Epidemiology Flashcards
•A study of the distribution and determinants of health-related states or events in specified populations and the application of this study to the prevention and control of health problems
Epidemiology
•Concerned not only with death, illness and disability but also with more positive health states and most importantly, with the means to improve health
Epidemiology
•Confidence in the conclusions drawn from the sample depends in part on the sample size
Defined Populatuion
Search for causality
determining natural history
determinig health status of the population
evaluation interventions
- Measures and do not intervene
- DESCRIPTIVE – case report, case series
- ANALYTICAL – correlational, case-control, cohort
Observational
•Randomized controlled trials
•Experimental or Interventional
•people who are susceptible to a given disease and can be define by demographic, geographic or environmental factors
population at risk
represents the rate of occurrence of new cases arising in a given period in a specified population
incidence
•frequency of existing cases in a defined population at a given point in time
prevalence
Expresses the risk of being ill
The main measure of acute disease or conditions, but also used for chronic diseases
More useful for studies of causation
incidence
Estimates the probability of the population being ill at the period of time being studied
Useful in the study of burden of chronic diseases and implication for health services
prevelance
prevelance
•total # of cases at any time during a specified period divided by the number of cases at any time during a specified period, divided by the population at risk midway through the period
period prevalence rate
Incidence
cumulative incidence
•measures the denominator only at the beginning of a study and is often presented as cases per 1000 population
cumulative incidence
•A measure of disease severity and is defined as the proportion of cases with a specified disease or condition who die within a specified time
Case Fatality Rate
•does not take into account that the chance of dying varies according to age, sex, race, socioeconomic class and other factors
crude mortality rate
Age-Specific Death Rate
Proportionate Mortality Rate
•Ratio of the number of deaths from a given cause per 100 or 1000 total deaths in the same period
Proportionate Mortality Rate
Infant Mortality Rate
Maternal Mortality Rate
Varaibles used in interpreteing epidemiologic data?
Person, Place, Time
- Most important factor
- Show greater variation than rates defined by almost any other personal attribute
Age
•a person’s income level, education level, and type of occupation
socioeconomic status
•Gradual changes in the frequency of disease over long periods of time (chronic diseases)
Secular Changes
•Increases and decreases in the frequency of the disease over a period of several years or within a year (many infectious diseases)
Cyclic (Seasonal) Trends
•May indicate the response of a group of people circumscribed in place to a common source of infection, contamination, or other etiologic factor to which they were exposed almost simultaneously
Point Epidemics
•a closely grouped series of events or cases of a disease or other health related phenomena with well-defined distribution patterns in relation to time or place or both
Clustering
