Module 1

Question 1

what does GATE stand for

Answer 1

Graphic Approach to epidemiology

Question 2

PECOT

Answer 2

P - population of participants
E - exposure groups
C - comparison group
O - outcomes
T - time

Question 3

CGO

Answer 3

Comparison group occurrence B/CG/t

Question 4

EGO

Answer 4

exposure group occurrence A/EG/t

Question 5

Features of a Cohort study

Answer 5

• long-term follow-up
• allocation by observation
• time going down
• common confounding
• can measure incidents and prevalence

Question 6

Incidence

Answer 6

Measure of the onset of a disease. e.g deaths, may be hard to measure

Question 7

Prevalence

Answer 7

measure how much disease is in the population

Question 8

What is an issue with measuring prevalence

Answer 8

That prevalence is a dirty measure as it has the cure and death rate involved with the calculation. not good for temporary events e.g asthma attack

Question 9

What is one way to measure prevalence

Answer 9

Go back in time e.g during the past year have you xyz

Question 9

RCT

Answer 9

Randomized control trial - best if ethical and practical

Question 10

Why cannot do an RCT

Answer 10

if the intervention may be harmful, we cannot get people to do it as it may compromise health. only if the potential benefit to health.

Question 10

How is an RCT conducted

Answer 10

By random allocation of individuals or groups

Question 10

What is ethical around harmful exposures

Answer 10

It is not ethical to intervene but it is ethical to observe

Question 11

Why are long term RCT hard to do

Answer 11

Many people do not remain in their groups long-term
Ethical errors
often hard to recruit pop that are representative

Question 12

RD

Answer 12

EGO - CGO
It is the absolute difference
Has units

Question 13

RR

Answer 13

EGO/CGO
No units
Relative difference

Question 14

No Effect line RD

Answer 14

0

Question 15

No Effect line RR

Answer 15

1

Question 16

RRI

Answer 16

relative risk increase
If RR is over 1 can go RR/1 to get percentage increase

Question 17

RRD

Answer 17

If RR less than 1. Can go 1-RR/1 to get percentage decrease

Question 18

Maintenance Error

Answer 18

Loss to follow up
Did they change groups

Question 19

Blind or Objective measures

Answer 19

Subjective vs Objective
Double Blind
How were outcomes measured

Question 20

Ecological studies

Answer 20

Allocation of populations to EG or CG
very common confounding
cheap to do
can be cross sect, cohort or RCT

Question 21

Cross Sectional

Answer 21

Measure done at one point in time
reverse causality
Cheaper
Measuring prevalence

Question 22

Meta Analysis

Answer 22

Can combine multiple studies to one large study. increases sample size and decreases the random error

Question 23

narrow definition of health

Answer 23

the absence of death, disease or disability

Question 24

broad definition of health

Answer 24

the capacity to do what matters most to you

Question 25

study validity

Answer 25

a study with only a small amount of random or non-random error is considered to be a valid study

Question 26

recruitment error

Answer 26

are the participants a representative sample from a known population?

Question 27

layers of the triangle

Answer 27

setting, eligible population, actual participants

Question 28

confounding

Answer 28

when the exposure is mixed with another factor that is also associated with the outcome

Question 29

stratified analysis

Answer 29

dividing the study into sub-studies (strata) so participants with the confounder are all in one sub-study

Question 30

regression to the mean

Answer 30

repeating measurements or studies with extreme results multiple times usually gives less extreme results

Question 31

random sampling errors

Answer 31

the smaller the sample, the greater the chance the sample will be different from the whole population

Question 32

95% CI

Answer 32

there is about a 95% chance that the true value in a population lies within the 95% confidence interval

Question 33

bradford hill criteria: [7]

Answer 33

• temporality
• strength of association
• reversibility
• biological gradient (dose-response)
• biological plausibility
• consistency of association
• specificity

Question 34

temporality (BH)

Answer 34

• first the cause then the disease
• essential to establish a causal relation

Question 35

strength of association (BH)

Answer 35

the stronger the association, the more likely to be causal in absence of known biases

Question 36

reversibility (BH)

Answer 36

the demonstration that under controlled conditions, a change in exposure results in a change in the outcome

Question 37

biological gradient (BH)

Answer 37

incremental change in disease rates in conjunction with corresponding changes in exposure

Question 38

biological plausibility of association (BH)

Answer 38

does the association make sense biologically?

Question 39

consistency of association (BH)

Answer 39

replication of the findings by different investigators, at different times, in different places, with different methods

Question 40

specificity of association

Answer 40

a cause leads to a single effect and an effect has a single cause

Question 41

the epidemiological triad

Answer 41

host, environment and agent

Question 42

a cause of a disease

Answer 42

an event, condition, characteristic (or combination of these factors) which play an essential role in producing the disease

Question 43

sufficient cause

Answer 43

the whole pie

a minimum set of conditions - without any one component disease would not occur

Question 44

component cause

Answer 44

each factor/slice is a component cause

Question 45

necessary cause

Answer 45

a factor (or component cause) that must be present for a specific dis-ease to occur

Question 46

problems with the causal pie model

Answer 46

assumes all causes are deterministic and fails to capture dose-response relations as a continuum