module 1: measuring health and dis-ease in populations Flashcards
lectures 1-12 (44 cards)
What is epidemiology
The study of frequency (or occurrence) of dis-ease in different populations
What does “dis-ease” mean?
Any health related event or health-related ‘state’
What is an occurrence
The transition from a non-diseased state to a dis-eased state
How do epidemiologists define health & dis-ease?
Narrow: the absence of death, disease or disability
Broad: the capacity to do what matters most to you
What is a population?
Any group of people who share a common factor
What are the visual components of the GATE frame?
Triangle, Circle, Square, Arrow
What does the triangle represent in the GATE frame?
The participant (or study) population
Divided into 3 parts:
Setting, eligible population, number of study population
What does the circle represent in the GATE frame?
Specific sub-denominators (exposure group and comparison group)
What does the square represent in the GATE frame?
The numberators (dis-ease outcomes)
What does the arrow represent in the GATE frame?
Time
How to deal with numerical data in GATE frame?
They can be converted to categorical data or average values can be calculated as dis-ease occurrence
What is incidence?
The measure of onsets of dis-ease occurring during a period of time from the population
What is prevalence
A measure of the number of people with dis-ease at a point of time
What is PECOT
Population, Exposure/Comparison groups, Outcomes, Time
What are the components of RAMBOMAN
Recruitment error
Allocation error
Maintenance error
Blind or objective measurement
Analyses
What are the types of epidemiological studies
Individual participant cohort study
Individual participant RCTs
Individual participant Cross-sectional study
Ecological studies
Describe the properties of individual participant RCTs
Longitudinal, experimental
Random allocation minimises confounding
Ethical limitations
Expensive, small studies
Often combined in a meta-analysis (due to high random error)
Describe the properties of individual participant cohort studies
Longitudinal, observational,
Allocation by measurement
Cheaper than RCTs
Confounding common
Maintenance error common
Describe the properties of individual participant cross-sectional studies
Measures prevalence
Observational
Allocation by measurement and prevalence measured at same time
No maintenance error
Possible reverse causality and confounding
What are the properties of ecological studies
Investigates international trends (incidence and prevalence)
Cheaper and quicker than other studies because data is already collected
Low random error
Confounding and measurement error common
What is the equation for RR and RD
RR = EGO/CGO
RD = EGO-CGO
What is confounding
When the exposure is mixed with another factor that is also associated with the outcome
What is the criteria in the Bradford Hill Framework
- Temporality
- Strength of association
- Reversibility
- Biological gradient (dose-response)
- Biological plausability of association
- Consistency of association
- Specificity of association
What is the definition of a 95% confidence interval (95% CI)
There is about a 95% chance that the true value in a population lies within the 95% confidence interval