Epi 505 – ActivEpi Lesson 2 Outline


How to Obtain Data

·      Interview (Face to face, telephone, mail, e-mail, …)

·      Review existing records (medical records, work records, …)

·      Laboratory

·      Examination (physical, CAT scan, ultrasonography …)


Select Appropriate Study Design (Lesson 3)

·      Clinical Trial

·      Cohort

·      Case-Control

·      Cross-Sectional

·      Other


In class example: relationship between

Diet -> Breast cancer





Physical activity


Measuring the Variables - Decisions needed on exact definitions.  For example

·      Illness in Sydney beach study – self report vs. physician dx?

·      Define “swimming”

·      Define “water quality”


Measures of Disease Frequency (Lesson 4)



Risk of disease in exposed: R(E)

Risk of disease in nonexposed: R(not E)

Risk Ratio

Consider potential biases/flaws (Lessons 7-11):

·      Study design

·      Selection of participants (selection bias)

·      Information collected from/on participants (information bias)

·      Confounding


Methods of data analysis


Biases and flaws may lead to incorrect conclusions



Yes-P = swam in polluted water

Yes-NP = swan in non-polluted water

No = did not swim

Test for trend (Lesson 14)


Examples of Epidemiologic Studies


Alcohol consumption and breast cancer in the Nurses Health Study

Example of cohort study

       Identify group of disease-free subjects

       Collect exposure information

       Follow over time

Results: alcohol associated with breast cancer with dose response effect


Bogalusa Outbreak

Legionnaires disease in Bogalusa

Example of case-control study

Result: associated with misting machine for vegetables at a grocery store


The Rotterdam Study of Alzheimer’s Disease

Cohort study of 8000 elderly

Assessed relation of smoking to Alzheimer’s accounting for age, gender, education, and alcohol consumption.

Result: smoking associated with increased risk of Alzheimer’s