BHS Epidemiology 2

Question 1

A study follows 500 smokers and 500 non-smokers for 10 years to compare lung cancer rates. What study design is this?

Accepted Answer

Prospective cohort study

Answer

A prospective cohort study follows exposed and unexposed groups forward in time to measure disease incidence.

Question 2

The number of existing cases of a disease in a population at a specific point in time is called:

Accepted Answer

Point prevalence

Answer

Point prevalence measures all existing cases (new and old) at a single point in time.

Question 3

Which measure of association is most commonly reported in a cohort study?

Accepted Answer

Relative risk

Answer

Relative risk (risk ratio) compares incidence rates between exposed and unexposed groups and is directly calculable in cohort studies.

Question 4

Berkson's bias is a type of selection bias that occurs in:

Accepted Answer

Hospital-based case-control studies

Answer

Berkson's bias arises when hospital controls have different exposure rates than the general population, distorting associations.

Question 5

An investigator finds that the association between coffee and pancreatic cancer disappears after adjusting for smoking. This illustrates:

Accepted Answer

Confounding by smoking

Answer

When an apparent association is explained by a third variable related to both exposure and outcome, confounding is present.

BHS - Bachelor of Health Science Practice Test