Biostatistics & Study Design USMLE Step 1 Practice Question
A epidemiologic study examining 5,000 patients finds coffee consumption associated with higher lung cancer incidence (RR 2.1). However, after stratifying data by smoking status, the association disappears in both smokers (RR 1.0) and nonsmokers (RR 1.0). Chest CT confirms lung cancer diagnosis in 312 patients. Notably, no difference in coffee consumption exists between cancer and control groups when analyzed separately by smoking. Which phenomenon best explains the original association between coffee and lung cancer?
Answer choices
- AType I error
- BConfoundingCorrect answer
- CEffect modification
- DLead-time bias
- ESelection bias
- FBerkson's paradox
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