Association of diabetes mellitus and dementia: the Rotterdam Study

Dementia and non-insulin-dependent diabetes mellitus (NIDDM) are highly prevalent disorders in the elderly. Diabetes has repeatedly been reported to affect cognition, but its relation with dementia is uncertain. We therefore studied the association between diabetes and dementia in the Rotterdam Study, a large population-based study in the elderly. Of 6330 participants, aged 55 to 99 years old, complete information on diabetes and presence of dementia was available. Diabetes was diagnosed as use of anti-diabetes medication or random or post-load serum glucose over 11 mmol/1. Dementia was diagnosed through a stepped approach, including a sensitive screening of all participants and a comprehensive diagnostic work-up. Diabetes was present in 724 (11.4%) subjects. Of the 265 dementia patients 59 (22.3%) had diabetes. Multiple logistic regression analyses, adjusting for age and sex differences, revealed a positive association between diabetes and dementia (odds ratio: 1.3, 95% confidence interval 1.0-1.9). In particular, strong associations were found between dementia and diabetes treated with insulin (odds ratio: 3.2, 95% confidence interval: 1.4-7.5) The relation was strongest with vascular dementia but was also observed with Alzheimer's disease. These associations were independent of educational attainment, smoking, body mass index, atherosclerosis, blood pressure and antihypertensive drug treatment, and could not be explained by clinical cerebra infarctions. The results suggest that NIDDM is associated with dementia. Alzheimer's disease may be more frequent in elderly diabetic patients treated with insulin.

Dietary antioxidants and cognitive function in a population-based sample of older persons. The Rotterdam Study

Antioxidants have been implicated in processes related to atherosclerosis, aging, and selective neuronal damage, all of which may ultimately affect cognitive function. In a sample of older persons, the authors examined the cross-sectional relation between cognitive function and dietary intake of beta-carotene and vitamins C and E. The data were derived from 5,182 community participants aged 55-95 years in the population-based Rotterdam Study in the period 1990 to 1993. Dietary intake was estimated from a semi-quantitative food frequency questionnaire and categorized into five levels of intake. Cognitive function was measured with the 30-point Mini-Mental State Examination (MMSE) and characterized as unimpaired (> 25 points) or impaired (< or = 25 points). Logistic regression analysis was used to estimate the odds ratio (OR) and 95% confidence interval (CI) for cognitive impairment. After adjustment for age, education, sex, smoking, total caloric intake, and intake of other antioxidants, a lower intake of beta-carotene was associated with impaired cognitive function (< 0.9 mg vs. > or = 2.1 mg intake, OR = 1.9, 95% CI 1.2-3.1; p for trend < 0.04). There was no association between cognitive function and intake of vitamins C and E. These cross-sectional observations are compatible with the view that beta-carotene-rich foods may protect against cognitive impairment in older people. The finding could also reflect unmeasured confounding, measurement error, or a change in food habits that resulted from rather than preceded the onset of cognitive impairment.

Vascular risk factors, atherosclerosis, cerebral white matter lesions and cerebral perfusion in a population-based study

We studied risk factors for cerebral vascular disease (blood pressure and hypertension, factor VIIc, factor VIIIc, fibrinogen), indicators of atherosclerosis (intima-media thickness and plaques in the carotid artery) and cerebral white matter lesions in relation to regional cerebral blood flow (rCBF) in 60 persons (aged 65-85 years) recruited from a population-based study. rCBF was assessed with single-photon emission tomography using technetium-99m d, l-hexamethylpropylene amine oxime (99mTc-HMPAO). Statistical analysis was performed with multiple linear regression with adjustment for age, sex and ventricle-to-brain ratio. A significant positive association was found between systolic and diastolic blood pressure and temporo-parietal rCBF. In analysis with quartiles of the distribution, we found a threshold effect for the relation of low diastolic blood pressure (</=60 mmHg) and low temporo-parietal rCBF. Levels of plasma fibrinogen were inversely related to parietal rCBF, with a threshold effect of high fibrinogen levels (>3.2 g/l) and low rCBF. Increased atherosclerosis was related to low rCBF in all cortical regions, but these associations were not significant. No consistent relation was observed between severity of cerebral white matter lesions and rCBF. Our results may have implications for blood pressure control in the elderly population.

Prevalence of epilepsy in the elderly: the Rotterdam Study

We assessed the prevalence of epilepsy in an elderly population in The Netherlands. The study was conducted from 1991 to 1993 as part of the Rotterdam Study, a population-based door-to-door study of all elderly people living in Ommoord, a suburb of Rotterdam, and included 5,559 persons aged 55-95 years. All subjects were screened for epilepsy through direct questions regarding the existence of epilepsy and antiepileptic drug (AED) use, in addition to relevant questions from the World Health Organization (WHO) protocol for epidemiologic studies of neurologic diseases. Further evaluation of screen positives was made by a panel of 1 study physician and 4 epileptologists, who also classified all confirmed cases of epilepsy according to the classifications of the International League Against Epilepsy (ILAE). The overall prevalence of active epilepsy in our study population was 0.9% including special syndromes and 0.8% excluding special syndromes. The prevalence increased with age from 0.7% for those aged 55-64 years to 1.2% for those aged 85-94 years. The increase with age was detected among men and women both. Our study confirms other findings showing that the prevalence of active epilepsy increases with age in the elderly. The prevalence figures in our study were high as compared with those of other population-based studies. Epilepsy appears to be a major cause of morbidity in the elderly.

Risk of dementia in patients with Parkinson's disease, epilepsy, and severe head trauma: a register-based follow-up study

The authors investigated the risk of developing dementia for persons aged 50-75 years who suffered from Parkinson's disease, epilepsy, or severe head trauma. They compared the risk in this patient group with the risk in a reference group in a follow-up study based on the linked databases of three Dutch nationwide morbidity registers over the years 1980-1989. The overall relative risk of developing dementia within 8 years in patients with Parkinson's disease who were initially free of dementia was 3.0 (95% confidence interval (CI) 2.9-3.1). Risk was especially increased in younger Parkinson's disease patients (relative risk (RR) = 13.2, 95% CI 6.2-28.6). For patients with epilepsy, the overall relative risk was 1.5 (95% CI 1.4-1.7). Severe head trauma was not associated with an increased risk of dementia (RR = 1.0, 95% CI 0.9-1.1). These findings suggest that Parkinson's disease is an important risk factor for dementia, with a particularly high risk in young patients with Parkinson's disease. Patients with epilepsy may bear a moderately increased risk of developing dementia. This study does not support earlier findings in retrospective case-control studies of an increased risk of dementia in head trauma patients.

Prevalence of Parkinson's disease in the elderly: the Rotterdam Study

We assessed the prevalence of Parkinson's disease (PD) in a general elderly population in the Netherlands. The study formed part of the Rotterdam Study, a population-based door-to-door study, and included 6,969 persons 55 years of age or older living in a suburb of Rotterdam, the Netherlands. All participants were examined, and those who either had at least one possible cardinal sign of parkinsonism at the neurologic screening, reported that they had PD, or were taking antiparkinsonian drugs were invited for further evaluation. The prevalence of PD in this population was 1.4% (1.2% for men, 1.5% for women). Prevalence increased with age, and prevalence figures were 0.3% for those aged 55 to 64 years, 1.0% for those 65 to 74, 3.1% for those 75 to 84, and 4.3% for those 85 to 94. The corresponding age-specific figures for men were 0.4%, 1.2%, 2.7%, and 3.0%, and for women, 0.2%, 0.8%, 3.4%, and 4.8%. Among 95- to 99-year-old women the prevalence was 5.0%. Twelve percent of the subjects with PD were detected through the screening and had not been diagnosed previously.

Do nonsteroidal anti-inflammatory drugs decrease the risk for Alzheimer's disease? The Rotterdam Study

Based on reports that the use of nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce the risk for Alzheimer's disease (AD), we studied the cross-sectional relation between NSAID use and the risk for AD in a population-based study of disease and disability in older people. After controlling for age, education, gender, and use of benzodiazepines, we found a relative risk (RR) for AD of 0.38 (0.15 to 0.95) when comparing NSAID users (n = 365) to NSAID non-users (n = 5,893). To address confounding by indication or contraindication, we compared NSAID users with a subset of NSAID non-users who were using topical medication for ear, eye, or dermatologic conditions (n = 365). In this comparison, the adjusted RR for AD was 0.54 (0.16 to 1.78). These findings are compatible with a possible protective effect of NSAIDs on the risk for AD.

Prevalence of Alzheimer's disease and vascular dementia: association with education. The Rotterdam study

OBJECTIVE

To estimate the prevalence of dementia and its subtypes in the general population and examine the relation of the disease to education.

DESIGN

Population based cross sectional study.

SETTING

Ommoord, a suburb of Rotterdam.

SUBJECTS

7528 participants of the Rotterdam study aged 55-106 years.

RESULTS

474 cases of dementia were detected, giving an overall prevalence of 6.3%. Prevalence ranged from 0.4% (5/1181 subjects) at age 55-59 years to 43.2% (19/44) at 95 years and over. Alzheimer's disease was the main subdiagnosis (339 cases; 72%); it was also the main cause of the pronounced increase in dementia with age. The relative proportion of vascular dementia (76 cases; 16%), Parkinson's disease dementia (30; 6%), and other dementias (24; 5%) decreased with age. A substantially higher prevalence of dementia was found in subjects with a low level of education. The association with education was not due to confounding by cardiovascular disease.

CONCLUSIONS

The prevalence of dementia increases exponentially with age. About one third of the population aged 85 and over has dementia. Three quarters of all dementia is due to Alzheimer's disease. In this study an inverse dose-response relation was found between education and dementia--in particular, Alzheimer's disease.

Assessment of cerebral perfusion with single-photon emission tomography in normal subjects and in patients with Alzheimer's disease: effects of region of interest selection

The shape, size and location of regions of interest (ROIs) show considerable variability between single-photon emission tomography (SPET) studies in aging and Alzheimer's disease, but the possible influence on study results remains unknown. We compared three different ROIs in a SPET study with 60 controls and in 48 patients with probable Alzheimer's disease diagnosed according to the NINCDS-ADRDA criteria. Regional cerebral blood flow (rCBF) was assessed with SPET using technetium-99m d,l-hexamethylpropylene amine oxime (99mTc-HMPAO), normalized to the mean activity in a cerebellar reference slice. The three different ROIs were: a multi-slice and a single-slice ROI with reference to the normal brain anatomy (using an anatomical atlas), and a rectangular (2 x 4 pixels) ROI in the frontal, temporal, temporoparietal and occipital cortices. No differences were observed for the means of rCBF values between the single-slice and multi-slice ROI's with reference to the normal anatomy, but some variability was present for individual comparisons. In contrast, significantly higher mean rCBF values were obtained with the single-slice rectangular ROIs in all four regions for both patients and controls and considerable variability was shown for individual subjects. After analysis with multivariate logistic regression and receiver operator characteristic curves, the ability of SPET to discriminate between controls and Alzheimer patients was similar in the three methods for mild and moderate Alzheimer patients (Global Deterioration Scale = GDS of 3 and 4). However, with increasing dementia severity (GDS > 4) the rectangular ROIs showed lower ability to discriminate between groups compared to the single-slice and multi-slice anatomically defined ROIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral white matter lesions, vascular risk factors, and cognitive function in a population-based study: the Rotterdam Study

Cerebral white matter lesions are a common finding on MRI in elderly persons. We studied the prevalence of white matter lesions and their relation with classic cardiovascular risk factors, thrombogenic factors, and cognitive function in an age- and gender-stratified random sample from the general population that consisted of 111 subjects 65 to 84 years of age. Overall, 27% of subjects had white matter lesions. The prevalence and severity of lesions increased with age. A history of stroke or myocardial infarction, factor VIIc activity, and fibrinogen level were each significantly and independently associated with the presence of white matter lesions. Significant relations with blood pressure level, hypertension, and plasma cholesterol were present only for subjects aged 65 to 74 years. White matter lesions tended to be associated with lower scores on tests of cognitive function and were significantly associated with subjective mental decline. This study suggests that classic cardiovascular risk factors, as well as thrombogenic factors, are associated with white matter lesions in subjects over 65 years of age in the general population, and that these lesions may be related to cognitive function.

Cardiovascular disease and distribution of cognitive function in elderly people: the Rotterdam Study

OBJECTIVE

To investigate the distribution of cognitive function in elderly people and to assess the impact of clinical manifestations of atherosclerotic disease on this distribution.

DESIGN

Single centre population based cross sectional door to door study.

SETTING

Ommoord, a suburb of Rotterdam, the Netherlands.

SUBJECTS

4971 subjects aged 55 to 94 years.

MAIN OUTCOME MEASURE

Cognitive function as measured by the mini mental state examination.

RESULTS

The overall participation rate in the study was 80%. Cognitive test data were available for 90% of the participants. Increasing age and lower educational level were associated with poorer cognitive function. Previous vascular events, presence of plaques in the carotid arteries, and presence of peripheral arterial atherosclerotic disease were associated with worse cognitive performance independent of the effects of age and education. On average the differences were moderate; however, they reflected the net result of a shift of the total population distribution of cognitive function towards lower values. Thereby, they resulted in a considerable increase in the proportion of subjects with scores indicative of dementia.

CONCLUSIONS

These findings are compatible with the view that atherosclerotic disease accounts for considerable cognitive impairment in the general population.

Cognitive correlates of ventricular enlargement and cerebral white matter lesions on magnetic resonance imaging. The Rotterdam Study

BACKGROUND AND PURPOSE

Ventricular enlargement and white matter lesions are frequent findings on cerebral magnetic resonance imaging scans of elderly subjects. In demented subjects they seem related to the severity of the dementia, but in nondemented subjects their clinical significance is less clear. We investigated the relation of size of the lateral ventricles and white matter lesions with cognitive function in a population-based random sample of nondemented elderly persons.

METHODS

The study population consisted of 90 subjects, aged 65 to 84 years, who were randomly selected from the cohort of the Rotterdam Study, and who were not demented. The presence of white matter lesions and the ventricle-to-brain ratio were assessed on magnetic resonance scans. Participants were tested with a neuropsychological battery that covered a broad range of cognitive functions.

RESULTS

Ventricular enlargement and white matter lesions were both and independently associated with poorer performance on all tests. After adjustment for age and sex, ventricular enlargement was significantly associated with worse scores on tests assessing global cognitive function (Mini-Mental State Examination, P = .02; Groninger Intelligence Test, P = .01), memory (Word List Learning delayed recall, P = .03), and executive control functions (Stroop part II, P = .02; Trial Making Test B, P < .01); for white matter lesions the differences were significant for tests measuring executive control functions and mental speed (Trail Making Test A and B, P = .01 and P < .01, respectively; verbal fluency, P = .01), and memory (Word List Learning delayed recall, P = .04).

CONCLUSIONS

This study suggests that white matter lesions are primarily related to impairment of subcorticofrontal functions, whereas enlargement of the lateral ventricles is associated with disturbances of cortical functions as well.

The diagnostic value of SPECT with Tc 99m HMPAO in Alzheimer's disease: a population-based study

We studied the diagnostic accuracy of single-photon emission computed tomography (SPECT) with technetium 99m-labeled hexamethylpropylene amine oxime (Tc 99m HMPAO) in 48 patients with probable Alzheimer's disease (AD) according to NINCDS-ADRDA criteria and in 60 controls recruited from a population-based study. With logistic regression, we identified decreased temporal regional cerebral blood flow as the best discriminating variable between patients and controls. Receiver-operator characteristic curves showed that the discriminative ability of SPECT improved with increasing dementia severity. With specificity set at 90%, sensitivity figures were 42% in mild, 56% in moderate, and 79% in severe AD. The diagnostic gain as a function of the prior probability of the disease being present was computed for those with mild AD. When the prior probability varied at around 50%, the diagnostic gain for mild AD patients was substantial (a maximum of 34%) for a positive test result but poor for a negative test result. The results suggest that the practical usefulness of SPECT as a diagnostic adjunct in patients suspected of having mild AD is confined to situations in which, on clinical grounds, there is considerable diagnostic doubt.

Cerebral white matter lesions and atherosclerosis in the Rotterdam Study

Cerebral white matter lesions (WML) seen on magnetic resonance imaging scans are associated with cardiovascular disease and vascular risk factors. To assess the association between WML and atherosclerosis, we studied 111 people, aged 65 to 85 years, randomly sampled, and stratified by age and sex, from participants in the Rotterdam Study. Cerebral T2-weighted magnetic resonance images in the axial plane were obtained for all subjects. Carotid atherosclerosis was ultrasonographically assessed by the presence of stenosis, measurement of intima to media wall thickness (IMT), and the presence of atherosclerotic plaques. A possible or definite myocardial infarction on an electrocardiogram was used as an indicator of coronary atherosclerosis. The ankle to arm systolic blood pressure ratio (ABI) was determined, and peripheral arterial disease was defined as an ABI lower than 0.90 in at least one side. Carotid atherosclerosis was significantly more pronounced in people with WML. The difference in common carotid IMT was 0.13 mm (95% confidence interval [CI] 0.04-0.21), whereas the odds ratio of WML associated with plaques in the carotid bifurcation was 3.9. The degree of internal carotid artery stenosis was not, however, associated with WML. The mean ABI was significantly lower in people with WML than in those without lesions with a difference of -0.11 (95% CI -0.21 to -0.01). The odds ratio of WML associated with peripheral arterial disease and a possible or definite myocardial infarction was 2.4 and 3.1, respectively. We conclude that atherosclerosis, indicated by increased common carotid IMT, carotid plaques, and a lower ABI, is related to WML.

Epidemiologic approach to the study of dementing diseases: a nested case-control study in European incidence studies of dementia

In 1994 several European studies will have available risk factor information on incident cases of dementia collected in prospective community-based studies. These centers will collaborate in a nested-case control study based on the pooled cases and a sample of the non-diseased respondents. This paper describes the general design and the risk factors to be studied in a European nested case-control study of Alzheimer's disease and vascular dementia.

A community-based study of dementia: the Rotterdam Elderly Study

The Rotterdam Elderly Study is designed as a community-based prospective follow-up study. The study population consists of almost 12,000 individuals aged 55 years and over who are living in an urban area in Rotterdam, the Netherlands. The objective of the study is to investigate the prevalence, incidence and determinants of neurogeriatric disorders, cardiovascular diseases, locomotor diseases and ophthalmologic diseases. In this paper we give a general outline of the Rotterdam Elderly Study, and a detailed description of the case finding and diagnostic procedures for the study of dementia. The risk factors for dementia that are assessed in the study are summarized.

The prevalence of vascular dementia in Europe: facts and fragments from 1980-1990 studies. EURODEM-Prevalence Research Group

We selected, reanalyzed, and compared data from current prevalence studies of vascular dementia in Europe. Inclusion criteria were: dementia defined by the Diagnostic and Statistical Manual for Mental Disorders, edition 3, or equivalent criteria; case finding through direct individual examination; appropriate sample size; and inclusion of institutionalized persons. Mixed dementia was combined with vascular dementia. Of the 23 surveys of dementia considered, five fulfilled the inclusion criteria. Age-specific prevalence varied more widely for men than for women; differences were greater in older ages. The prevalence increased steeply with advancing age in all countries, and was generally higher in men; it declined over 15 years in the age class of 80 to 89 years in one Swedish population. Within populations, Alzheimer's disease was generally more common than vascular dementia. Unfortunately, prevalence studies of vascular dementia are limited in Europe and worldwide, and their comparison is impeded by the lack of common diagnostic criteria.

Frequency and distribution of Alzheimer's disease in Europe: a collaborative study of 1980-1990 prevalence findings. The EURODEM-Prevalence Research Group

We reanalyzed and compared current prevalence estimates of Alzheimer's disease in Europe. Studies characterized as follows qualified for comparison: dementia defined by the Diagnostic and Statistical Manual for Mental Disorders, 3rd edition, or equivalent criteria; Alzheimer's disease diagnosed by the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association or equivalent criteria; case-finding through direct individual examination; appropriate sample size; and inclusion of institutionalized persons. Of the 23 European surveys of dementia considered, six fulfilled the inclusion criteria. When age and sex were considered, there were no major geographic differences in the prevalence of Alzheimer's disease across Europe. Overall European prevalence (per 100 population) for the age groups 30 to 59, 60 to 69, 70 to 79, and 80 to 89 years was, respectively, 0.02, 0.3, 3.2, and 10.8. Prevalence increased exponentially with advancing age and, in some populations, was consistently higher in women. Prevalence remained stable over 15 years in one study.

The prevalence of dementia in Europe: a collaborative study of 1980-1990 findings. Eurodem Prevalence Research Group

To obtain age- and gender-specific estimates of the prevalence of dementia in Europe and to study differences in prevalence across countries, we pooled and re-analysed original data of prevalence studies of dementia carried out in some European countries between 1980 and 1990. The study followed these steps: census of existing datasets, collection of data in a standardized format, selection of datasets suitable for comparison, comparison of age and gender patterns. From the 23 datasets of European surveys considered, 12 were selected for comparison. Only population-based studies in which dementia was defined by DSM-III or equivalent criteria and in which all subjects were examined personally were included. Studies in which institutionalized subjects were not investigated were excluded. Age- and gender-specific prevalences were compared within and across studies and overall prevalences were computed. Although prevalence estimates differed across studies, the general age- and gender-distribution was similar for all studies. The overall European prevalences for the five-year age groups from 60 to 94 years, were 1.0, 1.4, 4.1, 5.7, 13.0, 21.6 and 32.2%, respectively. In subjects under 75 years the prevalence of dementia was slightly higher in men than in women; in those aged 75 years or over the prevalence was higher in women. The prevalence figures nearly doubled with every five years of increase in age.

Medical history and the risk of Alzheimer's disease: a collaborative re-analysis of case-control studies. EURODEM Risk Factors Research Group

In a re-analysis of eight case-control studies on Alzheimer's disease we explored several medical conditions that had previously been suggested as possible risk factors for Alzheimer's disease. History of hypothyroidism was increased in cases as compared to controls (relative risk 2.3; 95% confidence interval 1.0-5.4). Severe headaches and migraine were inversely related to Alzheimer's disease (relative risk 0.7; 95% confidence interval 0.5-1.0). More cases than controls reported epilepsy before onset of Alzheimer's disease (relative risk 1.6; 95% confidence interval 0.7-3.5), especially for epilepsy with an onset within 10 years of onset of dementia. Neurotropic viruses, allergic conditions, general anaesthesia and blood transfusions were not associated with Alzheimer's disease.