Educational attainment and socioeconomic status of patients with autopsy-confirmed Alzheimer disease

Cognitive performance protects against Alzheimer's disease independently of educational attainment and intelligence

Mendelian-randomization (MR) studies using large-scale genome-wide association studies (GWAS) have identified causal association between educational attainment and Alzheimer's disease (AD). However, the underlying mechanisms are still required to be explored. Here, we conduct univariable and multivariable MR analyses using large-scale educational attainment, cognitive performance, intelligence and AD GWAS datasets. In stage 1, we found significant causal effects of educational attainment on cognitive performance (beta = 0.907, 95% confidence interval (CI): 0.884-0.930, P < 1.145E-299), and vice versa (beta = 0.571, 95% CI: 0.557-0.585, P < 1.145E-299). In stage 2, we found that both increase in educational attainment (odds ratio (OR) = 0.72, 95% CI: 0.66-0.78, P = 1.39E-14) and cognitive performance (OR = 0.69, 95% CI: 0.64-0.75, P = 1.78E-20) could reduce the risk of AD. In stage 3, we found that educational attainment may protect against AD dependently of cognitive performance (OR = 1.07, 95% CI: 0.90-1.28, P = 4.48E-01), and cognitive performance may protect against AD independently of educational attainment (OR = 0.69, 95% CI: 0.53-0.89, P = 5.00E-03). In stage 4, we found significant causal effects of cognitive performance on intelligence (beta = 0.907, 95% CI: 0.877-0.938, P < 1.145E-299), and vice versa (beta = 0.957, 95% CI: 0.937-0.978, P < 1.145E-299). In stage 5, we identified that cognitive performance may protect against AD independently of intelligence (OR = 0.74, 95% CI: 0.61-0.90, P = 2.00E-03), and intelligence may protect against AD dependently of cognitive performance (OR = 1.17, 95% CI: 0.40-3.43, P = 4.48E-01). Collectively, our univariable and multivariable MR analyses highlight the protective role of cognitive performance in AD independently of educational attainment and intelligence. In addition to the intelligence, we extend the mechanisms underlying the associations of educational attainment with AD.

Relationships between educational attainment, hypertension, and amyloid negative subcortical vascular dementia: The brain-battering hypothesis

Purpose

Many epidemiological studies suggest that lower education levels and vascular risk factors increase the likelihood of developing Alzheimer's disease dementia (ADD) and subcortical vascular dementia (SVaD). However, whether the brain-battering hypothesis can explain the relationship between education levels and the clinical diagnosis of dementia remains controversial. The objective of this study was to investigate whether vascular risk factors mediate the association between education level and the diagnosis of amyloid-beta positive (Aβ+) ADD and amyloid-beta negative (Aβ-) SVaD.

Methods

We analyzed 376 participants with Aβ normal cognition (Aβ- NC), 481 with Aβ+ ADD, and 102 with Aβ- SVaD. To investigate the association of education level and vascular risk factors with these diagnoses, multivariable logistic regression analysis was used, with age, sex, and APOE ε4 carrier status used as covariates. Path analysis was performed to investigate the mediation effects of hypertension on the diagnosis of Aβ- SVaD.

Results

The Aβ- SVaD group (7.9 ± 5.1 years) had lower education levels than did the Aβ- NC (11.8 ± 4.8 years) and Aβ+ ADD (11.2 ± 4.9 years) groups. The frequencies of hypertension and diabetes mellitus were higher in the Aβ- SVaD group (78.4 and 32.4%, respectively) than in the Aβ- NC (44.4 and 20.8%) and Aβ+ ADD (41.8 and 15.8%, respectively) groups. Increased education level was associated with a lower risk of Aβ- SVaD [odds ratio (OR) 0.866, 95% confidence interval (CI), 0.824–0.911], but not Aβ+ ADD (OR 0.971, 95% CI 0.940–1.003). The frequency of hypertension was associated with a higher risk of developing Aβ- SVaD (OR 3.373, 95% CI, 1.908–5.961), but not Aβ+ ADD (OR 0.884, 95% CI, 0.653–1.196). In the path analysis, the presence of hypertension partially mediated the association between education level and the diagnosis of Aβ- SVaD.

Conclusion

Our findings revealed that education level might influence the development of Aβ- SVaD through the brain-battering hypothesis. Furthermore, our findings suggest that suitable strategies, such as educational attainment and prevention of hypertension, are needed for the prevention of Aβ- SVaD.

Psychosocial and Trauma-Related Stress and Risk of Dementia: A Meta-Analytic Systematic Review of Longitudinal Studies

Stress has deleterious effects on brain health and yet, the prognostic value of psychosocial stress regarding the most common types of dementias, including Alzheimer disease, is still unclear. The primary aim of this systematic review was to explore the association between psychosocial stress and late onset dementia. We classified 24articles from Medline, PsycINFO, CINAHL, and Web of Science, as pertaining toxic categories of psychosocial and trauma-related stress (low socio-economic status [SES] related inequalities, marital status, posttraumatic stress disorder, work stress, "vital exhaustion" [VE], and, combined stressors). Using the Quality of Prognosis Studies in Systematic Reviews tool, we judged the quality of evidence to be low. This systematic review provided some non-robust, yet suggestive evidence that the above psychosocial types of stress are associated with increased risk of dementia in later life. Future robust, longitudinal studies with repeated validated measures of psychosocial stress and dementiaare required to strengthen or refute these findings.

Smoking mediates the relationship between SES and brain volume: The CARDIA study

OBJECTIVE

Investigate whether socioeconomic status (SES) was related to brain volume in aging related regions, and if so, determine whether this relationship was mediated by lifestyle factors that are known to associate with risk of dementia in a population-based sample of community dwelling middle-aged adults.

METHODS

We studied 645 (41% black) participants (mean age 55.3±3.5) from the Coronary Artery Risk Development in Young Adults (CARDIA) study who underwent brain magnetic resonance imaging. SES was operationalized as a composite measure of annual income and years of education. Gray matter volume was estimated within the insular cortex, thalamus, cingulate, frontal, inferior parietal, and lateral temporal cortex. These regions are vulnerable to age-related atrophy captured by the Spatial Pattern of Atrophy for Recognition of Brain Aging (SPARE-BA) index. Lifestyle factors of interest included physical activity, cognitive activity (e.g. book/newspaper reading), smoking status, alcohol consumption, and diet. Multivariable linear regressions tested the association between SES and brain volume. Sobel mediation analyses determined if this association was mediated by lifestyle factors. All models were age, sex, and race adjusted.

RESULTS

Higher SES was positively associated with brain volume (β = .109 SE = .039; p < .01) and smoking status significantly mediated this relationship (z = 2.57). With respect to brain volume, smoking accounted for 27% of the variance (β = -.179 SE = .065; p < .01) that was previously attributed to SES.

CONCLUSION

Targeting smoking cessation could be an efficacious means to reduce the health disparity of low SES on brain volume and may decrease vulnerability for dementia.

Resistance and resilience to Alzheimer's disease pathology are associated with reduced cortical pTau and absence of limbic-predominant age-related TDP-43 encephalopathy in a community-based cohort

Alzheimer's disease neuropathologic change (ADNC) is defined by progressive accumulation of β-amyloid plaques and hyperphosphorylated tau (pTau) neurofibrillary tangles across diverse regions of brain. Non-demented individuals who reach advanced age without significant ADNC are considered to be resistant to AD, while those burdened with ADNC are considered to be resilient. Understanding mechanisms underlying ADNC resistance and resilience may provide important clues to treating and/or preventing AD associated dementia. ADNC criteria for resistance and resilience are not well-defined, so we developed stringent pathologic cutoffs for non-demented subjects to eliminate cases of borderline pathology. We identified 14 resistant (85+ years old, non-demented, Braak stage ≤ III, CERAD absent) and 7 resilient (non-demented, Braak stage VI, CERAD frequent) individuals out of 684 autopsies from the Adult Changes in Thought study, a long-standing community-based cohort. We matched each resistant or resilient subject to a subject with dementia and severe ADNC (Braak stage VI, CERAD frequent) by age, sex, year of death, and post-mortem interval. We expanded the neuropathologic evaluation to include quantitative approaches to assess neuropathology and found that resilient participants had lower neocortical pTau burden despite fulfilling criteria for Braak stage VI. Moreover, limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) was robustly associated with clinical dementia and was more prevalent in cases with high pTau burden, supporting the notion that resilience to ADNC may depend, in part, on resistance to pTDP-43 pathology. To probe for interactions between tau and TDP-43, we developed a C. elegans model of combined human (h) Tau and TDP-43 proteotoxicity, which exhibited a severe degenerative phenotype most compatible with a synergistic, rather than simply additive, interaction between hTau and hTDP-43 neurodegeneration. Pathways that underlie this synergy may present novel therapeutic targets for the prevention and treatment of AD.

Neighborhood Socioeconomic Status and Cognitive Function in Late Life

Neighborhood socioeconomic status (NSES) is associated with cognitive function, independently of individual demographic, health, and socioeconomic characteristics. However, research has been largely cross-sectional, and mechanisms of the association are unknown. In 1992-1993, Cardiovascular Health Study participants (n = 3,595; mean age = 74.8 years; 15.7% black) underwent cognitive testing and magnetic resonance imaging of white matter hyperintensities (WMH), and their addresses were geocoded. NSES was calculated using 1990 US Census data (block groups; 6 measures of wealth, education, and occupation). The Modified Mini-Mental State Examination (3MS) was used to assess general cognition, and the Digit Symbol Substitution Test (DSST) was used to assess speed of processing annually for 6 years. Associations of race-specific NSES tertiles with 3MS, DSST, and WMH were estimated using linear mixed-effects models accounting for geographic clustering, stratified by race, and adjusted for demographic, health, and individual socioeconomic status (education, income, lifetime occupational status) variables. In fully adjusted models, higher NSES was associated with higher 3MS scores in blacks (mean difference between highest and lowest NSES = 2.4 points; P = 0.004) and whites (mean difference = 0.7 points; P = 0.02) at baseline but not with changes in 3MS over time. NSES was marginally associated with DSST and was not associated with WMH. Adjustment for WMH did not attenuate NSES-3MS associations. Associations of NSES with cognition in late adulthood differ by race, are not explained by WMH, and are evident only at baseline.

Influence of socio-demographic features and apolipoprotein E epsilon 4 expression on the prevalence of dementia and cognitive impairment in a population of 70-74-year olds: the InveCe.Ab study

The age-specific prevalence rates of dementia vary widely. Studies focusing on specific age groups are needed to provide reliable estimates for healthcare providers and policy makers. We estimated the prevalence of dementia, dementia subtypes and cognitive impairment in "InveCe.Ab" (ClinicalTrials.gov, NCT01345110), a single-step multidimensional population-based study of 70-74-year olds living in Abbiategrasso (Milan, Italy). We also looked for associations with socio-demographic factors and the presence of the apolipoprotein E-ɛ4 allele. The overall dementia prevalence was 3% (95%CI: 2.1-4.1%) [Alzheimer's disease (AD): 1.2% (95%CI 0.6-1.9%); vascular dementia (VD): 1.4% (95%CI: 0.8-2.2%)]. Being single was found to be a risk factor for vascular dementia; subjects born in southern Italy were shown to be at greater risk both of overall dementia and of vascular dementia. The prevalence of cognitive impairment, with or without subjective cognitive complaints (cognitive impairment, no dementia, CIND) was 7.8% (95%CI: 6.4-9.4%). As regards the CIND subgroups, the prevalence of subjects with subjective cognitive complaints (mild cognitive impairment, MCI) was 5.0% (95%CI 3.9-6.3%), while the prevalence of those without MCI (CIND-other) was 2.8% (95%CI: 1.9-3.8). The males had a higher risk of MCI and CIND-other; the older subjects were more likely to have MCI, and those born in north-eastern Italy to have CIND-other. The prevalence of AD was higher among the apolipoprotein E-ɛ4 carriers. Our data highlight the importance of dementia and cognitive impairment in the transitional period from adulthood to old age, and reveal the presence of different associations with socio-demographic and genetic factors.

Impact of socioeconomic status on initial clinical presentation to a memory disorders clinic

BACKGROUND

Dementia affects 15% of Canadians 65 and older, and the prevalence is expected to double over the next two decades. Low socioeconomic status (SES) can increase the risk of Alzheimer's disease (AD) and the precursor mild cognitive impairment (MCI), but it is unknown what the relationship of SES is on initial clinical presentation to a memory disorders clinic.

METHODS

Data from 127 AD and 135 MCI patients who presented to our Memory Disorders Clinic from 2004 to 2013 were analyzed retrospectively. We examined the relationship between SES (measured using Hollingshead two-factor index) and (1) diagnosis of either AD or MCI; (2) age when first presented to clinic; (3) objective cognitive tests to indicate clinical severity; and (4) the use of cognitive enhancers, medication for treating mild-to-moderate AD patients.

RESULTS

AD patients had lower SES than MCI patients (p < 0.001, r = 0.232). Lower SES was associated with a greater age at initial time of diagnosis (χ2 = 11.5, p = 0.001). In MCI patients, higher SES individuals outperformed lower SES individuals on the BNA after correcting for the effect of age (p = 0.004). Lower SES was also associated with decreased use of cognitive enhancers in AD patients (p < 0.001, r = 0.842).

CONCLUSION

Individuals with lower SES come into memory clinic later when the disease has progressed to dementia, while higher SES individuals present earlier when the disease is still in its MCI stage. There were more higher SES individuals who presented to our memory clinic. Higher SES is associated with better cognitive functioning and increased use of cognitive enhancers. The health policy implication is that we need to better engage economically disadvantaged individuals, perhaps at the primary care level.

Different multivariate techniques for automated classification of MRI data in Alzheimer's disease and mild cognitive impairment

Automated structural magnetic resonance imaging (MRI) processing pipelines and different multivariate techniques are gaining popularity for Alzheimer's disease (AD) research. We used four supervised learning methods to classify AD patients and controls (CTL) and to prospectively predict the conversion of mild cognitive impairment (MCI) to AD from baseline MRI data. A total of 345 participants from the AddNeuroMed cohort were included in this study; 116 AD patients, 119 MCI patients and 110 CTL individuals. High resolution sagittal 3D MP-RAGE datasets were acquired and MRI data were processed using FreeSurfer. We explored the classification ability of orthogonal projections to latent structures (OPLS), decision trees (Trees), artificial neural networks (ANN) and support vector machines (SVM). Applying 10-fold cross-validation demonstrated that SVM and OPLS were slightly superior to Trees and ANN, although not statistically significant for distinguishing between AD and CTL. The classification experiments resulted in up to 83% sensitivity and 87% specificity for the best techniques. For the prediction of conversion of MCI patients at baseline to AD at 1-year follow-up, we obtained an accuracy of up to 86%. The value of the multivariate models derived from the classification of AD vs. CTL was shown to be robust and efficient in the identification of MCI converters.

Relationship between education and dementia: an updated systematic review

OBJECTIVE

The purpose of this study was to review the relationship between education and dementia.

METHODS

A systematic literature review was conducted of all published studies examining the relationship between education and dementia listed in the PubMed and PsycINFO databases from January 1985 to July 2010. The inclusion criteria were a measure of education and a dementia diagnosis by a standardized diagnostic procedure. Alzheimer disease and Total Dementia were the outcomes.

RESULTS

A total of 88 study populations from 71 studies met inclusion criteria. Overall, 51 studies (58%) reported significant effects of lower education on risk for dementia, whereas 37 studies (42%) reported no significant relationship. A relationship between education and risk for dementia was more consistent in developed regions compared with developing regions. Age, sex, race/ethnicity, and geographical region moderated the relationship.

CONCLUSIONS

Lower education was associated with a greater risk for dementia in many but not all studies. The level of education associated with risk for dementia varied by study population and more years of education did not uniformly attenuate the risk for dementia. It seemed that a more consistent relationship with dementia occurred when years of education reflected cognitive capacity, suggesting that the effect of education on risk for dementia may be best evaluated within the context of a lifespan developmental model.

A multicentre community-based study of dementia cases and subcases in older people in China--the GMS-AGECAT prevalence and socio-economic correlates

BACKGROUND

Previous studies indicated overall relatively low prevalence of dementia in older people in China, which may be biased by studied samples or methods. We determined the prevalence of dementia cases and subcases in China and examined their socio-economic correlates.

METHODS

Using the Geriatric Mental State interview, we examined random samples of 2917 participants aged ≥ 65 years in urban and rural Anhui, China in 2001-2003, and 3327 in four other provinces in 2008-2009. Dementia cases and subcases were diagnosed by Geriatric Mental State-Automated Geriatric Examination for Computer Assisted Taxonomy.

RESULTS

Age-standardised prevalence for cases and subcases of dementia in the Anhui elders was 7.20% (95%CI 6.29%-8.20%) and 10.5% (9.38%-11.6%), and in the four provinces, 9.86% (8.80%-10.9%) and 8.51% (7.51%-9.52%). The matched figures among the participants who were literate were 3.05% (2.08%-4.02%) and 10.0% (8.38%-11.6%), and 4.92% (3.89%-5.96%) and 6.76% (5.55%-7.96%), respectively. There were higher prevalence rates of dementia cases and subcases in the rural elders than in the urban. Both the Anhui and four-province studies showed an obvious association of dementia with higher and lower incomes among elders who had lower educational levels or had the lowest occupational class. The highest risk of dementia was found in those who were illiterate but had the highest income or had the job of business/nonmanual labouring.

CONCLUSIONS

People in China have a higher prevalence of dementia than previously reported. Its U-shaped relationship with income and the excess subcases prevalence predicates a significant burden of disease, both now and for the future, suggesting preventive strategy for dementia in China.

Impact of socioeconomic status on the prevalence of dementia in an inner city memory disorders clinic

BACKGROUND

Socioeconomic status (SES) has been identified as a possible risk factor for the development of dementia, with low SES shown to be associated with a higher prevalence of dementia, increased psychiatric comorbidity and worse baseline cognitive functioning. Few studies have actually looked at the impact of SES within a clinical population using multiple measures of SES and cognition.

METHODS

Data on 217 patients seen in an Inner City Memory Disorders Clinic were analyzed with respect to demographic status, clinical status and SES. Correlations were then examined looking at the relationship of SES to clinical variables and neurocognitive status. Regression analysis was undertaken to examine the relative contribution of individual sociodemographic factors to a diagnosis of dementia.

RESULTS

In general, there was wide variation in the sample examined with respect to most measures of SES. Approximately one third (36%) of the sample had a diagnosis of dementia, the mean age was 66.1 years and the mean Mini-mental State Examination score was relatively high (25.4). There was a strong association between age, individual annual income range, education, medical comorbidity and a diagnosis of dementia, with increased age and medical comorbidity being the strongest predictors.

CONCLUSION

Increased age, low education, high medical comorbidity and low annual income are all associated with a diagnosis of dementia in an inner city setting. Age and medical comorbidity appear to be more strongly associated with a diagnosis of dementia than SES in an inner city setting.

Evaluating Spousal Abuse as a Potential Risk Factor for Alzheimer’s Disease: Rationale, Needs and Challenges

BACKGROUND

Repetitive head trauma is an identified risk factor for Alzheimer's disease (AD). The violence in wife assault is repetitive and targets the head. This association provides a rationale for studying the relationship between spousal abuse and AD.

DESIGN

To preliminarily evaluate the possibility of an increased susceptibility for AD in women subjected to spousal abuse and to identify challenges associated with such a study, we performed a pilot case-control study involving women with AD and compared the incidence of spousal abuse against two control groups. Forty consecutive women with AD referred to a Memory Disorders Clinic were enrolled. Individuals were evaluated at three visits (0, 3, 9 months) and were followed for an additional 12 months to ensure that no other diagnosis emerged. Two control groups were likewise assessed.

RESULTS

17.5% (7/40) of the women (average age 71 years) with AD reported spousal abuse with head trauma. In control group 1, 5.0% (2/40) and in control group 2, 7.5% (3/40) of the women reported spousal abuse with head trauma.

CONCLUSIONS

The development of AD may be a potential long-term consequence of wife assault. Our study suggests spousal abuse as a possible risk factor for AD, and supports the need for larger studies. However, there are practical challenges associated with the successful execution of such a study.

Potential occupational risks for neurodegenerative diseases

BACKGROUND

Associations between occupations and neurodegenerative diseases (NDD) may be discernable in death certificate data.

METHODS

Hypotheses generated from 1982 to 1991 study were tested in data from 22 states for the years 1992-1998. Specific occupations and exposures to pesticides, solvents, oxidative stressors, magnetic fields, and welding fumes were evaluated.

RESULTS

About one third (26/87) of the occupations hypothesized with neurodegenerative associations had statistically significant elevated mortality odds ratios (MOR) for the same outcome. Occupations with the largest MORs were (a) for presenile dementia (PSD)-dentists, graders/sorters (non-agricultural), and clergy; (b) for Alzheimer's disease (AD)-bank tellers, clergy, aircraft mechanics, and hairdressers; (c) for Parkinson's disease (PD)-biological scientists, clergy, religious workers, and post-secondary teachers; and (d) for motor neuron disease (MND)-veterinarians, hairdressers, and graders and sorters (non-agricultural). Teachers had significantly elevated MORs for all four diseases, and hairdressers for three of the four. Non-horticultural farmers below age 65 had elevated PD (MOR = 2.23, 95% CI = 1.47-3.26), PSD (MOR = 2.22, 95% CI = 1.10-4.05), and AD (MOR = 1.76, 95% CI = 1.04-2.81). Sixty hertz magnetic fields exhibited significant exposure-response for AD and, below age 65, for PD (MOR = 1.87, 95% CI = 1.14-2.98) and MND (MOR = 1.63, 95% CI = 1.10-2.39). Welding had elevated PD mortality below age 65 (MOR = 1.77, 95% CI = 1.08-2.75).

CONCLUSIONS

Support was observed for hypothesized excess neurodegenerative disease associated with a variety of occupations, 60 Hz magnetic fields and welding.

Functional brain abnormalities in young adults at genetic risk for late-onset Alzheimer's dementia

Fluorodeoxyglucose positron emission tomography (PET) studies have found that patients with Alzheimer's dementia (AD) have abnormally low rates of cerebral glucose metabolism in posterior cingulate, parietal, temporal, and prefrontal cortex. We previously found that cognitively normal, late-middle-aged carriers of the apolipoprotein E epsilon4 allele, a common susceptibility gene for late-onset Alzheimer's dementia, have abnormally low rates of glucose metabolism in the same brain regions as patients with probable AD. We now consider whether epsilon4 carriers have these regional brain abnormalities as relatively young adults. Apolipoprotein E genotypes were established in normal volunteers 20-39 years of age. Clinical ratings, neuropsychological tests, magnetic resonance imaging, and PET were performed in 12 epsilon4 heterozygotes, all with the epsilon3/epsilon4 genotype, and 15 noncarriers of the epsilon4 allele, 12 of whom were individually matched for sex, age, and educational level. An automated algorithm was used to generate an aggregate surface-projection map that compared regional PET measurements in the two groups. The young adult epsilon4 carriers and noncarriers did not differ significantly in their sex, age, educational level, clinical ratings, or neuropsychological test scores. Like previously studied patients with probable AD and late-middle-aged epsilon4 carriers, the young epsilon4 carriers had abnormally low rates of glucose metabolism bilaterally in the posterior cingulate, parietal, temporal, and prefrontal cortex. Carriers of a common Alzheimer's susceptibility gene have functional brain abnormalities in young adulthood, several decades before the possible onset of dementia.

[Detection of cognitive impairment in the population of persons older than 64 years: first phase of the Cuida'l project]

OBJECTIVE. To know the proportion of people with positive result in test. Design. Cross sectional study in 53 health centers. SETTING. Primary care.

PARTICIPANTS

Aleatory sample of non-institutionalised, elder than 64 years patients attended in the 53 health centers.

MEASUREMENTS

VARIABLES

age, sex, civil status, and educational level. The detection of cognitive deterioration (CD) was carried out in primary care units with Folstein's Mini Mental Test (MMT) and the Isaacs Set-Test in case of illiteracy. Cut-off points 24 and 27 respectively. CD predictor variables analysis with logistic regression.

MAIN RESULTS

The tests were applied to 4,467 individuals (56.1% females). There were found as possible cases of CD 399 patients (72.2% with MMSE). Positive percentage was 7.78% (95% CI, 5.69%-10.99%) in males and 9.45% (95% CI, 7.31%-12.43%) in female, adjusting with indirect method, according to the 1996 Catalonia list of inhabitants. Significant predictor factors were found with the multivariate analyses: primary educational level in front of illiteracy (OR=1.40, 95% CI, 1.13%-1.74%) and age-groups: 74-79 years, 75-79 years and y >= 80 years in front of <70 years old (OR=1,48, 95% CI, 1.02%-2.14%, OR=2.29; 95% CI, 1.60%-3.28% and OR=5,02; 95% CI, 3.59%-7.03% respectively).

CONCLUSIONS

The cognitive deterioration prevalence increases with age and it is less frequent in individuals with higher studies Using MMSE and Set-Test we found several possible cases of cognitive deterioration in our population.

Association between the psychosocial network and dementia--a case-control study

In a case-control study, we investigated the possible etiological relevance to dementia of psychosocial network factors, such as marital status, confidants and close relatives, sports activities, cultural activities, club membership; and education. In 23 general practices we recruited 195 patients with dementia. Of these, 108 were suffering from possible Alzheimer's disease, 59 from possible vascular dementia and 28 from secondary or unclassified dementia. A total of 229 control subjects was recruited: 122 population controls and 107 dementia-free ambulatory patients. Data were gathered in a structured personal interview and analyzed using logistic regression, to control for age, region, sex, dementia in parents, education and smoking. There were significantly decreased odds ratios for the number of confidants, sports activities, and cultural activities at age 30, at age 50 and at 10 years before data collection. When all psychosocial network factors were included simultaneously in the logistic regression model, these factors remained statistically significant, indicating independent effects. Restriction of the analysis to cases with possible Alzheimer's disease or to cases with possible vascular dementia led to similar results. Adjustment for the psychosocial network neutralized the otherwise protective effect of education for dementia of any type and for possible vascular dementia. In keeping with the results from recently published studies, these results support a protective role for the psychosocial network-especially for the number of confidants and for sports and cultural activities-in the etiology of dementia.

Lifetime principal occupation and risk of Alzheimer's disease in the Kungsholmen project

BACKGROUND

Some studies suggest that manual work is associated with dementia. This study is aimed at identifying the specific occupational categories that may be related to dementia.

METHODS

A cohort of 913 non-demented subjects aged 75 + years was longitudinally examined twice over 6 years to detect incident dementia using the DSM-III-R diagnostic criteria. The lifetime longest occupations of all subjects were divided into different categories according to the occupation-based classification system. Data were analyzed with Cox models.

RESULTS

During the follow-up period, 260 subjects were diagnosed with dementia (197 with Alzheimer's disease). Manual work was associated with an increased risk of dementia, and the association was dependent on educational level. Compared with non-manual work, manual work involving goods production had a multi-adjusted relative risk (95% CI) of 1.6 (1.0-2.5, P = 0.046) for Alzheimer's disease and 1.4 (0.9-2.1) for dementia.

CONCLUSIONS

An association between goods production, manual work and Alzheimer's disease found in this study suggests that factors in the mid-twentieth century goods production environment may be involved in the development of Alzheimer's disease.

Education, occupation, and prevalence of dementia: findings from the Conselice study

Information about the epidemiology of dementia in Italy is still limited, although this cognitive disorder represents a serious public health concern. We estimated the prevalence of dementia and dementia subtypes in the elderly population of a Northern Italian municipality, Conselice, in the Emilia Romagna region (n = 1,016 subjects aged 65-97 years). The associations of dementia with two modifiable risk factors, education and occupation, were also evaluated. Overall dementia prevalence was 5.9% (95% confidence interval 4.3-7.8), exponentially increased with age, and was higher among women. Of the dementia cases, 50% were Alzheimer's disease (AD), but an unusually high prevalence (45%) was found for vascular dementia (VD). After adjustment for age and gender, education but not occupation was associated with both AD and VD. This association could not be explained by occupation, life habits, and previous history of hypertension or cardiovascular disease.

Dementia epidemiology

Determining the incidence and prevalence of dementia is an inexact science. Dementia is difficult to define and detect in the population. Even with the difficulties of determining prevalence and incidence, it is clear that dementia causes a substantial burden on our society. Problems with diagnostic inaccuracy and insidious disease onset influence our ability to observe risk factor associations; factors related to survival may be mistaken for risk/protective factors. Current studies suggest that factors influencing brain development or cognitive reserve may delay the onset of AD, perhaps through a protective mechanism or a delay in diagnosis caused by improved performance on cognitive tests. The recent identification of genes that cause dementia suggests that these genes or their biochemical pathways may be involved in the pathogenesis of nonfamilial cases. The contribution of genes that cause disease in and of themselves may be smaller than that of genes that act to metabolize or potentiate environmental exposures. The interaction between gene and environment should be increasingly well studied in the future. Epidemiology must take advantage of these molecular advances. The tasks of public health and epidemiology should still involve prevention, the nonrandom occurrence of disease, and its environmental context in addition to heredity. The tools to address these tasks should continue to be refined.

The challenge of assessing a patient with dementia and head injury

Alzheimer's disease is emerging as a major health challenge for the 21st century. The reported case study discusses a 74-year-old woman with dementia of the Alzheimer type who sustained a head injury when she fell down the basement stairs. Differentiating the head injury from the preexisting dementia was complicated and required creative and astute assessment. Objective assessment tools discussed include the Mini-Mental State Examination, a delirium guide, and the Tinetti assessment tool. Predisposition to delirium is significant because of the comorbidities associated with cognitive impairment and head injury. Interventions to prevent delirium are recommended.

Alzheimer's disease: its diagnosis and pathogenesis

A hypothesis has been presented that links many of the identified and putative risk factors for AD and suggests a mechanism for their action. Crawford (1996, 1998) proposes an association between AD and cerebral blood flow (CBF) by citing evidence that many of the factors that are linked with an increased risk of AD also decrease CBF (e.g., old age, depression, underactivity, head trauma). Similarly, it is suggested factors that increase CBF are associated with a decreased risk of AD (e.g., education, exercise, smoking, NSAIDs). Although the authors acknowledge that reduced CBF is not sufficient to cause AD, the reported positive and negative associations provide tantalizing evidence for a common mode of action for many of the equivocal risk factors reported to date. This hypothesis is also consistent with other data that links microvascular damage and impaired blood flow (de la Torre, 1997, 2000) and low education with increased cerebrovascular disease (Del Ser et al., 1999). Gaining a better understanding of the interaction between AD and vascular disease is of great importance. Not only will it provide insights into the pathogenesis of AD, but it may also provide us with a rare opportunity for the treatment and possible prevention of AD. A great many risk factors for vascular disease have been identified and intervention programs have successfully reduced the incidence of heart disease and stroke. The potential exists to provide the same level of success with AD.

Apolipoprotein E and intellectual achievement

OBJECTIVES

To determine whether apolipoprotein E (apo E) genotype influences intellectual achievement in cognitively normal individuals.

DESIGN

Between 1994 and 1999 we performed apo E testing on 1,000 self-described cognitively normal residents of Maricopa County and detailed neuropsychological testing on a subset of 250.

SETTING

Tertiary care academic medical center.

PARTICIPANTS

Cognitively normal adults genotyped for apo E.

MEASUREMENTS

Measures of intellectual background included years of education and a demographically based estimate of intellectual capacity (demographic intellectual quotient (DIQ)). Measures of intellectual achievement, which included Wechsler Adult Intelligence Scale revised (WAIS-R), information (WAISI), and vocabulary (WAISV) scores, occupational intellectual requirements (OIR), and census-derived estimates of household income, were compared between apo E genetic subgroups while adjusting for intellectual background and demographic variables.

RESULTS

WAISI, WAISV, OIR, and income correlated with age, sex, education, and DIQ, but after controlling for these variables there were no clinically significant differences between apo E-e4 homozygotes and noncarriers on any measure.

CONCLUSIONS

No clinically significant differences between genotypes were observed for the effects of education and DIQ on WAISI, WAISV, OIR, or income, although a larger sample size would be required to exclude smaller, clinically insignificant differences.