Quiz 9, Module Case-control
9. How would you set up the classic 2x2 table using the above information to test the hypothesis that cases are more likely to have consumed Quench-It than controls?
- See the 2x2 table
- Calculate the odds of exposure among cases
- Calculate the odds of exposure among controls
- Calculate the exposure Odds Ratio (OR)
- Calculate the odds of Susser Syndrome among the exposed
- Calculate the odds of Susser Syndrome among the unexposed
- Calculate the disease Odds Ratio
- Interpret your findings
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| Case | Control | Total | |
|---|---|---|---|
| Exposed (Quench-it) | 50 | 56 | 106 |
| Unexposed (No Quench-it) | 62 | 168 | 230 |
| Total | 112 | 224 | 336 |
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Odds of exposure among cases (# of Cases exposed) / (# of Cases unexposed)
50 / 62 = 0.806
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Odds of exposure among controls (# of Controls exposed) / (# of Controls unexposed)
56 / 168 = 0.333
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OR = (Odds of Exposure among Cases) / (Odds of Exposure among Controls)
OR = (50/62) / (56/168) = 2.4 or 0.806 / 0.333 = 2.4
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Odds of disease among exposed (# of Cases Exposed) / (# of Controls Exposed)
50 / 56 = 0.893
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Odds of disease among unexposed (# of Cases Unexposed) / (# of Controls Unexposed)
62 / 168 = 0.369
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OR = Odds of disease among Exposed / Odds of disease among Unexposed
OR = (50/56) / (62/168) = 2.4 or 0.893/0.369 = 2.4
none:
Individuals with Susser Syndrome (cases) have 2.4 times higher odds of having consumed Quench-It than those without Susser Syndrome (controls). Conversely, individuals who drank Quench-It have a 2.4 times higher odds of developing Susser Syndrome than those who did not drink Quench-It. The OR = 2.4 supports a positive association between Susser Syndrome and Quench-It consumption.
