Field EpidemiologyFall 2000

Patty Kissinger, PhD

John L. Clayton, MPH

Megan O’Brien, MPH

Field Epidemiology

• To provide students with data collection, data management, analytic, writing, and presentation skills

• Each student conducts an epidemiologic study using either existing data sources or they collect their own data

• The course has an in-class data management and analysis component in addition to field work

• A culminating capstone experience

Field Epidemiology (3 credits)

• First and Second Semester, Periods I and II

• Pre-requisites: EPID 601 or 603, BIOS 603, BIOS 620, and BIOS 623, 624, or 625

• Recommended EPID 712, EPID 624, BIOS 706, BIOS 715

• Recommented Text: Methods in Observational Epidemiology Kelsey JL, Thompson WD, Evans AS.

Field Epidemiology

• Discuss the role of an epidemiologist

• Discuss criteria for causality

• Describe the basic study designs

• Review possible projects

• Assign preceptors

• Discuss class logistics

Role of an Epidemiologist

• Surveillance

• Outbreak investigation

• Hypothesis testing or strength of association

• Evaluation

• Prediction of disease occurrence

• Communication

A Team Approach to Research and Evaluation

• Research team

• Epidemiologist

• Behavioralist

• Biostatistician

• Program manager

• Clinicians

• Consumers

Criteria for Causality (Hill, 1971)

• Strength of association

• Dose-response relationship

• Lack of temporal ambiguity

• Consistency of findings

• Biological plausibility

• Coherence of evidence

• Specificity of the association

Study Designs

• Descriptive• Analytic• Experimental• Correlation• Case report/case series• Cross-sectional• Cohort/Case-Control• Community trial

Study Designs

Descriptive Analytic Experimental

correlational

case report/case series

cross-sectional

case control

cohort

clinical trial

community trial

Cross-sectional

• Classification of exposure and disease at the same time– Descriptive in nature– Hypothesis generation– Cannot determine causality– Fast and generally inexpensive

Analytic Studies

• Case-Control

• Cohort (follow-up)

• Quasi-experimental

Case-Control

• Subjects are chosen on the basis of whether they do (case) or do not (control) have the disease of interest

• Particularly useful for diseases with low prevalence, or long latency

• Efficient in time and cost• Can evaluate a wide range of etiologic factors• Susceptible to selection bias, recall bias

Case-Control cont’d

• Definition and selection of cases

• Selection of controls

Case Control

• Classify by disease status

Exposed

UnexposedDisease

No Disease

Unexposed

Exposed

Cohort

• Classify by exposure status

Exposed

Unexposed

Disease

No Disease

Disease

No Disease

Experimental Studies (clinical trials)

• Investigator allocates the exposure

Exposed

Unexposed

Disease

No Disease

Disease

No Disease

Potential Subjects

Randomization

Confounding

• Exposure / Disease relationship

• Confounder – related to both the exposure and the disease

Validity and Generalizability

• Total population

• Study sample

Field Epidemiology Home Page

http://www.tulane.edu/~hivstd/epi714/john’s/Master/epi714.htm

Exercises

Assignments

Field Work

Late Policy

Assignments that are received late will lose points. Assignments are due by midnight on the designated due date. Each week the assignment is late, the student will lose one letter grade (e.g. 10 points on a 100 point scale). For example, if the assignment is 1-7 days late, one letter grade will be lost, if the assignment is 8-14 days late, two letter grades will be lost, etc. After 4 weeks, no credit will be given for the assignment. In order to not lose points for late assignments, students must contact Dr. Kissinger prior to the due date, and the she will use her discretion in grading that assignment.

HOP Clinic Requirements

• Wear your student ID

• Dress appropriately (no hats, jeans, shorts)

• Be on time

• Respect the clinic staff

• Respect patients

• Maintain confidentiality / sign form

• All analyses must occur at HOP