Cross Sectional Studies

Question 1

Cross sectional studies are also called _____

Answer 1

Prevalence studies

• selected group within the population is sampled once and exposures and diseases are simultaneously measured
• disease has already been diagnosed and subjects are living with disease
• diseases need to have a significant duration

Question 2

Unlike prevalence studies ______

Answer 2

Animals are not followed in time to establish disease incidence

Question 3

Advantages of cross sectional studies

Answer 3

• short, fast, inexpensive (one time data gathering)
• can gather prevalence data on several diseases and exposures
• provides preliminary evidence for further study

Question 4

Since you are measuring prevalence of disease, you need to select for animals that have ______

Answer 4

Survived acute effects, or have a less progressive presentation

• survival bias
• P=ID, so things that affect duration can influence prevalence

Question 5

What is the measure of association?

Answer 5

Prevalence ratio
- is analogous to relative risk
- prevalence of disease in exposed is ____ times the prevalence of disease in unexposed
Prevalence odds ratio
- odds of prevalence exposure in cases is ____ that of non-cases

Question 6

Would you use a cross sectional study for a disease with extremely short duration or high fatality?

Answer 6

No!