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Biomedical subjects

C Wolfson

Publications and source records attributed to C Wolfson.

At least 19 recordsLinked to original sources
PubMed2004

Social networks and self-rated health in two French-speaking Canadian community dwelling populations over 65.

The objective was to evaluate the associations between older persons' health status and their social integration and social networks (family, children, friends and community), in two French-speaking, Canadian community dwelling populations aged 65 years and over, using the conceptual framework proposed by Berkman and Thomas. Data were taken from two 1995 surveys conducted in the city of Moncton (n = 1518) and the Montreal neighbourhood of Hochelaga-Maisonneuve (n = 1500). Social engagement (a cumulative index of social activities), networks consisting of friends, family and children and social support were measured using validated scales. Multiple logistic regressions based on structured inclusion of potentially mediating variables were fitted to estimate the associations between health status and social networks. Self-rated health was better for those with a high level of social integration and a strong network of friends in both locations. In addition, in Hochelaga-Maisonneuve family and children networks were positively associated with good health, though the effect of friend networks was attenuated in the presence of disability, good social support from children was associated with good health. Age, sex and education were included as antecedent variables; smoking, alcohol consumption, exercise, locus of control and depressive symptoms were considered intermediary variables between social networks and health. In conclusion, social networks, integration and support demonstrated unique positive associations with health. The nature of these associations may vary between populations and cultures.

Activities of Daily Living↗
PubMed2002

Human herpes virus 6 and multiple sclerosis.

OBJECTIVES: To systematically review the published evidence for a relationship between human herpes virus 6 (HHV-6) and multiple sclerosis (MS). MATERIALS AND METHODS: The medical literature was searched using MEDLINE and the Cochrane database. Retrieved studies are presented according to the experimental technique(s) used. The studies are rated for quality using a priori defined criteria. RESULTS: Twenty-eight studies were retrieved. A total of 12 different experimental techniques were used. Four of these techniques provided evidence for a relationship between HHV-6 and MS, but none were able to show a causative relationship. CONCLUSIONS: The available literature provides some support for a relationship between HHV-6 and MS. The limitations of the available studies and directions for future research are discussed.

Antibodies, Viral↗
PubMed2001

Progression of impairment in patients with vascular cognitive impairment without dementia.

Little is known about progression, short of dementia, in vascular cognitive impairment. In the Canadian Study of Health and Aging, 149 participants (79.3 +/- 6.7 years; 61% women) were found to have vascular cognitive impairment, no dementia (CIND). After 5 years, 77 participants (52%) had died and 58 (46%) had developed dementia. Women were at greater risk of dementia (OR 2.1, 1.0 to 4.5). Of 32 participants alive without dementia, cognition had deteriorated in seven and improved in four. Half of those with vascular CIND developed dementia within 5 years, suggesting a target for preventive interventions.

Aged↗
PubMed2001

A reevaluation of the duration of survival after the onset of dementia.

BACKGROUND: Dementia shortens life expectancy; estimates of median survival after the onset of dementia have ranged from 5 to 9.3 years. Previous studies of people with existing dementia, however, may have underestimated the deleterious effects of dementia on survival by failing to consider persons with rapidly progressive illness who died before they could be included in a study (referred to as length bias). METHODS: We used data from the Canadian Study of Health and Aging to estimate survival from the onset of symptoms of dementia; the estimate was adjusted for length bias. A random sample of 10,263 subjects 65 years old or older from throughout Canada was screened for cognitive impairment. For those with dementia, we ascertained the date of onset and conducted follow-up for five years. RESULTS: We analyzed data on 821 subjects, of whom 396 had probable Alzheimer's disease, 252 had possible Alzheimer's disease, and 173 had vascular dementia. For the group as a whole, the unadjusted median survival was 6.6 years (95 percent confidence interval, 6.2 to 7.1). After adjustment for length bias, the estimated median survival was 3.3 years (95 percent confidence interval, 2.7 to 4.0). The median survival was 3.1 years for subjects with probable Alzheimer's disease, 3.5 years for subjects with possible Alzheimer's disease, and 3.3 years for subjects with vascular dementia. CONCLUSIONS: Median survival after the onset of dementia is much shorter than has previously been estimated.

Age of Onset↗
PubMed2001

Multiple sclerosis and varicella zoster virus infection: a review.

We have evaluated the epidemiological evidence for an aetiological role of varicella zoster virus (VZV) infection in the development of multiple sclerosis (MS). A MEDLINE search of the English language literature for 1965-99 identified 40 studies. These studies were categorized as seroepidemiological (13), case-control (23), historical cohort (2) or ecological (2). One study used both case-control and historical cohort methodologies. Studies were then classified according to methodological rigour, using criteria derived from published guidelines for the epidemiological study of MS. There was a large variability in the quality of evidence. The five studies with the best methodology failed to show an increased risk of MS associated with varicella or zoster infections. At the present time there is insufficient evidence to support an important aetiological role of VZV infection in the development of MS.

Adolescent↗
PubMed2001

A recommended method for obtaining the age at onset of dementia from the CSHA database.

In studies of dementia, the age at onset (AAO) of the disease is often described without indicating how it was obtained. We used the "CAMDEX algorithm," an ad hoc procedure, to compute the AAO of dementia from the CSHA database. An AAO could be calculated for 983 of 1,132 subjects with dementia. A similar procedure (the "clinical algorithm") was used to calculate a second AAO, which was compared to that obtained by the first algorithm. The CAMDEX and clinical algorithms produced mean AAOs of dementia of 80.5 years (SD = 9.2 years, n = 983) and 79.6 years (SD = 9.7 years, n = 829), respectively. The sample correlation coefficient between the CAMDEX and clinical algorithms was .899 while the intraclass correlation coefficient, ICC(2,1), was .898. This method could prove useful for researchers using the CSHA data who need an AAO for those subjects with dementia.

Age of Onset↗
PubMed2001

Reliable individual change scores on the 3MS in older persons with dementia: results from the Canadian Study of Health and Aging.

We examined the degree of interrater agreement on the Modified Mini-Mental State Examination (3MS), administered both in the home and at the clinical examination, to determine the boundaries of reliable individual changes for 257 community-dwelling older persons who received a diagnosis of dementia at CSHA-1. Individual score differences were approximately normally distributed (mean of differences 0.2; SD 8.0; 95% confidence interval -16 to 16). The intraclass correlation coefficient was 0.85. Except for the language of testing, there was no relationship between score differences and the determinants investigated (i.e., age, education, type and severity of dementia). This study provides evidence that, in a time frame compatible with no change in cognition, the discrepancy between repeat 3MS scores can be as large as +/- 16. These limits represent the range of variability consistent with no change and should be considered when interpreting individual change scores.

Aged↗
PubMed2001

The Canadian Study of Health and Aging: organizational lessons from a national, multicenter, epidemiologic study.

The Canadian Study of Health and Aging was a large, multidisciplinary, national core study--with a number of "add-on" investigations--of the epidemiology of dementia and the health of older people. This structure was a fiscally prudent way to balance between mandated and investigator-initiated inquiry. In hindsight, several important features of the study would be repeated. Future studies might profitably consider a longer funding period for analysis, and a more strategic approach to in-depth, supplementary studies.

Aged↗
PubMed2001

Factors associated with long-term institutionalization of older people with dementia: data from the Canadian Study of Health and Aging.

BACKGROUND: In Canada, half the people with dementia live in institutions. Factors associated with institutionalization should be identified with the goal of implementing strategies not only to permit those with dementia to stay in their homes as long as is feasible but also to ensure that steps are taken for timely institutionalization when appropriate. METHODS: Informal caregivers of 326 individuals with dementia living in the community were identified and interviewed as part of the Canadian Study of Health and Aging (CSHA). These subjects were contacted again 2.5 and 5 years after the baseline interview to collect information on the status of their care recipients. Survival analyses using clinical data for the individuals with dementia and data from the interviews with their informal caregivers were carried out using Cox proportional hazard modeling to estimate the hazard ratio (HR). RESULTS: Over the 5-year period, 166 individuals with dementia (50.9%) were institutionalized and the median time to admission was 41 months. From the multivariate analysis, the factors significantly associated with institutionalization were: type of dementia (Alzheimer's disease: HR = 1.83), severity of disability (mild: 1.51; moderate: 2.34; total impairment: 4.02), caregiver's age over 60 (1.83), caregiver not a spouse or child (1.55), and severe caregiver burden (1.71). Caregiver's burden was associated with the care-receiver's behavioral disturbance (partial r =.55) and the caregiver's depressive mood (r =.55). CONCLUSIONS: Screening caregivers for burden and depression and designing interventions to decrease the consequences of behavioral disturbance on caregivers would be relevant avenues to explore to decrease institutionalization of people with dementia.

Aged↗
PubMed2001

High daily doses of benzodiazepines among Quebec seniors: prevalence and correlates.

BACKGROUND: Use of high daily doses of benzodiazepines is generally contraindicated for seniors. While both patient and physician factors may influence the use of high daily doses, previous research on the effect of patient factors has been extremely limited. The objectives of this study were to determine the one year prevalence of use of high daily doses of benzodiazepines, and examine physician and patient correlates of such use among Quebec community-dwelling seniors. METHODS: Patient information for 1423 community-dwelling Quebec seniors who participated in the Canadian Study of Health and Aging was linked to provincial health insurance administrative data bases containing detailed information on prescriptions received and prescribers. RESULTS: The standardized one year period prevalence of use of high daily doses of benzodiazepines was 7.9%. Use of high daily doses was more frequent among younger seniors and those who had reported anxiety during the previous year. Patients without cognitive impairment were more likely to receive high dose prescriptions from general practitioners, while those with cognitive impairment were more likely to receive high dose prescriptions from specialists. CONCLUSION: High dose prescribing appears to be related to both patient and physician factors.

Journal Article↗
PubMed2000

Multiple sclerosis and antecedent infections: a case-control study.

OBJECTIVES: To determine whether there is an excess of respiratory tract infections in the 5-week, 3-month, and 12-month periods before MS symptom onset and if there is an association between MS and a history of infectious mononucleosis (IM). BACKGROUND: The etiology of MS remains unknown, but infection is frequently suggested as a putative etiologic agent. Epidemiologic studies have produced inconsistent evidence for an etiologic role of respiratory tract infections (RTI) and IM in MS. METHODS: The authors performed a case-control study using the General Practice Research Database from the United Kingdom. There were 225 subjects with definite or probable MS, and 900 controls matched for age, sex, and physician practice. Using computerized patient records, the authors compared the mean rates of RTI per patient in the 5-week, 3-month, and 12-month periods before the date of onset of the first symptoms compatible with MS (index date). They also compared histories of IM. RESULTS: In all periods, an increased frequency of RTI was associated with a significantly increased risk of MS. A history of IM was associated with greater than five times the risk of MS (OR = 5.5 [95% CI 1.5 to 19.7]). CONCLUSIONS: These results support an association between a history of IM and subsequent MS. Respiratory tract infections may precipitate disease onset.

Adult↗
PubMed2000

Development of simple cognitive function measures in a community dwelling population of elderly in Spain.

OBJECTIVE: To develop and assess the consistency and validity of simple cognitive function measures for an elderly population with low levels of formal education for use in a longitudinal study of dementia. METHODS: Data were from the population longitudinal study 'Growing old in Leganés' (Spain). In 1993, a random sample of 1540 people over 65 was drawn from the City Roll of Leganés from which 1284 (83%) were successfully interviewed. Measures of memory and orientation were based on the SPMSQ (Short Portable Mental Status Questionnaire), the Barcelona test and the short story from EPESE (Established Populations Epidemiologic Studies of the Elderly). Non-response to a test item was coded as an error. Internal consistency was assessed by factor analysis and Cronbach's alpha. Construct validity was examined with multiple linear regressions of the proposed measurements on variables chosen from the existing literature on cognitive function. RESULTS: Two factors, memory and orientation, emerged from the factor analysis. Internal consistency of the proposed indexes for memory and orientation was acceptable. Memory and orientation scores were summed into one summary index of cognition. Associations between covariates and both cognitive indexes were in the expected direction. Among those highly functional, orientation was influenced by illiteracy due to higher error rates in the time orientation items based on dates; however, memory and summary scores were not significantly different by literacy status. A large proportion of the variance in IADL was explained by the memory and orientation measures. CONCLUSION: The memory and orientation indexes are valid and reliable measurements of cognitive function for use in a population of community dwelling elderly with low levels of formal education and high rates of illiteracy.

Aged↗
PubMed2000

Do patient factors alter the relationship between physician characteristics and use of long-acting benzodiazepines?

Despite known hazards associated with their use, long-acting benzodiazepines are frequently used in the treatment of older adults. While such use has been linked to physician characteristics, the effect of patient factors has not been considered. To investigate this, data from 1423 Quebec community-dwelling subjects of the Canadian Study of Health and Aging were linked to records of prescriptions billed to the provincial health insurance program during the year following study entry. The standardized one-year period prevalence of any use of long-acting benzodiazepines was 12.2%. Among benzodiazepine users, long-acting benzodiazepine use was more common among male patients and patients of earlier graduating prescribers and specialist prescribers. However, the effect of the latter two factors were modified by patient self-reported anxiety. This study demonstrates that consideration of patient factors may be necessary to obtain an accurate estimate of the association between at least some physician factors and use of long-acting benzodiazepines.

Aged↗
PubMed2000

Undetected dementia in community-dwelling older people: the Canadian Study of Health and Aging.

OBJECTIVE: To estimate the frequency and correlates of undetected dementia in community-dwelling older people. DESIGN: Secondary analysis of data from the Canadian Study of Health and Aging (CSHA) prevalence survey of dementia. SETTING: All 10 provinces of Canada excluding Indian reserves and military units. PARTICIPANTS: A total of 252 community-dwelling older adults diagnosed with dementia in the CSHA survey. MAIN OUTCOME MEASURE: Undetected dementia, defined as occurring in persons who meet standard diagnostic criteria for dementia but who report never having seen a doctor for memory problems. RESULTS: Of the 252 subjects, 64% had undetected dementia. Subjects with mild functional impairment were significantly more likely to have undetected dementia (odds ratio = 2.4, 95% confidence interval 1.2, 5.0). Older subjects and those with mild cognitive impairment showed a trend toward undetected dementia, although the results did not achieve statistical significance. Educational level, number of comorbid conditions, and degree of social support were not significantly associated with undetected dementia. CONCLUSIONS: A large number of older persons are living in the community with undetected dementia. These older people may be at significant risk for delirium, motor vehicle accidents, medication errors, and financial difficulties. As preventive strategies are developed and new cognitive enhancing therapies emerge, we need to reexamine our current guidelines about screening for cognitive impairment in older adults.

Aged↗
PubMed2000

Long-term continuous use of benzodiazepines by older adults in Quebec: prevalence, incidence and risk factors.

OBJECTIVE: To determine the prevalence and incidence of long-term use of benzodiazepines and to assess patient-, prescriber-, and drug-related risk factors. DESIGN: Cohort study. PARTICIPANTS: 1,423 community-dwelling older adults in Quebec who participated in the Canadian Study of Health and Aging (CSHA1). MEASUREMENTS: Patient characteristics were obtained from the CSHA1 database. These were linked to provincial health insurance data to ascertain benzodiazepine use and prescriber characteristics. MAIN OUTCOME MEASURE: Use of benzodiazepines for at least 135 of the first 180 days following initiation of use. RESULTS: Twelve-month prevalence of long-term continuous use, standardized by age and gender to the Quebec population, was 19.8%. Twelve-month cumulative incidence of long-term continuous use was 1.9%. Older patients were more likely to proceed to long-term continuous use. CONCLUSIONS: Risk of long-term continuous use of benzodiazepines seems to increase with age. This association was found to be independent of gender, health status, anxiety, cognitive status, benzodiazepine type, and physician characteristics.

Adult↗
PubMed2000

Hemostatic markers in patients at risk of cerebral ischemia.

BACKGROUND: Increased levels of markers of hemostasis may assist in the determination of the extent of carotid occlusive disease and the identification of neurologically intact individuals at increased risk of ischemic events. METHODS: We conducted a prospective study of 304 subjects, including 82 with a recent (< or =7 days) transient ischemic attack (TIA), 157 asymptomatic individuals with a cervical bruit, and 65 control subjects. Baseline evaluation included a neurological assessment, ECG, cervical ultrasonography, and cerebral CT and/or MRI. Levels of markers of coagulation and fibrinolytic activity were also determined. Results were analyzed in relation to the degree of carotid disease and the subsequent occurrence of cerebral and cardiac ischemic events. RESULTS: Over a mean follow-up period of 2.8 years (SD, 1.3 years), 114 ischemic events occurred. Survival analyses showed that prothrombin fragment 1.2 (F(1.2)) was a predictor of time to cerebral and cardiac ischemic events in the combined TIA and asymptomatic bruit group (relative risk [RR], 1.46; 95% CI, 1.18 to 1.81) as well as in the asymptomatic bruit group separately (RR, 1.70; 95% CI, 1.14 to 2.53). In the TIA group, both F(1.2) (RR, 2.36; 95% CI, 1.19 to 4.68) and severe (> or =80%) carotid stenosis (RR, 3.53; 95% CI, 1.19 to 10.51) were predictive of time to ischemic stroke, myocardial infarction, or vascular death. CONCLUSIONS: In patients with TIAs and in asymptomatic individuals with cervical bruits, F(1.2) levels were found to be independent predictors of subsequent cerebral and cardiac ischemic events. Our results are consistent with an active role of the coagulation system through upregulation of thrombin in carotid disease progression and in the pathogenesis of ischemic events in patients at risk.

Aged↗