Epidemiology Lecture

Introduction to Risk

• Definition of risk and risky behavior
• Examples of risk in health:
  • Smoking and lung cancer
  • Changing behaviors to reduce heart disease

Measuring Risk

• Contingency Tables: Used to display numbers for computing risk.
• Relative Risk (RR): A measure to compare the risk of an event between two groups.
• Relative Risk Reduction (RRR): The proportional reduction in risk between the control group and the treatment group.
• Absolute Risk Reduction (ARR): The difference in risk between the control group and the treatment group.

Analytical Epidemiology

• Focuses on discovering and describing relationships between risk factors and outcomes.
• Risk Factor: An independent variable that may change the probability of an outcome (e.g., smoking as a risk factor for lung cancer).
• Association vs. Causation:
  • Often, it’s not clear if a risk factor is causal.
  • Best we can often say is that a risk factor is associated with an outcome.
  • Control of outcomes can sometimes be achieved by controlling risk factors.
• Statistical Relationships:
  • Association implies a numerical statistical relationship between exposure and outcome.
  • Example: Statistical relationship between smoking (exposure) and lung cancer (outcome).