Epidemiology & Prevention USMLE Step 1 Practice Question
A epidemiologic study examining 5,000 patients (mean age 62, 55% male) finds coffee consumption associated with lung cancer (RR 2.1, p<0.05). Chest CT confirms adenocarcinoma in 340 subjects. When data are stratified by smoking status, the association disappears in both smokers and nonsmokers. Notably, no dose-response relationship exists between coffee quantity and cancer risk. Which of the following best explains the original association?
Answer choices
- AConfoundingCorrect answer
- BEffect modification
- CSelection bias
- DType I error
- ELead-time bias
- FReverse causality
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