The influence of education on clinically diagnosed dementia incidence and mortality data from the Kungsholmen Project.

BACKGROUND: The relationship between education and Alzheimer disease (AD) or dementia has been widely examined and the evidence obtained is mixed. Several hypotheses have been proposed to explain the observed association between them. OBJECTIVE: To further understand the relationship between education and incidence of clinically diagnosed AD or dementia. SUBJECTS AND METHODS: A community-based, dementia-free cohort of 1296 aged 75 years and older was followed up to detect incident AD or dementia cases using Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition criteria. The vital status of all subjects who underwent the clinical examination at follow-up (n = 983) was ascertained for 5 years further. Data were analyzed with Cox proportional hazards model after adjustment for main potential confounders. RESULTS: Over an average (SD) of 2.8 (1.0) years of follow-up, 147 subjects were diagnosed as having dementia (109 subjects as having AD). Among those who were clinically examined at follow-up, 88 died with dementia (68 died with AD) within 5 years. Subjects with a low level of education (<8 vs > or =8 years) had a relative risk of 2.6 (95% confidence interval, 1.5-4.4) for AD and 1.7 (95% confidence interval, 1.1-2.6) for dementia. A low educational level was significantly related to all-cause mortality (relative risk, 1.3; 95% confidence interval, 1.0-1.7; P<.05), but not to the mortality of subjects with AD (relative risk, 1.1; 95% confidence interval, 0.5-2.2) or dementia (relative risk, 0.9; 95% confidence interval, 0.5-1.5). CONCLUSIONS: A low level of education is related to an increased incidence of clinical AD or dementia, but not to the mortality of subjects with AD or dementia. These findings can be accounted for by the "cognitive reserve" hypothesis. Alternatively, the observed association between educational level and incidence of AD or dementia may partly reflect detection bias, by which subjects with a low level of education tend to be clinically diagnosed at an earlier point in time.

Mortality from dementia in advanced age: a 5-year follow-up study of incident dementia cases.

Five-year follow-up of a community-based, 77+ old cohort including incident dementia cases was used to evaluate the impact of dementia on the risk of death, taking into account other chronic conditions potentially related to death, and contrasting Alzheimer's disease (AD), and vascular dementia (VaD). In this population, 70% of the dementia cases died during the five years after diagnosis, with a mortality rate specific for dementia of 2.4 per 100 person-years. After controlling for sociodemographic variables and comorbidity, 14% of all deaths could be attributed to dementia with a risk of death among demented subjects twice as high as that for non-demented people. Mortality risk ratios were 2.0 (95% confidence interval 1.5-2.7) for AD and 3.3 (95% confidence interval 2.0-5.3) for VaD. This study confirms that dementing disorders are a major risk factor for death. Even in the oldest old (85+), dementia shortens life, especially among women.

Institutionalization in the elderly: the role of chronic diseases and dementia. Cross-sectional and longitudinal data from a population-based study.

A population-based study of 1810 persons, aged 75+, was investigated to evaluate the role of dementia and other chronic diseases as determinants of institutionalization in the elderly. The study population was examined at baseline and after a 3-year interval. After adjustment for sociodemographic characteristics, functional dependence, dementia, cerebrovascular disease and hip fracture were associated with living in an institution at baseline. Additionally, functional dependence, hip fracture and dementia were also associated with moving to an institution during the 3-year follow-up. In a similar analysis, including only nondemented subjects, the Mini-Mental State Examination emerged as one of the strongest determinants. The population attributable risk percentage of institutionalization during the 3-year follow-up due to dementia was 61%. This study confirms that dementia and cognitive impairment are the main contributors to institutionalization in the elderly, independently of their sociodemographic status, social network, or functional status.

Prognostic factors in very old demented adults: a seven-year follow-up from a population-based survey in Stockholm.

OBJECTIVE: To detect prognostic factors in very old demented subjects with Alzheimer's disease (AD), vascular dementia (VaD), and other types of dementia (OD). DESIGN: Follow-up clinical examinations of dementia patients from a population-based study after 3- and 7-year intervals. SETTING AND PARTICIPANTS: In an established population aged 75 years and older in Stockholm, Sweden, there were 133 cases of AD, 52 of VaD, and 38 of OD. MAIN OUTCOME MEASURES: Predictors of survival at 3- and 7-year follow-up examinations were evaluated by Cox proportional hazard models. Progression was measured as the annual rate of change in Mini-Mental State Examination (MMSE) scores. Linear models were used to evaluate predictors of progression. RESULTS: Older age, male gender, low education, comorbidity, and functional disability predicted shorter 7-year survival in the 223 prevalent dementia cases. Other factors, including type of dementia, dementia severity, and duration of the disease were not significant. The average rate of cognitive decline in the 81 mild to moderate demented subjects who survived 3 years was 2.4 MMSE points per year. Type of dementia (AD vs OD), higher baseline cognitive function, and greater functional disability predicted faster decline. Despite similar survival probability, predictors of death varied as a function of dementia type: Older age (for AD and VaD), comorbidity (for AD and OD), and functional dependency (for VaD). In AD, prognostic factors were similar to those described for the combined dementia groups, with the exception of an accelerated cognitive decline among women. CONCLUSIONS: Although methodological difficulties exist, it is possible to identify demented subjects with worse prognoses (shorter survival and faster cognitive decline) by using clinical and demographic data. Clinicians and healthcare planners should be aware of the potential usefulness of functional dependence as a prognostic indicator. Finally, the need for careful clinical examinations of demented subjects is stressed by the increased mortality found among those demented who are also affected by other chronic conditions.

Alzheimer's disease and vascular dementia. Some points of confluence.

The lack of biologic markers for Alzheimer's disease and vascular dementia, the controversy regarding the definition of vascular dementia, and the new evidence of vascular risk factors for Alzheimer's disease suggest that the traditional differentiation between Alzheimer's disease and vascular dementia is no longer very clear. We believe that both vascular and degenerative mechanisms contribute to the development of dementia, especially in very old age. The question of whether they are two independent parallel processes or interacting pathologies needs to be clarified.

Worldwide prevalence and incidence of dementia.

Dementia is a common and disabling disorder in the elderly. Because of the worldwide aging phenomenon, existing in both developed and developing countries, dementia has a growing public health relevance. This article reviews the prevalence and incidence data for dementia reported in the international literature in the last 10 years. Results from 36 prevalence and 15 incidence studies have been examined. Prevalence is equal to 0.3 to 1.0 per 100 people in individuals aged 60 to 64 years, and increases to 42.3 to 68.3 per 100 people in individuals 95 years and older. The incidence varies from 0.8 to 4.0 per 1,000 person years in people aged 60 to 64 years, and increases to 49.8 to 135.7 per 1,000 person years when the population was older than 95 years. The international comparison allows the following conclusions: (i) both prevalence and incidence show little geographical variation, as differences between countries seem to reflect methodological rather than real differences [the low prevalence of dementia in Africa needs to be confirmed by incidence data]; (ii) both incidence and prevalence figures increase with age even in the advanced ages; (iii) regarding dementia types, most of the inconsistency in results from different studies is due to vascular dementia rather than to Alzheimer's disease (AD); (iv) it is still unclear if the reported higher frequency of vascular dementia in Asian populations is due to differential distribution of genetic and/or environmental factors, or due to methodological differences; (v) different dementia types might have different age distributions.

Epidemiology of vascular dementia: some results despite research limitations.

Vascular dementia, the second most common dementia after Alzheimer disease, has great potential for prevention and treatment. Epidemiological data provide the basis for planning primary prevention and clinical trials. Nevertheless, general consensus on disease definition and diagnostic criteria are still not well defined. Despite these limitations, some results from the Kungsholmen project, an epidemiological longitudinal study of people 75 years and older, are presented here.

Natural history of Alzheimer's disease and other dementias: review of the literature in the light of the findings from the Kungsholmen Project.

The elderly population is increasing more than any other sector of the population. Dementia, a prevalent condition in the elderly, increases disability, morbidity and mortality among older people. For these reasons the possibility of predicting progression and prognosis has enormous importance. Despite the fact that dementia has gained widespread recognition in the past few decades, the knowledge of its natural history, in terms of progression and prognosis are not yet completely understood. However, thanks to longitudinal research, which has only recently begun to proliferate, not only is better comprehension of the continuity of the cognitive decline possible, but also the identification of some prognostic factors.

Risk and protective effects of the APOE gene towards Alzheimer's disease in the Kungsholmen project: variation by age and sex.

BACKGROUND: The risk effect of APOE epsilon 4 allele for Alzheimer's disease is acknowledged, whereas the putative protective effect of epsilon 2 allele remains in debate. OBJECTIVES: To investigate whether those inconsistent findings may be attributable to differences in age and sex composition of the study populations. METHODS: A community dementia free cohort (n = 985) aged > or =75 years was followed up to detect Alzheimer's disease cases (DSM-III-R criteria). Data were analysed using Cox models with adjustment for major potential confounders. RESULTS: Over a median 5.6 year follow up, Alzheimer's disease was diagnosed in 206 subjects. Compared with APOE epsilon 3/epsilon 3 genotype, the relative risk (RR) of Alzheimer's disease was 1.4 (95% confidence interval (CI), 1.0 to 2.0; p = 0.03) for heterozygous epsilon 4 allele and 3.1 (95% CI, 1.6 to 5.9) for homozygous epsilon 4 allele. The association between epsilon 4 allele and Alzheimer's disease risk was stronger in men than in women (RR related to the interaction term epsilon 4 allele by sex, 0.4; 95% CI, 0.2 to 0.9). The epsilon 4 allele accounted for one third of Alzheimer's disease cases among men, but only one tenth among women. The epsilon 2 allele was related to a reduced Alzheimer's disease risk mainly in people aged <85 years (RR, 0.4; 95% CI, 0.2 to 0.8). The RR of Alzheimer's disease related to the interaction term of epsilon 2 allele by age was 2.4 (95% CI, 1.0 to 6.0; p = 0.06). CONCLUSIONS: The APOE genotype specific effects on Alzheimer's disease vary by age and sex, in which the epsilon 4 allele has a stronger risk effect in men, and the epsilon 2 allele confers a protective effect only in younger-old people.

Association of stroke with dementia, cognitive impairment, and functional disability in the very old: a population-based study.

BACKGROUND AND PURPOSE: Stroke is a major cause of disability in the elderly and is also related to the development of dementia, which is another important source of disability in old age. The aim of the present study was to examine the potential impact of stroke on cognitive and functional status in a community-based cohort of individuals aged 75 years and older. METHODS: The data were derived from a cross-sectional survey on aging and dementia that included all inhabitants of the Kungsholmen district in central Stockholm who were aged >/=75 years. Cases of stroke were identified through the computerized inpatient register system that has been widely used to study stroke in Sweden. Dementia was defined according to the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised. Dementia onset was considered the appearance, according to an informant, of the first symptom. Cognitive impairment without dementia was defined as the presence of a Mini-Mental State Examination score of <24 and the absence of dementia. Functional disability was assessed according to Katz Index of independence in activities of daily living. RESULTS: The prevalence of stroke was 10. 0% in men and 8.0% in women. One third of stroke survivors were diagnosed as demented, which was 3 times higher than those without stroke: adjusted odds ratio (OR) was 3.6 (95% confidence interval, 2. 5 to 5.8). Stroke was also significantly related to cognitive impairment without dementia (adjusted OR, 2.4 [95% confidence interval, 1.3 to 4.6]). The population-attributable risks of dementia and cognitive impairment in relation to stroke were 18.4% and 8.5%, respectively. Among the 49 stroke patients with dementia, 15 cases (30.6%) had missing information on dementia onset, 22 (44. 9%) had been reported by the informant to have dementia-related symptoms after or close to the occurrence of stroke, and 12 (24.5%) had symptoms before stroke occurrence. The prevalence rates of disability in activities of daily living were much higher among stroke patients than among stroke-free subjects, even after adjustment for age, sex, heart disease, hip fracture, and dementia: the corresponding adjusted ORs for bathing, dressing, toileting, transfer, and continence were 3.5 (2.4 to 5.3), 2.2 (1.4 to 3.3), 3. 0 (2.0 to 4.5), 3.3 (1.9 to 5.7), and 2.1 (1.3 to 3.3), respectively. After dementia and hip fracture, stroke was the third largest contributor to disability in bathing, dressing, and transfer. Stroke was the second contributor to disability in toileting. CONCLUSIONS: Stroke is strongly associated with dementia, although it may relate to dementia in different ways: it can be the main cause or a precipitating factor of dementia, or they may share common etiological bases. Together with dementia and hip fracture, stroke is a major contributor to disability in most aspects of activities of daily living in very old people.

Dementia is the major cause of functional dependence in the elderly: 3-year follow-up data from a population-based study.

OBJECTIVES: The purpose of this investigation was to study the role of dementia and other common age-related diseases as determinants of dependence in activities of daily living (ADL) in the elderly. METHODS: The study population consisted of 1745 persons, aged 75 years and older, living in a district of Stockholm. They were examined at baseline and after a 3-year follow-up interval. Katz's index was used to measure functional status. Functional dependence at baseline, functional decline, and development of functional dependence at follow-up were examined in relation to sociodemographic characteristics and chronic conditions. RESULTS: At baseline, factors associated with functional dependence were age, dementia, cerebrovascular disease, heart disease, and hip fracture. However, only age and dementia were associated with the development of functional dependence and decline after 3 years. In a similar analysis, including only nondemented subjects. Mini-Mental State Examination scores emerged as one of the strongest determinants. The population attributable risk percentage of dementia in the development of functional dependence was 49%. CONCLUSIONS: In a very old population, dementia and cognitive impairment make the strongest contribution to both the development of long-term functional dependence and decline in function.

Cognitive support at episodic encoding and retrieval: similar patterns of utilization in community-based samples of Alzheimer's disease and vascular dementia patients.

The hypothesis that Alzheimer's disease (AD) and vascular dementia (VaD) differ in the pattern of episodic memory was examined in this study. Demented patients with AD and VaD and normal old adults were assessed on episodic memory tasks, including free recall and recognition of slowly and rapidly presented unrelated words and free and cued recall of organizable words. Results showed a general deficit in both demented groups across all memory variables, although the AD and VaD patients were indistinguishable across all measures. The normal old showed proficient utilization of more study time, organizability, and category cues. By contrast, the AD and VaD patients were able to benefit from cognitive support only when guidance was provided at both encoding and retrieval. In addition, in the normal old, recall of unrelated words was characterized by a relatively equal contribution from primary and secondary memory, whereas the demented patients relied predominantly on primary memory. The results suggests a similarity between AD and VaD patients with regard to the nature of the episodic memory impairment, despite etiologic differences between the diseases.

Severity of dementia and institutionalization in the elderly: prevalence data from an urban area in Sweden.

This study investigated the severity of dementia in relation to disease type and sociodemographic variables. The dementia cases were detected with a two-phase study design in a population aged over 74 years in Stockholm. The prevalence of questionable, mild, moderate, and severe dementia was 1.0, 3.1, 5.5, and 2.3 per 100, respectively. Women aged over 84 had the highest prevalence of severe dementia. More severe cases and a higher institutionalization rate were present for vascular dementia than for Alzheimer's disease. Fifty-five percent of the demented subjects but only 3% of the nondemented were institutionalized. The institutionalized demented subjects were affected mostly by moderate-severe dementia (88.6%), while the noninstitutionalized were affected more often by a questionable-mild form (68.3%).

Hypertension in the elderly population: prevalence data from an urban area in Sweden.

Data from the total urban elderly population (75 years and older) in Kungsholmen, Stockholm, were used to calculate age- and sex-specific prevalence of hypertension. Blood pressure was measured as part of the examination in the population survey (the Kungsholmen Project). The blood pressure of 1751 elderly people and any antihypertensive treatment were recorded. The prevalence of hypertension was 54 and 59 per 100 population for men and women, respectively. No great variation was observed with age or sex. Isolated systolic hypertension was most frequent with increasing prevalence in advanced ages, while isolated diastolic hypertension and systolic and diastolic hypertension showed a tendency of decreased prevalence with age. In the subjects studied, 18% were being treated for hypertension. Hypertension was detected in 47% of those not undergoing treatment. Among those, 76% had high blood pressure measurements. Our data demonstrate that hypertension is a prevalent disease in the very old, in both sexes, and support the need for hypertension screening programs as well as programs to evaluate the efficacy and benefits of treatment in this age group.