31. Epidemiology 2 Flashcards
1
Q
Define ‘prevalence’
A
- proportion of individuals in population who have disease of interest at specific instant
- provides estimate of probability/risk that an individual will be ill at a point in time
2
Q
Equation for prevalence
A
number of existing cases of disease/total population
3
Q
What is point prevalence?
A
prevalence at a given point in time
- point of time may be fixed calendar day or fixed point in series of events like 2nd post-op day of GA for lower 8s
4
Q
Define ‘incidence’
A
- quantifies the number of new cases of disease that develop in population at risk during defined time period
5
Q
Equation of cumulative incidence
A
number of new cases of disease during given time period/total population at risk
6
Q
Equation for incident rate
A
number of new cases of a disease during given time period/total person-time of observation
7
Q
What is an index?
A
- numerical value describing relative status of a population on a graduated scale
- with definite upper and lower limits designed to permit and facilitate comparison
- with other populations classified by same criteria and methods
8
Q
Uses of indices
A
- to describe the prevalence of disease/condition in population and describe severity of diseases/conditions
- study and compare heath status of individual and population
- to provide data for epidemiological studies
- for planning oral health policy
- to evaluate success of preventative interventions
9
Q
Desirable properties of Indices
A
- equally sensitive across scale to changes in disease severity and disease progression
- simple to apply, objective, clear and unambiguous
- should be valid (faithfully record disease supposed to identify)
- should be reliable (consistent and repeatable)
- measurements amenable to statistical analysis
- acceptable to participant
10
Q
Define ‘valid’
A
actually measures what test purports to measure
11
Q
Define ‘reliable’
A
- consistency and repeatability in hands of an examiner or group of examiners
12
Q
Define ‘chance’
A
- a possibility/probability of something happening
- an opportunity
13
Q
What is chance’s relevance in epidemiology?
A
- measurements made are nearly always due to random variation
- so are research findings simply due to chance rather than an actual ‘true’ difference/similarity?
14
Q
Define ‘bias’
A
- inclination or prejudice in favour of a particular person , thing or viewpoint to influence unfairly
- a systematic error relating to measurement of a variable - e.g way things are measured, way ps are selected, way data were analysed
15
Q
Define ‘confounding’
A
- an error in the interpretation of measurement (even measurement is accurate)
- confounder is prognostically linked to outcome of interest and is unevenly distributed between the study groups
