In a cohort study, the risk ratio of developing diabetes was 0.86 when comparing consumers of tea (the exposed) to those who did not drink tea (the unexposed). Which one statement is correct?

Correct Answer: A

Rationale: Risk ratio (RR) = 0.86 means the risk of diabetes in tea drinkers is 86% of that in non-drinkers, indicating a lower risk (A). B is false (RR > 1 would indicate higher risk). C is incorrect; RR alone suggests direction, though significance requires p-value or CI (not given). D is false; RR = 0.86 shows a difference, albeit modest, not 'no difference' (RR = 1).

Correct Answer: C

Rationale: Relative risk (C) is the ratio of disease incidence in exposed vs. unexposed, reflecting risk among exposed. A is total cases, B is new cases, D is excess risk.

Correct Answer: A

Rationale: Incidence rate (A) measures new cases over time. B, C, and D are test performance metrics, not frequency.

Correct Answer: B

Rationale: Cohort studies (B) track groups over time for disease onset (e.g., Framingham). A is case-control, C is cross-sectional, D is RCT.

Correct Answer: C

Rationale: Cohort studies (C) compare exposed vs. unexposed groups for outcomes (e.g., cancer rates). A is snapshot, B is retrospective, D is experimental.