PHS 2101 Lecture Notes - Lecture 4: Relative Risk, Cohort Study, Odds Ratio
14 May 2019
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Document Summary
Epidemiology: study of the distribution and determinants of disease frequency in human populations. Disease or health outcome must have a clear definition of what is to be counted or studied. Disease frequency: rates: frequency of occurrence in the population, denominator is the population at risk. Incidence rate: rate of new cases appearing in a defined population in a given period of time: prevalence rate: frequency in population at a given time. Epidemic curve: graphs the when of an outbreak, # of cases day by day, legionairre"s disease 1976 outbreak. Study designs: cohort study, exposure > outcome (rate, relative risk i. (frequency of exposure)/(frequency of unexposure) = relative risk, direct ii. If it"s 1. 0, # of exposed and unexposed are the same: they"re looking at the study prospectively, case- control, compare groups with and without disease , what was probability of previous exposure, odds ratio. 3: test effect of intervention: experiment, control vs treated.
