Derrick A Bennett

Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century

This overview of population-based studies of incidence, prevalence, mortality, and case-fatality of stroke was based on studies from 1990. Incidence (first stroke in an individuals lifetime) and prevalence were computed by age, sex, and stroke type. Age-standardised incidence and prevalence with the corresponding 95% CI were plotted for each study to facilitate comparisons. The review shows that the burden of stroke is high and is likely to increase in future decades as a result of demographic and epidemiological transitions in populations. The main features of stroke epidemiology include modest geographical variation in incidence, prevalence, and case-fatality among the--predominantly white--populations studied so far, and a stabilisation or reversal in the declining secular trends in the pre-1990s rates, especially in older people. However, further research that uses the best possible methods to study the incidence, risk factors, and outcome of stroke are urgently needed in other populations of the world, especially in less developed countries where the risk of stroke is high, lifestyles are changing rapidly, and population restructuring is occurring.

Blood Pressure and Stroke An Overview of Published Reviews

Background— The last few years have seen a considerable increase in the amount of information available concerning blood pressure (BP) and stroke associations. This article provides an overview of published reviews of the effects on stroke seen in trials of BP-lowering drugs and compares these with the results available from cohort studies. Summary of Review— We present a review of major overviews of prospective cohort studies and an updated meta-analysis of >40 randomized controlled trials of BP lowering, which included >188 000 participants and approximately 6800 stroke events. Cohort studies now indicate that in the Asia Pacific region as well as in North America and Western Europe, each 10 mm Hg lower systolic BP is associated with a decrease in risk of stroke of approximately one third in subjects aged 60 to 79 years. The association is continuous down to levels of at least 115/75 mm Hg and is consistent across sexes, regions, and stroke subtypes and for fatal and nonfatal events. The proportional association is age dependent but is still strong and positive in those aged 80 years. Data from randomized controlled trials, in which mean age at event was approximately 70 years, indicate that a 10 mm Hg reduction in systolic BP is associated with a reduction in risk of stroke of approximately one third. Per mm Hg systolic BP reduction, the relative benefits for stroke appear similar between agents, by baseline BP levels, and whether or not individuals have a past history of cardiovascular disease. There is, however, evidence of greater benefit with a larger BP reduction. Conclusions— The epidemiologically expected benefits of BP lowering for stroke risk reduction are broadly consistent across a range of different population subgroups. There are greater benefits from larger BP reductions, and initiating and maintaining BP reduction for stroke prevention is a more important issue than choice of initial agent.

Treatment with drugs to lower blood pressure and blood cholesterol based on an individual's absolute cardiovascular risk

In this review, we outline the rationale for targeting blood pressure and blood cholesterol lowering drug treatments to patients at high absolute cardiovascular risk, irrespective of their blood pressure or blood cholesterol levels. Because the specific levels of blood pressure and cholesterol are of little clinical relevance when considered in isolation from other risk factors, terms such as hypertension or hypercholesterolaemia have limited value. Separate management guidelines for raised blood pressure and blood cholesterol need to be replaced by integrated cardiovascular risk management guidelines, and absolute cardiovascular risk prediction scores should be used routinely. Since cardiovascular risk factors interact with each other, moderate reductions in several risk factors can be more effective than major reductions in one. An affordable daily pill combining low doses of various drugs could be useful for the many individuals with slightly abnormal cardiovascular risk factors.

A Randomized, Controlled Trial of Quadriceps Resistance Exercise and Vitamin D in Frail Older People: The Frailty Interventions Trial in Elderly Subjects (FITNESS)

OBJECTIVES:u2003 To determine the effectiveness of vitamin D and home‐based quadriceps resistance exercise on reducing falls and improving the physical health of frail older people after hospital discharge.

Falls After Stroke Results From the Auckland Regional Community Stroke (ARCOS) Study, 2002 to 2003

Background and Purpose— Falls are an important issue in older people. We aimed to determine the incidence, circumstances, and predictors of falls in patients with recent acute stroke. Methods— The Auckland Regional Community Stroke (ARCOS) study was a prospective population-based stroke incidence study conducted in Auckland, New Zealand (NZ) during 2002 to 2003. Among 6-month survivors, the location and consequences of any falls were ascertained by self-report as part of a structured interview. Multivariable logistic regression was used to establish associations between risk factors and “any” and “injurious” falls. Results— Of 1104 stroke survivors who completed an interview, 407 (37%) reported at least 1 fall, 151 (37% of fallers, 14% of stroke survivors) sustained an injury that required medical treatment, and 31 (8% of fallers, 3% of stroke survivors) sustained a fracture. The majority of falls occurred indoors at home. Independent factors associated with falls were depressive symptoms, disability, previous falls, and older age. For injurious falls, the positively associated factors were female sex and NZ/European ethnicity and dependence before the stroke, whereas higher levels of activity and normal cognition were negatively associated factors. Conclusions— Falls are common after stroke, and their predictive factors are similar to those for older people in general. Falls prevention programs require implementation in stroke services.

Psychosocial factors and chronic fatigue syndrome

This study investigated the number and severity of life events, Type A behaviour, coping strategies and social support differences between chronic fatigue and irritable bowel syndrome patients prior to illness and between these groups and healthy controls. Although few differences were found between the groups for life events, a number of interesting results emerged with regard to different aspects of Type A behaviour, various coping strategies and social support. These findings are discussed with respect to existing research in the field.

Review of analytical methods for prospective cohort studies using time to event data: single studies and implications for meta-analysis

Prospective cohort studies are extremely important in epidemiological research as they give direct information on the sequence of events, which can be used to demonstrate causality. They also have the advantage that many diseases can be studied simultaneously. However, they are usually very time consuming and expensive to run. In addition, practitioners of evidence-based medicine prefer to make decisions based on several studies rather than a single study, hence the need for meta-analysis. The use of meta-analyses in order to synthesize the evidence from randomized controlled trials is extremely popular in medicine and is also being utilized increasingly in epidemiology. The statistical methodology for meta-analyses of epidemiological studies is a long way behind in terms of the advances made in the methodology for randomized controlled trials. Numerous methodological issues, particularly in respect to dealing with biases inherent in these types of studies, have made the results of meta-analyses of epidemiological studies that use summary data open to criticism. This review mainly concentrates on analytical methods for prospective cohort studies that have survival outcomes. In addition, the implications for meta-analysis assuming that the analyst has access to individual participant data are also discussed. The approaches are described with respect to underlying theory and assumptions. It is hoped that this review will promote the use of these approaches in meta-analyses conducted in epidemiology as well as providing some directions for future research.

Psychological discriminators of subjects at different stages of the eating disturbed spectrum

Abstract Eating disturbed subjects and dieters completed an interview administered questionnaire covering stress, coping, social support, personality and eating attitudes followed by structured probes. The two groups of subjects reported differences in coping styles, levels of social support and personality traits. Life stress was not found to be significantly different between the two groups. Personality traits made a significant contribution to separating the two groups even after adjusting for eating pathology. The “individual-difference approach” may be more useful in improving our understanding of the aetiology of disturbed eating behaviour and its treatment.