How is epidemiology best defined?

Epidemiology is best defined as the study of how diseases affect the health and illness of populations. This definition captures the core focus of epidemiology, which is to understand the distribution, patterns, and determinants of health-related states or events in specified populations. By studying these elements, epidemiologists can identify risk factors for disease, outline how diseases spread, and evaluate the effectiveness of public health interventions.

The emphasis on populations distinguishes epidemiology from clinical medicine, which often focuses on individual patients. It seeks to uncover broader trends rather than concentrating solely on individual cases or pharmaceutical effects. The field includes analyzing various factors like environmental, social, and biological dynamics that contribute to health outcomes on a community or population level, thereby enabling effective prevention and control strategies.