Imaging Studies and APOE Genotype in Persons at Risk for Alzheimer's Disease

Many studies have investigated APOE-related differences in cerebral structure, blood flow, metabolism, and activation in an attempt to detect early brain changes in subjects at risk for Alzheimer's disease (AD). Structural magnetic resonance imaging studies have produced conflicting results, with some failing to detect APOE-related differences and others suggesting that epsilon4 carriers have more pronounced atrophy, particularly at medial temporal structures. All functional imaging studies done during rest in middle-aged and elderly subjects have found decreased cerebral metabolism for epsilon4 carriers (mostly in areas that usually are affected by AD), and some have reported faster cerebral metabolic reductions over time. Areas with decreased resting cerebral perfusion and metabolism, in addition to other areas with increased perfusion, have been reported in young epsilon4 carriers. Imaging studies done during the performance of various cognitive tasks in middle-aged and elderly subjects, and a single study in young subjects, have produced mixed results with regionally nonspecific increased, decreased, or nondifferential APOE-related activations depending on the cognitive task used. APOE-related findings in imaging studies of nondemented subjects may be the result of incipient AD pathologic changes or of genetic heterogeneity in brain structure and function

Cognitive Reserve: Implications for Diagnosis and Prevention of Alzheimer's Disease

Epidemiologic evidence suggests that higher occupational attainment and education, as well as increased participation in intellectual, social, and physical aspects of daily life, are associated with slower cognitive decline in healthy elderly and may reduce the risk of incident Alzheimer's disease (AD). There is also evidence from structural and functional imaging studies that patients with such life experiences can tolerate more AD pathology before showing signs of clinical dementia. It has been hypothesized that such aspects of life experience may result in functionally more efficient cognitive networks and, therefore, provide a cognitive reserve that delays the onset of clinical manifestations of dementia. In this article, we review some of the relevant literature of the noted associations between markers of cognitive reserve and AD and discuss the possible mechanisms that may explain these associations

Verbal Fluency Predicts Mortality in Alzheimer Disease

OBJECTIVES: To assess the predictive value of neuropsychologic profiles, at diagnosis, for mortality in incident Alzheimer disease (AD). BACKGROUND: Rate of AD progression varies significantly across individuals for reasons that are not well understood. Several studies have linked rapid decline with disproportionately impaired executive functioning, presumably reflecting greater impairment of frontal networks. To the extent that differential neuropsychologic profiles reflect various neuropathologic presentations of AD, such profiles may inform survival estimates early in the disease. METHODS: Five neuropsychologic indices were used to characterize performance in 161 individuals at diagnosis of AD during a 15-year, longitudinal, primarily community-based study. RESULTS: Fifty-two percent of participants reached the mortality end point with a median survival of 5.52 years (95% confidence interval, 4.41-6.63). Cox proportional hazards analyses indicated that older age at diagnosis was associated with higher risk of mortality (risk ratios, 1.08; 95% confidence interval, 1.04-1.12) whereas Hispanic ethnicity predicted lower mortality [0.22 (0.09-0.55)]. Controlling for these 2 demographic variables, higher verbal fluency scores at diagnosis predicted lower mortality [0.69 (0.49-0.96)]. CONCLUSIONS: Disproportionate impairment of both category and letter fluency at the earliest stages of AD predicts mortality. The prognostic value of these tests may derive from their general psychometric properties, or may reflect the measures' sensitivity to an early or critical level of compromise to frontal networks

Mediterranean Diet, Inflammatory and Metabolic Biomarkers, and Risk of Alzheimer's Disease

We aimed to investigate the association between adherence to the Mediterranean diet (MeDi) and Alzheimer's disease (AD) risk in a prospective study. Specifically, we analyzed reduced inflammation and improved metabolic profile as a potential medium through which the MeDi reduced the risk of AD. During a 4-year follow-up, 118 incident AD cases were identified among the 1219 non-demented elderly (age ⩾ 65) subjects who provided dietary information and blood samples at baseline. We used high-sensitivity C-reactive protein (hsCRP) as an index of systemic inflammation, and fasting insulin and adiponectin as indexes of metabolic profile. We investigated whether there was a change in the association between MeDi and incident AD risk when the biomarkers were introduced into multivariable adjusted COX models. Better adherence to MeDi was associated with lower level of hsCRP (p =0.003), but not fasting insulin or adiponectin. Better adherence to MeDi was significantly associated with lower risk for AD: compared to those in the lowest tertile of MeDi, subjects in the highest tertile had a 34% less risk of developing AD (p-for-trend =0.04). Introduction of the hsCRP, fasting insulin, adiponectin, or combinations of them into the COX model did not change the magnitude of the association between MeDi and incident AD. Ultimately, the favorable association between better adherence to MeDi and lower risk of AD did not seem to be mediated by hsCRP, fasting insulin, or adiponectin. Other aspects of inflammatory and metabolic pathways not captured by these biomarkers, or non-inflammatory or non-metabolic pathways, may be relevant to the MeDi-AD association

Mediterranean Diet, Inflammatory and Metabolic Biomarkers, and Risk of Alzheimer's Disease

We aimed to investigate the association between adherence to the Mediterranean diet (MeDi) and Alzheimer's disease (AD) risk in a prospective study. Specifically, we analyzed reduced inflammation and improved metabolic profile as a potential medium through which the MeDi reduced the risk of AD. During a 4-year follow-up, 118 incident AD cases were identified among the 1219 non-demented elderly (age ⩾ 65) subjects who provided dietary information and blood samples at baseline. We used high-sensitivity C-reactive protein (hsCRP) as an index of systemic inflammation, and fasting insulin and adiponectin as indexes of metabolic profile. We investigated whether there was a change in the association between MeDi and incident AD risk when the biomarkers were introduced into multivariable adjusted COX models. Better adherence to MeDi was associated with lower level of hsCRP (p =0.003), but not fasting insulin or adiponectin. Better adherence to MeDi was significantly associated with lower risk for AD: compared to those in the lowest tertile of MeDi, subjects in the highest tertile had a 34% less risk of developing AD (p-for-trend =0.04). Introduction of the hsCRP, fasting insulin, adiponectin, or combinations of them into the COX model did not change the magnitude of the association between MeDi and incident AD. Ultimately, the favorable association between better adherence to MeDi and lower risk of AD did not seem to be mediated by hsCRP, fasting insulin, or adiponectin. Other aspects of inflammatory and metabolic pathways not captured by these biomarkers, or non-inflammatory or non-metabolic pathways, may be relevant to the MeDi-AD association

Mediterranean Diet and Alzheimer Disease Mortality

BACKGROUND: We previously reported that the Mediterranean diet (MeDi) is related to lower risk for Alzheimer disease (AD). Whether MeDi is associated with subsequent AD course and outcomes has not been investigated. OBJECTIVES: To examine the association between MeDi and mortality in patients with AD. METHODS: A total of 192 community-based individuals in New York who were diagnosed with AD were prospectively followed every 1.5 years. Adherence to the MeDi (0- to 9-point scale with higher scores indicating higher adherence) was the main predictor of mortality in Cox models that were adjusted for period of recruitment, age, gender, ethnicity, education, APOE genotype, caloric intake, smoking, and body mass index. RESULTS: Eighty-five patients with AD (44%) died during the course of 4.4 (+/-3.6, 0.2 to 13.6) years of follow-up. In unadjusted models, higher adherence to MeDi was associated with lower mortality risk (for each additional MeDi point hazard ratio 0.79; 95% CI 0.69 to 0.91; p = 0.001). This result remained significant after controlling for all covariates (0.76; 0.65 to 0.89; p = 0.001). In adjusted models, as compared with AD patients at the lowest MeDi adherence tertile, those at the middle tertile had lower mortality risk (0.65; 0.38 to 1.09; 1.33 years' longer survival), whereas subjects at the highest tertile had an even lower risk (0.27; 0.10 to 0.69; 3.91 years' longer survival; p for trend = 0.003). CONCLUSION: Adherence to the Mediterranean diet (MeDi) may affect not only risk for Alzheimer disease (AD) but also subsequent disease course: Higher adherence to the MeDi is associated with lower mortality in AD. The gradual reduction in mortality risk for higher MeDi adherence tertiles suggests a possible dose-response effect

Extrapyramidal Signs Before and After Diagnosis of Incident Alzheimer Disease in a Prospective Population Study

Background: Extrapyramidal signs (EPSs) are commonly accepted as a feature of Alzheimer disease (AD) and may influence both the profile of impairment and prognosis. Objective: To examine rates of occurrence and risk factors for all types of EPSs and to describe the impact of EPSs over time on the clinical course of AD. Design: Longitudinal study. Setting: The Washington Heights Hamilton Heights Inwood Columbia Aging Project. Patients: A total of 388 patients with incident AD (mean age, 79 years; 71.4% female). Outcome Measures: Extrapyramidal signs rated by means of a standardized portion of the Unified Parkinson's Disease Rating Scale; prevalence and incidence rates and cumulative risk for non–drug-induced EPSs; and rates of change in EPSs over time, taking into account potential covariates. Results: Extrapyramidal signs were detected in 12.3% of patients at first evaluation and 22.6% at last evaluation. In a multivariate-adjusted generalized estimating equation model of change, total EPS score increased at an annual rate of 1.3%. Women (relative risk [RR], 1.57; P = .03), older patients (RR, 1.03; P = .02), and those with EPSs at baseline (RR, 2.07; P = .001) had greater rates of cognitive decline. Conclusions: Extrapyramidal signs occur frequently and progress significantly in AD. Patients with incident AD and concomitant EPSs have a greater rate of cognitive decline than do patients with incident AD but without EPSs

Premorbid Weight, Body Mass, and Varsity Athletics in ALS

Several famous athletes have been affected by ALS, and some epidemiologic studies have indicated that vigorous physical activity (heavy labor or athletics) is a risk factor for the disease. In a case-control study of 279 patients with motor neuron diseases and 152 with other neurologic diseases, the authors found that subjects with motor neuron diseases were more likely than controls to report they had always been slim or they had been varsity athletes. For slimness, the odds ratio (OR) was 2.21; 95% CI, 1.40 to 3.47. For varsity athletics, the OR was 1.70; CI, 1.04 to 2.76

Leisure Activity and Cognitive Decline in Incident Alzheimer Disease

Background: High rates of leisure activity have been associated with reduced risk of Alzheimer disease (AD). Objective: To determine whether prediagnosis leisure activity modifies the rate of cognitive decline in patients with AD. Design: Inception cohort followed up longitudinally for a mean of 5.3 years (up to 13.9 years). Setting: Urban community. Participants: A total of 283 patients with incident AD (mean age, 79 years; 56.2% Hispanic and 31.1% African American). Main Outcome Measures: Change in a composite cognitive score from diagnosis on and during the entire study follow-up. Results: In multivariate-adjusted generalized estimating equation models of postdiagnosis change (n = 133), each leisure activity was associated with an additional yearly decline of 0.005 of a z-score unit in cognitive score (P = .17). In models expanded to include cognitive change during study follow-up, including evaluations before and after diagnosis (n = 283), each activity was associated with an additional yearly decline of 0.005 of a z-score unit in cognitive score (P = .03). The association was strongest for intellectual activities. Conclusions: Greater participation in prediagnosis leisure activities, especially intellectual activities, was associated with faster cognitive decline, supporting the hypothesis that the disease course in AD may vary as a function of cognitive reserve