Lecture 1 (Intro) Flashcards
Epidemiology
- Study of distribution and determinants of health states and events in specific pops
- Application to control of problems
Ojectives of epi
- Describe extent
- ID risk factors, etiology
- Evaluate measures/health care
- Provide foundation for policy
Primary prevention
- Prevent smtg f/occurring in 1st place
- Ex: sunscreen to prevent skin cancer
Secondary prevention
- ID and treatment of ppl who have already developed a disease/precursors (early enough that intervention will still be effective)
- Ex: screening for cancer
2 main types of epi studies
1) Experimental: conditions controlled by investigator, assigns subjects to treatment/control grp, effect determined by comparing outcomes
2) Observational: investigator doesn’t control, rather observes nature taking its course (can be descriptive or analytic)
2 main types of observational studies
1) Descriptive: aims to describe distribution of disease/health-related variables using routinely collected data (hyp generation, not testing)
2) Analytic: observes relationship btwn exposure and a disease (tests hyps, suggests causation/preventative methods)
3 eras of epi
1) Sanitary (1800-1875): miasma, clustering, etc.
2) ID Era (1875-1950): germ theory, role of host/enviro, occupation exposures
3) Chronic Disease (1950+): ID under control, multifactorial causation/risk factors
Black box approach to epi
-Emphasis on risk factor ID, 2ndary concern re: mechanisms
England Cholera (1854)
Miasma theory: soil at low elevations –> miasmata mist
Snow’s Germ Theory of Cholera
- Caused by un-ID’d germ
- Contamination by water, food, bedding, clothing
- Prior obvs: follow trade routes, sick –> healthy but treaters don’t always get it (therefore not airborne)
Cholera diffs by water supply company
- S + V: high DR (8.5x risk), Lambeth: very low DR
- Natural experiment (cohort study)
