Cohort Study and Control Study

Question 1

What are risk factors?

Answer 1

Lifestyle
Physical environment
Social environment
Genetic
Early life
Medical interventions

Question 2

How is a cohort study designed?

Answer 2

Subjects usually free of disease
Groups defined according to risk factors exposure
Followed up over time
Compare incidence of disease in exposed and unexposed

Question 3

How to work out the population attributable risk (par) ?

Answer 3

Par = AR x risk factor prevalence

Question 4

Selection and Information bias?

Answer 4

Selection bias is the bias regarding selection of participants, sampling frame and response rate to follow up
Information bias is error, risk factor measurement and outcome measurement

Question 5

What is confounding?

Answer 5

Variable associated with both exposure and outcome

Causes bias if not recognised

Question 6

What is the purpose of matching?

Answer 6

Makes allowance for confounded more efficient and can reduce bias
It must be allied for in analysis

Question 7

What are the factors that suggest causation?

Answer 7

Strength of association
Dose response relationship
Temporality 
Consistency
Experimental evidence
Plausibility