3,886 individuals who underwent regular clinical and cognitive assessments from 1993 to 2012. Of 3,886 older adults, 1,269 (32.7%) were APOE*E4 carriers. Compared with noncarriers, APOE*E4 carriers had faster cognitive decline (ß = -0.027 units/year, 95% confidence interval (CI): -0.032, -0.023). In contrast, persons with 2-3 and 4-5 healthy lifestyle factors had slower cognitive decline (ß = 0.008 units/year (95% CI: 0.002, 0.014) and ß = 0.019 units/year (95% CI: 0.011, 0.026), respectively) compared with those with 0-1 factor. In analyses stratified by APOE*E4 status, adherence to a healthy lifestyle (e.g., 4-5 factors vs. 0-1 factors) was associated with a slower rate of cognitive decline in both APOE*E4 carriers (ß = 0.029, 95% CI: 0.013, 0.045) and noncarriers (ß = 0.013, 95% CI: 0.005, 0.022). These results underscore the impact of a healthy lifestyle on cognition, particularly among persons with a genetic predisposition, who are more vulnerable to cognitive decline as they age.

Racial Differences in Dietary Relations to Cognitive Decline and Alzheimer's Disease Risk: Do We Know Enough?

The elderly population in the US is increasing and projected to be 44% minority by 2060. African Americans and Hispanics are at increased risk of cognitive impairment and Alzheimer's disease compared to non-Hispanic whites. These conditions are associated with many other adverse health outcomes, lower quality of life, and substantial economic burden. In the past few decades, diet has been identified as an important modifiable risk factor for cognitive decline and Alzheimer's disease. Some studies report poor diet quality among African American and Hispanic older adult populations compared to their white counterparts. We have a limited understanding of how diet affects brain health in different racial-ethnic groups. One primary reason for our lack of knowledge is that most cohort studies are of majority non-Hispanic white participants. Moreover, those that do include minority participants do not publish their findings stratified by racial-ethnic groups, and likely have a less accurate measurement of dietary intake among minority groups. In this review, we summarize the current, albeit limited, literature on racial/ethnic differences in dietary relations to dementia outcomes. We will also discuss methodological issues in conducting nutrition studies in diverse cultures, and suggestions for future research directions. Overcoming the gaps will make it possible to make dietary recommendations for Alzheimer's prevention that are more relevant for different racial/ethnic groups and set us on a faster track to reduce health disparities.

Healthy lifestyle and the risk of Alzheimer dementia: Findings from 2 longitudinal studies.

OBJECTIVE: To quantify the impact of a healthy lifestyle on the risk of Alzheimer dementia. METHODS: Using data from the Chicago Health and Aging Project (CHAP; n = 1,845) and the Rush Memory and Aging Project (MAP; n = 920), we defined a healthy lifestyle score on the basis of nonsmoking, ≥150 min/wk moderate/vigorous-intensity physical activity, light to moderate alcohol consumption, high-quality Mediterranean-DASH Diet Intervention for Neurodegenerative Delay diet (upper 40%), and engagement in late-life cognitive activities (upper 40%), giving an overall score ranging from 0 to 5. Cox proportional hazard models were used for each cohort to estimate the hazard ratio (HR) and 95% confidence interval (CI) of the lifestyle score with Alzheimer dementia, and a random-effect meta-analysis was used to pool the results. RESULTS: During a median follow-up of 5.8 years in CHAP and 6.0 years in MAP, 379 and 229 participants, respectively, had incident Alzheimer dementia. In multivariable-adjusted models, the pooled HR (95% CI) of Alzheimer dementia across 2 cohorts was 0.73 (95% CI 0.66-0.80) per each additional healthy lifestyle factor. Compared to participants with 0 to 1 healthy lifestyle factor, the risk of Alzheimer dementia was 37% lower (pooled HR 0.63, 95% CI 0.47-0.84) in those with 2 to 3 healthy lifestyle factors and 60% lower (pooled HR 0.40, 95% CI 0.28-0.56) in those with 4 to 5 healthy lifestyle factors. CONCLUSION: A healthy lifestyle as a composite score is associated with a substantially lower risk of Alzheimer's dementia.

Self-reported health behaviors and longitudinal cognitive performance in late middle age: Results from the Wisconsin Registry for Alzheimer's Prevention.

BACKGROUND: Studies have suggested associations between self-reported engagement in health behaviors and reduced risk of cognitive decline. Most studies explore these relationships using one health behavior, often cross-sectionally or with dementia as the outcome. In this study, we explored whether several individual self-reported health behaviors were associated with cognitive decline when considered simultaneously, using data from the Wisconsin Registry for Alzheimer's Prevention (WRAP), an Alzheimer's disease risk-enriched cohort who were non-demented and in late midlife at baseline. METHOD: We analyzed longitudinal cognitive data from 828 participants in WRAP, with a mean age at baseline cognitive assessment of 57 (range = 36-78, sd = 6.8) and an average of 6.3 years (standard deviation = 1.9, range = 2-10) of follow-up. The primary outcome was a multi-domain cognitive composite, and secondary outcomes were immediate/delayed memory and executive function composites. Predictors of interest were self-reported measures of physical activity, cognitive activity, adherence to a Mediterranean-style diet (MIND), and interactions with each other and age. We conducted linear mixed effects analyses within an Information-theoretic (IT) model averaging (MA) approach on a set of models including covariates and combinations of these 2- and 3-way interactions. The IT approach was selected due to the large number of interactions of interest and to avoid pitfalls of traditional model selection approaches. RESULTS: Model-averaged results identified no significant self-reported health behavior*age interactions in relationship to the primary composite outcome. In secondary outcomes, higher MIND diet scores associated with slower decline in executive function. Men showed faster decline than women on delayed memory, independent of health behaviors. There were no other significant interactions among any other health behaviors and cognitive trajectories. CONCLUSIONS: When multiple covariates and health behaviors were considered simultaneously, there were limited weak associations with cognitive decline in this age range. These results may be explained alone or in combination by three alternative explanations: 1) the range of cognitive decline is in middle age is too small to observe relationships with health behaviors, 2) the putative associations of these health behaviors on cognition may not be robust in this age range, or 3) the self-reported measures of the health behaviors may not be optimal for predicting cognitive decline. More study may be needed that incorporates sensitive measures of health behaviors, AD biomarker profiles, and/or other disease comorbidities.

Brain Bromine Levels Associated with Alzheimer's Disease Neuropathology.

BACKGROUND: Bromine is a naturally occurring element that is widely present in the human environment in various chemical forms primarily as flame retardants, pesticides, and water treatments. OBJECTIVE: In this exploratory study, we investigated the association of brain bromine concentrations on Alzheimer's disease (AD) neuropathology, cerebral infarcts, and Lewy bodies. METHODS: The study was conducted in 215 deceased participants of the Memory and Aging Project, a clinical-pathologic cohort study. Brain bromine levels were measured using instrumental neutron activation analysis. Multiple brain regions were assessed for diffuse and neuritic plaques, neurofibrillary tangles, cerebral macro-and microinfarcts, and Lewy bodies. Standardized measures of AD pathology (Braak, CERAD, NIA-Reagan, global AD pathology) were computed. RESULTS: In linear regression models, the higher brain bromine levels were associated with more AD neuropathology (Braak (p trend = 0.01); CERAD (p trend = 0.02); NIA-Reagan (p trend = 0.02). CONCLUSION: Bromine accumulation in the brain is associated with higher level of AD neuropathology. The potential deleterious effects of this element on AD need further exploration.

Determination of Vitamin D and Its Metabolites in Human Brain Using an Ultra-Pressure LC-Tandem Mass Spectra Method.

BACKGROUND: Low serum total 25-hydroxyvitamin D3 [25(OH)D3] concentrations have been associated with cognitive impairment. However, it is unclear if serum 25(OH)D3 concentrations are a valid indicator of the concentrations of vitamin D and its metabolites in human brain. OBJECTIVES: The aim of this study was to develop and validate a method to quantify vitamin D3, 25(OH)D3, and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] in human brain. METHODS: The assay developments were performed using porcine brains. Liquid extraction was used in homogenized samples (∼0.1 g each) prior to analysis by LC-MS/MS with electrospray ionization following derivatization with 4-phenyl-1,2,4-triazoline-3,5-dione. This method was then applied to the determination of vitamin D and its metabolites in a whole human brain obtained from the National Development and Research Institutes. RESULTS: The method showed good linearity of vitamin D3, 25(OH)D3, and 1,25(OH)2D3 over the physiological range (R 2 = 0.9995, 0.9968, and 0.9970, respectively). The lowest detection limit for vitamin D3, 25(OH)D3, and 1,25(OH)2D3 in porcine brain was 25, 50 and 25 pg/g, respectively. The method was successfully applied to the determination of vitamin D3 and its metabolites in the prefrontal cortex, middle frontal cortex, middle temporal cortex, cerebellum, corpus callosum, medulla, and pons of a human brain. All analyzed human brain regions contained 25(OH)D3, with corpus callosum containing 334 pg/g compared with 158 pg/g in cerebellum. 1,25(OH)2D3 was only detected in prefrontal and middle frontal cortices at a very low level. No vitamin D3 was detected in any examined areas of this single human brain. CONCLUSIONS: To the best of our knowledge, this study is the first report of the measurement of concentrations of vitamin D metabolites in human brain. This validated method can be applied to postmortem studies to obtain accurate information about the presence and role of vitamin D and its metabolites in human brain and neurodegenerative diseases.

Dietary Patterns and Self-reported Incident Disability in Older Adults.

BACKGROUND OR OBJECTIVES: Disability in older adults is associated with low quality of life and higher mortality. Diet may be a potentially important public health strategy for disability prevention in aging. We examined the relations of the Mediterranean, Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diets to functional disability in the Rush Memory and Aging Project. METHODS: A total of 809 participants (mean age = 80.7 ± 7.2 years, 74% female) without functional disability at baseline were followed for an average of 5.3 years. Standardized measures for self-reported disability including, activities of daily living ADL), instrumental ADL, and mobility disability were assessed annually. The diet scores were computed based on a validated food frequency questionnaire administered at baseline. RESULTS: In Cox proportional hazards models adjusted for age, sex, education, smoking, physical activity, and total calories, the second (hazard ratio = 0.75, 95% CI: 0.60-0.95) and third tertiles (hazard ratio = 0.67, 95% CI: 0.53-0.86) of MIND diet scores had lower rates of ADL disability compared to the lowest tertile (p for trend = .001), whereas only the third tertiles of the Mediterranean (hazard ratio = 0.73, 95% CI: 0.57-0.94) and DASH (hazard ratio = 0.75, 95% CI: 0.59-0.95) diets were significantly associated with ADL disability. Instrumental ADL disability was inversely and linearly associated with the MIND diet score only (p for trend = .04). Mobility disability was associated with the MIND (p for trend = .02), Mediterranean (p for trend = .05) and DASH (p for trend = .02) diet scores. CONCLUSION: These findings are encouraging that diet may be an effective strategy for the prevention of functional disability in older adults.

Relation of DASH- and Mediterranean-like dietary patterns to cognitive decline in older persons.

OBJECTIVES: We examined whether accordance to the DASH (Dietary Approach to Stop Hypertension) and Mediterranean diets is associated with slower cognitive decline in a prospective Chicago cohort study of older persons, the Memory and Aging Project. METHODS: The sample comprised 826 Memory and Aging Project participants (aged 81.5 ± 7.1 years) who completed a 144-item food frequency questionnaire at baseline and 2 or more cognitive assessments over 4.1 years. Dietary scores were computed for accordance to the DASH diet (0-10) and the Mediterranean diet (MedDietScore) (0-55). For both, higher scores reflect greater accordance. Both patterns share at least 3 common food components. Cognitive function was assessed annually with 19 cognitive tests from which global cognitive scores and summary measures are computed. RESULTS: The mean global cognitive score at baseline was 0.12 (range, -3.23 to 1.60) with an overall mean annual change in score of -0.08 standardized units. Only 13 participants had possible dementia. The mean DASH score was 4.1 (range, 1.0-8.5) and the MedDietScore was 31.3 (range, 18-46). In mixed models adjusted for covariates, a 1-unit difference in DASH score was associated with a slower rate of global cognitive decline by 0.007 standardized units (standard error of estimate = 0.003, p = 0.03). Similarly, a 1-unit-higher MedDietScore was associated with a slower rate of global cognitive decline by 0.002 standardized units (standard error of estimate = 0.001, p = 0.01). CONCLUSIONS: These findings support the hypothesis that both the DASH and Mediterranean diet patterns are associated with slower rates of cognitive decline in the same cohort of older persons.

Systemic inflammation in non-demented elderly human subjects: brain microstructure and cognition.

The purpose of this study was to test the hypothesis that higher levels of systemic inflammation in a community sample of non-demented subjects older than seventy years of age are associated with reduced diffusion anisotropy in brain white matter and lower cognition. Ninety-five older persons without dementia underwent detailed clinical and cognitive evaluation and magnetic resonance imaging, including diffusion tensor imaging. Systemic inflammation was assessed with a composite measure of commonly used circulating inflammatory markers (C-reactive protein and tumor necrosis factor-alpha). Tract-based spatial statistics analyses demonstrated that diffusion anisotropy in the body and isthmus of the corpus callosum was negatively correlated with the composite measure of systemic inflammation, controlling for demographic, clinical and radiologic factors. Visuospatial ability was negatively correlated with systemic inflammation, and diffusion anisotropy in the body and isthmus of the corpus callosum was shown to mediate this association. The findings of the present study suggest that higher levels of systemic inflammation may be associated with lower microstructural integrity in the corpus callosum of non-demented elderly individuals, and this may partially explain the finding of reduced higher-order visual cognition in aging.

CD33 Alzheimer's disease locus: altered monocyte function and amyloid biology.

In our functional dissection of the CD33 Alzheimer's disease susceptibility locus, we found that the rs3865444(C) risk allele was associated with greater cell surface expression of CD33 in the monocytes (t50 = 10.06, P(joint) = 1.3 × 10(-13)) of young and older individuals. It was also associated with diminished internalization of amyloid-ß 42 peptide, accumulation of neuritic amyloid pathology and fibrillar amyloid on in vivo imaging, and increased numbers of activated human microglia.

Dietary approaches to stop hypertension patterns in older Latinos with or at risk for hypertension.

BACKGROUND: Older Latinos represent a growing segment of our population, yet little is known about whether older Latinos are following the recommended Dietary Approaches to Stop Hypertension (DASH) eating plan, which promotes certain food groups to reduce blood pressure (BP) over and above established strategies. Among Latinos, greater acculturation to the American society has been associated with suboptimal dietary choices and risk for chronic diseases. Therefore, the purpose of this study was to assess differences in DASH accordance/adherence by BP status taking into account level of acculturation. METHODS: This was a descriptive, cross-sectional study involving older Latinos wherein DASH accordance and adherence were calculated on the basis of nutrient analyses of food frequency questionnaires. A DASH score of 4.5 or higher indicated accordance, and a DASH Adherence Index greater than 0 indicated adherence. Blood pressure was measured in triplicate using Omron HEM-907XL and was categorized according to BP level and/or antihypertensive medication. The Acculturation Rating Scale for Mexican Americans-II was used to rate level of acculturation. RESULTS: Participants were 169 Latinos, primarily women (73%) and older (66 ± 9.0 years); the majority were hypertensive (66%), preferred speaking in Spanish (85%), and were more Latino oriented (63%) with respect to acculturation status. Overall, participants were moderately DASH accordant (4.2 ± 1.6) and DASH adherent (-0.8 ± 0.8). Acculturation scores (odds ratio, 1.4-1.7, P < 0.02) were predictive of hypertensive status (defined as BP ≥ 140/90 mm Hg) regardless of which dietary score was modeled. CONCLUSION: Based on these findings, greater attention should be paid to identification of traditional Latino foods and food preparation that are consistent and acceptable to this older community in effort to foster greater DASH accordance and improve BP status.

Nigral pathology and parkinsonian signs in elders without Parkinson disease.

OBJECTIVE: Motor symptoms such as mild parkinsonian signs are common in older persons, but little is known about their underlying neuropathology. We tested the hypothesis that nigral pathology is related to parkinsonism in older persons without Parkinson disease (PD). METHODS: More than 2,500 persons participating in the Religious Orders Study or the Memory and Aging Project agreed to annual assessment of parkinsonism with a modified version of the Unified Parkinson Disease Rating Scale and brain donation. Brains from 744 deceased participants without PD were assessed for nigral neuronal loss and α-synuclein immunopositive Lewy bodies. RESULTS: Mean age at death was 88.5 years. Mean global parkinsonism was 18.6 (standard deviation, 11.90). About ⅓ of cases had mild or more severe nigral neuronal loss, and about 17% had Lewy bodies. In separate regression models that adjusted for age, sex, and education, nigral neuronal loss and Lewy bodies were both related to global parkinsonism (neuronal loss: estimate, 0.231; standard error [SE], 0.068; p < 0.001; Lewy bodies: estimate, 0.291; SE, 0.133; p = 0.029). Employing a similar regression model that included both measures, neuronal loss remained associated with global parkinsonism (neuronal loss: estimate, 0.206; SE, 0.075; p = 0.006). By contrast, the association between Lewy bodies and global parkinsonism was attenuated by >60% and was no longer significant (Lewy bodies: estimate, 0.112; SE, 0.148; p = 0.447), suggesting that neuronal loss may mediate the association of Lewy bodies with global parkinsonism. INTERPRETATION: Nigral pathology is common in persons without PD and may contribute to loss of motor function in old age.

Nutritional determinants of cognitive aging and dementia.

The objective of this review is to provide an overview of nutritional factors involved in cognitive aging and dementia with a focus on nutrients that are also important in neurocognitive development. Several dietary components were targeted, including antioxidant nutrients, dietary fats and B-vitamins. A critical review of the literature on each nutrient group is presented, beginning with laboratory and animal studies of the underlying biological mechanisms, followed by prospective epidemiological studies and randomised clinical trials. The evidence to date is fairly strong for protective associations of vitamin E from food sources, the n-3 fatty acid, DHA, found in fish, a high ratio of polyunsaturated to saturated fats, and vitamin B12 and folate. Attention to the level of nutrient intake is crucial for interpreting the literature and the inconsistencies across studies. Most of the epidemiological studies that observe associations have sufficient numbers of individuals who have both low and adequate nutrient status. Few of the randomised clinical trials are designed to target participants who have low baseline status before randomising to vitamin supplement treatments, and this may have resulted in negative findings. Post-hoc analyses by some of the trials reveal vitamin effects in individuals with low baseline intakes. The field of diet and dementia is a relatively young area of study. Much further work needs to be done to understand dietary determinants of cognitive aging and diseases. Further, these studies must be particularly focused on the levels of nutrient intake or status that confer optimum or suboptimal brain functioning.

Association of fecal incontinence with physical disability and impaired cognitive function.

OBJECTIVES: Fecal incontinence is a common health problem for older people and is associated with significant morbidity and cost. In this study, we report on the association of fecal incontinence with physical disability and impaired cognitive function in a large bi-racial population of individuals aged 65 yr and older. METHODS: Study subjects are participants of the Chicago Health and Aging Project (CHAP), an ongoing study of older Chicago residents. A total of 6,099 participants completed the baseline in-home interview and assessments used in this analysis. Physical disability was assessed using a performance-based measure of basic physical functions and three commonly used self-report measures. Impaired cognitive function was assessed using a global measure of the averaged scores of four cognitive tests. The question used to determine the presence of fecal incontinence was: "In the past few months have you ever lost control of your bowels when you didn't want to?" RESULTS: In multiple logistic regression models adjusted for age, sex, and race, fecal incontinence was correlated with the presence of physical disability and impaired cognitive function on every measure. For example, using the performance-based measure of physical function, the odds of prevalent fecal incontinence were higher by 20% (OR 1.20, 95% CI 1.2-1.2) for each additional unit higher on the performance score, indicating a lower physical performance. The prevalence odds ratio for fecal incontinence was decreased by 51% for each one-point increase in the global cognitive score, indicating higher cognitive function. We found a statistically significant interaction between both race and physical disability and race and impaired cognitive function, such that the associations were stronger in blacks than in non-blacks. These associations remained after further adjustment for diabetes and stroke, and the intake of psychoactive medications. CONCLUSION: In urban, community-dwelling, older adults, fecal incontinence may be more common among persons with physical disability and impaired cognitive function.

Relative weight and mobility: a longitudinal study in a biracial population of older adults.

PURPOSE: We examined the association of relative weight with mobility and changes in mobility over time and whether these associations differed by race. METHODS: Data come from a prospective, population-based, observational study of adults aged 65 years or older. Mobility outcomes were assessed at baseline and two follow-up interviews at 3-year intervals. The study included 4195 participants with a mean age of 73.8 +/- 6.3 (SD) years; 61.4% were women, and 60.9% were black. Assessment of mobility included a brief self-report instrument and a performance-based walk test. Body mass index (BMI, kilograms per square meter) was used as a measure of relative weight. We used generalized estimating equation models to examine change in mobility outcomes over time as a function of BMI. RESULTS: Average BMI was 26.6 +/- 5.7 kg/m(2), with 34.0% overweight and 23.4% obese. BMI showed a significant curvilinear association with mobility outcomes at baseline (p < 0.001), but was not associated with change in mobility during follow-up. Maximum mobility levels occurred at a significantly higher level of BMI among blacks than whites. CONCLUSIONS: Higher levels of BMI may lead to mobility impairments earlier in life, but there is little evidence that they increase the rate of decline in mobility in older age itself.

Physical activity, cognitive activity, and cognitive decline in a biracial community population.

BACKGROUND: Findings from studies investigating whether physical activity reduces the risk of cognitive decline in old age have been inconsistent. OBJECTIVE: To examine whether participation in physical activity by older adults reduces the rate of cognitive decline after accounting for participation in cognitively stimulating activities. DESIGN: A prospective population study conducted from August 1993 to January 2003, with an average follow-up of 6.4 years. SETTING: A biracial community population on the south side of Chicago. PARTICIPANTS: Participants were 4055 community-dwelling adults 65 years and older who were able to walk across a small room and had participated in at least 2 of the 3 follow-up assessments. MAIN OUTCOME MEASURE: Annual rate of cognitive change as measured by a global cognitive score, which consisted of averaged standardized scores from 4 cognitive tests. RESULTS: In a mixed model adjusted for age, sex, race, and education, each additional physical activity hour per week was associated with a slower rate of cognitive decline by 0.0007 U/y (P = .04). However, with further adjustments (1) for participation in cognitive activities (beta = .0006, P = .10), (2) for depression and vascular diseases (beta = .0005, P = .19), and (3) by excluding participants whose global cognitive score at baseline was at or below the 10th percentile (beta = .0002, P = .45), the coefficients were smaller and no longer statistically significant. CONCLUSION: These data do not support the hypothesis that physical activity alone protects against cognitive decline among older adults.

Distress proneness and cognitive decline in a population of older persons.

The association between distress proneness and cognitive decline was examined in older residents of a biracial community in Chicago. At baseline, participants completed four cognitive tests that yielded a global measure (baseline mean=101.2; standard deviation (SD)=7.8), and a brief measure of the tendency to experience negative emotions (mean=16.5; SD=6.7) based on the Neuroticism scale of the NEO Five-Factor Inventory. Cognitive testing was repeated twice at three-year intervals. In mixed models that controlled age, sex, race, and education, for each point on the distress proneness scale, global cognitive score was 0.12 unit lower at baseline (p<0.001) and annual rate of decline increased by 0.01 unit (p=0.002), or about 2%. Thus, cognitive decline was about 30% faster in a person highly prone to distress (score=24, 90th percentile) compared to the one low in distress proneness (score=9, 10th percentile). This effect was unchanged after controlling for level of cognitive activity or excluding people with cognitive impairment at baseline, but it was reduced to a trend (p=0.059) after controlling for depressive symptoms. The results suggest that the tendency to experience psychological distress is associated with increased cognitive decline in old age.