39. A retrospective cohort study investigating a potential occupational hazard and a rare disease is conducted. What critical challenge often arises in this type of study?
A.
Ease of follow-up.
B.
Difficulty in obtaining reliable historical exposure data.
✓
C.
High cost.
D.
Ethical concerns about randomization.
📖 Additional Information
Ease of follow-up.
Difficulty in obtaining reliable historical exposure data.
