Lecture 1 Flashcards
What is classic def of Epidemiology?
-The study of the distribution and determinants of health-related states or events in specified populations and the application of this study to the control of health problems
What is distribution?
- Who? Where? When?
- Which animals are affected (ages, breed,
location, time)?
What is Determinants?
- Why? How?
- Why are the specific animals affected and others not? What “risk factors” are “causing” this?
What is the approach of epidemiology?
Step 1: is there an ASSOCIATION btwn factor and Dz?
Step 2: If yes, what is the CAUSAL relationship?
What are Descriptive studies
(OBSERVATIONAL)
- Case Report
- Case Series
- Cross-sectional*
What are Analytical studies
OBSERVATIONAL
- Ecological
- Cross-sectional*
- Case-control
- Cohort
Descriptive vs analytical studies
Descriptive
- Usually early stage of investigation
- Usually answer Who? Where? When?
- No comparison group (uncontrolled)
- Allow formulating hypotheses
Analytic
- Usually later stage of investigation
- Usually answer Why? How?
- Use a comparison group (controlled)
- Allow testing hypotheses
Case Report
a single case/patient
- the ‘first’ one
- an unusual one
- no comparison, only to ‘what we know’
Case Series
a group of cases
- allows presentation of variation
Cross Sectional study
what makes it Descriptive vs analytic
- includes both diseased and non-diseased
individuals - allows estimate of disease prevalence (descriptive)
- sometimes comparisons are done between groups (analytic)
Ecological study
- study unit is group while unit of interest is individual
Case Control study
longitudinal study
- sampling based on OUTCOME/ Dz status
Cohort study
longitudinal study
- sampling, if applied, based on exposure status
Experimental study
longitudinal study
- exposures/treatments are assigned by researchers
Meta-analysis
Systematical evaluation of a collection of studies
