Acknowledgements
Grateful acknowledgement is made to the following sources for permission to reproduce material in this course.Couse image: Sharon Drummond in Flickr made available under Creative Commons...
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Aggleton, P. (1990) Health, London, Routledge.Aldridge, A. and Levine, K. (2001) Surveying the Social World: Principles and Practice in Survey Research, Buckingham, Open University Press.Armstrong, D....
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View Article4 Conclusion
Epidemiological research can be particularly useful in promoting public health because it provides evidence to enable public health practitioners to identify priorities and explore causal or risk...
View Article3.3 Quasi-experimental design
One response to some of these difficulties has been to use a modified or quasi-experimental design. Instead of using a control group formed by random assignment, the investigator may choose a highly...
View Article3.2.4 Intervention studies
Whereas the types of study described so far, including case-control studies, are purely observational in nature (i.e. they only observe what is happening), intervention studies involve intervening with...
View Article3.2.3 Cohort studies
These focus on groups of people who show certain attributes or characteristics (e.g. with respect to their health behaviour). The groups are then observed over a period of time in order to discover...
View Article3.2.2 Case-control studies
These focus on determining disease causation. The ‘case’ is a person who has a particular symptom or medical condition. Thus, the focus is on a group of cases which is then compared with a ‘control...
View Article3.2.1 Cross-sectional studies
Cross-sectional studies measure the prevalence of conditions or characteristics of people in a population at a point in time or over a short period. Although they are essentially descriptive studies,...
View Article3.2 Types of epidemiological studies
Epidemiological studies generally fall into four broad categories:cross-sectional studiescase-control studiescohort studiesintervention studies.Each of these is addressed in turn the sections that follow.
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3.1 The epidemiological triad
The epidemiological triad is best represented diagrammatically (see Figure 19). This represents the interaction between an agent, host or persons and environment or place within a specific time...
View Article3 Analytic epidemiology
Causation of ill health is difficult to determine. Apart from infectious diseases, most evidence relates to the risk associated with particular factors, rather than the direct causes of ill health....
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2.2.4 Time: when do health problems occur?
The question of when (in time) diseases occur or peak is of considerable interest in epidemiology. For example, it is well established that a range of well-known infectious diseases (e.g. measles,...
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2.2.3 Place: where do the problems occur?
The cholera epidemic of the 1850s, mentioned in Section 2, demonstrates the influence of geographical and environmental factors on the occurrence of disease. Disease patterns also vary internationally;...
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2.2.2 Persons: which groups in the population have health problems?
In order to discover the patterns of disease distribution, data is needed on the personal characteristics of the population: the age groups, proportions of men and women, and occupational groups. Other...
View Article2.2.1 Notifiable diseases
The diseases listed below are notifiable and should be reported to the Office of National Statistics.The list is as follows –Diseases notifiable (to Local Authority Proper Officers) under the Health...
View Article2.2 Descriptive epidemiology
A large part of the epidemiological task is concerned with surveillance. Public Health Departments and agencies such as the Health Protection Agency quite literally keep watch on the incidence and...
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2.1.2 Morbidity statistics
Epidemiology also involves estimating the frequency and distribution of diseases in populations. Measures of disease frequency are tools with which to describe how common an illness is in relation to...
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2.1.1 Mortality statistics
Mortality data from death certificates and from census and population registers are routinely collected; from these the death rate in a population can be calculated. To calculate a death rate the...
View Article2 Early studies in epidemiology
The following three examples serve to illustrate, albeit very briefly, the origins of modern epidemiology.In the mid-nineteenth century, Dr John Snow suspected that drinking water might have caused the...
View Article1 Defining epidemiology
Epidemiology has been defined as ‘the study of how often diseases occur in different groups of people and why’ (Coggon et al., 2003, p. 1). It is concerned not only with the distribution of disease...
View ArticleLearning outcomes
After studying this course, you should be able to:explain and practise some key techniques in epidemiologyunderstand some routine methods of data analysisapply these techniques in a practical sense.
View ArticleIntroduction
In 2006 it was reported in the media that there was, in the UK, a 60% rise in Chlamydia infection. Syphilis and gonorrhoea were on the increase, while HIV infection was not diminishing. Heart disease...
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