A case-control study on mobile phone use and glioma enrolls patients from a neurosurgery ward. Controls are selected from the orthopedic ward of the same hospital. Which type of bias is most likely introduced?

• A Recall bias
• B Neyman's prevalence-incidence bias
• C Berkson's bias ✓
• D Observer bias

Explanation

Berkson's bias (hospital admission rate bias) occurs in case-control studies when both cases and controls are selected from hospital inpatients. Hospitalized controls over-represent people with conditions that alter their exposure patterns, distorting the exposure-disease association. If orthopedic patients use mobile phones differently than the general population, the OR will be biased. Recall bias relates to differential exposure reporting; Neyman's bias is a survival/prevalence-incidence issue; observer bias involves differential measurement.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.