Analytical epidemiological studies Flashcards
Give the 3 observational study types?
Cross-sectional studies
Cohort Studies
Case-Control Studies
What are cross sectional studies?
Studies in which data on the factor and outcome of interst in the population being studied are recorded at the same time. individuals are selected without regard to exposure or disease status.
Provide a snapshot of events at a particuat time
Best suited studying pernament factors i.e. sexx breed
What are Cohort studies?
Studies in which 2 or more proups within a population are defined according to their exposure or non-exposure to a risk factor of interest and followed through time to determine the frequency of occurence of the outcome of interest
What are case studies?
Studies which consists of comparing a diseased group (cases) to a non-diseased group (controls) based on the collection of information on prior exposure to one or more risk factors
Cross sectional studies:
Cost and duration
Allow study of multiple causes
Suitable for study or rare diseases
Allow estimation of incidence in exposed and non exposed
Cost and duration: Relatively quick and inexpensive
Allow study of multiple causes: YES
Suitable for study of rare diseases: Require moderate sample size
Allow estimation of incidence in exposed and non exposed: NO
Cohort studies:
Cost and duration
Allow study of multiple causes
Suitable for study or rare diseases
Allow estimation of incidence in exposed and non exposed
Cost and duration: Relatively expensive and of lon duration
Allow study of multiple causes: NO
Suitable for study or rare diseases: Require large sample sizes
Allow estimation of incidence in exposed and non exposed: YES
Case control
Cost and duration
Allow study of multiple causes
Suitable for study or rare diseases
Allow estimation of incidence in exposed and non exposed
Cost and duration: Relatively quick and inexpensive
Allow study of multiple causes: YES
Suitable for study or rare diseases: YES
Allow estimation of incidence in exposed and non exposed: NO
Define Risk
Probability that an event will occur at a given time or during a given time period
In relation with disease we can use risk to denote the probability of diseasedeveloping or infection acuired in an individual in a specified time interval
Define risk factor
Factor associated with an increase in the probaility of occurrence of an outcome of interest
What is diagnosis?
Presence/absence of the risk factor increases/decreases the likelihood of disease or severity
What is prediction? in relation to risk
Estimating the likely future frequecny of disease among comparable individuals
What is Causality? in relation to risk
In some cases risk factors are causally associated with the condition
What is prevention? in relation to risk
Reducing the exposureto the risk factor can be used to prevent disease, even if the disease mechanism is unknown
