Exam 2: Cross-sectional Studies

Question 1

Describe cross sectional (prevalence) studies

Answer 1

A selected group within the population is sampled once and exposure(s) and disease(s) are simultaneously measured
—disease has already been diagnosed and subjects are living with disease (prevalence)
—disease needs to be those with a significant duration. Disease of short duration will be few
Animals not followed in time to establish disease incidence

Question 2

What are the advantages to cross sectional studies?

Answer 2

Short, fast, inexpensive
Can gather prevalence data on several diseases and exposures
—measure of association: prevalence odds ratio
Provides preliminary evidence for further study

Question 3

What is assessed in cross-sectional studies?

Answer 3

Strength of association of risk factor and outcome
—Temporal relationship is difficult to establish
Absolute risks in the population

Question 4

Look at examples

Answer 4

Look at examples