Class 2 Flashcards
What does epidemiology do
It compares groups (study populations) in order to detect differences pointing towards:
- aetiological clues
- the scope of prevention
- the identification of high risk or priority groups in society
What may define study populations in epidemiology
Study group may be defined by age/sex/location or may even be the same group studied over time. We then compare how often an event occurs in that compared with another e.g. male vs female. This was used to identify the association between smoking and lung cancer.
What are the 3 main aims of epidemiology when advising a patient of health condition
Description - the amount and distribution of disease in human populations. Explanation - highlight natural history and identify aetiological factors for the disease, usually done by combining epidemiological data with data from other disciplines
Disease control - provide basis on which preventative measure, public health practices and therapeutic strategies can be developed, implemented, monitored + evaluated for purpose of disease control
You want to describe it, explain it, then control it.
What is the key difference between epidemiology and clinical medicine
Epidemiology studies population groups. Clinical medicine studies individual patients.
Using epidemiology, how is risk estimated in a population group
The risk may be expressed as a percentage of the population e.g. 1% of men ages X to Y will have an MI.
Everyone from the numerator must have come from the denominator and everyone in the denominator must have ability to enter the numerator.
Events/population at risk: (number of death from MI in men aged 55-64 in grampian in 1990)/(Number of men aged 55-64 in grampian in 1990)
Give examples of diseases which may have high/low in cadence and low/high prevalence
High incidence with low prevalence - minor illnesses e.g. cold
Low incidence with high prevalence - chronic illnesses e.g. diabetes
What is relative risk and how is it measured
It is the measure of then strength of an association between a suspected risk factor and the disease under study.
Relative risk = (incidence of disease in exposed group)/ (incidence of disease in unexposed group):
incidence of LC in populations smoking 20 a day = 25/100
incidence of LC in populations that don’t smoke = 10/100
therefore RR = 0.25/0.10 = 2.5
List some sources of epidemiological data
Mortality data Hospital activity stats Reproductive health stats Cancers stats Accident stats GP morbidity Health and household surveys Social security stats Drug misuse databases Expenditure data from NHS
What is the name of the Health literacy action plan for Scotland
Making It Easy
What are SIGN guidelines based on
They are based on systematic reviews of the available scientific literature and aim to aid the transition of new knowledge into action
Give 3 aims of SIGN guidelines
They aim to:
- help health and social care professionals and patients understand medical evidence and use it to make decisions about health care
- reduce unwarranted variations in practice to make sure patients get the best care available no matter where they live
- improve healthcare across Scotland by focusing on patient important outcomes
What is a descriptive study
Attempt to describe the amount and distribution of a disease in a given population. These type of studies do bot provide definitive conclusions about disease causation, but may give clues to possible risk factors and candidate aetiologies. Such studies are usually cheap, quick and give valuable initial overview of a problem.
What is a cross sectional study
Observations are made at a single point in time. Conclusions are drawn about the relationship between diseases and other variables of interest in a defined population. Provides results quickly; however, it is impossible to determine causation.
What are case control studies
2 groups of people are compared: a group of individuals with the disease (cases) + a group of individuals who do not have the disease (controls). Information is gathered about each group in an attempt to identify aetiological factors. The average exposure between the 2 groups is then expressed as an odds ratio or relative risks (RRs may be used cohort studies and randomised trials). Confidence intervals or “p-values” may be presented as a guide to whether the result could be a chance finding.
What is a cohort study
Baseline data is collected on exposure from a group of people who do not have the disease. The group is then subdivided in terms of exposure status. The group is then followed through time until a sufficient number have developed the disease to allow analysis. Results are usually expressed as RRs with confidence intervals or P-values.
