1 - Intro to epidemiology Flashcards
What is the origin of the word epidemiology?
Epi = on or upon Demos = people Logos = study of
What is epidemiology?
= study of a population
= “the study of distribution & determinants of health-related states or events in specified populations & the application
How did Hippocrates view disease?
Looked at dx as an imbalance in fluids (or humors) → melancholy, phlegm, bile, blood
How did Hippocrates view disease?
Looked at dx as an imbalance in fluids (or humors) → melancholy, phlegm, bile, blood
Who is John Grant?
Published landmark analysis of mortality data → 1st to quantify patterns of birth, death & dx occurrence
Who is the father of modern vital statistics & surveillance?
William Farr (1800)
Who is the father of epidemiology & why?
John Snow (1854) Conducted studies of cholera outbreaks
What is meant by a sporadic dx?
dx that occurs infrequently & irregularly
What is meant by an endemic dx?
- Constant &/or usual presence of dx (or infectious agent) in a population within a geographic area
- Amount of dx that is usually present in a community
What is the difference b/w an outbreak & epidemic?
Epidemic = increase, often sudden Outbreak = same definition as epidemic but often used for more limited g
Descriptive epidemiology
Describes the cases of a dx (When do they appear? What ages? Group-defining characteristic?)
Analytic epidemiology
Looks for a certain etiology
Systematic comparison of gp of dx cases to healthy ppl
Descriptive epidemiology uses a system similar to the 5Ws in a newspaper report, what are the synonyms?
- Case definition
- Person
- Place
- Time
- Causes/ risk factors/ modes of transmission
What are the 2 key features of a cross-sectional study?
- Take a snapshot of a population at a single pt in time
- Measure dx prevalence in relation to the exposure prevalence
What are the 2 key features of an ecological study?
- Population is the unit of analysis
- An exposure status that is the property of the population
-ves & +ves of ecological studies
- ves:
- Lack of individual level info
- Link seen b/w variables on an aggregate level doesn’t necessarily mirror link at individual level (ecological fallacy or bias)
- Can’t detect complicated relationships
+ves:
- Quick & inexpensive → bc often rely on pre-existing data
- Analysis & presentation are simple + easy to understand
-ves & +ves of cross-sectional studies
Advantages
- Generalizability
- Low cost
Limitations
- Can’t infer temporal sequence b/w exposure & dx
- Identify a high proportion of prevalent cases of long duration
Uses of cross-sectional studies
Public health planning
Etiologic research
