More than the epidemiology of Alzheimer's disease: contributions of the Canadian Study of Health and Aging

[Diagnosis and treatment of early forms of cognitive impairment: possibilities of influencing neuronal energy metabolism. Resolution of the Council of Experts]

Diagnosis and treatment of early forms of cognitive impairment: possibilities of influencing neuronal energy metabolism. Resolution of the Council of Experts.

The Medicinal Chemistry of Caffeine

The purine alkaloid caffeine is the most widely consumed psychostimulant drug in the world and has multiple beneficial pharmacological activities, for example, in neurodegenerative diseases. However, despite being an extensively studied bioactive natural product, the mechanistic understanding of caffeine's pharmacological effects is incomplete. While several molecular targets of caffeine such as adenosine receptors and phosphodiesterases have been known for decades and inspired numerous medicinal chemistry programs, new protein interactions of the xanthine are continuously discovered providing potentially improved pharmacological understanding and a molecular basis for future medicinal chemistry. In this Perspective, we gather knowledge on the confirmed protein interactions, structure activity relationship, and chemical biology of caffeine on well-known and upcoming targets. The diversity of caffeine's molecular activities on receptors and enzymes, many of which are abundant in the CNS, indicates a complex interplay of several mechanisms contributing to neuroprotective effects and highlights new targets as attractive subjects for drug discovery.

The impact of adjusting for pure predictors of exposure, mediator, and outcome on the variance of natural direct and indirect effect estimators

It is now well established that adjusting for pure predictors of the outcome, in addition to confounders, allows unbiased estimation of the total exposure effect on an outcome with generally reduced standard errors (SEs). However, no analogous results have been derived for mediation analysis. Considering the simplest linear regression setting and the ordinary least square estimator, we obtained theoretical results showing that adjusting for pure predictors of the outcome, in addition to confounders, allows unbiased estimation of the natural indirect effect (NIE) and the natural direct effect (NDE) on the difference scale with reduced SEs. Adjusting for pure predictors of the mediator increases the SE of the NDE's estimator, but may increase or decrease the variance of the NIE's estimator. Adjusting for pure predictors of the exposure increases the variance of estimators of the NIE and NDE. Simulation studies were used to confirm and extend these results to the case where the mediator or the outcome is binary. Additional simulations were conducted to explore scenarios featuring an exposure-mediator interaction as well as the relative risk and odds ratio scales for the case of binary mediator and outcome. Both a regression approach and an inverse probability weighting approach were considered in the simulation study. A real-data illustration employing data from the Canadian Study of Health and Aging is provided. This analysis is concerned with the mediating effect of vitamin D in the effect of physical activity on dementia and its results are overall consistent with the theoretical and empirical findings.

Vitamin D status, cognitive decline and incident dementia: the Canadian Study of Health and Aging

OBJECTIVE

Vitamin D could prevent cognitive decline because of its neuroprotective, anti-inflammatory and antioxidant properties. This study aimed to evaluate the associations of plasma 25-hydroxyvitamin D (25(OH)D) concentrations with global cognitive function and incident dementia, including Alzheimer's disease (AD).

METHODS

The Canadian Study of Health and Aging is a 10-year cohort study of a representative sample of individuals aged 65 years or older. A total of 661 subjects initially without dementia with frozen blood samples and follow-up data were included. Global cognitive function was measured using the validated Modified Mini-Mental State (3MS) examination. A consensus diagnosis of all-cause dementia and AD was made between the physician and the neuropsychologist according to published criteria. Cognitive decline for a 5-year increase in age at specific 25(OH)D concentrations was obtained using linear mixed models with repeated measures. Hazard ratios of incident dementia and AD were obtained using semi-parametric proportional hazards models with age as time scale.

RESULTS

Over a mean follow-up of 5.4 years, 141 subjects developed dementia of which 100 were AD. Overall, no significant association was found between 25(OH)D and cognitive decline, dementia or AD. Higher 25(OH)D concentrations were associated with an increased risk of dementia and AD in women, but not in men.

CONCLUSION

This study does not support a protective effect of vitamin D status on cognitive function. Further research is needed to clarify the relation by sex.

Is Benzodiazepine Use Associated With the Risk of Dementia and Cognitive Impairment–Not Dementia in Older Persons? The Canadian Study of Health and Aging

Background: The use of benzodiazepines in relation to cognitive decline remains an area of controversy in aging populations. Objective: This study aims to evaluate the risk of cognitive impairment–not dementia (CIND), Alzheimer disease (AD), and all-cause dementia with benzodiazepine use. The effect modification by sex was also investigated. Methods: Data come from the Canadian Study of Health and Aging, a 10-year multicentric study involving 10 263 participants randomly selected, 65 years and older, living in the community and in institutions. Current exposure to benzodiazepines was assessed in a face-to-face interview or self-reported in a questionnaire. Cox proportional hazard regression models, using age as time scale, were conducted to estimate hazard ratios, with adjustment for sex, education, smoking, alcohol intake, depression, physical activity, nonsteroidal anti-inflammatory drug use, and vascular comorbidities. Results: Data sets included 5281 participants for dementia as the outcome, 5015 for AD, and 4187 for CIND. Compared with nonusers, current use of benzodiazepines was associated with an increased risk of CIND (hazard ratio = 1.36; 95% CI = 1.08-1.72) in the simplest model. Results remained similar in the fully adjusted model (hazard ratio = 1.32; 95% CI = 1.04-1.68). There was no association between benzodiazepine use and the risk of dementia or AD. All these effects were similar between men and women. Conclusion and Relevance: Benzodiazepine use in older people from the general population is related to subsequent occurrence of cognitive dysfunction but not implicated in the pathogenesis of dementia or AD. Caution should be exercised when prescribing benzodiazepines to preserve global cognitive function.

Exposure to polychlorinated biphenyls and organochlorine pesticides and risk of dementia, Alzheimer's disease and cognitive decline in an older population: a prospective analysis from the Canadian Study of Health and Aging

BACKGROUND

Little attention has been paid to neurotoxicants on the risk of dementia. Exposure to known neurotoxicants such as polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides is suspected to have adverse cognitive effects in older populations.

OBJECTIVE

To assess whether plasma concentrations of PCBs and OC pesticides are associated with the risk of cognitive decline, Alzheimer's disease (AD) and of all-cause dementia in the Canadian older population.

METHODS

Analyses were based on data from the Canadian Study of Health and Aging, a 3-phase, 10-year population-based study of individuals aged 65+ years. Analyses included 669 clinically assessed subjects, of which 156 developed dementia including 108 incident cases of AD. Subjects were screened at each phase with the 100-point Modified Mini-Mental State Examination (3MS), a measurement of global cognitive function. Statistical analyses included Cox proportional hazards model when the outcome was dementia or AD, and a repeated-measure mixed model when the outcome was the 3MS score.

RESULTS

No association of PCB and OC pesticides with the risk of dementia and AD was observed. Elevated concentrations of PCB congeners nos 118, 153, 156, 163, and OC pesticides 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDT) and its metabolite 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) were significantly associated with cognitive decline as assessed with the 3MS. A posteriori analyses suggested that only p,p'-DDE was significantly related to a higher cognitive decline in time based on the 3MS among incident cases of dementia compared to subjects remaining nondemented.

CONCLUSION

PCB and OC pesticide plasma concentrations were not related to the incident diagnosis of neither dementia, nor AD. Using the 3MS scores as the outcome, higher concentrations of four PCB congeners and two OC pesticides were associated with lower cognitive performances in subjects. The association of p,p'-DDE with cognitive decline in time in incident cases of dementia merits further investigation.

Mental Disorders Among Elderly People in Baghdad, Iraq, 2017

This study aimed to estimate the prevalence and determinants of mental disorders (MDs) among elderly people residing in nursing homes (NHs) and those living with their families (WF) in Baghdad, Iraq, 2017. A cross-sectional study was conducted on all elderly individuals residing in all NHs in Baghdad and an equal number of elderly people residing WF. MDs were defined based on Kessler Psychological Distress Scale (K10). We used relevant World Health Organization-accredited tools to identify the types of MDs. The prevalence of MDs among elderly people was 38.7%, being statistically significantly ( P < .01) higher among those in NH (55.8%) compared with those living WF (21.5%). The proportion of types of MDs among NH versus WF residents was as follows: depression (35.4% vs 16.6%), anxiety (32.6% vs 9.9%), dementia (19.3% vs 5%), and suicide thoughts (25.4% vs 4.4%). The multivariate analysis showed many factors that were associated with MD. Low income, dependency on others, and being neglected were stronger determinant of MD among elderly people living WF. However, chronic joint pain, visual impairment, auditory impairment, and economic status deterioration were stronger determinant among those in NHs. The prevalence of MDs in the NH is more than double the prevalence in the community. We recommended enhancing elderly mental health care services including curative, preventive, and promotive activities.

Impact of Coffee and Cacao Purine Metabolites on Neuroplasticity and Neurodegenerative Disease

Increasing evidence suggests that regular consumption of coffee, tea and dark chocolate (cacao) can promote brain health and may reduce the risk of age-related neurodegenerative disorders. However, the complex array of phytochemicals in coffee and cacao beans and tea leaves has hindered a clear understanding of the component(s) that affect neuronal plasticity and resilience. One class of phytochemicals present in relatively high amounts in coffee, tea and cacao are methylxanthines. Among such methylxanthines, caffeine has been the most widely studied and has clear effects on neuronal network activity, promotes sustained cognitive performance and can protect neurons against dysfunction and death in animal models of stroke, Alzheimer's disease and Parkinson's disease. Caffeine's mechanism of action relies on antagonism of various subclasses of adenosine receptors. Downstream xanthine metabolites, such as theobromine and theophylline, may also contribute to the beneficial effects of coffee, tea and cacao on brain health.

Validation and diagnostic accuracy of predictive curves for age-associated longitudinal cognitive decline in older adults

BACKGROUND

The Mini-Mental State Examination continues to be used frequently to screen for cognitive impairment in older adults, but it remains unclear how to interpret changes in its score over time to distinguish age-associated cognitive decline from an early degenerative process. We aimed to generate cognitive charts for use in clinical practice for longitudinal evaluation of age-associated cognitive decline.

METHODS

We used data from the Canadian Study of Health and Aging from 7569 participants aged 65 years or older who completed a Mini-Mental State Examination at baseline, and at 5 and 10 years later to develop a linear regression model for the Mini-Mental State Examination score as a function of age and education. Based on this model, we generated cognitive charts designed to optimize accuracy for distinguishing participants with dementia from healthy controls. We validated our model using a separate data set of 6501 participants from the National Alzheimer's Coordinating Center's Uniform Data Set.

RESULTS

For baseline measurement, the cognitive charts had a sensitivity of 80% (95% confidence interval [CI] 75% to 84%) and a specificity of 89% (95% CI 88% to 90%) for distinguishing healthy controls from participants with dementia. Similar sensitivities and specificities were observed for a decline over time greater than 1 percentile zone from the first measurement. Results in the validation sample were comparable, albeit with lower sensitivities. Negative predictive value was 99%.

INTERPRETATION

Our innovative model, which factors in age and education, showed validity and diagnostic accuracy for determining whether older patients show abnormal performance on serial Mini-Mental State Examination measurements. Similar to growth curves used in pediatrics, cognitive charts allow longitudinal cognitive evaluation and enable prompt initiation of investigation and treatment when appropriate.

Use of Vitamin E and C Supplements for the Prevention of Cognitive Decline

Background: There are few studies of the association between the use of antioxidant vitamin supplements and the risk of Alzheimer’s disease (AD). Cognitive decline is generally viewed as part of the continuum between normal aging and AD. Objective: To evaluate whether the use of vitamin E and C supplements is associated with reduced risks of cognitive impairment, not dementia (CIND), AD, or all-cause dementia in a representative sample of older persons ≥65 years old. Methods: Data from the Canadian Study of Health and Aging (1991-2002), a cohort study of dementia including 3 evaluation waves at 5-yearly intervals, were used. Exposure to vitamins E and C was self-reported at baseline in a risk factor questionnaire and/or in a clinical examination. Results: The data set included 5269 individuals. Compared with those not taking vitamin supplements, the age-, sex-, and education-adjusted hazard ratios of CIND, AD, and all-cause dementia were, respectively, 0.77 (95% CI = 0.60-0.98), 0.60 (95% CI = 0.42-0.86), and 0.62 (95% CI = 0.46-0.83) for those taking vitamin E and/or C supplements. Results remained significant in fully adjusted models except for CIND. Similar results were observed when vitamins were analyzed separately. Conclusions: This analysis suggests that the use of vitamin E and C supplements is associated with a reduced risk of cognitive decline. Further investigations are needed to determine their value as a primary prevention strategy.

Mini-Mental State Examination (MMSE) for the detection of dementia in clinically unevaluated people aged 65 and over in community and primary care populations

BACKGROUND

The Mini Mental State Examination (MMSE) is a cognitive test that is commonly used as part of the evaluation for possible dementia.

OBJECTIVES

To determine the diagnostic accuracy of the Mini-Mental State Examination (MMSE) at various cut points for dementia in people aged 65 years and over in community and primary care settings who had not undergone prior testing for dementia.

SEARCH METHODS

We searched the specialised register of the Cochrane Dementia and Cognitive Improvement Group, MEDLINE (OvidSP), EMBASE (OvidSP), PsycINFO (OvidSP), LILACS (BIREME), ALOIS, BIOSIS previews (Thomson Reuters Web of Science), and Web of Science Core Collection, including the Science Citation Index and the Conference Proceedings Citation Index (Thomson Reuters Web of Science). We also searched specialised sources of diagnostic test accuracy studies and reviews: MEDION (Universities of Maastricht and Leuven, www.mediondatabase.nl), DARE (Database of Abstracts of Reviews of Effects, via the Cochrane Library), HTA Database (Health Technology Assessment Database, via the Cochrane Library), and ARIF (University of Birmingham, UK, www.arif.bham.ac.uk). We attempted to locate possibly relevant but unpublished data by contacting researchers in this field. We first performed the searches in November 2012 and then fully updated them in May 2014. We did not apply any language or date restrictions to the electronic searches, and we did not use any methodological filters as a method to restrict the search overall.

SELECTION CRITERIA

We included studies that compared the 11-item (maximum score 30) MMSE test (at any cut point) in people who had not undergone prior testing versus a commonly accepted clinical reference standard for all-cause dementia and subtypes (Alzheimer disease dementia, Lewy body dementia, vascular dementia, frontotemporal dementia). Clinical diagnosis included all-cause (unspecified) dementia, as defined by any version of the Diagnostic and Statistical Manual of Mental Disorders (DSM); International Classification of Diseases (ICD) and the Clinical Dementia Rating.

DATA COLLECTION AND ANALYSIS

At least three authors screened all citations.Two authors handled data extraction and quality assessment. We performed meta-analysis using the hierarchical summary receiver-operator curves (HSROC) method and the bivariate method.

MAIN RESULTS

We retrieved 24,310 citations after removal of duplicates. We reviewed the full text of 317 full-text articles and finally included 70 records, referring to 48 studies, in our synthesis. We were able to perform meta-analysis on 28 studies in the community setting (44 articles) and on 6 studies in primary care (8 articles), but we could not extract usable 2 x 2 data for the remaining 14 community studies, which we did not include in the meta-analysis. All of the studies in the community were in asymptomatic people, whereas two of the six studies in primary care were conducted in people who had symptoms of possible dementia. We judged two studies to be at high risk of bias in the patient selection domain, three studies to be at high risk of bias in the index test domain and nine studies to be at high risk of bias regarding flow and timing. We assessed most studies as being applicable to the review question though we had concerns about selection of participants in six studies and target condition in one study.The accuracy of the MMSE for diagnosing dementia was reported at 18 cut points in the community (MMSE score 10, 14-30 inclusive) and 10 cut points in primary care (MMSE score 17-26 inclusive). The total number of participants in studies included in the meta-analyses ranged from 37 to 2727, median 314 (interquartile range (IQR) 160 to 647). In the community, the pooled accuracy at a cut point of 24 (15 studies) was sensitivity 0.85 (95% confidence interval (CI) 0.74 to 0.92), specificity 0.90 (95% CI 0.82 to 0.95); at a cut point of 25 (10 studies), sensitivity 0.87 (95% CI 0.78 to 0.93), specificity 0.82 (95% CI 0.65 to 0.92); and in seven studies that adjusted accuracy estimates for level of education, sensitivity 0.97 (95% CI 0.83 to 1.00), specificity 0.70 (95% CI 0.50 to 0.85). There was insufficient data to evaluate the accuracy of the MMSE for diagnosing dementia subtypes.We could not estimate summary diagnostic accuracy in primary care due to insufficient data.

AUTHORS' CONCLUSIONS

The MMSE contributes to a diagnosis of dementia in low prevalence settings, but should not be used in isolation to confirm or exclude disease. We recommend that future work evaluates the diagnostic accuracy of tests in the context of the diagnostic pathway experienced by the patient and that investigators report how undergoing the MMSE changes patient-relevant outcomes.

P2X7 Receptor as a Therapeutic Target

P2X7 receptor is an ATP-gated cation channel that upon agonist interaction leads to cellular influx of Na(+) and Ca(2+) and efflux of K(+). P2X7 is expressed by a wide variety of cells and its activation mediates a large number of biological processes like inflammation, neuromodulation, cell death or cell proliferation and it has been associated to related pathological conditions including infectious, inflammatory, autoimmune, neurological, and musculoskeletal disorders and, in the last years, to cancer. This chapter describes structural features of P2X7, chemical properties of its agonist, antagonist, and allosteric modulators and summarizes recent advances on P2X7 receptor as therapeutic target in the aforementioned diseases. We also give an overview on recent literature suggesting that P2X7 single-nucleotide polymorphisms could be exploited as diagnostic biomarkers for the development of tailored therapies.

Status Report--Retracing the history of the early development of national chronic disease surveillance in Canada and the major role of the Laboratory Centre for Disease Control (LCDC) from 1972 to 2000

Health surveillance is the ongoing, systematic use of routinely collected health data to guide public health action in a timely fashion. This paper describes the creation and growth of national surveillance systems in Canada and their impact on chronic disease and injury prevention. In 2008, the authors started a review process to retrace the history of the early development of national chronic disease surveillance in Canada from 1960 to 2000. A 1967 publication describes the history of the development of the Laboratory of Hygiene from 1921 to 1967. This review is a sequel to that paper and describes the history of the development of national chronic disease surveillance in Canada before and after the formation of the Laboratory Centre for Disease Control (LCDC).

Plasma polychlorinated biphenyl and organochlorine pesticide concentrations in dementia: the Canadian Study of Health and Aging

BACKGROUND

Even though polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides are recognized as neurotoxicants, few studies have investigated their associations with dementia. Here, we assess associations of plasma PCB and OC pesticide concentrations with all-cause dementia and Alzheimer's disease (AD).

METHODS

Analyses are based on data from the Canadian Study of Health and Aging, a population-based study of men and women aged 65+ years at baseline. PCB and OC pesticide concentrations were measured in 2023 participants who had complete clinical evaluations and blood samples; 574 had dementia, including 399 cases of AD. Concentrations were log-transformed and used as continuous variables in logistic regression models to assess their individual associations with dementia and AD.

RESULTS

After adjustment for blood collection period, total plasma lipids, age, sex, education, apolipoprotein E e4 allele (ApoE4), tobacco and alcohol use, rural/urban residence, and comorbidities, elevated plasma PCB concentrations were not associated with increased prevalence of dementia and AD. Elevated concentrations of some OC pesticides and metabolites such as hexachlorobenzene, cis-nonachlor and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane were significantly associated with a reduced prevalence of dementia. A significant reduced prevalence of AD was also observed with elevated hexachlorobenzene concentrations. Other OC pesticides and metabolites were not associated with the prevalence of dementia or AD. No effect modification by sex and ApoE4 was observed for either dementia or AD.

CONCLUSIONS

Elevated plasma PCB and OC pesticide concentrations were not associated with higher prevalence of all-cause dementia and AD. The possibility of modest reductions in prevalence with specific OC pesticides remains to be further investigated given the cross-sectional design of this study.

Mild cognitive impairment: Profile of a cohort from a private sector memory clinic

BACKGROUND

Private hospital memory clinics might see a different clientele than university or academic institutes due to referral biases.

OBJECTIVE

To characterize the profile of patients with mild cognitive impairment (MCI) from a private sector memory clinic.

MATERIALS AND METHODS

MCI was diagnosed according to revised clinical criteria of Petersen et al. For a subset of patients with MCI medial temporal atrophy and cerebral small vessel disease (white matter lesions and lacunes) were rated on magnetic resonance imaging (MRI) scans and analyzed for their contribution towards cognitive impairment.

RESULTS

Subjects with MCI formed one-third (113/371) of this memory clinic sample from a private hospital. MCI could be effectively diagnosed and subtyped using a brief cognitive scale (Concise Cognitive Test (CONCOG)). The amnestic MCI (single and multiple domains) subtype comprised the majority of cases with MCI. In a subsample of 33 patients, lacunar infarcts were more common than white matter lesions and hippocampal atrophy and were inversely associated with verbal fluency.

CONCLUSIONS

MCI may be more commonly encountered in private hospital settings probably due to early referrals. It is possible to diagnose and subtype MCI using a brief cognitive instrument such as the CONCOG. In this sample, lacunar infarcts were more commonly encountered than medial temporal atrophy in such patients.

Carer levels of concern on driving and other activities in older people that put others at risk

OBJECTIVES

Early signs of dementia may raise concerns in family members as to the safety of the affected person when engaged in common activities. Here we report on the relative frequency of such concerns using data from the three waves of the Canadian Study of Health and Aging (CSHA). Our focus is on driving, cooking and paying bills, with a prediction that most carers' concern would be over driving.

METHOD

Participants were 2780 Canadians over 65 years, who underwent the first wave of CSHA and were subsequently followed during the next two waves.

RESULTS

As predicted, concerns about driving were relatively more common than concerns about cooking and handling finances (P = 0.021) in the cognitively intact group, with the opposite order observed in the group with dementia.

CONCLUSION

Carer concerns for those diagnosed with dementia shift with the progression of cognitive changes, with concerns declining over the 10-year period.

Prevalence and correlates of potentially undetected dementia among residents of institutional care facilities in Ontario, Canada, 2009-2011

OBJECTIVES

This study aims to determine the prevalence of potentially undetected dementia among institutional care facility residents in Ontario, Canada, and to identify factors associated with undetection.

METHODS

We utilized a population-based secondary data analysis approach, pertaining to data from the Canadian Institute for Health Information's Continuing Care Reporting System, 2009-2011. Potentially undetected dementia was defined as having severely impaired cognitive function and requiring extensive assistance on activity of daily living (ADL) but no records of dementia diagnoses. Cognitive function was measured by the Cognitive Performance Scale (CPS), 0 (intact) to 6 (very severe impairment), and ADL by a hierarchy scale, 0 (independent) to 6 (total dependence).

RESULTS

Of the 242,957 residents who had no records of dementia diagnoses, 11.6% (n = 28,078) had a CPS score ≥4 (severe impairment or higher) and ADL score ≥3 (required extensive assistance or more). Data from 11,614 demented residents with corresponding CPS and ADL scores were used for comparison. Residents without dementia diagnosis were younger (77 vs. 84 years), more likely to have never married (20% vs. 6%), and have longer admission (4 vs. 2.8 years). The most significant factors for no diagnoses were never married (adjusted odds ratio = 2.1, 95% confidence interval [CI] = 1.91-2.29), admitted to hospital-based facilities (adjusted odds ratio = 1.58, 95% CI = 1.48-1.69), presence of schizophrenia (adjusted odds ratio = 1.43, 95% CI = 1.22-1.69), depression (adjusted odds ratio = 1.23, 95% CI = 1.16-1.29), and diabetes mellitus (adjusted odds ratio = 1.32, 95% CI = 1.26-1.40).

CONCLUSIONS

A large number of residents who had poor cognitive function and inadequate ADL ability did not have dementia diagnoses on record. Social and comorbid conditions were contributing factors to potentially undetected dementia.

Empirical likelihood-based confidence intervals for length-biased data

Logistic or other constraints often preclude the possibility of conducting incident cohort studies. A feasible alternative in such cases is to conduct a cross-sectional prevalent cohort study for which we recruit prevalent cases, that is, subjects who have already experienced the initiating event, say the onset of a disease. When the interest lies in estimating the lifespan between the initiating event and a terminating event, say death for instance, such subjects may be followed prospectively until the terminating event or loss to follow-up, whichever happens first. It is well known that prevalent cases have, on average, longer lifespans. As such, they do not constitute a representative random sample from the target population; they comprise a biased sample. If the initiating events are generated from a stationary Poisson process, the so-called stationarity assumption, this bias is called length bias. The current literature on length-biased sampling lacks a simple method for estimating the margin of errors of commonly used summary statistics. We fill this gap by using the empirical likelihood-based confidence intervals by adapting this method to right-censored length-biased survival data. Both large and small sample behaviors of these confidence intervals are studied. We illustrate our method by using a set of data on survival with dementia, collected as part of the Canadian Study of Health and Aging.

Cognitive screening of older adults: the utility of pentagon drawing

BACKGROUND

Drawing tests have a long history in neuropsychological assessment. A popular geometric figure has been the two intersecting pentagons from the Bender Gestalt test. Reproducing the pentagons is the main visuospatial task on the original Mini-Mental State Examination (MMSE), remaining in use in revised versions of that widely used screening test. Scoring criteria on the MMSE are binary: perfect reproduction of the figure is required, while the Modified MMSE of Teng and Chui (1987) uses a more refined ten-point scoring for the elements of the figure.

METHODS

Here, I report on the use of pentagon drawing from 8,702 older community-dwelling Canadians (59.3% female), with a mean age of 75.5 years (SD = 6.99) and 10.1 years of education (SD = 3.89). Mean scores for the whole sample are reported, as well as for subsamples who underwent a full clinical assessment and were diagnosed as cognitively intact, with dementia, or cognitively impaired, but without dementia. Logistic regression was used to evaluate the utility of pentagon drawing as a diagnostic tool to diagnose cognitive impairment.

RESULTS

Binary scoring was less effective in discriminating groups than the ten-point system and showed weaker properties by other criteria.

CONCLUSIONS

The discussion focuses on the role of simple, non-verbal tasks in the cognitive screening of older adults.

Challenges in managing the diet of older adults with early-stage Alzheimer dementia: a caregiver perspective

Caregivers (CG) of older adults suffering from Alzheimer disease (AD) are confronted by many challenges when caring for their family member; these include dietary management.

OBJECTIVES

To identify difficulties in dietary management encountered by CG taking part in the Nutrition Intervention Study (NIS), and to gather their opinions on the intervention.

DESIGN, SETTING AND PARTICIPANTS

Thirty-three CG of individuals with AD from the NIS intervention group were contacted. Individual interviews were conducted and analyzed using qualitative data analysis, and themes around challenges related to dietary practices experienced by CG were identified.

RESULTS

Twenty-four CG were interviewed; 58% were aged 70 and older and 58% were the patient's spouse. Three major thematic categories emerged: 1. Dietary challenges and coping strategies used by CG; 2. CGs' opinion about the NIS; 3. CG interest in participating in a nutrition education support service. Changes in food habits and increasing dependency on the CG were the major themes related to dietary challenges.

CONCLUSION

A better understanding of the CG's experience is essential for the development of nutrition interventions adapted to the needs of older adults with AD and their CG.

Nonsteroidal anti-inflammatory drug use and the risk of cognitive impairment and Alzheimer's disease

BACKGROUND

Some observational studies have established an association between exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) and a decreased risk of subsequently developing Alzheimer's disease (AD). Mild cognitive impairment or cognitive impairment, not dementia (CIND) is more likely to convert to AD, and no specific preventive method is currently available. The objective of this study was to determine the association of NSAID use in 5276 cognitively normal subjects of the Canadian Study of Health and Aging, a 10-year population-based cohort study, with the incidence of CIND, AD, and all-cause dementia.

METHODS

Hazard ratios were calculated from Cox proportional hazards models with age as the time scale according to three study samples including 824 cases of dementia (563 cases of AD), 630 cases of dementia (435 cases of AD), and 883 cases of CIND, respectively. Adjustments were made for gender, education, lifestyle factors, comorbid diseases, and vascular risk factors.

RESULTS

Lower risks for AD and all-cause dementia were significantly associated with the use of any NSAIDs and the salicylates without barbiturates subgroup in the study sample including subjects with CIND at baseline. There was a weak association between any NSAIDs and the risk of CIND (hazard ratio, 0.87; 95% confidence interval, 0.76-1.00).

CONCLUSION

These results suggest that there is an association between NSAID use and a lower incidence of AD and, to a lesser extent, of CIND.

Prevalence of dementia and mild cognitive impairment in a Bulgarian urban population

BACKGROUND

Prevalence of cognitive impairment and dementia has not been studied in Bulgaria up to date. A 2-phase cross-sectional study was designed in order to determine the prevalence of dementia, its subtypes, and mild cognitive impairment in a Bulgarian population.

METHODS

The study sample consisted of 605 participants over the age of 65, residents of the city of Varna. A total of 540 participants (89%) completed the screening phase of the study. All positive screens and a control group were included in the diagnostic phase of the study, where comprehensive neuropsychological, clinical, and imaging assessments were performed.

RESULTS

Dementia was diagnosed in 39 persons (7.2%) and 36 had mild cognitive impairment (6.7%). Alzheimer's disease was the most frequent type of dementia (3.1%), followed by vascular dementia (2.0%).

DISCUSSION

Our results support the hypothesis that prevalence of vascular cognitive impairment may be higher in Bulgaria than in most European countries.

Epidemiology of cognitive aging and Alzheimer's disease: contributions of the cache county utah study of memory, health and aging

Epidemiological studies of Alzheimer's disease (AD) provide insights into changing public health trends and their contribution to disease incidence. The current chapter considers how the population-based approach has contributed to our understanding of lifetime exposures that contribute to later disease risk and may act to modify onset of symptoms. We focus on the findings from a recent survey of an exceptionally long-lived population, the Cache County Utah Study of Memory, Health, and Aging. This study is confined to a single geographic population has allowed estimation of the genetic and environmental influences on AD expression across the expected human lifespan of 95+ years. Given the emphasis of this text on the behavioral neurosciences of aging, we highlight within the current chapter the particular contributions of this population-based study to the neuropsychology of aging and AD. We also discuss hypotheses generated from this survey with respect to factors that may either accelerate or delay symptom onset in AD and the conditions that appear to be associated with successful cognitive aging.

Polychlorinated biphenyls and organochlorine pesticides in plasma of older Canadians

No nationwide study has ever measured polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) body burden in Canadians aged 65 years and over. The objective of this study was to determine plasma concentrations of PCB congeners and OCPs in participants from a sub-cohort of the Canadian Study of Health and Aging and to examine the effects of socio-demographic, anthropometric and lifestyle characteristics on selected organochlorine concentrations. Archived plasma samples collected from 2023 subjects were analyzed by gas chromatography-mass spectrometry using negative chemical ionization for 15 PCB congeners and 11 OCPs. Descriptive statistics were used to report PCB congeners and OCP plasma concentrations. Multivariate models were used to study whether age at blood collection, sex, education, body mass index, rural residence, geographic region, smoking status and alcohol intake influences PCB 153, the most abundant congener, and the major OCP (beta-hexachlorocyclohexane, hexachlorobenzene, trans-nonachlor, p,p'-DDE) plasma concentrations. Statistical analyses were restricted to 1979 subjects and 17 organochlorine compounds for which at least 50% of the samples had concentrations above the limit of detection. Of these, 775 were men (mean age: 82.2 years) and 1204 were women (mean age: 84.6 years). The median concentrations (ng/g lipid) of PCB 153 in the plasma of men and women were 70.9 and 75.4, respectively. The levels of the sum of PCBs and the sum of dioxin-like PCBs were 276 and 31.3 for men, and 300 and 45.5 for women, respectively. The median concentrations (ng/g lipid) of p,p'-DDE, the most abundant OCP, were 565 for men and 828 for women. All compounds were positively and significantly intercorrelated (rs=0.39-0.99; p<0.001). Except for trans-nonachlor, the multivariate models revealed that age and male sex were the determining characteristics that showed, respectively, strongly positive and negative associations with selected organochlorine concentrations. These plasma concentrations from a large population based study can be considered as baseline data for body burdens of older Canadians.

Road safe seniors: Screening for age-related driving disorders in inpatient and outpatient settings

INTRODUCTION

Older drivers are increasing in number and they often have health conditions that place them at high risk for motor-vehicle crashes (MVC). Screening is underutilized, and is rarely done in hospital settings.

METHODS

A convenience sample of 755 older adults completed age related driving disorders screening at University of California, San Diego inpatient and outpatient health centers. Screening included three strength/frailty tests, two vision tests (acuity and fields), and two cognitive tests, based on AMA recommendations. The average age of participants was 72.5; 55.5% were male and 94% English-speaking; 17.8% of older adults failed at least one aspect of screening.

RESULTS

In multivariate analysis, significant associations of failed status were age, male sex, selfrestrictions of driving, and inpatient screening locations. The screening identified one in six adults to be 'high-risk' for age related driving disorders. Screening was effective and feasible in both inpatient and outpatient settings.

IMPACT ON INDUSTRY

As the driving population ages, industry, government and health car providers need to plan for the management of driving impairments in older adults.

Clinical decision trees for predicting conversion from cognitive impairment no dementia (CIND) to dementia in a longitudinal population-based study

The lack of gold standard diagnostic criteria for cognitive impairment in the absence of dementia has resulted in variable nomenclature, case definitions, outcomes, risk factors, and prognostic utilities. Our objective was to elucidate the clinical correlates of conversion to dementia in a longitudinal population-based sample. Using data from the Canadian Study of Health and Aging, a machine learning algorithm was used to identify symptoms that best differentiated converting from nonconverting cognitively impaired not demented participants. Poor retrieval was the sole predictor of conversion to dementia over 5 years. This finding suggests that patients with impaired retrieval are at greater risk for progression to dementia at follow-up. Employing significant predictors as markers for ongoing monitoring and assessment, rather than as clinical markers of conversion, is recommended given the less than optimal specificity of the predictive algorithms.

Home health care for the elderly: associated factors and characteristics of access and health care

OBJECTIVE

To assess factors associated with home health care for the elderly and its characteristics based on different care models, the Family Health Strategy and traditional primary care.

METHODS

A population-based cross-sectional study was conducted in a representative sample of 1,593 individuals aged >60 years living in the urban area of the city of Bagé, Southern Brazil, in 2008. A multistage sampling was carried out. Data was collected during individual interviews about access to services, providers' involvement, users' satisfaction and health status after care. Poisson regression model was used for estimating crude and adjusted prevalence ratios, their related 95% confidence intervals and p-values (Wald test).

RESULTS

Home health care was statistically associated with prior history of stroke, signs of dementia and disability in activities of daily living. The family was requested 75% of home care visits. Medical doctors provided most of the care in traditional primary care settings while nursing staff provided most care within the Family Health Strategy. Approximately 78% of the elderly received care within 24 hours after the request and 95% of them positively evaluated the care received. Two thirds of the elderly reported improved health status.

CONCLUSIONS

The variables associated with home health care were consistent with fragility indicators included in the Brazilian National Health Policy for the Elderly, reinforcing the role of this strategy for promoting equitable health care to elderly population. Users' satisfaction and the positive impact on their health status confirm home as a setting for providing care.

Age-related driving disorders: screening in hospitals and outpatients settings

AIM

Older drivers are increasing in number and they often have health conditions that place them at high risk for motor vehicle crashes. The aims of this study were to: (i) evaluate the feasibility and acceptability of screening inpatients and outpatients over the age of 60 years for age-related driving disorders; and (ii) determine the patient characteristics associated with screening outcomes.

METHODS

A convenience sample of 397 participants completed age-related driving disorders screening at University of California, San Diego, inpatient and outpatient settings. Eligibility criteria included California-licensed drivers over the age of 60 years who were English or Spanish speaking. Baseline screening included driving habits, restrictions, history of crashes, and medical history, including medications. Screening included visual acuity, visual fields, three strength frailty tests and two cognitive tests.

RESULTS

The average age of participants was 72 years; 59% were male and 12% Hispanic. Almost 20% of older adults failed at least one test, and were labeled 'high risk' for age-related driving disorders. In multivariate analysis, significant predictors of high-risk status were age, male sex, self-restrictions of driving and use of larger amounts of prescription drugs. Screening took approximately 15 min and participant satisfaction was high.

CONCLUSION

A brief screening evaluation identified one in five adults to be 'high risk' for age-related driving disorders. Screening was effective in both outpatient and inpatient settings, was well received and simple to administer.

Cognitive function and mortality in a community-based elderly cohort of first-ever stroke survivors and control subjects

OBJECTIVE

We sought to determine the frequency and incidence of cognitive impairments not dementia, dementia, and mortality in first-ever stroke survivors and control subjects.

METHODS

We conducted a longitudinal follow-up of a cohort of first-ever stroke survivors (n=98) and age-/sex-matched control subjects (n=92).

RESULTS

At baseline, 37 stroke survivors and 4 control subjects fulfilled Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for dementia. From baseline to follow-up, 6 new patients in the nondemented stroke cohort and 4 patients in the stroke-free cohort developed dementia, giving an incidence of 3.97 (95% confidence interval [CI] 1.46-8.65) and 1.78 (95% CI 0.49-4.57), respectively. The stroke cohort had a more than 2-fold increased risk for developing dementia (relative risk=2.14, 95% CI 0.64-7.13). The cumulative rate of mortality in the stroke cohort was 11.03 per 100 person-years (95% CI 7.7-15.3) and in the stroke-free cohort it was 3.47 per 100 person-years (95% CI 1.13-8.1). The risk for mortality after controlling for dementia cases at baseline was more than 2.5 times that of the stroke-free cohort.

CONCLUSIONS

A first-ever stroke increases the risk of developing dementia, Mortality in our stroke cohort was still higher than that observed in the stroke-free cohort. Improved survival poststroke may be contributing to an increased risk for cognitive impairment or dementia in this population.

Should older adults be screened for dementia?

The question of whether to screen for dementia and Alzheimer's disease (AD) has been discussed in many forums throughout the world. Generally, medical advisory groups and policy-making groups have recognized the importance of early diagnosis but have uniformly avoided making recommendations to screen at-risk populations. This presentation reflects the support for reconsidering the importance of screening individuals at risk or above a certain age. In this statement, the majority of the authors support the consideration of dementia risk factors in individuals at age 50, with routine yearly screening after 75. Other authors remain concerned that the benefits of treatments of early disease do not yet support a general screening recommendation. These statements are made to encourage progress toward the development of a consensus regarding the widespread institution of screening policy. Accordingly, members of the worldwide scientific community are invited to add their perspective by contributing short commentaries (1500 words) on this subject.

Omega-3 fatty acids and risk of dementia: the Canadian Study of Health and Aging

BACKGROUND

Omega-3 polyunsaturated fatty acids (n-3 PUFAs) may protect against dementia, although epidemiologic studies have yielded inconclusive results. Fish is the main dietary source of n-3 PUFAs and is sometimes contaminated with mercury. This neurotoxicant may modify the association with dementia.

OBJECTIVE

We evaluated the association of erythrocyte membrane total n-3 PUFAs, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and blood mercury with the incidence of dementia and Alzheimer disease (AD) in the Canadian Study of Health and Aging (CSHA) with adjustment for confounders including apolipoprotein E epsilon4 (APOE epsilon4) status.

DESIGN

The CSHA is a cohort study of a representative sample of persons aged > or =65 y, conducted from 1991 to 2002. A subsample of 663 nondemented CSHA subjects with a complete clinical examination, blood samples, and follow-up information was eligible for prospective analyses on laboratory measurements. Of these, 149 were incident cases of dementia, including 105 with AD.

RESULTS

In adjusted Cox regression models with age as the time scale, there were no associations between total n-3 PUFAs, DHA, or EPA and dementia or AD. In contrast, a mercury concentration in the highest quartile was associated with a reduced risk of dementia (hazard ratio: 0.53; 95% CI: 0.33, 0.88). However, significant risk reductions were limited to subjects with concentrations of both n-3 PUFAs and mercury that were above the median. There was no modification of risk by APOE epsilon4 status.

CONCLUSIONS

No associations between n-3 PUFAs and dementia or AD were found. The results regarding mercury may indicate a spurious association.

100 years after Alzheimer: contemporary neurology practice assessment of referrals for dementia

BACKGROUND

The prevalence of dementia is placing an increased burden on specialists.

METHODS

Canadian neurologists responded to a structured questionnaire to assess reasons for referral and services provided as well as to compare the neurologists' perceptions of their practice characteristics against cases seen over a 3-month period.

RESULTS

The audit confirmed the participants' perception that family practitioners are the main referral source (358/453, 79%). Sixty-two percent of patients had undergone clinical investigation for dementia prior to being seen by the neurologist; 39% (177/453) were on pharmacotherapy at the time of referral, 68% were initiated on pharmacotherapy by the neurologist. A fifth of the referrals did not meet clinical criteria for dementia, which may be directly related to the prevalence of prior workup that did not include mental status testing.

CONCLUSIONS

Neurologists currently treat patients referred for dementia who may already have been adequately evaluated and treated by primary care providers.

First Link: Strengthening Primary Care Partnerships for Dementia Support

While primary care faces many challenges, including an increasing prevalence of older individuals, emerging knowledge about the potential benefits of collaborative partnerships has encouraged the development of new means of providing and supporting primary care. First Link™ is an innovative program involving collaborations among primary care providers, Alzheimer Societies, and other health professionals. The program aims to support persons with Alzheimer's and related diseases after the diagnosis is made and to link them with support services earlier in the disease course. This paper describes the First Link program, provides an overview of a study currently underway to evaluate it, and identifies some of the benefits and challenges associated with this partnership.

[Risk factors and protective factors of the insanities]

The Alzheimer's disease (AD) is multifactorial. How to explain this group of very heterogeneous factors? Many of them can be considered as biopsychosocial risk factors. In other words, the risk factors, in link with the physiological functioning and a physiopathology, are difficultly dissociable of contingencies of psychological and/or social nature. The vital lead could be the stress bound to these variables, be it biological or psychosocial. It remains to ask the question of the preventive efficiency of treatments to relieve the impact of the traumatizing events of life that entail a depressive state or a state of posttraumatic stress. The hippocamp has to be the object of a quite particular attention. AD is a disease of the adaptation. This integrative model combines three vulnerabilities: a genetic vulnerability which would be there to dictate the type of lesions, their localization and the age of occurence; a psychobiographic vulnerability corresponding to a personality with inadequate mechanisms of defence, precarious adaptability in front of the adversity, weak impact strength and biography built on events of life during childhood, then during the grown-up life of traumatic nature, with a psychosocial environment insufficiently auxiliary; a neuroendocrinologic vulnerability which would base on a deregulation of the corticotrope axis, acquired during its infantile maturation, hampered by too premature stress. It would lead to a bad biological adaptability in stress later, at the origin of the observable lesions in the insanities.

Selecting process quality indicators for the integrated care of vulnerable older adults affected by cognitive impairment or dementia

Background

This study aimed at evaluating face and content validity, feasibility and reliability of process quality indicators developed previously in the United States or other countries. The indicators can be used to evaluate care and services for vulnerable older adults affected by cognitive impairment or dementia within an integrated service system in Quebec, Canada.

Methods

A total of 33 clinical experts from three major urban centres in Quebec formed a panel representing two medical specialties (family medicine, geriatrics) and seven health or social services specialties (nursing, occupational therapy, psychology, neuropsychology, pharmacy, nutrition, social work), from primary or secondary levels of care, including long-term care. A modified version of the RAND^®/University of California at Los Angeles (UCLA) appropriateness method, a two-round Delphi panel, was used to assess face and content validity of process quality indicators. The appropriateness of indicators was evaluated according to a) agreement of the panel with three criteria, defined as a median rating of 7–9 on a nine-point rating scale, and b) agreement among panellists, judged by the statistical measure of the interpercentile range adjusted for symmetry. Feasibility of quality assessment and reliability of appropriate indicators were then evaluated within a pilot study on 29 patients affected by cognitive impairment or dementia. For measurable indicators the inter-observer reliability was calculated with the Kappa statistic.

Results

Initially, 82 indicators for care of vulnerable older adults with cognitive impairment or dementia were submitted to the panellists. Of those, 72 (88%) were accepted after two rounds. Among 29 patients for whom medical files of the preceding two years were evaluated, 63 (88%) of these indicators were considered applicable at least once, for at least one patient. Only 22 indicators were considered applicable at least once for ten or more out of 29 patients. Four indicators could be measured with the help of a validated questionnaire on patient satisfaction. Inter-observer reliability was moderate (Kappa = 0.57).

Conclusion

A multidisciplinary panel of experts judged a large majority of the initial indicators valid for use in integrated care systems for vulnerable older adults in Quebec, Canada. Most of these indicators can be measured using patient files or patient or caregiver interviews and reliability of assessment from patient-files is moderate.

A Planning System Based on Markov Decision Processes to Guide People With Dementia Through Activities of Daily Living

Older adults with dementia often cannot remember how to complete activities of daily living and require a caregiver to aid them through the steps involved. The use of a computerized guidance system could potentially reduce the reliance on a caregiver. This paper examines the design and preliminary evaluation of a planning system that uses Markov decision processes (MDPs) to determine when and how to provide prompts to a user with dementia for guidance through the activity of handwashing. Results from the study suggest that MDPs can be applied effectively to this type of guidance problem. Considerations for the development of future guidance systems are presented.

Challenges in the epidemiological investigation of the relationships between physical activity, obesity, diabetes, dementia and depression

There are many challenges facing epidemiologists wishing to investigate relationships between physical activity, obesity, diabetes, dementia and depression, all of which are complex fields in their own right. There is a large literature investigating the relationship between diabetes and dementia but less, as yet, on the other exposures and outcomes. In this literature there is a diversity of definitions making rigorous systematic review problematic. There is a need to define hypotheses in this area very clearly and to identify studies that have addressed the specific question. Such exercises have not been carried out to date but would enlighten the research area and point more clearly to questions which remain to be answered. Our own research group has examined the specific question of risk of development of dementia in relation to levels of HbA(1)c, as a marker of glycaemic control and showed that although not related to dementia, it is related to incidence of severe cognitive impairment.