Incidence and lifetime risk of dementia and Alzheimer's disease in a Southern European population

Lobo A, Lopez‐Anton R, Santabárbara J, de‐la‐Cámara C, Ventura T, Quintanilla MA, Roy JF, Campayo AJ, Lobo E, Palomo T, Rodriguez‐Jimenez R, Saz P, Marcos G. Incidence and lifetime risk of dementia and Alzheimer’s disease in a Southern European population. Objective: To calculate both the incidence rates and the lifetime risk (LTR) of dementia and Alzheimer’s disease (AD). Methods: A two‐phase case‐finding procedure was implemented in a cohort of 4057 cognitively intact individuals 55+ years of age living in Zaragoza, Spain, and followed‐up at 2.5 and 4.5 years. Age‐ and sex‐specific incidence rates were calculated. A mortality‐adjusted, multivariate model was used to document LTRs. Results: The incidence rate of dementia continued to rise after the age of 90 years, but was slightly lower than in North and West European studies. Only a tendency for an increased LTR with age was observed. Thus, LTR was 19.7% for a 65‐year‐old woman and 20.4% at the age of 85 years, the corresponding figures for AD being 16.7% and 17.6%. The LTR of AD was higher in women and was about twice as high among illiterate individuals when compared with individuals with higher educational levels. Conclusions: The incidence rate of dementia in this Southern European city was slightly lower than in previous studies in North‐West Europe. LTR of dementia and AD seems to be slightly increased with age. The association of illiteracy with higher LTR of AD is intriguing.     

Prevalence of very mild to severe dementia in Denmark

Objectives - The prevalence of dementia has been estimated in several countries and a meta-analysis has shown moderate and severe dementia in people aged 65 years and older to be between 4% and 6%. The Odense study is aiming to estimate the prevalence and incidence of dementia and to identify risk factors. Material and methods - A total of 3346 persons, equivalent to 64.5% of a random sample of 5237 persons aged 65–84 years living in the municipality of Odense, Denmark, underwent a two phase diagnostic procedure including a screening with CAMCOG, the cognitive section of The Cambridge Examination for Mental Disorders of the Elderly, seven neuropsychological tests, medical examination, and CT scan. The severity of dementia was assessed by the CDR (Clinical Dementia Rating). Results - The prevalence rate was 7.1%, including the very mildly demented, defined as persons rated questionably demented according to the CDR scale. The prevalence rate of very mild dementia was 2.8%. The proportion of cases with very mild dementia decreased with increasing age while the prevalence rate increased. Conclusion - Inclusion of very mild cases of dementia resulted in a higher prevalence rate than generally reported, and the prevalence rate increased exponentially with age which was mainly due to Alzheimer's disease.     

The Comprehensive Psychopathological Rating Scale in patients with dementia of Alzheimer type and multiinfarct dementia

ABSTRACT– Eighteen patients with the clinical diagnosis dementia of Alzheimer type (AD/SDAT) and 20 patients with the clinical diagnosis multiinfarct dementia (MID) were interviewed using a subscale to the Comprehensive Psychopathological Rating Scale (CPRS), consisting of items measuring psychopathological symptoms and signs commonly seen in patients with dementia. The aim of the investigation was to evaluate whether a difference in psychopathology between AD/SDAT and MID could be observed during a semistructured psychiatric interview using the CPRS. In both groups the duration of illness was similar and the dementia mild to moderate. All patients were subjected to somatic, psychiatric, laboratory, neurophysiologic and neuroradiologic examinations in order to obtain the correct clinical diagnoses. The results show that patients with AD/SDAT have a more variable psychopathology than patients with MID. Patients with MID were rated lower on all items used, especially those concerning verbal and personal contact. This might explain the generally accepted opinion that patients with MID have better contact with their surroundings and better preservation of their personality, even though they have the same degree of dementia as patients with AD/SDAT.     

The prevalence of dementia as measured by the Cambridge Mental Disorders of the Elderly Examination

General practice patients aged 75 years and over were screened for cognitive impairment using the Mini-Mental State Examination. Those scoring 23 or below and a sample of those scoring 24 or 25 were assessed using the Cambridge Mental Disorders of the Elderly Examination (CAMDEX), a structured interview schedule specifically designed to detect mild dementia. The CAMDEX includes a mental state examination, a psychiatric history, detailed cognitive testing and an information interview. The prevalence of dementia in 2311 patients was found to be 10.5%, about half that found in most earlier studies. Possible reasons for this low rate are discussed.     

Epidemiology of dementia in Ashkelon

A population study aimed at evaluating the influence of education on the prevalence of dementia was carried out in Ashkelon, a rural city in Israel. The whole population aged over 75 years was screened, with a very low refusal rate. Altogether, 1501 people were examined, using DSM III-R criteria for dementia. The prevalence of dementia increased with age and was higher among females and immigrants to Israel from Africa and Asia. The most significant correlation was with a low level of education, which completely explained the ethnic differences and partially the female predominance in the frequency of dementia. Our study confirms that schooling appears to be an important protective factor against the development of dementia. Received: 24 October 2000, Received in revised form: 13 August 2002, Accepted: 14 October 2002 This study was partially supported by grants from the Chief Scientist of the Ministry of Health, Israel, and from the Miriam Turjanski de-Gold and Dr. Roberto Gold Fund for neurological research, Argentina. Correspondence to Professor A. D. Korczyn     

Epidemiology of dementia in Nigeria: results from the Indianapolis–Ibadan study

We determined the prevalence of dementia in a cohort of 2494 elderly Nigerians residents in Idikan Community, Ibadan, Nigeria. We utilized the Community Screening Instrument for Dementia to select subjects for clinical assessment in the second stage. The findings were compared with those of 2212 African Americans living in Indianapolis, studied simultaneously using similar methodology. The overall age-adjusted prevalence rates of dementia and Alzheimer's disease in Ibadan were 2.29% and 1.41%, respectively. These rates were much lower than the respective values of 8.24% and 6.24% obtained for African Americans. In Ibadan, Alzheimer's disease accounted for 64.3% of the cases, with old age and female gender being the significant risk factors, whilst 'living with others' appeared to be protective (P < 0.05). Amongst African Americans, on the other hand, old age, rural living below the age of 19 years, low educational attainment and family history of dementia were the risk factors. There was a lack of association between Alzheimer's disease and possession of the apolipoprotein E epsilon4 allele in the Nigerian sample, unlike the finding in African Americans, where significant association was shown. In addition, the frequencies of the vascular risk factors investigated were lower in Nigerians. Our results showed lower prevalence of dementia and Alzheimer's disease in Nigerians, compared with African Americans. There was no association between Alzheimer's disease and apolipoprotein E (epsilon4 allele) in the former. The differences in the frequencies of vascular risk factors between Nigerian subjects and African Americans would suggest involvement of environmental factors in disease process.     

Prevalence of dementia in a Japanese elderly population

The geriatric community study was conducted by the Aichi Prefecture (Japan) Project. The psychiatric epidemiological survey was conducted using a stratified random sampling method. 3106 community residents over the age of 65 years, randomly selected from the whole Aichi Prefecture of Japan, were interviewed; 476 had suspected dementia. The second interviews and the neurologic examinations were carried out by psychiatrists. The prevalence of dementia was estimated to be 5.8% (moderate and severe, 2.2%; mild 3.6%) of the aged population in the community. Cerebrovascular dementia (CVD) or multi-infarct dementia (MID) was found in 2.8%, senile dementia of the Alzheimer type (SDAT) in 2.4%, and dementia due to other causes in 0.6%. CVD (MID) was diagnosed more frequently in men, and SDAT in women.     

Prevalence of Alzheimer's type dementia in an elderly Arab population.

The aim of this study was to estimate the prevalence of dementia of the Alzheimer type (DAT) in an Arab Israeli community. Epidemiological studies of dementia have rarely been reported in Arab populations. The target population, aged 60 years or older, comprised 821 persons (362 males) who, on 1 October 1995, were residents of the rural area of Wadi Ara. These persons were examined for symptoms of dementia (DSM-IV criteria), using a semistructured questionnaire for collection of demographic and medical data. Age, gender, and education-specific prevalence rates were calculated for this population and compared to those obtained in other studies. DAT was diagnosed in 20.5% of this population. Its prevalence increased steeply with age, from 8% among those younger than 70 years to 33% among those aged 70-79 and 51% among those 80 years or older. Illiteracy was very common in this population, and strongly associated with higher prevalence of DAT (27% vs. 4%, P < 0.001). DAT was more prevalent among females than males (25% vs. 15%, P < 0.001). However, illiteracy was also significantly more frequent among women (96% vs. 42%, P < 0.001). After correction for illiteracy, the gender difference lost statistical significance. Few women smoked, but among men, the prevalence of DAT in those who smoked was lower as compared to non-smokers (14% vs. 23%, a non-significant difference). These results were confirmed by logistic regression wherein DAT was included as the dependent variable and age, illiteracy, gender and smoking as independent variables (OR=2.8, 2.8, 1.2 and 0.7, respectively; P < 0.005 for each, except for smoking). Our findings suggest that this population is unique because of extremely high rates of dementia. While the results support a protective effect of schooling against the development of dementia, other factors (e.g. genetic) must be sought to explain this high frequency.     

Prevalence of dementia in the city of Helsinki

The Helsinki Aging Study is based on a random sample of 795 subjects aged 75-years (N = 274), 80-years (N = 266) and 85-years (N = 255). A clinical examination including Clinical Dementia Rating (CDR)-scale was carried out in 82% of the cases. 93 demented subjects were found, 17 of whom had mild dementia. The prevalence of moderate and severe dementia was 2.9%, 10.3% and 23.3% in the age groups of 75-year-olds, 80-year-olds and 85-year-olds, respectively. If we take into account also the mild cases, we get the prevalence of dementia 4.6%, 13.1% and 26.7% in the above mentioned age groups, respectively. The proportion of mild dementias was lower than expected, which probably reflects both the difficulties to recognize mild dementia in an elderly population and the relatively small compensatory capacity of elderly people.     

The GBS scale in multi-infarct dementia and senile dementia of Alzheimer type

The GBS profile was assessed for 39 patients with multi-infarct dementia (MID) and 34 patients with senile dementia of Alzheimer type (SDAT). The MID patients fulfilled the DSM-III criteria for multi-infarct dementia and had a score of 7 points or more on the Hachinski Ischemic Scale (HIS) and a score of 4 points or less on the Gustafson/Nilsson Alzheimer Scale (GNAS). The SDAT patients fulfilled DSM-III criteria for primary degenerative dementia and had a score of 5 points or more on the GNAS and a score of 6 points or less on the HIS. The total GBS score, the GBS subscale and relative subscale scores for intellectual functioning were significantly higher in patients with SDAT as compared with patients with MID. However, these subscale scores were considerably dispersed and nearly totally overlapping between patients with MID and SDAT, which implicates that the discriminative value is minimal. The validity between the GBS versus HIS and between the GBS versus GNAS was divergent, suggesting that the GBS scale has its own unique validity. In conclusion, the study does not support the hypothesis that the GBS profile may be of diagnostic value in clinical differentiation between multi-infarct dementia (MID) and senile dementia of Alzheimer type (SDAT).     

Stroke Epidemiology in Argentina. Design of a Population-Based Study in General Villegas (EstEPA)

Background

Epidemiological data on stroke is scarce in Latin America. Estudio Epidemiológico Poblacional sobre Accidente Cerebrovascular (EstEPA) is a population-based program planned to assess prevalence, incidence, mortality, and burden of disease for stroke in the Department of General Villegas, province of Buenos Aires, Argentina.

A survey of services for younger people with dementia

Objective. To identify the provision of services for younger people with dementia by trusts in England and to examine their attitudes towards specialization. Design. Postal survey. Participants. Hospital and community trusts in England. Of 354 trusts, 304 responded (84%). Main outcome measures. Provision of general adult and old age psychiatry services: type of services provided for younger people with dementia and specialists providing these services; provision of specialists services for younger people with dementia; attitudes towards developing specialists services; assessment of need. Results. The majority of services were provided by trusts with existing psychiatric services, in particular old age psychiatry services. Specialization was uncommon and practised by only 12 trusts. In contrast, 101 trusts saw the development of specialists services as ‘necessary’, especially those trusts who had investigated the needs of younger patients with dementia (p = 0.001). Conclusion. This survey supports the notion that trusts and purchasers should undertake to assess the needs of younger patients with dementia. Role of specialization is discussed. © 1997 John Wiley & Sons, Ltd.     

Epidemiology of multiple sclerosis in the Canary Islands (Spain): a study on the island of La Palma

Objective: To determine the prevalence of multiple sclerosis (MS) on the Island of La Palma, Canary Islands, Spain. Methods: A population-based transverse study was carried out on the Island of La Palma (population: 81,507), from 1995 to 1998. The 15 December 1998 was established as prevalence day. Sources of information were periodically obtained from case records from public primary care centres, private hospitals, private centres, magnetic resonance units and others. In accordance with the Poser criteria all cases of definite or probable MS were included. Results: 34 cases of MS were found on prevalence day (9 male and 25 female): 32 cases were clinically definite and 2 were clinically probable MS. Crude prevalence was 42/100,000. Incidence during time of study was 2.25/100,000. Conclusions: The island of La Palma could be considered as an area of medium-high risk, the risk being higher than that expected because of the geographical latitude of the island. This study confirms the hypothesis of the high prevalence of MS in Spain. We have not found significant clinical differences in MS patients from those in other studies. Received: 7 August 2000, Received in revised form: 22 November 2001, Accepted: 16 April 2002 Correspondence to M. A. Hernández     

Event-Related Potentials in Senile Dementia of Alzheimer's Type, Multiinfarct Dementia and Parkinson's Disease

Abstract: We investigated event-related potentials (P300) in three types of demented patients. Fourteen patients with senile dementia of Alzheimer's type (SDAT), 15 with multiinfarct dementia (MID), 8 with Parkinson's disease with dementia and 29 normal controls participated in this study. We measured the latencies of N100 and P300 at Pz after odd-ball paradigm stimulation. N100 peaks were within the normal range in all patients. However, P300 peaks were significantly delayed in all demented patients. There were no statistical differences in the mean latencies of P300 in each demented group. P300 latencies were found to be negatively correlated with Hasegawa's dementia scale. These results suggest that regardless of its cause dementia has similar influences on the P300 latency and P300 may be a useful means to assess the degree of dementia.     

Prevalence of dementia in a semi-urban population in Sri Lanka: report from a regional survey

BACKGROUND: The prevalence of dementia in Sri Lanka, which has a rapidly ageing population, is unknown. OBJECTIVE: This study aimed to determine the prevalence of Alzheimer's disease (AD) and other dementias in a semi-urban elderly Sinhala-speaking population in Ragama, Sri Lanka. METHODS: The study was conducted in two phases. Phase I: After informed consent 703 subjects aged > or =65 years from the study area (population 15 828) were screened for cognitive impairment using the Sinhalese Mini Mental State Examination. Subjects scoring < or =17 were regarded as suspected dementia cases. Phase II: All subjects who screened positive in phase I were included in phase II for detailed evaluation for dementia according DSM IV and NINCDS-ADRDA criteria which included structured neuropsychiatric assessment, laboratory investigations, an axial CT scan of the brain and an informant interview. RESULTS: In the study sample, 61% were female and 86% were between 65-75 years. 42 subjects screened positive in phase I. Of these, 28 subjects were diagnosed as having dementia, giving an overall prevalence rate of 3.98% (95% Confidence Intervals (CI) =2.6-5.7%). Of these, 20 (71.4%) had probable AD, four had vascular dementia (14.3%), two had mixed (vascular and AD) dementia (7.1%), one had Lewy body dementia, and one had dementia due to syphilis. Greater age, illiteracy and female gender were associated with higher prevalence of dementia. CONCLUSION: Comparison with other community studies performed in North India suggests that dementia prevalence is higher in Sri Lanka. This may be due to regional differences in disease incidence.     

Presenile dementia: Sufferers,carers and services

An extensive search was made for people with presenile dementia (PSD) still under 65 years living in the Southampton Health District. Twenty-seven sufferers were identified. People with PSD had a high degree of cognitive, behavioural and self-care disabilities and carers showed considerable stress. Services were received from the old age psychiatry team, and to a lesser extent from social services and the Community Rehabilitation Unit. Community psychiatric nurses were the commonest form of support. The four sufferers in receipt of no services were less impaired. Identified needs included more counselling and advice and specific provision for the more physically active sufferer.     

Epidemiology of traumatic brain injury: a population based study in western Sweden

Background – This study on traumatic brain injury (TBI) is based on prospective and retrospective population based data from a head injury register in Borås. Methods – Data was collected from the hospital emergency unit, the discharge register, the regional neurosurgical clinic and the coroner's records during 1 year. This district is mixed urban and rural with a population of 138 000. Results – The 753 cases identified represent an incidence of 546 per 100 000 which includes deaths (0.7%), hospital admissions (67%) and attendance at the emergency department in patients not admitted (32%). Males (644 per 100 000), had 1.46 higher overall rate than females (442 per 100 000). The external causes were dominated by fall from same level (31%) and fall from different level (27%) followed by traffic accidents (16%) and persons hit by objects (15%). Conclusions – The incidence of TBI found in this study is high but well in accordance with earlier published Swedish studies.     

CANDID—counselling and diagnosis in dementia: a national telemedicine service supporting the care of younger patients with dementia

Objectives. To audit and evaluate the introduction of a novel support service for younger people with dementia, their families and the professionals caring for them. Design. A retrospective review of all calls received by a telephone helpline over a 2-year period. Setting. CANDID (Counselling and Diagnosis in Dementia) offers direct access, by telephone and e-mail, to specially trained nurse/counsellors who record the caller's query, provide emotional support and practical advice. In addition to general advice, clinical details are held for patients registered with the service so that the advice given can be tailored to the patient's specific need and routed via the general practitioner for action. Advice is reviewed by a consultant neurologist and a psychiatrist. Subjects. Callers to the CANDID helpline, who made a total of 1121 calls. Main outcome measures. Details of the caller and of the patient they were caring for. Reason for calling and advice given to the caller. Results. Of the 1121 calls received during the first 2 years of operation, 547 were ‘registered’ calls relating to 241 individual patients where more specific advice could be given through the GP. The remaining 574 ‘generic’ calls were from members of the public and healthcare professionals who had heard about the service and were seeking information and advice. Reasons for calls were divided into three broad categories: general information; clinical advice; and advice on social issues. Among the registered callers, 50% of calls were for clinical advice. Letters were sent to GPs on 67 occasions; 48 (56%) provided information only for the GP, 16 (24%) advised a secondary referral and eight (12%) advised on the use of specific medication. Conclusions. The service has become rapidly accepted and used by families of patients and members of the public. Healthcare professionals have made less use of the service than anticipated, but it is hoped that this will increase as information about the service becomes disseminated. © 1998 John Wiley & Sons, Ltd.     

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.