Lecture 2, part 1

Question 1

What are the objectives of epidemiology?

Answer 1

Determine the extent of dz in a pop
ID patterns and trends in dz occurrence
ID the causes of dz
Evaluate the effectiveness of prevention and tx activities

Question 2

What are the steps in measuring the occurrence of a dz?

Answer 2

Develop a definition of a particular dz
Count the number of people affected by the dz
Determine the size of the pop from which the diseased cases arose
Account for the passage of time

Question 3

What do case definitions allow for?

Answer 3

Standardization across settings

Question 4

On what are case definitions usually based?

Answer 4

A combo of physical and pathological exams, diagnostic test results, and signs and sx

Question 5

Case definitions include what criteria?

Answer 5

Person
Place
Time
Clinical features

Question 6

Definition of person

Answer 6

Key characteristics that cases share in common

Question 7

Exs of person

Answer 7

Age group
Sex
Occupation
Race

Question 8

Definition of place

Answer 8

Specific geographic location or facility

Question 9

Exs of place

Answer 9

Resident of state or county
Nursing home
School

Question 10

Definition of time

Answer 10

Linear period of time associated with illness onset

Question 11

Ex of time

Answer 11

Onset of illness btwn Jan 1 and March 4, 2021

Question 12

Definition of clinical features

Answer 12

Signs and sx or maybe specific laboratory criteria

Question 13

Exs of clinical features

Answer 13

SOB
Cough
Fever

Question 14

What is a conceptual definition?

Answer 14

Theoretical idea of what needs to be measured

Question 15

Aspects of conceptual definitions

Answer 15

Scientifically defines a specific concept
Generally broad or abstract

Question 16

What is an operational definition?

Answer 16

What we are actually measuring

Question 17

Aspects of operational definitions

Answer 17

Redefines the concept in specific measurable terms
How a variable is measured in a given study

Question 18

Characteristics of early case definitions

Answer 18

May be broad (not specific, increased sensitivity)

Question 19

As additional information is gathered, what occurs with case definitions?

Answer 19

They become more focused and specific

Question 20

When will case definitions be more accurate?

Answer 20

When definitions include more specific criteria

Question 21

On what are case definitions dependent?

Answer 21

The resources and data available

Question 22

How can case definitions vary? What are the levels of case definitions?

Answer 22

By level of diagnostic certainty
Confirmed
Probable
Suspect

Question 23

What is the progression of dz?

Answer 23

People are infected
People have sx
They seek care
They could be hospitalized
They could die
These circles get smaller and smaller

Question 24

What are the various methods for counting cases?

Answer 24

OB ixs
Reportable dz registries
Clinic/hospital records, insurance claims
Vital stats records
Surveys/questionnaires

Question 25

What are challenges in case counting?

Answer 25

Clinically diagnosed cases often represent only a fraction of all actual cases
Data sources may be limited

Question 26

What is an ex of case definition changing over time?

Answer 26

HIV
Used to be very limited to unexpected Kaposi’s sarcoma and Pneumocystis carinii pneumonia
Expanded three times more to include antibody testing, CD4 count, and 27 clinical conditions