Epidemiology of the dementias: recent developments and new approaches

Clock-Drawing Test as a Screening Tool for Cognitive Impairment Associated With Fecal Immunochemical Test Collection Errors

PURPOSE

The purposes of this study were to determine if (1) certain demographic characteristics (potential predictors) of participants, and (2) clock-drawing test results (as a screening test for cognitive impairment) were associated with fecal immunochemical test (FIT) sample collection errors.

METHODS

Patients scheduled for an upcoming colonoscopy were asked to collect stool samples using 5 different FITs. Patients completed a questionnaire that included the clock-drawing test. Errors included mistakes or omissions in recording the stool collection date and errors in stool collection. Each clock drawing was scored by 2 reviewers using 2 established methods.

RESULTS

Of the 1,448 participants with a clock drawing, 63% were female with a mean age of 63 years. In this population there were 83% White, 6% Black, and 24% Hispanic persons. Cognitive impairment was found in 292 patients by the Mendes-Santos method. Kappa coefficient for the 2 clock-drawing scores was 0.79 (P <.001). The multivariable generalized linear mixed model for FIT collection errors indicated being female (adjusted odds ratio [AOR], 1.64; 95% CI, 1.09-2.48), having an 8th grade or less education (AOR, 3.40; 95% CI, 1.87-6.18), and having an abnormal Mendes-Santos method clock score (AOR, 1.65; 95% CI, 1.08-2.54) were associated with significantly more errors.

CONCLUSION

Among the participants who do not have dementia, FIT collection errors were made not only by those who had abnormal clock drawing, but also, by those with normal clock drawings. Subjects being female, having 8th grade education or less, and having an abnormal clock drawing scored by Mendes-Santos's method were associated with FIT collection errors.

Automatic extraction and assessment of lifestyle exposures for Alzheimer's disease using natural language processing

INTRODUCTION

Previous biomedical studies identified many lifestyle exposures that could possibly represent risk factors for dementia in general or dementia due to Alzheimer's disease (AD). These lifestyle exposures are mainly mentioned in free-text electronic health records (EHRs). However, automatic extraction and assessment of these exposures using EHRs remains understudied.

METHODS

A natural language processing (NLP) approach was adopted to extract lifestyle exposures and intervention strategies from the clinical notes of 260 patients with clinical diagnoses of AD dementia and 260 age-matched cognitively unimpaired persons. Statistics of lifestyle exposures were compared between these two groups. The mapping results of the NLP extraction were evaluated by comparing the results with data captured independently by clinicians.

RESULTS

Thirty out of fifty-five potentially relevant lifestyle exposures were mentioned in our clinical note dataset. Twenty-two dietary factors and three substance abuses that were potentially relevant were not found in clinical notes. Patients with AD dementia were significantly exposed to more of the potential risk factors compared to the cognitively unimpaired subjects (χ2 = 120.31, p-value < 0.001). The average accuracy of the automated extraction was 74.0% in comparison with the manual review of randomly selected 50 sample documents.

DISCUSSION AND CONCLUSION

We illustrated the feasibility of NLP techniques for the automated evaluation of a large number lifestyle habits using free-text EHR data. We found that AD dementia patients were exposed to more of the potential risk factors than the comparison group. Our results also demonstrated the feasibility and accuracy of investigating putative risk factors using NLP techniques.

The Epidemiological Scale of Alzheimer's Disease

Alzheimer's disease (AD) has increased from a few cases in a country at the beginning of the 20th century to an incidence of recording a case every 7 seconds in the world. From a rare disease it has reached the top 8 of major health problems in the world. One of the epidemiological problems of AD is the fact that authors from different countries use different reporting units. Some report numbers to 100,000 inhabitants, others to 1,000 inhabitants and others report the total number of cases in a country. Standardization of these reports is strictly necessary. The rise in incidence and prevalence with age is known, but interesting to see is that the incidence and prevalence do not rise in a parallel manner with age as simple logic would assume. Between the ages of 60 and 90, the incidence in men increases two times and in women 41 times, prevalence increase in men is 55.25-fold and in women 77-fold. Regarding the women/men ratio, the incidence is 20.5-fold increased, and prevalence is merely 1.3936-fold increased. These numbers raise concerns about the evolution of the disease. Regarding mild cognitive impairment (MCI)/AD ratio, only about 1 in 2 people get AD (raising?) issues about the pathogenic disease relatedness.

Solution NMR studies of recombinant Aβ(1-42): from the presence of a micellar entity to residual β-sheet structure in the soluble species

Amyloid-β (Aβ) peptide is the major component found in senile plaques of Alzheimer's disease patients. The 42-residue fragment Aβ(1-42) is proposed to be one of the most pathogenic species therein. Here, the soluble Aβ(1-42) species were analyzed by various liquid-state NMR methods. Transient formation of a micelle species was observed at the onset of the aggregation kinetics. This micelle is dissolved after approximately one day. Subsequent loss of this species and the formation of protofibrils are proposed to be the route of fibril formation. Consequently, the observed micelle species is suggested to be on an off-pathway mechanism. Furthermore, characterization of the NMR-observable soluble species shows that it is a random-coil-like entity with low propensities for four β-strands. These β-strands correlate with the β-strand segments observed in Aβ fibrils. This finding indicates that the 3D structure of the fibrils might already be predisposed in the soluble species.

Dementia

INTRODUCTION

Dementia is characterised by chronic, global, non-reversible deterioration in memory, executive function, and personality. Speech and motor function may also be impaired.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments on cognitive symptoms of dementia (Alzheimer's, Lewy body, or vascular)? What are the effects of treatments on behavioural and psychological symptoms of dementia (Alzheimer's, Lewy body, or vascular)? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2011 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 49 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review, we present information relating to the effectiveness and safety of the following interventions: acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine), antidepressants (clomipramine, fluoxetine, imipramine, sertraline), antipsychotics (haloperidol, olanzapine, quetiapine, risperidone), aromatherapy, benzodiazepines (diazepam, lorazepam), cognitive behavioural therapy (CBT), cognitive stimulation, exercise, ginkgo biloba, memantine, mood stabilisers (carbamazepine, sodium valproate/valproic acid), music therapy, non-steroidal anti-inflammatory drugs (NSAIDs), omega 3 (fish oil), reminiscence therapy, and statins.

Genetic studies in Alzheimer's disease

Alzheimer's disease (AD), the most common cause of dementia in aged populations, is believed to be caused by both environmental factors and genetic variations. Extensive linkage and association studies have established that a broad range of loci are associated with AD, including both causative and susceptibility (risk factor) genes. So far, at least three genes, APP, PS1, and PS2, have been identified as causative genes. Mutations in these genes have been found to cause mainly early-onset AD. On the other hand, APOE has been identified to be the most common high genetic risk factor for late-onset AD. Polymorphisms in the coding region, intron, and promoter region of certain genes constitute another kind of genetic variation associated with AD. A number of other genes or loci have been reported to have linkage with AD, but many show only a weak linkage or the results are not well reproduced. Currently, the measurable genetic associations account for about 50% of the population risk for AD. It is believed that more new loci will be found to associate with AD, either as causative genes or genetic risk factors, and that eventually the understanding of genetic factors in the pathogenesis of AD will be important for our efforts to cure this illness.

Naftidrofuryl for dementia

BACKGROUND

Dementia is a brain disorder characterized by the permanent loss of higher cognitive functions. A number of vasodilatory drug treatments are prescribed for dementia. Naftidrofuryl is one such medicine which is reported to improve clinical symptoms significantly. The efficacy and possible adverse events of naftidrofuryl need to be reviewed systematically and assessed critically to inform clinical practice and guide the continued search for new treatment regimens.

OBJECTIVES

To evaluate the efficacy and safety of naftidrofuryl in the treatment of dementia.

SEARCH METHODS

We searched ALOIS: the Cochrane Dementia and Cognitive Improvement Group's Specialized Register on 11 January 2011 using the terms: naftidrofuryl. ALOIS contains records of clinical trials from major healthcare databases (MEDLINE, EMBASE, PsycINFO, LILACS and CINAHL), trial registries (such as ClinicalTrials.gov) and grey literature sources.

SELECTION CRITERIA

Randomised placebo-controlled trials in which patients with dementia were treated with naftidrofuryl were considered eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, assessed trial quality, and extracted data using data extraction forms. The domains assessed for risk of bias were sequence generation, allocation concealment, blinding, incomplete outcome data, and selective outcome reporting. We used odds ratios (OR) for reporting dichotomous data, and mean differences (MD) and standardized mean differences (SMD) for continuous data. We assessed statistical heterogeneity using the I(2) statistic.

MAIN RESULTS

We identified nine randomised controlled trials involving 847 patients with Alzheimer's disease, vascular dementia, mixed dementia, senile dementia and unspecified dementia. The beneficial effects were found on functional performance and behaviour (-1.04 standardized points, 95% CI -1.73 to -0.35, P = 0.003) with a high-level heterogeneity (I(2) = 54%), and mood (-0.80 standardized points, 95% CI -1.26 to -0.34, P=0.0006) for patients with dementia, as well as on cognitive function (-0.36 standardized points, 95% CI -0.71 to -0.02, P=0.04). However, this was not confirmed by clinical global measures. Naftidrofuryl was found to be well-tolerated by patients with dementia.

AUTHORS' CONCLUSIONS

Oral administration of naftidrofuryl is well-tolerated by patients with dementia.The low-quality evidence shows that, by use of naftidrofuryl, people with dementia may benefit on performance, behaviour, cognition, and mood. However, the benefit on global impression is inconsistent and unconvincing.

Beneficial effect of repetitive transcranial magnetic stimulation combined with cognitive training for the treatment of Alzheimer's disease: a proof of concept study

The current drug treatment for Alzheimer's disease (AD) is only partially and temporary effective. Transcranial magnetic stimulation (TMS) is a non-invasive technique that generates an electric current inducing modulation in cortical excitability. In addition, cognitive training (COG) may improve cognitive functions in AD. Our aim was to treat AD patients combining high-frequency repetitive TMS interlaced with COG (rTMS-COG). Eight patients with probable AD, treated for more than 2 months with cholinesterase inhibitors, were subjected to daily rTMS-COG sessions (5/week) for 6 weeks, followed by maintenance sessions (2/week) for an additional 3 months. Six brain regions, located individually by MRI, were stimulated. COG tasks were developed to fit these regions. Primary objectives were average improvement of Alzheimer Disease Assessment Scale-Cognitive (ADAS-cog) and Clinical Global Impression of Change (CGIC) (after 6 weeks and 4.5 months, compared to baseline). Secondary objectives were average improvement of MMSE, ADAS-ADL, Hamilton Depression Scale (HAMILTON) and Neuropsychiatric Inventory (NPI). One patient abandoned the study after 2 months (severe urinary sepsis). ADAS-cog (average) improved by approximately 4 points after both 6 weeks and 4.5 months of treatment (P < 0.01 and P < 0.05) and CGIC by 1.0 and 1.6 points, respectively. MMSE, ADAS-ADL and HAMILTON improved, but without statistical significance. NPI did not change. No side effects were recorded. In this study, rTMS-COG (provided by Neuronix Ltd., Yokneam, Israel) seems a promising effective and safe modality for AD treatment, possibly as good as cholinesterase inhibitors. A European double blind study is underway.

Dementia

INTRODUCTION

Dementia is characterised by chronic, global, non-reversible deterioration in memory, executive function, and personality. Speech and motor function may also be impaired.

METHODS AND OUTCOMES

We conducted a systematic review and aimed to answer the following clinical question: What are the effects of treatments on cognitive symptoms of dementia (Alzheimer's, Lewy body, or vascular)? What are the effects of treatments on behavioural and psychological symptoms of dementia (Alzheimer's, Lewy body, or vascular)? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2008 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

RESULTS

We found 33 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

CONCLUSIONS

In this systematic review, we present information relating to the effectiveness and safety of the following interventions: acetylcholinesterase inhibitors (donepezil, galantamine, rivastigmine), antidepressants (clomipramine, fluoxetine, imipramine, sertraline), antipsychotics (haloperidol, olanzapine, quetiapine, risperidone), aromatherapy, benzodiazepines (diazepam, lorazepam), cognitive behavioural therapy (CBT), cognitive stimulation, exercise, ginkgo biloba, memantine, mood stabilisers (carbamazepine, sodium valproate/valproic acid), music therapy, non-steroidal anti-inflammatory drugs (NSAIDs), omega 3 (fish oil), reminiscence therapy, and statins.

The role of adenosine in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder of the central nervous system manifested by cognitive and memory deterioration, a variety of neuropsychiatric symptoms, behavioral disturbances, and progressive impairment of daily life activities. Current pharmacotherapies are restricted to symptomatic interventions but do not prevent progressive neuronal degeneration. Therefore, new therapeutic strategies are needed to intervene with these progressive pathological processes. In the past several years adenosine, a ubiquitously released purine ribonucleoside, has become important for its neuromodulating capability and its emerging positive experimental effects in neurodegenerative diseases. Recent research suggests that adenosine receptors play important roles in the modulation of cognitive function. The present paper attempts to review published reports and data from different studies showing the evidence of a relationship between adenosinergic function and AD-related cognitive deficits. Epidemiological studies have found an association between coffee (a nonselective adenosine receptor antagonist) consumption and improved cognitive function in AD patients and in the elderly. Long-term administration of caffeine in transgenic animal models showed a reduced amyloid burden in brain with better cognitive performance. Antagonists of adenosine A2A receptors mimic these beneficial effects of caffeine on cognitive function. Neuronal cell cultures with amyloid beta in the presence of an A2A receptor antagonist completely prevented amyloid beta-induced neurotoxicity. These findings suggest that the adenosinergic system constitutes a new therapeutic target for AD, and caffeine and A2A receptor antagonists may have promise to manage cognitive dysfunction in AD.

Dementia of the Alzheimer type

Dementia of the Alzheimer type is a progressive, fatal neurodegenerative condition characterized by deterioration in cognition and memory, progressive impairment in the ability to carry out activities of daily living, and a number of neuropsychiatric symptoms. This narrative review summarizes the literature regarding descriptive epidemiology, clinical course, and characteristic neuropathological changes of dementia of the Alzheimer type. Although there are no definitive imaging or laboratory tests, except for brain biopsy, for diagnosis, brief screening instruments and neuropsychiatric test batteries used to assess the disease are discussed. Insufficient evidence exists for the use of biomarkers in clinical practice for diagnosis or disease management, but promising discoveries are summarized. Optimal treatment requires both nonpharmacological and pharmacological interventions, yet none have been shown to modify the disease's clinical course. This review describes the current available options and summarizes promising new avenues for treatment. Issues related to the care of persons with dementia of the Alzheimer type, including caregiver burden, long-term care, and the proliferation of dementia special care units, are discussed. Although advances have been made, more research is needed to address the gaps in our understanding of the disease.

Occupational risk factors in Alzheimer's disease: a review assessing the quality of published epidemiological studies

Epidemiological evidence of an association between Alzheimer's disease (AD) and the most frequently studied occupational exposures--pesticides, solvents, electromagnetic fields (EMF), lead and aluminium--is inconsistent. Epidemiological studies published up to June of 2003 were systematically searched through PubMed and Toxline. Twenty-four studies (21 case-control and 3 cohort studies) were included. Median GQI was 36.6% (range 19.5-62.9%). Most of the case-control studies had a GQI of <50%. The study with the highest score was a cohort study. Likelihood of exposure misclassification bias affected 18 of the 24 studies. Opportunity for bias arising from the use of surrogate informants affected 17 studies, followed by disease misclassification (11 studies) and selection bias (10 studies). Eleven studies explored the relationship of AD with solvents, seven with EMF, six with pesticides, six with lead and three with aluminium. For pesticides, studies of greater quality and prospective design found increased and statistically significant associations. For the remaining occupational agents, the evidence of association is less consistent (for solvents and EMF) or absent (for lead and aluminium).

Non-invasive measurement of vagus activity in the brainstem - a methodological progress towards earlier diagnosis of dementias?

In Alzheimer's disease (AD), mild functional disturbances should precede gross structural damage and even more clinical symptoms, possibly by decades. Moreover, alterations in the brainstem are supposed to occur earlier as cortical affections. Based on these considerations, we developed a new method aiming at the measurement of vagal brainstem functioning by means of evoked potentials after electrical stimulation of the cutaneous representation of the vagus nerve in the external auditory channel. In the current study, a first sample of patients with Alzheimer's disease (n = 7) and mild cognitive impairment (n = 3) were investigated (6m, 4f, range from 57 to 78 y, mean age 68.6 years). Vagus somatosensory evoked potentials (VSEP) were characterized by significantly longer latencies as compared to healthy age- and gender-matched controls (p < 0.05). Future large scale studies - also including preclinical stages of AD - have to assess the value of this non-invasive, fast and cheap method in the early diagnosis of neurodegenerative disorders.

Risk factors for incident Alzheimer's disease in African Americans and Yoruba

INTRODUCTION

The incidence rate of Alzheimer's disease (AD) was found to be 2 times lower in Yoruba than in African Americans. This study was aimed at identifying the factors associated with increased risk of incident AD in the two communities.

METHODOLOGY

A two-stage design with initial screening using the CSI'D followed by neuropsychological test battery, relations' interview and physician assessment in a sub-sample.NINCDS-ADRDA criteria were met for AD. The risk factor variables assessed included demographic, lifestyle, medical and family history items.

RESULTS

In the Yoruba, AD was associated with age (OR = 1.07) and female gender (OR = 2.93). In African Americans, age (OR = 1.09) and rural living (OR = 2.08) were the significant risk factors, while alcohol was protective (OR = 0.49).

DISCUSSION

Age was a significant risk factor for AD at both sites. The higher risk of incident AD in the Yoruba female, and in African Americans who resided in rural areas in childhood were similar with the prevalence cases. Alcohol emerged a protective factor in African Americans. More studies are required, including biological measurements, to adequately explain the differences in rates.

Personal experience of aging in the children of a parent with dementia

We investigated whether adults with a parent with dementia experience their personal aging differently than adults whose parents do not have dementia. Semi-structured interviews were conducted with 25 adults who had a parent with dementia and 25 controls. We found that, although in a general sense the two groups were quite similar in their personal experiences of aging, there were specific differences. The children of parents with dementia had a health-concept in which there was substantial emphasis on mental health. Moreover, they linked the dementia of their parent to their own aging and worried about developing a dementia syndrome themselves. They also held different attitudes with regard to end-of-life decisions. Finally, participants having a parent with dementia gave more extensive answers to simple questions. This overall response suggests more involvement with growing older and finitude in the children of parents with dementia.

The neuropsychology of heading and head trauma in Association Football (soccer): a review

Association Football (soccer) is the most popular and widespread sport in the world. A significant proportion of the injuries suffered in football are head injuries involving trauma to the brain. In normal play, head trauma frequently arises from collisions, but some researchers have claimed that it also may arise as a consequence of heading the ball. Although assessments based on biomechanical analyses are equivocal on the potential for brain injury due to football heading, a growing literature seems to support the claim that neuropsychological impairment results from general football play and football heading in particular. However, this review suggests a distinction is required between the neuropsychological effects of concussive and subconcussive head trauma and that all of the neuropsychological studies conducted so far suffer from methodological problems. At best, a few of these studies may be regarded as exploratory. The review concludes that presently, although there is exploratory evidence of subclinical neuropsychological impairment as a consequence of football-related concussions, there is no reliable and certainly no definitive evidence that such impairment occurs as a result of general football play or normal football heading. The neuropsychological consequences of football-related subconcussive effects await confirmatory investigation.

Evidence for parent of origin effect in late-onset Alzheimer disease

Evidence for a parent of origin effect in Alzheimer disease was obtained from a sample of 148 sibships on which affection status of the parents was sought using family history interviews. The parent study recruited families with two or more affected sibs for late onset AD utilizing rigorous diagnostic criteria. In 74 families, there was evidence of an affected parent, 49 maternal and 25 paternal. Genome scan data were analyzed for the sample as a whole and for the maternal and paternal families separately, using Genehunter-ASM. Seven regions with Z(lr) scores >or=2 were identified, four in maternal families (chr. 10,12,19,20) and three in paternal families (chr. 1,7,13). With the exception of the chromosome 10 finding, analysis by parent of origin greatly increased evidence of linkage in areas showing no linkage in the overall analyses. For example, a chr. 12 region reached a LOD = 2.29 among maternal families whereas the same region showed a LOD = 0.3 when all families were analyzed together. The strongest findings among maternal families (chr. 10 and 12) were followed up with fine mapping that resulted in an increase in maximum LOD scores from 2.7-3.2 on chr. 10, and 2.29-2.42 on chr. 12. These analyses highlight the importance of parent of origin effects in late-onset AD families and identify several genomic regions that may include genes linked to late-onset AD specific to disease transmission from the mother and require further investigation.

Depression, menopause and estrogens: is there a correlation?

Women have a higher incidence of depression than men. The lifetime incidence of endogenous depression in women is twice the incidence in males. Because depression in the elderly is an important public health concern, an eventual correlation between menopause and depression is of practical importance. The relevant literature is reviewed. There are suggestive data that estrogen deficiency may increase the susceptibility for depression. Furthermore, here is suggestive evidence from observational studies and a limited number of randomized, controlled trials that estrogen therapy after menopause improves mood and cognition. However, the clinical relevance of estrogen administration is unproved. There are weak data that estrogens might be considered for mild depressive symptoms attributed to hot flushes, sleep disturbances, or other climacteric symptoms. No hard data exist to indicate whether estrogen could be used as adjunct therapy for other depressive disorders during the menopausal transition or postmenopausal period, but newer findings suggest that estrogens may improve the effect of serotonin reuptake inhibitors.

Predictors of decline in MMSE scores among older Mexican Americans

BACKGROUND

The purpose of this analysis was to examine the association of sociodemographic variables and health-related conditions with 5-year declines in cognitive function among Mexican American elderly persons.

METHODS

The cognitive function of 1759 participants was assessed by using the Mini-Mental State Examination (MMSE) in 1993/1994 and again in 1998/1999. Cognitive decline was defined by two sets of criteria: (1) a drop to 17 or below on the MMSE at follow-up, and (2) a decline of at least three points, the mean change in MMSE scores among respondents who obtained scores at or above the 5th percentile distribution at baseline.

RESULTS

Cognitive decline was significantly associated with sociodemographic variables including age, education, marital status, and household composition. In addition, respondents with reported vision impairment, stroke, and diabetes were at increased risk for cognitive decline after controlling for multiple potential confounders.

CONCLUSION

Although age and education have been reported as the more salient predictors of cognitive deterioration, other sociodemographic and several medical conditions including stroke and diabetes should be considered as part of cognitive aging studies among Mexican American elders.

Clock drawing: analysis in a retirement community

OBJECTIVE

To test the hypothesis that performance on a clock-drawing test in a mailed survey to an older cohort is associated with known and potential risk and protective factors for Alzheimer's disease.

DESIGN

The Leisure World Cohort Study is an ongoing study, begun in 1981, of nearly 14,000 older adults. In November 1992, the 8,406 living cohort members were mailed a follow-up questionnaire.

SETTING

Leisure World Laguna Hills, a southern California retirement community.

PARTICIPANTS

The study population is a predominantly white, well-educated, upper-middle-class community; approximately two-thirds are women. Data from 4,843 cohort members (mean age 80 years; range 52-101) were analyzed.

MEASUREMENTS

The questionnaire included a clock-drawing task: a predrawn circle 3 1/4 inches (8.3 cm) in diameter was provided with instructions "In the circle below, draw in the numbers as on a clock face. Make no erasures." Clocks were scored on 7 items: all numbers 1-12 present without adding extra or omitting numbers, sequencing of numbers, position of numbers, orientation of numbers to circle, consistent number style (either Arabic or Roman), tilt of numbers, and superfluous marks. A total clock score was calculated by summing the number of correct individual items (0-7). We also classified individuals as cognitively impaired by a previously suggested method: individuals were affected if they did not have three numbers drawn in the upper left quadrant of the clock face.

RESULTS

Ninety percent or more of the participants across all ages placed the numbers 1 to 12 on their clocks without omissions or additions; 35% completed the clock drawing without error. The mean total clock scores decreased with each successive 5-year age group in both men and women. Regression analysis indicated a significant effect for age (b = -0.15, P <.0001), education (b = 0.05, P =.0001), smoking (b = 0.13, P =.03), and female gender (b = -0.05, P =.05) and a marginally significant effect of nonrheumatoid arthritis (b = 0.05, P =.07) on total clock score. No other measured variable had a significant effect. Cognitively impaired individuals were more likely to be female and older. After adjusting for age and gender, they were also more likely to be hypertensive and to have taken blood pressure medication and less likely to be college graduates, have glaucoma or arthritis, and to have taken vitamin supplements.

CONCLUSION

The clock-drawing task is an appealing measure of cognitive function for large epidemiological studies because it is a simple, self-administered test that is easily adapted to mail surveys and correlates with more-detailed and more-time-consuming cognitive screens. Although it is relatively free of influence by language, cultural, or ethnic factors, our study shows that even in a highly educated population, clock drawing is influenced by educational level and other known risk factors for Alzheimer's disease. Thus a clock-drawing task may help predict cognitive frailty and future disability in older people. Such determination can direct high-risk individuals to earlier diagnosis, potential therapies, and better management.

Alzheimer's disease: insights from epidemiology

While a complete understanding of the pathogenesis of Alzheimer's disease (AD) remains elusive, many conclusions can be drawn from the numerous epidemiological studies undertaken to date. Prevalence and incidence estimates show consistency, following a roughly exponential pattern with a doubling of both parameters roughly every five years after age 65. Roughly 7% of the population aged 65 and over has AD. The clinical course of the disease is reasonably well established and mortality rates rise with increasing levels of cognitive deficit. Four risk factors for AD are firmly established: increasing age, the presence of the apolipoproteinE-epsilon4 allele, familial aggregation of cases, and Down's syndrome. Numerous other associations have been shown in some studies, but not in others. For example, women generally appear at higher risk than men, as do people with lower levels of education; depression is probably prodromal; head injury is an established risk factor, and may interact with the apoE gene; several occupational exposures appear hazardous, and exposure to aluminum in the water supply confers excess risk. Hypertension and other vascular symptoms appear to predispose to AD, which is now seen as nosologically closer to vascular dementia than was previously believed. Several apparently protective factors have been identified, although preventive trials based on these have so far shown minimal effectiveness. The use of non-steroidal anti-inflammatory drugs to treat arthritis is associated with a reduced risk of AD, as is estrogen use by post-menopausal women. Physical activity appears beneficial, as does a diet with high levels of vitamins B6, B12 and folate. while red wine in moderate quantities appears protective. This review concludes with a discussion of the strengths and limitations of current epidemiological methods for studying Alzheimer's disease.

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.

Age-specific incidence rates of Alzheimer's disease: the Baltimore Longitudinal Study of Aging

OBJECTIVE

To estimate age-specific incidence rates of AD in the Baltimore Longitudinal Study of Aging (BLSA).

BACKGROUND

The BLSA is a volunteer cohort of normal subjects followed longitudinally with biennial evaluations at the Gerontology Research Center of the National Institute on Aging.

METHODS

Subjects are 1236 participants (802 men, 434 women) in the BLSA with longitudinal follow-up between January 1985 and May 1998. The average length of follow-up was 7.5 years, with participants evaluated every 2 years by physical, neurologic, and neuropsychological examinations. Using Diagnostic and Statistical Manual of Mental Disorders, 3rd ed., revised and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria, the authors diagnosed dementia and AD.

RESULTS

The authors diagnosed 155 cases of dementia, of which 114 (74%) were AD. Incidence rates of AD increased with age from an estimated 0.08% per year (95% CI 0.00 to 0.43) in the 60 to 65 age group to an estimated 6.48% per year (95% CI 5.01 to 8.38) in the 85+ age group for men and women combined. The doubling time of incidence rates was estimated to be approximately 4.4 years and the median time of conversion from mild cognitive impairment to diagnosis of AD was estimated to be 4.4 years. There was a trend for women to have higher incidence rates than men and for fewer years of education to be associated with higher incidence rates; however, these effects were not significant.

CONCLUSION

Incidence rates for AD in the BLSA are consistent with published rates in other studies. The longitudinally followed subjects of the BLSA offer a unique opportunity to prospectively investigate the antecedents of AD.

Interleukin-1 and the immunogenetics of Alzheimer disease

Established genetic causes of familial Alzheimer disease (AD) involve genes for beta-amyloid precursor protein (betaAPP), presenilin-1, and presenilin-2. For the more common sporadic forms of AD, increased risk has been associated with a number of genes; the most important of which is the epsilon4 allele of apolipoprotein E. Two recent studies, one clinical and one using postmortem material, now show increased risk for AD associated with certain polymorphisms in the genes encoding the alpha and beta isoforms of interleukin-1 (IL-1). IL-1 levels are elevated in Alzheimer brain, and overexpression of IL-1 is associated with beta-amyloid plaque progression. IL-1 interacts with the gene products of several other known or suspected genetic risk factors for AD, including betaAPP, apolipoprotein E, alpha1-antichymotrypsin, and alpha2-macroglobulin. IL-1 overexpression is also associated with environmental risk factors for AD, including normal aging and head trauma. These observations suggest an important pathogenic role for IL-1, and for IL-1-driven cascades, in the pathogenesis of AD.

Vascular risk factors for Alzheimer's disease: an epidemiologic perspective

Vascular disease and Alzheimer's disease are both common disorders, in particular among elderly subjects. Therefore, it can be expected that the joint occurrence of these two disorders is not a rare phenomenon. In recent years, evidence is increasing that the two may be more closely linked than just by chance. Epidemiological studies have suggested that risk factors for vascular disease and stroke are associated with cognitive impairment and Alzheimer's disease, and that the presence of cerebrovascular disease intensifies the presence and severity of the clinical symptoms of Alzheimer's disease. In this paper, current knowledge on the relation between vascular risk factors and risk indicators and Alzheimer's disease will be reviewed.

Worldwide prevalence and incidence of dementia

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

Understanding genetic testing for Alzheimer disease: medical and epidemiological background

To assess the potential benefits and risks of genetic testing for Alzheimer disease (AD), patients and families, health care providers, and policymakers must understand the medical and epidemiologic aspects of the disease. This paper provides a brief overview of the symptoms, progression, and etiology of AD, as well as of the prevalence and incidence of the disease. The established and the controversial risk factors thought to be associated with the development of AD are described. Current methods for diagnosing and treating AD are also reviewed.

Type-2 diabetes and cognitive function in a non-demented population

OBJECTIVES

To study if type-2 (non-insulin-dependent) diabetes mellitus (NIDDM) is associated with cognitive dysfunction independently of clinically diagnosed dementia in an elderly population.

MATERIAL AND METHODS

Cognitive function was investigated with a brief neuropsychological test battery in a non-demented elderly population consisting of 183 NIDDM (World Health Organization, 1985) patients and 732 non-diabetic subjects.

RESULTS

Patients with NIDDM were impaired in the Trail-Making Test parts A and C, which may be a reflection of mildly affected frontal lobe/executive functions. Women with NIDDM performed better than non-diabetic subjects in the Mini-Mental State Examination.

CONCLUSIONS

We conclude that NIDDM per se is not associated with impaired memory in the elderly, and the minor defects observed in tests of frontal lobe/executive functions are unlikely to affect daily living. In the non-demented population aged 69 78 years, NIDDM does not carry a significant risk of cognitive dysfunction, when compared to the non-diabetic subjects.

Risk of dementia in parents of probands with and without the apolipoprotein E4 allele. The EVA study

STUDY OBJECTIVE

Age, family history of dementia and the epsilon 4 allele of the apolipoprotein E gene have been associated with Alzheimer's disease (AD). Considering the strength of APOE-epsilon 4 as a genetic risk factor for AD, this factor might explain a large part of the association between AD and a family history of dementia. Therefore, in the general population, a higher frequency of dementia should be observed among parents of probands with at least one epsilon 4 allele than in parents of probands without this allele.

DESIGN, SETTING, AND PARTICIPANTS

The study investigated a sample of 1153 volunteers between 59 and 71 years old, genotyped for the APOE gene, all participating in the EVA study. Dementia in their parents was determined using a self reported questionnaire.

MAIN RESULTS

The frequency of dementia in 2164 parents was examined and it was found that 245 were demented. The percentage of demented parents was 13.0% in the subgroup of parents of subjects having one or two epsilon 4 alleles and 10.8% in the other subgroup. The relative risk of dementia among parents according to the APOE-epsilon 4 status of probands, was calculated using a Cox model adjusted for the educational level of parents and their history of stroke: RR = 1.21 (95% CI 0.90, 1.63).

CONCLUSION

This lack of association supports the observation that in the general population, APOE-epsilon 4 cannot explain a large part of family history of dementia.

Hormone replacement therapy and Alzheimer's disease

There is ample evidence to show the beneficial effect of estrogen on the risk and course of Alzheimer's disease (AD). Estrogen may play a role in the pathophysiology of AD through improvement of cerebral blood flow, stimulation of the neuron or gliacyte and interaction with genetic factors. Most etiological studies of estrogen replacement therapy and AD have been retrospective studies. In these studies, the history of estrogen use was obtained from an informant, limiting the validity of the findings. Of the three follow-up studies conducted to date, one has failed to show a protective effect. There is some evidence for a synergistic effect between estrogen and the genetic factors involved in AD. However, up until now, studies of estrogen replacement therapy have generally been too small and of low validity. Large scale, long-term population studies may clarify the role of estrogen replacement therapy in the prevention and therapy of AD.

Alzheimer's disease: the size of the problem, clinical manifestation and heterogeneity

Age is the major demographic risk factor for the development of Alzheimer's disease (AD) and the ageing of our society has contributed to the growing importance of AD. The problem of AD has been tackled from numerous clinical and scientific angles. The traditional clinico-pathological disease concept, which relies on the manifestation of a dementia syndrome and the elimination of other relevant systemic and brain diseases for a diagnosis of AD, accommodates a number of genetically and clinically heterogeneous conditions, but cannot promote our understanding of the preclinical pathogenetic processes and their interaction. If new molecular biological discoveries cannot be integrated with this traditional clinico-pathological model, it may have outlived its usefulness.

Increased F2-isoprostanes in Alzheimer's disease: evidence for enhanced lipid peroxidation in vivo

Alzheimer's disease (AD) includes a group of dementing neurodegenerative disorders that have diverse etiologies but the same hallmark brain lesions. Since oxidative stress may play a role in the pathogenesis of AD and isoprostanes are chemically stable peroxidation products of arachidonic acid, we measured both iPF2alpha-III and iPF2alpha -VI using gas chromatography-mass spectrometry in AD and control brains. The levels of both isoprostanes, but not of 6-keto PGF1alpha, an index of prostaglandin production, were markedly elevated in both frontal and temporal poles of AD brains compared to the corresponding cerebella. Levels were also elevated compared to corresponding areas of brains from patients who had died with schizophrenia or Parkinson's disease or from nonneuropsychiatric disorders. iPF2alpha -IV, but not iPF2alpha-III, levels were higher in ventricular CSF of AD brains relative to the non-AD brains. These data suggest that specific isoprostane analysis may reflect increased oxidative stress in AD.

Projections of Alzheimer's disease in the United States and the public health impact of delaying disease onset

OBJECTIVES

The goal of this study was to project the future prevalence and incidence of Alzheimer's disease in the United States and the potential impact of interventions to delay disease onset.

METHODS

The numbers of individuals in the United States with Alzheimer's disease and the numbers of newly diagnosed cases that can be expected over the next 50 years were estimated from a model that used age-specific incidence rates summarized from several epidemiological studies, US mortality rates, and US Bureau of the Census projections.

RESULTS

in 1997, the prevalence of Alzheimer's disease in the United States was 2.32 million (range: 1.09 to 4.58 million); of these individuals, 68% were female. It is projected that the prevalence will nearly quadruple in the next 50 years, by which time approximately 1 in 45 Americans will be afflicted with the disease. Currently, the annual number of new incident cases in 360,000. If interventions could delay onset of the disease by 2 years, after 50 years there would be nearly 2 million fewer cases than projected; if onset could be delayed by 1 year, there would be nearly 800,000 fewer prevalent cases.

CONCLUSIONS

As the US population ages, Alzheimer's disease will become an enormous public health problem. interventions that could delay disease onset even modestly would have a major public health impact.

Apolipoprotein E genotype, atherosclerosis, and cognitive decline: the Rotterdam Study

The apolipoprotein E4 allele (APOE epsilon 4) and atherosclerosis are risk factors for cognitive decline. We investigated whether the effects of APOE epsilon 4 and atherosclerosis on cognitive decline are independent. A population-based follow-up study was performed on 838 subjects who were non-demented at baseline. The Mini Mental State Examination (MMSE) score at follow-up was studied as a function of APOE epsilon 4 and atherosclerosis. Mild, non-significant effects on the MMSE score were found for atherosclerosis in the absence of APOE epsilon 4 and for APOE epsilon 4 in the absence of atherosclerosis. APOE epsilon 4 carriers with two or more indicators of atherosclerosis positive, had a significantly lower MMSE score at follow-up (mean difference -0.7 points; 95% confidence interval -1.1 to -0.2) relative to non-APOE epsilon 4 carriers with no evidence of atherosclerosis. Our findings suggest that the consequences of APOE epsilon 4 and atherosclerosis are not independent, and that particularly APOE epsilon 4 carriers with atherosclerosis are at increased risk of cognitive decline.

Dementia in Saudi Arabia: experience from a university hospital

OBJECTIVES

To describe the pattern of presentation, the types of dementia and the associated conditions in Saudi patients.

MATERIALS AND METHODS

Hospital-based study using DSM-IV and ICD 10 criteria for consensus diagnosis of cases from clinical information and results of investigations. Dementia subtypes were made according to NINCDS-ADRDA, NINDS-AIREN and ICD 10 criteria while CDR was used for severity grading.

RESULTS

A total of 77 demented patients (49 males, 28 females) were studied. The hospital frequency was 19.3/100,000 patients. The mean age at presentation was 74.6 years and age at onset was below 65 years in 17 patients. The types of dementia were: Alzheimer's disease (51.9%), vascular dementia (18.2%), mixed cases (15.6%), dementia with Parkinson's disease (7.8%) and treatable dementia (5.2%). Only 3 patients were in the severe clinical stage and infections were important causes of deterioration.

CONCLUSION

The hospital frequency appears to be low probably because of the relatively young population. The pattern of dementia with preponderance of AD is similar to that in western countries and intervention directed at the risk factors for stroke could reduce the burden of vascular dementia.

Five-year incidence and prediction of dementia and cognitive decline in a population sample of women aged 70-79 at baseline

OBJECTIVE

To determine the incidence of dementia and cognitive decline and their predictors in a population sample.

SETTINGS

A rural geographically defined population served by a single health centre.

SAMPLE

75% of the 70-74-year-old, 100% of the 75-79-year-old women registered with the practice.

METHOD

Interview the total sample using an augmented version of CAMDEX, including informant interview, and reaction times at baseline and 5 years later. IQ was estimated at baseline only.

RESULTS

365 women were interviewed at baseline, 237 at follow-up. Incidence of dementia of all severities was 3.1% per annum (95% CI, 2.2-4.3). CAMCOG declined by 12.6 points in those who became demented, MMSE by 3 points. Observed, self-reported and informant-reported cognitive difficulty at baseline all predicted later incidence of dementia. The additional use of estimated IQ and reaction times did not increase the efficiency of either cross-sectional detection of dementia or prediction of dementia at 5 years.

CONCLUSIONS

The incidence of dementia was in the range reported by other studies; slight cognitive decline was noted in the total population, increasing with age and marked in incident dementia. Of clinical importance was the finding that both the individuals and the informants of those who subsequently demented were aware of decline 5 years earlier. Simple and relatively easily administered cognitive tests were found to be the most efficient method of detection of dementia.

Alzheimer's disease: risk and protection

Only four risk factors for Alzheimer's disease can be regarded as confirmed--old age, family history of dementia, apo-E genotype and Down syndrome. Other disputed risk factors with some supporting evidence include ethnic group, head trauma and aluminium in drinking water. Possible protection factors, such as anti-inflammatory drugs, oestrogen replacement therapy and a high education level, are of great interest because they suggest possible preventive action.

Low education is a genuine risk factor for accelerated memory decline and dementia

A relatively high prevalence and incidence of dementia have been found in population strata with low levels of education in comparison to population strata with high levels of education. However, doubt remains whether this may be an artifact of education bias in the screening tests used. To investigate this matter, we analyzed results of two Dutch population surveys in which unbiased measures of memory decline were used. In the Longitudinal Aging Study Amsterdam (n = 1774) the percentage of words retained in a verbal learning test was found to be disproportionately low in the oldest age cohort (80-85 years) with less than 11 years of education. The Amsterdam Study of the Elderly (n = 4051) found a "dose-response" relationship between education and dementia prevalence. Cross-sectional and longitudinal results showed that, in less educated people, memory decline is faster and sets in at an earlier age. These findings indicate that the relationship between dementia and education is not just an artifact of case detection methods.

Menopause and the brain

Estrogen may have a beneficial effect on the risk and course of Alzheimer's disease (AD) through several mechanisms, including improvement of cerebral blood flow, stimulation of the neuron, or gliacyte and interaction with genetic factors. In this paper, the therapeutic and etiologic research of the role of estrogen in cognitive function and dementia is reviewed. Findings to date are promising but far from conclusive. In therapeutic research, interpretation of studies is hampered by the small sizes of the studies and differences in methodology. Most etiological studies have been limited to retrospective studies in which the history of estrogen use was obtained from an informant. Follow-up studies conducted to date have yielded controversial results. Further research is needed to elucidate the role of estrogen in the pathogenesis and progression of dementia. Subjects genetically susceptible for AD may prove to be an important high-risk group to target in preventive, therapeutic and etiologic research.