Definition and purpose of epidemiology

Summary

Epidemiology is the study and analysis of how health and disease are distributed in a defined population—specifically who is affected, when and where patterns occur, and what factors (determinants) contribute to those patterns. It focuses on understanding the distribution, patterns, and determinants of health and disease conditions, and then applying that knowledge to prevent disease. As a cornerstone of public health, epidemiology supports evidence-based practice and policy by identifying risk factors and helping target preventive healthcare. Epidemiologists contribute by assisting with study design, collecting and analyzing data statistically, and interpreting and disseminating results (including peer review and sometimes systematic review). The field also helps develop research methodology used in clinical research and public health studies. Epidemiology examines major topics such as disease causation and transmission, outbreak investigation, disease surveillance, and comparisons of treatment effects (e.g., in clinical trials), and it draws on other disciplines such as biology, statistics, social sciences, and engineering for exposure assessment.

Key Points

• 1

  Epidemiology studies the distribution (who, when, where) and determinants of health and disease in a population.

• 2

  Its purpose is to apply findings to prevent disease and guide evidence-based public health policy and practice.

• 3

  Epidemiologists use study design, data collection, statistical analysis, and dissemination to investigate disease patterns, causation, and treatment effects.