What is Epidemiology?

Epidemiology is the method used to find the causes of health outcomes and diseases in populations. In epidemiology, the patient is the community and individuals are viewed collectively. By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global). It is also the application of this study to the control of health problems (Source: Principles of Epidemiology, 3rd Edition).

What public health problems or events are investigated?
Environmental exposures
  • Lead and heavy metals
  • Air pollutants and other asthma triggers
Infectious diseases
  • Foodborne illness
  • Influenza and pneumonia
  • Increased homicides in a community
  • National surge in domestic violence
Non-infectious diseases
  • Localized or widespread rise in a particular type of cancer
  • Increase in a major birth defect
Natural disasters
  • Hurricanes Katrina and Rita (2005)
  • Haiti earthquake (2010)
  • World Trade Center (2001)
  • Anthrax release (2001)