Confounding is a particular challenge in nutritional epidemiology because

Correct Answer: D

Rationale: Confounding occurs when a third factor affects exposure and outcome. In nutritional epidemiology, dietary components (e.g., fat and calories) are correlated (D), complicating isolation of effects (e.g., does fat or total energy increase heart disease risk?). A and B are measurement issues, not confounding. C is false; methods like multivariable adjustment exist.

Correct Answer: A

Rationale: An epidemic curve (A) plots cases over time to show outbreak patterns (e.g., point source). B, C, and D are unrelated.

Correct Answer: B

Rationale: Confounding (B) distorts exposure-outcome links via a third variable (e.g., age in smoking-lung cancer). A is causation, C is effect, D is unrelated.

Correct Answer: C

Rationale: Recall bias (C) is common in retrospective studies (e.g., case-control) as memory distorts past exposures. A, B, and D occur but aren’t specific.

Correct Answer: C

Rationale: Cohort studies (C) suit rare exposures (e.g., radiation) by following exposed groups. A and B focus on outcomes, D is impractical for rare exposures.