Lecture 5 (19/7/21)

Question 1

Define Incidence

Answer 1

Measure of the number of new cases of diseases in a population, over a specified period of time.

Question 2

Example of Incidence

Answer 2

New cases of heart attacks occurring during the specified time of 5 years in a defined population.

Question 3

Define Prevalence

Answer 3

Measure of the number of current cases (new and preexisting) of diseases in a population, over a specified period of time.

Question 4

Prevalence is a…

Answer 4

Measure of the burden of disease.

Question 5

What is the relationship between Incidence and Prevalence?

Answer 5

As new cases are added, INCIDENCE increases;

These new cases add to PREVALENCE (burden of disease) until the patient is cured or dies.

Question 6

Use rheumatoid arthritis as an example of both Incidence and Prevalence.

Answer 6

Rheumatoid arthritis would have few new cases in a year (LOW INCIDENCE)
BUT
A higher total number of cases (HIGH PREVALENCE), as there will be many more cases diagnosed in previous years.

Question 7

Prevalence of a particular condition varies with what?

Answer 7

Incidence and duration of the condition.

Question 8

Define Morbidity

Answer 8

State of being symptomatic for a disease or condition, in a population during a specified period of time.

Question 9

Define Co-morbidity

Answer 9

The occurrence of 2 or more diseases in one person.

Question 10

Define Mortality

Answer 10

Number of deaths in a population over a specified period of time.

Question 11

What is Ratio?

Answer 11

Comparison of any 2 unrelated values.

Question 12

What are the 2 uses of Ratio? Give examples for each.

Answer 12

Used as:

1. Descriptive measure (e.g. Male: Female ratio)
2. Analytic tool (e.g. Occurrence of illness, injury, or death between 2 groups)

Question 13

What is Proportion?

Answer 13

The comparison of a part to the whole.

• type of ratio that relates a part to the whole

Question 14

Give an example of Proportion.

Answer 14

Fraction of clinic patients tested positive for Chlamydia.

Question 15

Proportion can be expressed as…

Answer 15

Decimal, Fraction, or Percentage.

Question 16

Define Proportionate mortality

Answer 16

Decimal, Fraction or Percentage of deaths in a specified population during a period of time that is due to different causes.

Question 17

The 2 uses of Proportion are:

Answer 17

1. Descriptive measure used in all fields
2. To describe the amount of disease that can be due to a particular exposure; or the amount of the population that tested positive/negative for a disease; etc.

Question 18

Define Rate

Answer 18

Measure of the frequency with which an event occurs in a defined population over a specified period of time.

Question 19

Define Attack rate

Answer 19

Proportion of the at-risk population that develops illness during an outbreak.

Question 20

Define Case-fatality rate

Answer 20

Proportion of persons with the disease who die from it.

Question 21

Define Burden of Disease (BOD)

Answer 21

Impact of an illness or health condition on a community or population.

Question 22

What is the best measure for the Burden of Disease?

Answer 22

Disability Adjusted Life Year (DALY)

Question 23

DALY combines both…

Answer 23

Years of life lost due to premature mortality and years of life lost due to disability.

Question 24

What is the aim of Descriptive Epidemiology?

Answer 24

Describing disease distribution by characteristics relating to TIME, PLACE, and PERSON/PEOPLE.

Question 25

Explain Descriptive Epidemiology

Answer 25

Provides a way of organizing and analyzing data to describe the variations in disease frequency by TIME, PLACE, and PERSON/PEOPLE.

Question 26

The 3 Epidemiologic variables in Descriptive Epidemiology are:

Hint: TPP

Answer 26

Time, Place, and Person

Question 27

The 3 types of descriptive epidemiologic studies are:

Answer 27

1. Individual case reports
2. Case series
3. Cross-sectional studies (e.g. survey of a population)

Question 28

State the synonyms for the 5 W’s Epidemiology.

Answer 28

What = health issue of concern

Who = person

Where = place

When = time

Why/how = causes, risk factors, modes of transmission.

Question 29

Define Analytic Epidemiology

Answer 29

This is concerned with the search for causes and effects, or the why and how.

Question 30

Why do Epidemiologists use Analytic Epidemiology?

Answer 30

To measure the association between a particular exposure and a disease, using information collected from individuals.

Question 31

The key feature of Analytic Epidemiology is ______.

Answer 31

A Comparison group

Group of infected individuals vs Control group - not infected

Question 32

Give 2 differences between Descriptive and Analytic Epidemiology.

Answer 32

1. Descriptive = Generates hypotheses of a disease or outbreak.
   Analytic = Tests hypotheses of a disease or outbreak.
2. Descriptive = Focuses on What, Who, When, and Where disease can occur.
   Analytic = Focuses on Why and How disease occurs.

Question 33

Give an example of Descriptive Epidemiology.

Answer 33

Examining case series by means of person, place, and time of first 100 patients with SARS.

Question 34

Give an example of Analytic Epidemiology.

Answer 34

Measuring risk factors for SARS such as contact with animals and infected people.