Instructor Resource

Chapter 1

Copyright © Scott B. Patten, 2015.

Permission granted for classroom use with Epidemiology for Canadian Students: Principles, Methods & Critical Appraisal (Edmonton: Brush Education Inc. www.brusheducation.ca).

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

http://commons.wikimedia.org/wiki/File:John_Snow.jpg

A basic paradigm

2 x 2 Contingency table   Has disease No disease Row totals

Exposed A B Nexposed

Not exposed C D Nnot exposed

Column totals Ndisease Nno disease

End