The Statistical Modeling of Aging and Risk of Transition Project: Data Collection and Harmonization Across 11 Longitudinal Cohort Studies of Aging, Cognition, and Dementia

Longitudinal cognitive trajectories and other factors associated with mixed neuropathologies (such as Alzheimer's disease with co-occurring cerebrovascular disease) remain incompletely understood, despite being the rule and not the exception in older populations. The Statistical Modeling of Aging and Risk of Transition study (SMART) is a consortium of 11 different high-quality longitudinal studies of aging and cognition (N=11,541 participants) established for the purpose of characterizing risk and protective factors associated with subtypes of age-associated mixed neuropathologies (N=3,001 autopsies). While brain donation was not required for participation in all SMART cohorts, most achieved substantial autopsy rates (i.e., > 50%). Moreover, the studies comprising SMART have large numbers of participants who were followed from intact cognition and transitioned to cognitive impairment and dementia, as well as participants who remained cognitively intact until death. These data provide an exciting opportunity to apply sophisticated statistical methods, like Markov processes, that require large, well-characterized samples. Thus, SMART will serve as an important resource for the field of mixed dementia epidemiology and neuropathology.

A profile of older community-dwelling home care clients with heart failure in Ontario

INTRODUCTION

The aging of the Canadian population is associated with a rising burden of heart failure (HF), a condition associated with significant morbidity, mortality and health service use.

METHODS

We used data from the Ontario Resident Assessment Instrument-Home Care database for all long-stay home care clients aged 65 years or older to (1) describe the demographic and clinical characteristics of home care clients with HF and (2) examine service use among home care clients with HF to promote management at home with appropriate services.

RESULTS

Compared with other home care clients, HF clients exhibit more health instability, take more medications, experience more comorbid conditions and receive significantly more nursing, homemaking and meal services. They are hospitalized more frequently, have significantly more emergency department visits and use more emergent care.

DISCUSSION

HF clients are a more complex group than home care clients in general. Patient self-care must be tailored to the clinical characteristics, patterns of service use and barriers to self-care of the client. This is particularly true for older, frail and medically complex HF patients, many of whom require home care services. This work provides a background upon which to base initiatives to help these higher-needs clients manage their HF at home with appropriate support and services.

A profile of older community-dwelling home care clients with heart failure in Ontario

Introduction

The aging of the Canadian population is associated with a rising burden of heart failure (HF), a condition associated with significant morbidity, mortality and health service use.

Methods

We used data from the Ontario Resident Assessment Instrument-Home Care database for all long-stay home care clients aged 65 years or older to (1) describe the demographic and clinical characteristics of home care clients with HF and (2) examine service use among home care clients with HF to promote management at home with appropriate services.

Results

Compared with other home care clients, HF clients exhibit more health instability, take more medications, experience more comorbid conditions and receive significantly more nursing, homemaking and meal services. They are hospitalized more frequently, have significantly more emergency department visits and use more emergent care.

Discussion

HF clients are a more complex group than home care clients in general. Patient self-care must be tailored to the clinical characteristics, patterns of service use and barriers to self-care of the client. This is particularly true for older, frail and medically complex HF patients, many of whom require home care services. This work provides a background upon which to base initiatives to help these higher-needs clients manage their HF at home with appropriate support and services.

Smoking affects the phenotype of Alzheimer disease

Because epidemiologic and in vitro evidence conflict, the authors studied the association between smoking and Alzheimer disease (AD) in 46 never, 47 former, and 15 active smokers with AD followed to autopsy. Disease parameters were examined by smoking status and amount smoked in bivariate tests and in multivariate models controlling for age, sex, education, and APOE status. Smoking status was not associated with cognitive or neuropathologic measures. However, active smokers were significantly younger at death and higher levels of smoking were associated with shorter disease duration.

Are tobacco and alcohol use related to Alzheimer's disease? A critical assessment of the evidence and its implications

Elucidation of the association of tobacco and alcohol use with Alzheimer's disease (AD) may advance etiological hypotheses and provide a theoretical basis for treatment. There is currently no cure or effective treatment for AD, and no cause has been established. Pharmacological evidence supports a plausible biological mechanism for the involvement of tobacco use: nicotine compensates for some of the cholinergic deficits observed in AD. Epidemiological evidence, however, is inconsistent, although recent meta-analyses also support a protective effect. Although smoking per se is certainly not advocated, further investigation of a potential protective effect of nicotine on AD is warranted. Pharmacological studies implicate alcohol use as a possible risk factor for AD; the epidemiological studies are again inconclusive. Alcohol consumption is associated with daily smoking and smokers are, in turn, more likely to consume alcohol. Since tobacco use may decrease the risk of developing AD and alcohol use may increase it, it is important to consider these two substances together: the effect of one may negate the other. This literature review critically evaluates the evidence for an association of tobacco and alcohol use with AD and identifies key issues for further research.

Risk factors for Alzheimer's disease: a population-based, longitudinal study in Manitoba, Canada

BACKGROUND

Current knowledge of risk factors for Alzheimer's disease (AD) is limited. Data from a longitudinal, population-based study of dementia in Manitoba, Canada were used to investigate risk factors for AD.

METHODS

Cognitively intact subjects completed a risk factor questionnaire assessing sociodemographic, genetic, environmental, medical and lifestyle exposures. Five years later, 36 subjects had developed AD and 658 remained cognitively intact.

RESULTS

Older subjects or those who had fewer years of education were at greater risk of AD. After adjusting for age, education and sex, occupational exposure to fumigants/ defoliants was a significant risk factor for AD (relative risk [RR] = 4.35; 95% CI : 1.05--17.90). A history of migraines increased the risk of AD (RR = 3.49; 95% CI : 1.39--8.77); an even stronger effect was noted among women. Self-reported memory loss at baseline was associated with subsequent development of AD (RR = 5.15; 95% CI : 2.36--11.27). Vaccinations and occupational exposure to excessive noise reduced the risk of AD.

CONCLUSIONS

Some well-known risk factors for AD were confirmed in this study and potential new risk factors were identified. The association of AD with a history of migraines and occupational exposure to defoliants/fumigants is of particular interest because these are biologically plausible risk factors.

Alcohol use and the risk of developing Alzheimer's disease

Some of the detrimental effects of heavy alcohol use on brain function are similar to those observed with Alzheimer's disease (AD). Although alcohol use may be a risk factor for AD, it is difficult to study this relationship because of similarities between alcoholic dementia and AD and because standard diagnostic criteria for alcoholic dementia have not yet been developed. Similar biological mechanisms may be involved in the effects of AD and alcohol abuse on the brain. Epidemiologic studies have investigated the relationship between alcohol use and AD but have not provided strong evidence to suggest that alcohol use influences the risk of developing AD. Further research is needed before the effect of alcohol use on AD is understood fully.

Is smoking associated with the risk of developing Alzheimer's disease? Results from three Canadian data sets

PURPOSE

To determine whether smoking is associated with Alzheimer's disease (AD).

METHODS

Analyses were conducted using three Canadian data sets: the University of Western Ontario Dementia Study (200 cases, 163 controls), the Canadian Study of Health and Aging (258 cases, 258 controls), and the patient database from the Clinic for Alzheimer Disease and Related Disorders at the Vancouver Hospital and Health Sciences Centre (566 cases, 277 controls). The association between smoking and AD was investigated using bivariate analyses and multiple logistic regression models adjusted for the potential confounders age, sex, educational level, family history of dementia, head injury, and hypertension.

RESULTS

The results of bivariate analyses were inconsistent across the three data sets, with smoking status a significant protective factor, a significant risk factor, or not associated with AD. The results of multiple logistic regression models, however, were consistent: any association between smoking status and AD disappeared in all three data sets after adjustment for confounders.

CONCLUSIONS

Smoking status was consistently not associated with AD across all three data sets after adjustment for confounders. Failure to adjust for relevant confounders may explain inconsistent reports of the influence of smoking on AD. Any protective effect of smoking may be limited to specific AD subtypes (e.g., early onset AD).

Does an interaction between smoking and drinking influence the risk of Alzheimer's disease? Results from three Canadian data sets

Investigation of the relationship of smoking and drinking to Alzheimer's disease (AD) may advance research on the cause of AD and provide a basis for treatment. Pharmacological mechanisms for an involvement of smoking and drinking are plausible but epidemiologic reports are inconsistent. Evidence of behavioural and physiological interactions suggests that tobacco and alcohol use may not only individually affect AD, but may also modify each other's effects. A modelling strategy was developed to examine the interaction between smoking and drinking on the risk of AD. Three Canadian data sets were analysed: the University of Western Ontario Dementia Study (UWODS) (n=363); the Canadian Study of Health and Aging (CSHA) (n=516), and the database from the Clinic for Alzheimer Disease and Related Disorders at the Vancouver Hospital and Health Sciences Centre, University of British Columbia site (UBC) (n=843). Multiple logistic regression models were adjusted for the potential confounders age, age squared, sex, education, family history of dementia, head injury and hypertension. Analysis of the CSHA provided evidence consistent with the hypothesis that smoking and drinking influence each other's effects on AD, with smoking reducing the risk of AD among drinkers. A similar interaction was marginally significant (p=0.052) in the UWODS data set, but not significant in the UBC data. Extension of these analyses, particularly in longitudinal studies and within genetic risk groups, is needed to determine whether this interaction can be replicated. If so, research on the biological interactions of nicotine and alcohol may provide a basis for the development of therapeutic interventions as well as providing clues to the cause of this disorder.

Psychosocial factors related to adolescent smoking: a critical review of the literature

OBJECTIVE

To extend the analysis of psychosocial risk factors for smoking presented in the United States surgeon general's 1994 report on smoking and health, and to propose a theoretical frame of reference for understanding the development of smoking.

DATA SOURCES

General Science Index, Medline, PsycLIT, Sociofile, Sociological Abstracts, and Smoking and Health. Holdings of the Addiction Research Foundation of Ontario Library as well as the authors' personal files.

STUDY SELECTION

Reviewed literature focused on studies that examined the association of sociodemographic, environmental, behavioural, and personal variables with smoking.

DATA SYNTHESIS

Adolescent smoking was associated with age, ethnicity, family structure, parental socioeconomic status, personal income, parental smoking, parental attitudes, sibling smoking, peer smoking, peer attitudes and norms, family environment, attachment to family and friends, school factors, risk behaviours, lifestyle, stress, depression/distress, self-esteem, attitudes, and health concerns. It is unclear whether adolescent smoking is related to other psychosocial variables.

CONCLUSIONS

Attempts should be made to use common definitions of outcome and predictor variables. Analyses should include multivariate and bivariate models, with some attempt in the multivariate models to test specific hypotheses. Future research should be theory driven and consider the range of possible factors, such as social, personal, economic, environmental, biological, and physiological influences, that may influence smoking behaviour. The apparent inconsistencies in relationships between parental socioeconomic status and adolescent disposable income need to be resolved as does the underlying constructs for which socioeconomic status is a proxy.

The degree and type of relationship between psychosocial variables and smoking status for students in grade 8: is there a dose-response relationship?

BACKGROUND

While most research focuses on simply analyzing the differences between smokers and non-smokers, dose-response analyses may be used to find evidence of the nature of the association between psychosocial variables and involvement with smoking in adolescence.

METHODS

For the study, 1,614 grade 8 students from Scarborough, Ontario, Canada, completed a self-administered questionnaire that included items on sociodemographic characteristics, experience with smoking, lifestyle, health and weight, work status, and social involvement as well as parental education, occupation, and family and peer smoking. A series of scales measuring self-esteem, stress, coping, social support, mastery, social conformity, and rebelliousness was incorporated.

RESULTS

Dose-response relationships were evidenced for all categories of variables and were demonstrated for the total group and, in most cases, for males and females when analyzed separately.

CONCLUSIONS

Relationships between variables are not "all or none," but may vary depending on amount or level of other factors. These relationships provide insight into the mechanisms underlying initiation to, maintenance of, and cessation of smoking and should be taken into account in programs to reduce or prevent adolescent tobacco use.

Trends in the characteristics of clients of alcohol/drug treatment services in Ontario

This paper summarizes the major trends in the characteristics of clients of alcohol/drug treatment services in Ontario from 1979 to 1989. Data were obtained from all provincial treatment programs by surveys undertaken in 1980, 1983, 1986 and 1989. Supplementary archival data are included on the use of American treatment programs by Ontario residents. Across the period of analysis, there has been a rapid increase in the number of alcohol/drug programs and the total treatment case-load. Trends in client characteristics include increased representation of women in the treatment case-load and a shift towards greater drug involvement with or without concomitant alcohol use. In contrast, there has been a small decrease in the proportion of young or elderly clients. The utilization of American treatment services by Ontario residents may partially reflect needs of special target groups, such as adolescents, which are not being met within the Ontario treatment system.