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Biomedical subjects

L Letenneur

Publications and source records attributed to L Letenneur.

At least 19 recordsLinked to original sources

Mortality with dementia: results from a French prospective community-based cohort.

Despite the magnitude of the problem, little is known about the duration of dementia. Survival and risk factors of mortality with dementia and the impact of dementia on the risk of death were investigated using the Personnes Agées Quid (PAQUID) prospective population-based cohort study between 1988 and 1998. Statistical models dealing with interval censoring were performed. Among 3,675 participants aged 65 years or older and initially nondemented, 2,923 have been followed up for 8 years. Of these, 281 persons with incident dementia were actively diagnosed. The mean age of onset of dementia was 82.3 years. In the total population, the relative risk of dying after developing dementia was estimated to be 1.82 (95% confidence interval (CI): 1.77, 2.68) when adjusted for sociodemographic variables and comorbidity. Deaths from cerebrovascular diseases and respiratory diseases were particularly increased among persons with dementia, compared with those without. The median survival time of the persons with dementia was estimated to be 4.5 years. Women with dementia had a longer survival than did men with dementia, particularly for Alzheimer-type dementia (relative risk = 0.47, 95% CI: 0.27, 0.83). Educational level was not significantly associated with survival in persons with dementia. These results provide further evidence of the malignancy of dementia, which will be a challenge for the 21st century.

Age of Onset↗

Benzodiazepine use in an elderly community-dwelling population. Characteristics of users and factors associated with subsequent use.

OBJECTIVES: The objective of this study was to describe determinants of current and subsequent benzodiazepine use in an elderly population, the Paquid cohort. METHODS: The study was conducted on a cohort of 2,792 community-dwelling subjects 65 years of age or more living in the Gironde department, southwestern France. Benzodiazepine use and its correlates were studied with data collected at inclusion in the cohort. Longitudinal analysis over a 5-year period of follow-up was done to identify baseline predictors of subsequent use. RESULTS: At baseline, prevalence rate of benzodiazepine use was 31.9%. It was associated with female gender [odds ratio (OR) = 2.0; 95% confidence interval (CI): 1.66, 2.46], previous psychiatric disease (OR = 2.87; 95% CI: 2.31, 3.56), concomitant antidepressant use (OR = 2.45; 95% CI: 1.59, 3.78), depressive symptomatology (OR = 1.70; 95% CI: 1.28, 2.26), multiple drug use (OR = 1.82; 95% CI: 1.50, 2.21), multiple chronic diseases (OR = 1.37; 95% CI: 1.12, 1.67) and poor self-perceived health (OR = 1.63; 95% CI: 1.33, 2.0). For the 1926 benzodiazepine non-users at inclusion and followed during 5 years, incidence rate of subsequent use was 5.37 per 100 person-years (95% CI: 4.76, 5.98). In multivariate Cox proportional hazards regression analysis, previous psychiatric diseases, poor self-perceived life satisfaction and polymorbidity were significantly associated with subsequent benzodiazepine use. CONCLUSIONS: Elderly people are heavy users of benzodiazepines. Independently from mental health status, those in poor health were most at risk of benzodiazepine use.

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Occupation during life and risk of dementia in French elderly community residents.

OBJECTIVE: To determine whether principal occupation during life is a risk factor for incident Alzheimer's disease, vascular dementia, or dementia with parkinsonism. METHODS: This study was carried out from the PAQUID (Personnes Agées QUID) cohort, an epidemiological study on normal and pathological aging after 65 years in the south west of France. At baseline, 2950 non-demented people living at home were identified and re-examined 1, 3, 5, 8, and 10 years later with identical standardised neurological and neuropsychological measures. Cox proportional hazards models with delayed entry were used, taking age as the time scale and adjusting for sex, education, tobacco, and wine consumption to estimate the risk ratio (RR) of incident dementia, Alzheimer's disease, vascular dementia, and dementia with parkinsonism associated with occupational category. RESULTS: Of the 2950 subjects, 393 became demented, of whom 251 had Alzheimer's disease, 112 had vascular dementia, and 27 had dementia with parkinsonism. The risk of Alzheimer's disease was not related to a given occupation. However the risk of dementia with parkinsonism seemed to be increased in farmers in comparison with professionals and managerials, particularly among women (RR 7.47; 95%CI, 1.80-31.07). CONCLUSION: The data suggest that occupation does not change the risk of Alzheimer's disease, which seems to be more influenced by cognitive abilities in childhood and adolescence than by occupation in adult life. However, being a farmer may increase the risk of dementia with parkinsonism among women; occupation could act by the way of differences in health behaviour or in exposure to environmental factors.

Age Distribution↗

Education and the risk for Alzheimer's disease: sex makes a difference. EURODEM pooled analyses. EURODEM Incidence Research Group.

The hypothesis that a low educational level increases the risk for Alzheimer's disease remains controversial. The authors studied the association of years of schooling with the risk for incident dementia and Alzheimer's disease by using pooled data from four European population-based follow-up studies. Dementia cases were identified in a two-stage procedure that included a detailed diagnostic assessment of screen-positive subjects. Dementia and Alzheimer's disease were diagnosed by using international research criteria. Educational level was categorized by years of schooling as low (< or =7), middle (8-11), or high (> or =12). Relative risks (95% confidence intervals) were estimated by using Poisson regression, adjusting for age, sex, study center, smoking status, and self-reported myocardial infarction and stroke. There were 493 (328) incident cases of dementia (Alzheimer's disease) and 28,061 (27,839) person-years of follow-up. Compared with women with a high level of education, those with low and middle levels of education had 4.3 (95% confidence interval: 1.5, 11.9) and 2.6 (95% confidence interval: 1.0, 7.1) times increased risks, respectively, for Alzheimer's disease. The risk estimates for men were close to 1.0. Finding an association of education with Alzheimer's disease for women only raises the possibility that unmeasured confounding explains the previously reported increased risk for Alzheimer's disease for persons with low levels of education.

Age Distribution↗

A hierarchical model of domains of disablement in the elderly: a longitudinal approach.

PURPOSE: the aims of this paper are to verify that a hierarchical relationship exists between the concepts of Activities of Daily Living (ADL), Instrumental Activities of Daily Living (IADL) and mobility and to use this hierarchical model to describe the evolution of disability. METHODS: 3751 elderly community dwellers were followed-up 3 and 5 years after baseline interview. A hierarchic disability scale was computed by summing up the number of domains (ADL, IADL, mobility) in which a subject was dependent. Coefficients of scalability and reproducibility of the scale were computed. The hierarchic scale was used to describe transitions between states at each follow-up. RESULTS: the hierarchical model fitted 99.3% of the subjects at baseline. At each follow-up most transitions were towards contiguous grades of disability in survivors, whatever their age. There was a significant trend towards increasing disability. Death rates were higher in subjects aged 75 and over, whatever their disability level. The patterns of evolution differed according to gender. CONCLUSIONS: the cumulative disability scale can be used to describe the evolution of disability with time in elderly community dwellers.

Activities of Daily Living↗

A cognitive screening battery for dementia in the elderly.

The objective of this study is to propose a screening instrument for dementia based on a reduced number of neuropsychological tests. The sample consists in the pooled data of the five follow-up visits of the Paquid cohort study on cerebral aging: the estimation sample included 2792 subjects (8830 observations) and the validation sample included 985 subjects (2643 observations). Among scores significantly associated with dementia, we retained only those that increased the specificity of the model for a sensitivity of one. Seven neuropsychological tests and the MMSE subscores were considered. The most discriminant combination of tests included the MMSE and the subscores "orientation to time" and "recall three objects," the Benton Visual Retention Test, and Isaacs' Set Test of verbal fluency. The specificity of this screening instrument was 0. 77 for a sensitivity of 1.

Activities of Daily Living↗

Incidence and predictors of drug-treated diabetes in elderly French subjects. The PAQUID Epidemiological Survey.

AIMS: To estimate the incidence and predictors of drug-treated diabetes in elderly subjects. METHODS: The PAQUID epidemiological survey, a population-based study, has followed up 3,777 subjects older than 65 years since 1988. At each visit (baseline, 1, 3, 5 and 8 years), treatment regimen was used to identify new drug-treated diabetic subjects. Potential predictors of drug-treated diabetes were collected during the baseline visit (body mass index (BMI), educational level, cigarette smoking and wine consumption, physical activity, depressive symptomatology, subjective health, treatment, and hypertension) and analysed by using a multivariate backward stepwise regression Cox model with delayed entry. RESULTS: The prevalence rate of drug-treated diabetes was 7.5% at baseline and 7.1% after 8 years' follow-up. The incidence rate of drug-treated diabetes was 3.8/1,000 person-years, 5.9/1,000 person-years in men and 2.4/1,000 person-years in women, with no significant variation according to age group. Male sex (relative risk (RR) 2.4, 95% confidence interval (CI) 1.4-4.0, P < 0.001, attributable risk (AR) 0.36), elevated BMI (for one point increase, RR 1.1, 95% CI 1.1-1.1, P < 0.001, > or = 25 vs. < 25, RR 2.1, 95% CI 1.2-3.5, AR 0.33), thiazide diuretics used alone (RR 5.9, 95% CI 1.8-19.6, P = 0.02), and poorer subjective health ('the same' vs. 'better' RR 1.8, 95% CI 1.0-3.1, P = 0.04; 'worse' vs. 'better' RR 2.3, 95% CI 0.9-5.7, P = 0.06) were independent predictors of drug-treated diabetes in this population. CONCLUSIONS: In older French individuals, men seem to be particularly exposed to drug-treated diabetes although being overweight was found to be a strong predictor as in younger populations.

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Genetic epidemiology of Alzheimer's disease.

The genetics of Alzheimer's disease is one of the most complex topics to study from an epidemiological point of view, particularly in population-based studies on polymorphisms of genes. The present review focuses primarily on some conflicting results on genetic epidemiology of Alzheimer's disease, and the major difficulties met in such studies.

Alleles↗

A perspective on animal protein production in sub-Saharan Africa.

A large survey of animal protein production in sub-Saharan Africa was performed. The objective was to identify specific production needed to ensure sustainable development. Starting from data collection and analysis to gain control of this information, the study proposes possible paths of evolution for supply and demand for animal production. Africa will be the continent where the demand will grow the most (together with Asia), because of demography and urbanization. Urbanization will represent an extraordinary opportunity for the development of animal production. In 2020, the global demand will be 20 million tons per year (7.3 in 1994) for meat, 45 million tons for milk (18.6 in 1994) and 2.9 million tons for eggs (1.1 in 1994). Red meat, which now provides 55.6% of present meat consumption will satisfy only 36.5% in 2020. This underlines the immense effort needed to intensify ruminant production and/or to develop monogastric production. Consequently, there is a need in tropical animal health and research for better knowledge and control of monogastric diseases and particularly those linked to intensification. The development of peri-urban milk production will require particular attention to hemoparasitic diseases. Globally, there is an urgent need to set up projects for the development of animal production.

Africa South of the Sahara↗

Smoking and eight-year mortality in an elderly cohort.

SETTING: The increasing numbers of elderly people highlight the question of smoking effects in this age group. OBJECTIVE: To investigate whether there is a relationship between smoking and 8-year mortality in a representative elderly cohort aged 65 years and over, residing in the department of Gironde, in the south-west of France. METHODS: Data were collected by a questionnaire administered during home visits. Every death was systematically recorded during the 8-year follow-up. RESULTS: The 2786 (99.8%) subjects included in the study were categorised into current smokers, former smokers and never smokers. Mortality was higher (P < 0.0001) in men (39.6%) than in women (29.4%). In men, the risk of mortality was higher (P = 0.01) among current (44.5%) and former smokers (41.4%) than in never smokers (32.5%). The risks were similar in never smokers and former smokers who had stopped more than 20 years previously. Tobacco consumption in pack-years was higher (P = 0.02) in those people who died during the follow-up period than in those who were still alive. Mortality due to respiratory disease (P = 0.008) and lung cancer (P < 0.0001) was significantly higher in current smokers than in former and never smokers. Adjusting for potential confounding factors, smoking remains significantly associated with mortality both in current (relative risk [RR] = 1.7, P < 0.001) and former smokers (RR = 1.3, P = 0.004). CONCLUSION: These results confirm the consequences of smoking even in the elderly, and raise the question of smoking prevention after 65 years of age.

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Marital status and risk of Alzheimer's disease: a French population-based cohort study.

OBJECTIVE: To analyze the relationship between marital status and risk of AD or dementia. METHODS: This study was carried out from the Personnes Agées QUID (PAQUID) cohort, an epidemiologic study on normal and pathologic aging after age 65 years. The PAQUID cohort began in 1988. Individuals were followed up at 1, 3, and 5 years, with an active detection of dementia. Marital status was divided into four categories: widowed, never married, divorced or separated, and the reference category, married or cohabitant. The longitudinal relationship between marital status and risk of incident AD or dementia was analyzed by a Cox model with delayed entry. RESULTS: Among the 3,675 individuals initially not demented, 2,106 were married or cohabitants, 1,287 were widowers, 179 were never married, and 103 were divorced or separated. Among the 2,881 individuals reevaluated at least once for the risk of dementia during the 5-year follow-up, 190 incident cases of dementia were identified, including 140 with AD. The relative risks (RRs) of dementia (RR = 1.91, p = 0.018) and of AD (RR = 2.68, p<0.001) were increased for the never-married individuals compared with those who were married or cohabitants. This excess of risk was specifically associated with AD. Adjustment for other risk factors of dementia (education, wine consumption), or for factors reflecting social environment, leisure activities, and depression, did not modify the risk of AD for never-married individuals (RR = 2.31, p = 0.02). CONCLUSIONS: We confirmed an association between marital status and AD, with an excess risk observed among never-married individuals. This association may provide clues about the pathogenesis of AD.

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Gender differences in the incidence of AD and vascular dementia: The EURODEM Studies. EURODEM Incidence Research Group.

OBJECTIVE: To study the difference in risk for dementing diseases between men and women. BACKGROUND: Previous studies suggest women have a higher risk for dementia than men. However, these studies include small sample sizes, particularly in the older age groups, when the incidence of dementia is highest. METHODS: Pooled analysis of four population-based prospective cohort studies was performed. The sample included persons 65 years and older, 528 incident cases of dementia, and 28,768 person-years of follow-up. Incident cases were identified in a two-stage procedure in which the total cohort was screened for cognitive impairment, and screen positives underwent detailed diagnostic assessment. Dementia and main subtypes of AD and vascular dementia were diagnosed according to internationally accepted guidelines. Sex- and age-specific incidence rates, and relative and cumulative risks for total dementia, AD, and vascular dementia were calculated using log linear analysis and Poisson regression. RESULTS: There were significant gender differences in the incidence of AD after age 85 years. At 90 years of age, the rate was 81.7 (95% CI, 63.8 to 104.7) in women and 24.0 (95% CI, 10.3 to 55.6) in men. There were no gender differences in rates or risk for vascular dementia. The cumulative risk for 65-year-old women to develop AD at the age of 95 years was 0.22 compared with 0.09 for men. The cumulative risk for developing vascular dementia at the age of 95 years was similar for men and women (0.04). CONCLUSION: Compared with men, women have an increased risk for AD. There are no gender differences in risk for vascular dementia.

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Rates and risk factors for dementia and Alzheimer's disease: results from EURODEM pooled analyses. EURODEM Incidence Research Group and Work Groups. European Studies of Dementia.

OBJECTIVE: To investigate the risk of AD associated with a family history of dementia, female gender, low levels of education, smoking, and head trauma. BACKGROUND: These putative factors have been identified in cross-sectional studies. However, those studies are prone to bias due to systematic differences between patients and control subjects regarding survival and how risk factors are recalled. METHODS: The authors performed a pooled analysis of four European population-based prospective studies of individuals 65 years and older, with 528 incident dementia patients and 28,768 person-years of follow-up. Patients were detected by screening the total cohort with brief cognitive tests, followed by a diagnostic assessment of those who failed the screening tests. Dementia was diagnosed with the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed. (revised), and AD was diagnosed according to National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria. Incident rates and relative risk (95% CI) express the association of a risk factor for dementia. RESULTS: Incident rates for dementia and AD were similar across studies. The incidence of AD increased with age. At 90 years of age and older the incidence was 63.5 (95% CI, 49.7 to 81.0) per 1,000 person-years. Female gender, current smoking (more strongly in men), and low levels of education (more strongly in women) increased the risk of AD significantly. A history of head trauma with unconsciousness and family history of dementia did not increase risk significantly. CONCLUSION: Contrary to previous reports, head trauma was not a risk factor for AD, and smoking did not protect against AD. The association of family history with the risk of AD is weaker than previously estimated on the basis of cross-sectional studies. Female gender may modify the risk of AD, whether it be via biological or behavioral factors.

Age Distribution↗

PHMPL: a computer program for hazard estimation using a penalized likelihood method with interval-censored and left-truncated data.

The Cox model is the model of choice when analyzing right-censored and possibly left-truncated survival data. The present paper proposes a program to estimate the hazard function in a proportional hazards model and also to treat more complex observation schemes involving general censored and left-truncated data. The hazard function estimator is defined non-parametrically as the function which maximizes a penalized likelihood, and the solution is approximated using splines. The smoothing parameter is chosen using approximate cross-validation. Confidence bands for the estimator are given. As an illustration, the age-specific incidence of dementia is estimated and one of its risk factors is studied.

Age Factors↗

Subjective health and mortality in French elderly women and men.

OBJECTIVES: To examine the predictive value of subjective health on mortality separately in women and men, independently of other health measures, and to explain the differences between sexes by way of cognition, depression, and disability. METHODS: The PAQUID (Personnes Agées QUID) cohort is a representative sample of 3,660 nondemented elderly community residents, aged 65 and older. The relationship between subjective health and 5-year mortality was studied using the Cox model with delayed entry. RESULTS: In men, subjective health was a predictor of mortality, independent of sociodemographic characteristics, physical health status, depressive symptomatology, cognitive function, and disability, particularly in the middle-range categories of subjective health. In women, the relationship between subjective health and mortality was explained by physical health status and disability. DISCUSSION: Self-rated health seems to be a better predictor of mortality in men than in women. In men, the way in which self-ratings of health are produced remains unknown. In order to better understand sex differences, the pathways from healthy life to dependency and death, and their related changes in subjective health, should be explored further.

Activities of Daily Living↗

Neuropsychological correlates of self-reported performance in instrumental activities of daily living and prediction of dementia.

This study examines the relationships between performance on neuropsychological tests and 4 instrumental activities of daily living (IADL) associated with an increased risk of dementia, in 1,792 nondemented elderly people included in the Personnes Agées Quid (PAQUID) study. There was a decline of neuropsychological performance on each test with increasing IADL dependency, in particular between Grades 1 and 2. Performances of the independent participants were very homogeneous. Each IADL had different specific associations with the neuropsychological tests. A principal component analysis showed three main factors explaining 49.6% of variance. The first factor was the common cognitive component of both instrumental tasks and neuropsychological tests. The second factor was specific to three IADL, whereas use of transportation had its main loading on the third factor. Only the first factor was predictive of the risk of incident dementia, suggesting that the predictive value of the 4 IADL was explained by their cognitive component.

Activities of Daily Living↗

Health, cognitive, and psychosocial factors as predictors of mortality in an elderly community sample.

STUDY OBJECTIVE: To examine whether cognitive and psychosocial factors predict mortality once physical health is controlled. DESIGN: A prospective study of community dwelling elderly. Mortality was assessed over a period of 3-4 years after the baseline assessment of predictors. The data were analysed using the Cox proportional hazards model. SETTING: Canberra and Queanbeyan, Australia. PARTICIPANTS: A sample of 897 people aged 70 or over and living in the community, drawn from the compulsory electoral roll. RESULTS: For the sample as a whole, the significant predictors of mortality were male sex, poor physical health, poor cognitive functioning, and low neuroticism. Men had an adjusted relative risk of mortality of 2.5 compared with women. For the male sub-sample, poor self rated health and a poor performance on a speeded cognitive task were significant predictors, while for women, greater disability, low systolic blood pressure, and a low score on a dementia screening test were the strongest predictors. CONCLUSIONS: Mortality was predicted by physical ill health and poor cognitive functioning. Psychosocial factors such as socioeconomic status, psychiatric symptoms, and social support did not add to the prediction of mortality, once sex, physical health, and cognitive functioning were controlled. Mortality among men was more than twice that of women, even when adjusted for other predictors.

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