Public Health & Epidemiology

Front 1

Randomized Control Trials, Cohort Studies and Case-Control Studies

Back 1

Analytic Studies

Front 2

Cross-Sectional Studies, Ecologic Studies, Case Series and Case Reports

Back 2

Descriptive Studies

Front 3

Disease is uncommon?

Back 3

Use case reports

Front 4

Disease is likely caused by one exposure?

Back 4

Use case reports

Front 5

The key outcome ofinterest can be measured better at a region or country level?

Back 5

Use Ecological studies

Front 6

A study to look at geographic correlations?

Back 6

Use Ecological Studies

Front 7

data collection may vary significantly between populationsor countries, making it uncertain whether comparisons are valid - which type of bias?

Back 7

Information/ measurement bias

Front 8

Studies that are of use in assessing the impact of vaccinationprograms & screening programs??

Back 8

Secular (time-trend) studies

Front 9

A study that examines the relationship between diseases & other variables of interest at one particular time

Back 9

Cross-sectional studies

Front 10

A study where it is difficult to establish whether the temporal sequence is fromthat of exposure to outcome or vice versa

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Cross-sectional studies

Front 11

A type of observational study that comparesthe frequency of exposure to a potential risk factor among peoplewith the disease with that in a comparable group without thedisease

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Case-control

Front 12

Important issues in case definition

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1) Case definition restrictions

2) Selection of prevalent cases vs incident cases

3) Selective survival

Front 13

What does the validity of case-control studies depend upon?

Back 13

the comparabilityof cases & controls

Front 14

What are the three basic principles of comparability which underlie attempts to minimizebias & confounding in selection of cases & controls?

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1- Study base

2- Deconfounding

3- Comparable Accuracy

Front 15

Methods of control selection

Back 15

Disease-based

Population-based

Front 16

Types of matching in case-control studies

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Individual matching

Frequency matching

Front 17

Number of controls should be less than ______controls per case, why?

Back 17

5 controls per case, because there is no further gain of power above four controls per case

Front 18

Potential problems in matching

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1) the more factors one attempts to match on, the more difficult itis to find a suitable control subject

2) Overmatching

Front 19

Matching for an apparent confounder that actually is a result of the exposure.

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Overmatching

Front 20

Potential biases in case-control studies

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Recall bias

Selection bias

Recording bias

Response bias

Interviewer bias

Front 21

Which study is usually quick & therefore cheap tocarryout?

Back 21

Case-control

Front 22

Which study can explore a range of potential causes in a single study?

Back 22

Case-control

Front 23

Which study may be the only way of exploring causal hypotheses in rare diseases?

Back 23

Case-control

Front 24

Which study cannot assess associations between matching variables & theoutcome?

Back 24

Case-control

Front 25

How do we select cohorts for common exposures?

Back 25

from specialist groups

Front 26

How do we select cohorts for rare exposures?

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from occupationalgroups & their medical records

Front 27

three basic types of comparison cohort

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1. The general population

2. Another occupational group

3. A sub‐group of the original assumed "exposed“ cohort: those subjectsreporting no exposure form the unexposed cohort against which theremaining exposed individuals are compared

Front 28

In which study can the temporal relationship between exposure and disease can beestablished?

Back 28

Cohort studies

Front 29

In which study can important measures such as Attribuable Risk & Population Attribuable Risk be estimated ?

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Cohort studies

Front 30

Which study can examine relationship between more than on disease related to a single exposure?

Back 30

Cohort studies

Front 31

Which study is useful when exposure is rare ?

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Cohort studies

Front 32

Which study has minimal selection & recall bias?

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Cohort studies

Front 33

Prospective cohort studies are expensive & difficult to managebecause the involve following large numbers of people for many years

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disadvantages of cohort studies

Front 34

Not very useful to study very rare diseases because very few exposedindividuals will develop the disease

Back 34

disadvantages of cohort studies

Front 35

Losses to follow‐up

Back 35

disadvantages of cohort studies

Front 36

Often requires large sample

Back 36

disadvantages of cohort studies

Front 37

Long time to complete

Back 37

disadvantages of cohort studies

Front 38

Exposure status can change with long follow up

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disadvantages of cohort studies

Front 39

What expresses the frequency at which a disease occurs in a population in a specified period of time?

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Disease rate

Front 40

The proportion (or %) of people with thedisease at a particular point in time??

Back 40

Prevalence

Front 41

the portion of the incidence ofa given disease in the exposed that is due to theexposure

Back 41

attributable risk

Front 42

the percentage of theincidence rate of a given disease in theexposed group that is due (attributable) toexposure

Back 42

attributable risk percent

Front 43

the portion of theincidence rate of a given disease in thepopulation (both exposed and non‐exposedgroups) that is attributable to the exposure

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population attributable risk

Front 44

the incidence rate ofa disease in the population that could beeliminated if the exposure were eliminated

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population attributable risk

Front 45

the incidence of adisease in the exposed group that would beeliminated if exposure was eliminated

Back 45

attributable risk

Front 46

the percentage of theincidence rate of a given disease in thepopulation (both exposed & non‐exposed)that is attributable to exposure

Back 46

population attributable risk percent

Front 47

the percentage of the incidence of adisease in the population that could beeliminated if exposure were eliminated

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population attributable risk percent

Front 48

howrepresentative the sample is of thepopulation means

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validity

Front 49

theability of the measure to produce thesame results under the same conditions means

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reliability

Front 50

Which bias occurs when a researcher measuring the outcome has knowledge of the subject’sexposure to a risk factor or intervention, and this knowledge affects how they assessoutcomes?

Back 50

Observer bias

Front 51

The impact of chance on the results of a study are usually expressed as _______

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P values & confidence intervals

Front 52

an event, condition, characteristic, orcombination of these factors which plays an important role inproducing the disease

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a cause

Front 53

Factors in causation that that facilitate themanifestation of disease, disability, ill‐health, or the use of services

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Enabling factors

Front 54

Factors in causation that are associated with thedefinitive onset of a disease; e.g. pollens in asthmatic attack

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Precipitating factors

Front 55

Factors which aggravates an alreadyestablished disease or state. e.g. repeated exposure to a toxic agent

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Reinforcing factors

Front 56

the process of determiningwhether observed associations are likely to be causal

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causal inference