Estimating the burden of early onset dementia; systematic review of disease prevalence.

Dementia is more common in older age but a number of people develop symptoms at a younger age and are said to have early onset dementia (EOD). Those with EOD face different challenges to those with onset later in life. It has been difficult to quantify this disease burden. This is a systematic review of papers reporting on the prevalence of EOD. A search of Medline and Embase was performed. This was followed by a hand search of the references of these papers. Eleven suitable studies were included. All of the data was from more economically developed countries. The studies were heterogeneous in their design hindering direct comparison. The majority of the papers looked at all types of dementia although many gave a breakdown of the prevalence of different subgroups. A variety of diagnostic criteria was employed. Figures of 38 to 260 per 100,000 are quoted by papers looking at various different types of dementia together with an onset of between 30 and 64 or up to 420 per 100,000 for those aged 55-64. Prevalence rises as age approaches 65. Epidemiological data for prevalence rates for EOD are sparse. EOD remains a rare condition with low case numbers. Assimilation and comparison of results from existing studies is difficult due to methodological heterogeneity. Cross-national standardization of methodology should be a priority for future research in this area.

Incremental patterns in the amount of informal and formal care among non-demented and demented elderly persons: results from a 3-year follow-up population-based study.

OBJECTIVE: Elderly care includes complex interactions between formal services, informal care, morbidity and disabilities. Studies of the incremental effects of formal and informal care are rare and thus the objective was to describe the longitudinal patterns in formal and informal care given to non-demented and demented persons living in a rural area in Sweden. METHODS: Transitions in the Kungsholmen-Nordanstig Project (n=919) was followed up 3 years later (n=579), presented as different combinations of informal and formal care, institutionalization and mortality. Number of hours spent on care was examined by the Resource Utilization in Dementia instrument (RUD). Bootstrapped descriptive statistics and regression models were applied. RESULTS: The overall mortality during follow-up was 34%, and 15% had been institutionalized. Of those who lived at home, those receiving only formal care had been institutionalized to the greatest extent (29%; p<0.05). In terms of hours, informal care decreased amongst demented. The ratio between demented and non-demented was greater at baseline, both regarding informal care (10:1 and 3:1, respectively) and formal care (5:1 and 4:1, respectively). People with mild cognitive decline and no home support at baseline had a great risk of being receiver of care (formal or informal) or dead at follow-up. CONCLUSIONS: The amount of informal care was lower for demented persons still living at home at follow-up than at baseline, probably due to selection effects (institutionalization and mortality). Mild cognitive decline of non-users of care at baseline was strongly associated with receiving care or being dead at follow-up.

Uncontrolled diabetes increases the risk of Alzheimer's disease: a population-based cohort study.

AIMS/HYPOTHESIS: Diabetes has been related to Alzheimer's disease with inconsistent findings. We aimed to clarify the association of diabetes with different dementing disorders taking into account glycaemic control, and to explore the link between glucose dysregulation and neurodegeneration. METHODS: A dementia-free cohort (n = 1,248) aged >or=75 years was longitudinally examined to detect dementia, Alzheimer's disease and vascular dementia (VaD) cases (Diagnostic and Statistical Manual of Mental Disorders, revised third edition [DSM-III-R] criteria). The Alzheimer's disease diagnoses were subdivided into Alzheimer's disease with stroke and Alzheimer's disease without hypertension, heart disease and stroke. Diabetes was ascertained based on medical history, or hypoglycaemic medication use, or a random blood glucose level >or=11.0 mmol/l, which included undiagnosed diabetes when neither a history of diabetes nor hypoglycaemic drugs use was present. Uncontrolled diabetes was classified as a random blood glucose level >or=11.0 mmol/l in diabetic patients. Borderline diabetes was defined as a random blood glucose level of 7.8-11.0 mmol/l in diabetes-free individuals. Cox models were used to estimate HRs. RESULTS: During the 9 year follow-up, 420 individuals developed dementia, including 47 with VaD and 320 with Alzheimer's disease (of the 320 Alzheimer's disease cases, 78 had previous, temporally unrelated stroke, and 137 had no major vascular comorbidities). Overall diabetes was only related to VaD (HR 3.21, 95% CI 1.20-8.63). Undiagnosed diabetes led to an HR of 3.29 (95% CI 1.20-9.01) for Alzheimer's disease. Diabetic patients with random blood glucose levels <7.8 mmol/l showed no increased dementia risk. Uncontrolled and borderline diabetes were further associated with Alzheimer's disease without vascular comorbidities. CONCLUSIONS/INTERPRETATION: Uncontrolled diabetes increases the risk of Alzheimer's disease and VaD. Our findings suggest a direct link between glucose dysregulation and neurodegeneration.

The impact of chronic multimorbidity and disability on functional decline and survival in elderly persons. A community-based, longitudinal study.

OBJECTIVE: We aimed to disentangle the effect of chronic multimorbidity and disability on 3-year functional decline and survival in the elderly. DESIGN: Prospective cohort study with a mean of follow-up of 2.8 years. SETTING: Swedish elderly persons from the Kungsholmen Project (1987-2000). SUBJECTS: A total of 1099 subjects, 77-100 years old, living in the community and institutions. MAIN OUTCOME MEASUREMENTS: Medical diagnoses (based on clinical examination, drug use, medical records and blood tests), and functional assessment (according to Katz Index) at baseline were investigated in relation to functional decline and death occurring during follow-up. RESULTS: At baseline, 12.1% of participants had disability, and 52.3% were affected by multimorbidity. During follow-up, 363 persons died and 85 worsened in functioning. The number of chronic conditions incrementally increased the risk of functional decline [hazard ratio (HR) increased from 1.5 in subjects with one disease to 6.2 in persons with 4+ diseases]. However, this was not the case for mortality, as the HR of death was the same for people with one disease as well as 4+ diseases (HR=2.3). Baseline disability had the highest impact on survival, independently of number of diseases [HR=8.1; 95% confidence interval (CI)=4.8-13.7 in subjects with one disease and HR=7.7; 95% CI=4.7-12.6 in those with 2+ diseases]. CONCLUSIONS: In the elderly subjects, chronic disability rather than multimorbidity emerged as the strongest negative prognostic factor for functionality and survival.

Education and dementia: what lies behind the association?

BACKGROUND: Low education seems to be associated with an increased risk of dementia and Alzheimer disease (AD). People with low education have unhealthier lifestyles and more cardiovascular risk factors, but it is unclear how this affects the association between education and dementia. METHODS: Participants of the Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study were derived from random, population-based samples previously studied in a survey in 1972, 1977, 1982, or 1987. After an average follow-up of 21 years, 1,449 individuals (72%) aged 65 to 79 participated in a re-examination in 1998. RESULTS: Compared to individuals with formal education of 5 years or less, those with 6 to 8 years of education had OR of 0.57 (95% CI 0.29 to 1.13), and those with 9 years of education or more had OR of 0.16 (95% CI 0.06 to 0.41) for dementia. The corresponding ORs for AD were 0.49 (0.24 to 1.00) and 0.15 (0.05 to 0.40). The associations remained unchanged after adjustments for several demographic, socioeconomic, vascular, and lifestyle characteristics. The results were similar among both men and women. ApoE4 did not modify the association, but the risk of dementia and AD was very low among ApoE4 noncarriers with high education. CONCLUSIONS: The association between low education and dementia is probably not explained by the unhealthy lifestyles of the less educated compared with higher educated persons. Higher educated persons may have a greater cognitive reserve that can postpone the clinical manifestation of dementia. Unhealthy lifestyles may independently contribute to the depletion of this reserve or directly influence the underlying pathologic processes.

The amount of informal and formal care among non-demented and demented elderly persons-results from a Swedish population-based study.

BACKGROUND: Developed countries are experiencing a dramatic increase in the proportion of elderly persons, as well as a progressive aging of the elderly population itself. Knowledge regarding the amount of formal and informal care and its interaction at population-based level is limited. OBJECTIVES: To describe the amount of formal and informal care for non-demented and demented persons living at home in a population-based sample. METHODS: The population consisted of all inhabitants, 75 + years, living in a rural community (n = 740). They were clinically examined by physicians and interviewed by nurses. Dementia severity was measured according to Washington University Clinical Dementia Rating Scale (CDR). Informal and formal care was examined with the RUD (Resource Utilization in Dementia) instrument. RESULTS: The amount of informal care was much greater than formal care and also greater among demented than non-demented. There was a relationship between the severity of the cognitive decline and the amount of informal care while this pattern was weaker regarding formal care. Tobit regression analyses showed a clear association between the number of hours of informal and formal care and cognitive decline although this pattern was much stronger for informal than formal care. CONCLUSIONS: Informal care substitutes rather than compliments formal care and highlights the importance of future studies in order to truly estimate the amount of informal and formal care and the interaction between them. This knowledge will be of importance when planning the use of limited resources, and when supporting informal carers in their effort to care for their intimates.

[Epidemiology of aging with focus on physical and mental functional ability]. / Aldrandets epidemiologi med fokus på fysisk och mental funktionsförmåga.

In the past decades, the "graying" of the population has emerged as a world-wide phenomenon, leading to an increased interest in research on aging. Many population-based studies have been initiated in several countries, such as the Kungsholmen Project in Stockholm, Sweden. These studies have shown that older adults can be recruited to participate in intensive physiological and clinical evaluations, and that longitudinal surveys are well accepted by the elderly. Comorbidity and physical and mental functioning have emerged as important variables for describing health status and identifying risk factors. Dementia arose as one of the most common diseases in the very old, as dementia prevalence nearly doubles every fifth year. Some risk factors for Alzheimer's disease have been identified and interesting working hypotheses have been suggested. The natural history of the dementias have been sufficiently outlined for allocating medical and social resources, and for counseling patients and relatives.

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.

Morbidity and comorbidity in relation to functional status: a community-based study of the oldest old (90+ years).

OBJECTIVES: To describe health and functional status in the oldest old; to explore the relationships of morbidity and functional status; and to verify whether this relationship was modified by gender. DESIGN AND SETTING: A community-based survey including all inhabitants aged > or = 90 living in central Stockholm, Sweden. All participants were clinically examined by physicians, cognitively assessed by psychologists, and interviewed by nurses. Diagnoses were made according to the International Classification of Diseases-Ninth Revision (ICD-9), the DSM-III-R criteria for dementia, and Katz index of activities of daily living. PARTICIPANTS: Of the 698 subjects in the study population, 99 (14%) had died and 29 (4%) moved before examination. Of the remaining subjects, 502 (88.1%) were examined, and the refusal rate was 11.9%. MEASUREMENTS: Age- and gender-specific prevalence figures, and age-, gender- and education-adjusted odds ratios (OR) were used. RESULTS: Of 502 examined subjects, 19% had no disease and 73% were functionally independent. Dementia was the most prevalent disease among women (42.2%), and cardio- and cerebrovascular diseases were the most frequent among men (42.4%). Women had higher prevalences of dementia (adjusted OR = 2.1, 95% confidence interval (CI) 1.2-3.7) and fractures and musculoskeletal diseases (adjusted OR = 2.8, 95% CI 1.1-7.3), whereas men had a higher prevalence of malignancy (OR = 0.2, 95% CI 0.1-0.7). Women were more disabled than men independent of age, education, and number of diseases (adjusted OR = 2.2, 95% CI 1.1-4.3). CONCLUSIONS: A great proportion of nonagenarians were functionally independent despite their advanced age. Further studies are needed to clarify the excess of disability among very old women.

Aging and the occurrence of dementia: findings from a population-based cohort with a large sample of nonagenarians.

CONTEXT: In spite of numerous studies on the occurrence of dementia, many questions remain, such as the relation between age, aging, and dementing disorders. This question is relevant both for understanding the pathogenetic mechanism of the dementias and for the public health prospective because of the increasing number of 85-year-old or older persons in our population. OBJECTIVE: To estimate the occurrence of dementia in the very old, including nonagenarians, in relation to age, gender, and different dementia types. DESIGN: An epidemiological survey where all participants were clinically examined by physicians, assessed by psychologists, and interviewed by nurses. The Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition (DSM-III-R) criteria for dementia were followed. A category of "questionable dementia" was added when all criteria were not fulfilled. A double diagnostic procedure was used for all subjects. SETTING: Community-based population, including all inhabitants of 2 areas in central Stockholm, Sweden (N = 1848). PARTICIPANTS: Of the 1848 subjects in the study population, 168 (9.1%) had died and 56 (3%) moved before examination. Of the remaining subjects, 1424 (87.7%) were examined, and the refusal rate was 12.3%. MAIN OUTCOME MEASURES: Age- and gender-specific prevalence figures, and gender- and education-adjusted odds ratios were used. RESULTS: At the end of the diagnostic procedure, 358 clinically definite cases of dementia and 101 questionable cases of dementia were identified. Alzheimer disease (AD) contributed to 76.5%, and vascular dementia (VaD) to 17.9%. The prevalence of dementia increases from 13% in the 77- to 84-year-old subjects to 48% among persons 95 years and older (from 18% to 61% when questionable cases were included). The odds ratio for subjects 90 to 94 years and 95 years and older in comparison with 77- to 84-year-old subjects was 3.7 (95% confidence interval [CI], 2.7-5.1) and 6.5 (95% CI, 3.9-10.8) for dementia, 4.8 (95% CI, 3.3-7.0) and 8.0 (95% CI, 4.6-14.0) for persons with AD, 2.3 (95% CI, 1.3-4.2) and 4.6 (95% CI, 1.9-11.2) for VaD, respectively. CONCLUSIONS: Dementia prevalence continues to increase even in the most advanced ages. This increase is especially evident among women and is more clear for AD. We believe that our prevalence data reflect the differential distribution of dementia risk.

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.

Attitudes and participation of the elderly in population surveys: data from a longitudinal study on aging and dementia in Stockholm.

The aim of this article was to assess the attitudes of older adults (age >74 years) toward research participation. A questionnaire was mailed to the study population (n=1197) which included people who had participated in a longitudinal study once, twice, three times, or more. The participants showed a positive attitude in general as 79% saw an advantage of participation and 72% did not report any negative reaction. Older elderly with impaired cognitive functioning and lower education showed the least positive attitude, reporting the first contact and the cognitive testing as the most stressful situations. The group who had participated more than once was the most positive, but more often refused some parts of the clinical examination. We conclude that: (1) more attention is necessary to the initial contact; (2) reduction of stressful or tiring examinations is recommended; and (3) complete information about the research, including the right to refuse individual parts of the study, must be given. Such procedures will improve both the quality and the ethics of the research.

Very old women at highest risk of dementia and Alzheimer's disease: incidence data from the Kungsholmen Project, Stockholm.

OBJECTIVE: To determine the incidence of different types of dementia in the very old, and to explore the relation with age and gender. DESIGN: A dementia-free cohort was followed for an average of three years in Stockholm, Sweden. At the end of the follow-up, the subjects were interviewed by nurses, clinically examined by physicians, and cognitively assessed by psychologists. Deceased cohort members were studied using death certificates, hospital clinical records, and discharge diagnoses. Dementia diagnoses were made according to the DSM-III-R criteria independently by two physicians. PARTICIPANTS: The cohort consisted of 1,473 subjects (75+ years old), of which 987 were clinically examined at follow-up, 314 died before the examination, and 172 refused to participate. RESULTS: During the follow-up, 148 subjects developed dementia. In the age-group 75 to 79, the incidence rates for dementia were 19.6 for women and 12.4 for men per 1,000 person-years, whereas for 90+ year-old subjects the corresponding figures were 86.7 and 15.0 per 1,000 person-years. A similar pattern of distribution by age and gender was seen for Alzheimer's disease. In each age stratum, the incidence rates of dementia and Alzheimer's disease were higher for women than for men. The age-adjusted odds ratio for women was 1.9 for dementia and 3.1 for Alzheimer's disease. CONCLUSIONS: (1) The incidence of dementia increases with age, even in the oldest age groups; (2) women have a higher risk of developing dementia than men, especially at very old ages; (3) this pattern is mainly due to the age and gender distribution of Alzheimer's disease, rather than vascular dementia.

Prevalence and correlates of depression in a population of nonagenarians.

BACKGROUND: Clinicians see many more nonagenarian patients now and there is a need for epidemiological data relating to this group. The aim of the present study was to investigate the prevalence of depressive symptoms and syndromes in this age group. METHOD: The DSM-IV and the ICD-10 criteria for depression were used and correlated with physical health, disability in daily life, gender, use of drugs, social circumstances and cognitive dysfunction. Data were derived from 329 persons aged 90 and over, registered in a parish of Stockholm, who had been extensively examined by physicians and nurses. RESULTS/CONCLUSIONS: The prevalence of Major Depressive Episode as defined in DSM-IV was 7.9%; and of mild, moderate and severe Depressive Episode (combined); as defined in ICD-10 9.1%. No gender difference was found. Disability in daily life and the use of psychotropic drugs were found to correlate with depressive symptoms and syndromes.