What are the chances of that happening 2

Question 1

What is an outcome?

Answer 1

Disease

Question 2

What is an outcome?

Answer 2

Disease

Question 3

What is bias?

Answer 3

Systematic error that distorts results and leads to wrong conclusions. It exists in all studies at any phase of research.

Question 4

What is cross sectional studies?

Answer 4

Descriptive study that measures of prevalence of health characteristics of a population a given time which assesses the burden of disease or health needs of a population.

Question 5

Why are cross sectional studies important?

Answer 5

Informing how to plan and allocate health resources

Question 6

What kind of study is a cross sectional study?

Answer 6

Both descriptive and analytical to identify correlations between exposure and outcomes.

Question 7

How are cross sectional studies conducted?

Answer 7

Surveys in order to collect data about prevalence.

Question 8

What are the benefits of cross sectional studies?

Answer 8

Cheap and easy to conduct. It is ethically safe and can measure prevalence for all factors under investigation. It is good for generating hypotheses and descriptive analysis. Data on variables

Question 9

What are the weaknesses of cross sectional studies?

Answer 9

It measures correlation but it is difficult to determine cause-effect relationships. Cannot estimate incidence and susceptible to bias due to recall and selection bias. It is not suitable to study rare diseases with a short duration.

Question 10

What is selection bias?

Answer 10

Participants are systematically different in their characteristics compared with eligible non-participants

Question 11

What is analytic epidemiology?

Answer 11

Quantifies the association between exposures and outcomes to test hypotheses about casual relationship.

Question 12

What are observational studies?

Answer 12

No intervention by investigator. It is an analysis of spontaneously occurring events It is used to explore aetiology (cause)

Question 13

What are the types of Observational studies?

Answer 13

Cohort and case-control.

Question 14

What is a cohort study?

Answer 14

Compare the outcomes of health following exposure with a control group. This allows for direct calculation of incidence, using relative risk.

Question 15

What is a cohort study most beneficial for?

Answer 15

Diseases with a long development time.

Question 16

What is case-control?

Answer 16

Compare the exposures once deciding on an outcome.

Question 17

How are cohort diseases framed?

Answer 17

Formulated using a question which covers population (such as children), exposure (such as a disease) and outcome (such as mortality.)

Question 18

What are the benefits of cohort studies?

Answer 18

Natural history and incidence of disease, especially the rare exposures. It is good for investigating diseases with a long development time and we can calculate incidence, relative risk and confidence intervals with this study. It reduces survivor bias. Minimal recall bias.

Question 19

What is attrition bias?

Answer 19

Systematic difference between people who leave the study and those who continue.

Question 20

What is the weaknesses of cohort study?

Answer 20

Costly and time-consuming due to long-follow up periods which can lead to attrition bias. It is susceptible to selection bias.

Question 21

What are case-control studies?

Answer 21

Determine association between an outcome and exposure. It is an observational study where groups are defined by outcome and it is retrospective.

Question 22

How are case-control studies formulated?

Answer 22

Questions have a framework of population, exposure, comparison and outcome.

Question 23

What are the strengths of case control studies?

Answer 23

Efficient in time and money and effective in long term study of diseases, especially rare diseases. Allows us to calculate useful estimates and study multiple risk factors at once.

Question 24

What are the weaknesses of case control studies?

Answer 24

Difficult to choose an appropriate control group and can become inefficient if frequency of exposure is low.

Question 25

What is experimental epidemiology?

Answer 25

Exposure and intervention to establish effectiveness and confirm hypotheses about causal relationships

Question 26

What type of study is a randomised control trial?

Answer 26

Experimental epidemiology

Question 27

What is a RCT?

Answer 27

Clinical trial to compare outcomes after participants receive an intervention. Best evidence and every participant has an equal chance of being selected.

Question 28

How is an RCT formulated?

Answer 28

Questions with population, intervention, comparator and outcome. Eg. In comparison to usual care, is prenatal counselling effective in reducing pre-eclampsiain women diagnosed with Lupus?

Question 29

What are the benefits of RCTs?

Answer 29

Establish causation, minimises bias, publishable and comparative.

Question 30

What are the weaknesses of RCT?

Answer 30

Expensive, logistically challenging. Results may not reflect reality. It has ethical limitations where informed consent does not occur, and the context of randomised patients with different backgrounds and support.

Question 31

How to mitigate bias?

Answer 31

Use pre-existing records, not select people based on outcome, consistently account for the study population, and using double blind or allocation concealment. To mitigate attrition bias using appropriate analyses such as intention