Epidemiology
Definition: Epidemiology is the study of the distribution and determinants of disease frequency in human populations (Epidemiology: Principles and Methods - MacMahon & Pugh).
In the field of epidemiology, two assumptions are made:
- Human disease does not occur at random.
- Human disease has causal and preventive factors that can be identified through systematic investigation of different populations or subgroups within a population in different places or at different periods of time.
(Epidemiology in Medicine - Hennekens & Buring)
Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations, and it serves as the foundation and logic of interventions made in the interest of public health and preventive medicine. It is considered a cornerstone methodology of public health research and is highly regarded in evidence-based medicine for identifying risk factors for disease and determining optimal treatment approaches.
Epidemiologists work on issues ranging from the practical (outbreak investigation, environmental exposure, and health promotion) to the theoretical (development of statistical, mathematical, philosophical, and biological theory). Epidemiologists employ a range of study designs from observational to experimental with the purpose of revealing unbiased relationships between exposures (nutrition, biological agents, stress, or chemicals) to outcomes (disease, wellness, and health indicators).
Epidemiologic studies are generally categorized as descriptive, analytic (aiming to examine associations and commonly hypothesized causal relationships), and experimental (a term often equated with clinical or community trials of treatments and other interventions).
The term 'epidemiologic triangle' is used to describe the intersection of Host, Agent, and Environment in analyzing an outbreak.
