Epidemiology Glossary Flashcards
(30 cards)
What is Attributable risk?
The difference between the incidence of outcome between the exposed group and control group.
Attributable risk = incidence in exposed - incidence in unexposed
(Basically how much of the risk is due to given exposure to a factor)
What is a case-control study?
A case-control study starts by defining groups according to the outcome (e.g. disease present or absent) and then looks back to establish the study factor (e.g. exposure present or absent). A case-control study has a backward directionality. A case-control study is unable to estimate relative risk. Always retrospective.
Pros: cheap, quick, good for investigating outbreaks.
What is a cohort study?
A cohort study starts by defining groups by the study factor (e.g. exposure present or absent) and then follows-up these exposure groups to detect the outcome (e.g. disease present or absent). A cohort study has a forward directionality. A cohort study is able to estimate relative risk since incidences are observed.
What is causality?
Causality is about identifying the causes of a disease. Bradford-hill criteria are usually used to determine causality.
What is confounding bias?
Confounding may occur if the effect of the study factor on the outcome is mixed in the data with the effect of another variable (= confounder).
What is critical appraisal?
The process of comprehending a scientific report and assessing its methods, results and conclusions in order to evaluate the drawbacks in the method and validity of the evidence in the report.
What is Cumulative incidence?
The number of new cases over a specified time period divided by the total population.
What is the Declaration of Helsinki?
A set of ethical principles when conducting research on human populations developed by the World Medical Association.
What does Endemic mean?
Endemic refers to the occurrence of a disease in a population at ‘normally’ expected levels
Endemic implies that a disease can maintain itself in a population without external input of cases.
What does Epidemic mean?
The occurrence of a disease in a population is higher than the ‘normally’ expected levels.
What is the epidemiological (demographic) transition?
The transition from high mortality rates, usually caused by infectious diseases, to lower mortality rates mainly caused by chronic diseases in a country or region.
What is epidemiology?
The study of the distribution and determinants of health-related events in specified populations and the application of study results to control health problems.
What are Bradford-hill criteria for causality?
strength of the association, biological gradient, lack of temporal ambiguity, specificity, experiment, plausibility, consistency of findings, coherence of evidence, analogy
Define Incidence?
The number of new cases in a given time period.
Define prevalence
Prevalence quantifies the number existing cases at any point in time
Prevalence= number of cases divided by total population number
What is publication bias?
When statistically significant papers are more likely to be published than paper which did not find statistically significant differences/correlations
What is relative risk?
A ratio measure of association. It is the incidence outcome in the exposed divided by the incidence of outcome in unexposed.
What is systematic error?
A type of error which acts on the results of the study systematically (consistently) and cannot be corrected with a larger sample size. This type of error persists throughout the experiment.
Can be minimised using matching, randomisation, and blinding.
What is tertiary prevent? Give an example.
Aims to prevent or minimise progression of disease at the clinical stage.
Examples: rehab programs, chronic disease management programs
What is primary prevent? Give an example.
Aim to prevent clinical stage of disease or reduce severity of disease.
Examples: screening, modified work for injured workers, excessive programs, low-dose drug programs, diet
What is primary prevention? Give examples.
Directed at reducing susceptibility of disease. Aims to prevent or reduce risk factors.
Examples: immunisations, education, legislation to ban hazardous substances/practices, reducing risk factors via diet
Define validity
Mean measurements are taken correctly. A study is valid if it studies what is supposed to have studied with correctly taken data as evidence, and the study has not suffered bias, error or confounding.
Define mortality
The number of total fatal cases of a disease in a given time period.
What is positive predictive value?
Number of true positives/total positives
