Case Control Study

Data
Analysis

Step 6: Data Analysis

The data collected yield the following counts:

Total number of Cases: 112
Total number of Controls: 224
Number of Cases who ingested Endurobrick: 28
Number of Controls who ingested Endurobrick: 56
Number of Cases who consumed Quench-it: 50
Number of Controls who consumed Quench-it: 56

You decide to test the hypothesis that cases are more likely to have ingested Endurobrick than controls. [See Gordis, pgs. 162-168]

How would you set up the classic 2x2 table using the above information to test this hypothesis?
[ Click Here to View the 2x2 Table]
a.	Calculate the odds of exposure among cases:	[ Check Answer ]
b.	Calculate the odds of exposure among controls:	[ Check Answer ]
c.	Calculate the exposure Odds Ratio (OR)	[ Check Answer ]
d.	Calculate the odds of Susser Syndrome among the exposed:	[ Check Answer ]
e.	Calculate the odds of Susser Syndrome among the unexposed:	[ Check Answer ]
f.	Calculate the disease Odds Ratio:	[ Check Answer ]
g.	Interpret your findings:	[ Check Answer ]

You now decide to test the hypothesis that cases are more likely to have consumed Quench-it than controls.

How would you set up the classic 2x2 table using the above information to test this hypothesis?
[ Click Here to View the 2x2 Table]
a.	Calculate the odds of exposure among cases:	[ Check Answer ]
b.	Calculate the odds of exposure among controls:	[ Check Answer ]
c.	Calculate the exposure Odds Ratio (OR)	[ Check Answer ]
d.	Calculate the odds of Susser Syndrome among the exposed:	[ Check Answer ]
e.	Calculate the odds of Susser Syndrome among the unexposed:	[ Check Answer ]
f.	Calculate the disease Odds Ratio:	[ Check Answer ]
g.	Interpret your findings:	[ Check Answer ]

10.	You wipe the sweat from your analytical brow and present your findings to your supervisor. What should you tell her?
		a.	It looks as though we've ruled out both Endurobrick and Quench-it as possible exposures. In my opinion, neither appears to be related Susser Syndrome development.
		b.	The data regarding both Endurobrick ingestion and Quench-it consumption are totally inconclusive. I think we should repeat the study with more participants.
		c.	While ingestion of Endurobrick does not cause Susser Syndrome, the data do indicate that consumption of Quench-it does cause Susser Syndrome.
		d.	The data clearly suggest that the consumption of Quench-it is associated with later development of Susser Syndrome whereas the ingestion of Endurobrick does not appear to be associated with Susser Syndrome. I think we might want to explore other potential exposure sources to be sure as well as to further characterize this association.

After reporting your results, you decided to do a little bit more detective work. You head over to the Public Health Laboratory records department and check the log file on Quench-it. Since its production, the Health and Food Safety Inspector has taken random samplings of Quench-it back to the lab to analyze it for any possible contamination. This is normal surveillance procedure. Looking the file you notice something interesting: during the time period between 2000 and 2002, a significant amount of Superclean was found in Quench-it, probably, you recall, a result of the old sterilization process. After 2002 when Glop Industries changed techniques, Quench-it was completely free of Superclean. Realizing the importance of this finding, you immediately report back to your supervisor.

Learning
Objectives

Introduction
to Study

Data
Analysis