Week 09 Flashcards
Epidemiology is the study of ….
causes, distribution and control of disease and death among certain populations
Case =
diagnosis that the person has disease or disability
Prevalence =
number of persons who are cases
Incidence =
number of new cases in certain time period (can be rate)
Prevalence is how condition is _____
NOW
Period prevalence is how condition is…
during a specific time period
Incidence is a measure of ____
risk
Disability- adjusted life year (DALY) measure of overall …..?
disease burden, as number of years lost due to ill-health, or early death
Lower values of DALYS is ….
better, means fewer years lost through illness, etc
Epidemiological studies are usually ______ designs, as other methods may not be ethical
observational
Cohort: Prospective (level II) are…
- following subjects over along time
- better validity and reliability
- Harder to do
Cohort: Retrospective studies (Level III-2) are….
- Historical, looks at exposure already taken place
- easier, less reliable
Case-control:NHMRC level III-3
- Subjects classified by disease status
- Cases and controls compared for earlier (historical) exposure to presumed causes or risks of disease
- Always retrospective - relies on old exposure data, cannot be prospective
Advantages case-control
- Quick and cheap
- Good when -> disease is rare smaller sample sizes viable, diseased (cases) had frequent exposure
Disadvantages of case control
- Controls similar in other ways to population may be hard to find - risk of sample selection bias
- Exposure history may be incomplete or invalid - biased
- Incidence rates cannot be calculated separately for exposed and non exposed in a case control study
