One Case, Case Series, Cross-sectional Sudies

Question 1

One case / case report

Answer 1

Regards an individual patient

Question 2

Case series

Answer 2

If you study several people with the same observation treatment…

Question 3

Cross-sectional study estimates and investigates

Answer 3

Estimate the prevalence

Investigate associations between risk factors and the outcome of interest - calculating the odds ratio

Question 4

Problem with cross-sectional studies

Answer 4

Time problem: we don’t know if they had the outcome before the exposure

Question 5

How to solve the problem the problem of the time in cross-sectional studies

Answer 5

To make sure everyone is healthy at the beginning

The results would be incidence and we would have a relative risk

This is no longer descriptive

Question 6

Reverse causality

Answer 6

Phenomenon that describes association between 2 variables different than what you would expect (obesity - sedentarism)

Question 7

Advantages cross-sectional studies

Answer 7

Simple
Economical

Question 8

Disadvantages cross-sectional studies

Answer 8

Only useful to think of, hypothesis, no analysis/conclusions

Problem with time sequence - there could be an inversion with time sequence

Question 9

In which cases would cross-sectional studies be better/less bad?

Answer 9

Variables that don’t change and are present before the outcome
- Ethnic group, blood type, genetic polymorphisms
- Specific environmental factors

Public health studies
Making hypothesis