6 - Epidemiology IV

Question 1

Define a risk factor.

Answer 1

Environmental, behavioural or biological factor confirmed by temporal sequence, usually increasing probability of a disease occurring. If removed, the probability reduces.

Question 2

What is the concept of cause?

Answer 2

• few diseases have a single cause
• most disease results from exposure of susceptible individuals to more than one casual agent
• however, exposure to causal agents does not necessarily result in disease

Question 3

What are confounding variables?

Answer 3

Association between groups of people that have certain characteristics and a higher probability of getting a disease

Question 4

Describe descriptive epidemiology.

Answer 4

• patterns and trends not causes
• hypothesis generating
• ecological fallacy (place effects vs people effects)

Question 5

What are the common indices of risk?

Answer 5

• absolute
• relative
• attributable

Question 6

Define absolute risk.

Answer 6

• most basic measure
• incidence rate of disease amongst those exposed to agent
• assumes no risk incurred by those not exposed to agent

Question 7

Define attributable risk.

Answer 7

• difference between incidence rates of those exposed to risk versus those not exposed
• represents risk attributable to factor

Question 8

Define relative risk.

Answer 8

• ratio of incidence rate of exposed group to non-exposed group
• measurement of proportionate increase in disease rates for exposed group
• makes allowance for those who develop disease without being exposed to agent

Question 9

Describe an observational study.

Answer 9

• search for association between factor and disease
• not experimental, investigation is not designed to expose group to factors, observes who already has been exposed
• observes what is happening normally in population
• tests specific hypothesis

Question 10

What are the different types of observational study?

Answer 10

• cohort
• case-control

Question 11

Describe a cohort study.

Answer 11

• prospective study
• recruit people who do not have disease and assess risk factors
• individuals are observed over period of time to measure frequency of occurrence of disease (exposed vs not)

Question 12

Describe a case-control study.

Answer 12

• retrospective study
• compare cases of disease with those without (controls)
• trace back to assess risk factors
• used as a preliminary investigation as less robust