Problem
A state epidemiologist wanted to investigate stomach cancer and shellfish consumption. She conducted a study with 125 stomach cancer cases and 125 controls, pair-matched on age and gender. After conducting the study, it was found that there were 35 pairs in which both cases and controls ate shellfish more than 3 times per week [exposed], and 15 pairs in which both cases and controls ate shellfish less than once per month (unexposed). There were 28 pairs where the control ate shellfish more than 3 times per week and the case rarely at shellfish, and 47 pairs where the case at shellfish more than 3 times per week and the control at shellfish rarely.
A. Construct the appropriate 2x2 table for this study using the information given.
B. Calculate the pair-matched odds ratio for stomach cancer from exposure to eating shellfish regularly compared to eating shell?sh rarely.
C. What does this odds ratio indicate?