Basic Epidemiologic Concepts

• Epidemiology - study of factors that determine the occurrence and distribution of disease in a population
• Epidemiology is a study on:

  • How people get sick and die
  • Who gets sick and dies
  • How to avoid getting sick
  • Who gets the disease and why
• The term "Epidemiology" was derived from:

  • Epi - among
  • Demos - people
  • Logos - study
• Epidemiologists - deal with data from groups of patients or even entire populations
• Epidemiologists study:

  • Both sick and well people
  • Crucial difference
  • Those with the disease
  • Those that are disease-free
• Epidemiology does the following:

  • Weighs and balances
  • Contrasts and compares
  • Use rates
• Epidemiology rates:

  • Events
  • Population at risk
• Events -  number of people to whom something happened
• Population at risk - all the people at risk for the event
• Epidemic - affects a greater than expected number of individuals at the same time
• Endemic - normal occurrence in a population
• Pandemic - geographically widespread; epidemic in >1 continent
• Epidemiologic Triangle - fundamental of studying epidemiology, consists of:

  • Agent
  • Environment
  • Individual as a function of time
• Agent -  infectious vs. noninfectious