Instructor Resource Chapter 1 Copyright © Scott B. Patten, Permission granted for classroom use with Epidemiology for Canadian Students: Principles, Methods & Critical Appraisal (Edmonton: Brush Education Inc.

Chapter 1. What is epidemiology?

Objectives Define epidemiology and key epidemiological terms. Identify the historical roots of epidemiological reasoning. Describe the importance of epidemiology to health research professionals.

Definitions Epidemiology is the study of the distribution and determinants of disease in populations. Distribution is the focus of descriptive epidemiology—essential for developing hypotheses about their etiology and for planning health services. Determinants are the focus of analytical epidemiology. A determinant influences the distribution of a disease in a population.

Disease Disease can refer to a conventional disease (e.g., pneumococcal pneumonia or cystic fibrosis). It can also be “shorthand” for any kind of health problem (e.g., obesity).

Populations Populations can be geographically or politically defined, but don’t need to be. For example, populations can be defined as: recreational skiers women children with disabilities enrolled in a particular school system

Exposures Exposure refers to the potential health effect of a determinant or potential determinant. For example: cigarette smoke radiation stress

John Snow

A basic paradigm 2 x 2 Contingency table Has diseaseNo diseaseRow totals Exposed ABN exposed Not exposedCDN not exposed Column totalsN disease N no disease

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