A county health department is evaluating several distinct epidemiological reports to synthesize data for an upcoming public health initiative. For each described study methodology or data calculation, select the appropriate epidemiological measure of disease frequency or association being utilized.
- Investigators analyzing an outbreak of Guillain-Barré syndrome compare affected patients with unaffected neighbors, calculating the ratio of the odds of recent gastrointestinal illness in both groups.Odds ratio
- During a 10-year longitudinal study, the incidence rate of newly diagnosed melanoma in a cohort with severe sunburn history is divided by the incidence rate in a cohort with no severe sunburn history.Relative risk
- A randomized controlled trial finds that a novel statin decreases the incidence of myocardial infarction by 0.04 compared to placebo; researchers calculate to evaluate the drug's clinical impact.Number needed to treat
- To determine the exact excess disease burden of air pollution, analysts subtract the incidence of asthma exacerbations in a clean-air county from the incidence in a heavily industrialized county.Attributable risk
Answer
The scenarios match their respective metrics as follows: The Guillain-Barré outbreak case-control study corresponds to Odds ratio; The melanoma longitudinal study corresponds to Relative risk; The statin trial calculation () corresponds to Number needed to treat; The air pollution analysis corresponds to Attributable risk.
Each epidemiological measure accurately matches a specific study design and mathematical calculation. The odds ratio is used for case-control studies where incidence is unknown. Relative risk is the ratio of incidence rates in cohort studies. Number needed to treat is the inverse of the absolute risk reduction. Attributable risk is the arithmetic difference between exposed and unexposed incidence rates.
Step-by-Step Solution
Key Concept
Different study designs and clinical questions require specific epidemiological measures: case-control studies use odds ratios, cohort studies use relative risks, excess burden is measured by attributable risk, and clinical impact by number needed to treat.