Population Health and Epidemiology Flashcards

A researcher finds an odds ratio of 2.5 (95% CI: 0.9–6.8) for the association between a dietary factor and colon cancer. What is the correct interpretation?

Answer: The result is not statistically significant at the 0.05 level

Because the 95% CI crosses 1.0, the result is not statistically significant at α = 0.05.

Which epidemiological study design provides the strongest evidence for causality?

Answer: Randomized controlled trial

Randomized controlled trials minimize confounding through randomization, providing the strongest causal evidence.

In Bradford Hill's criteria, which criterion addresses the plausibility of the cause-effect relationship based on current biological knowledge?

Answer: Biological plausibility

Biological plausibility requires that the association makes sense given existing biological and medical knowledge.

A screening test for colorectal cancer is applied to 10,000 people; 200 test positive, 50 have true disease (all test positive), and 150 are false positives. What is the specificity?

Answer: 98.4%

Specificity = TN / (TN + FP) = 9,800 / (9,800 + 150) = 9,800/9,950 ≈ 98.5%.

Which of the following best describes a systematic review?

Answer: A comprehensive synthesis of all relevant studies on a topic using explicit methods

Systematic reviews use pre-specified, reproducible search and selection criteria to synthesize evidence from multiple studies.

What does the number needed to harm (NNH) represent?

Answer: The number of patients who must be treated for one additional patient to experience harm

NNH = 1 / absolute risk increase; it quantifies how many patients need treatment before one additional harmful event occurs.

Which of the following is the primary goal of primary prevention?

Answer: Preventing the occurrence of disease in healthy individuals

Primary prevention targets risk factor reduction to prevent disease from ever occurring in at-risk populations.