epidemiology Flashcards
what is epidemiology?
the study of populations in order to determine the frequency and distribution of disease
what is the purpose of epidemiology?
identifying risk factors for disease and determining optimal tx approaches to clinical practice and preventive medicine
what are the major roles of epidemiology?
monitor infectious and non-infectious disease study natural history of diseases investigation of disease risk factors health care needs assessment development of preventive programmes evaluation of interventions health service planning
what are the 2 measures of disease frequency?
prevalence
incidence
what is prevalence?
measurement of all individuals affected by the disease w/i a particular period of time or point in time
what is incidence?
measurement of the number of new individuals who contract a disease during a particular period of time
what is a systemic sample?
individuals selected at regular intervals from population list
what is a stratified sample?
ensure small sub-groups adequately represented
what is a cluster sample?
use of groups as sampling units
what can go wrong in survey methodology?
sampling/selection bias response bias/ info bias measurement error observer variation loss to follow up
what are the properties of ideal index?
clear, unambiguous, not subjective ideally correspond w/ clinically important stages of the disease indicate tx needed w/i ability of examiners reproducible not time-consuming acceptable to px amenable to statistical analysis allow comparison with other studies
what are the limitations of BMF index?
teeth extracted for reasons not caries
influences by access eg interproximal surface
difficulty in differentiating fissure-sealant from rest.
influenced by past disease activity
threshold criteria of disease can vary
cannot be used for root caries
