Question

1. Confounding: A cohort study is conducted to assess the relationship between smoking and esophageal cancer.

	Cancer	No Cancer	Total
Smoker	110	140	250
Not a smoker	30	220	250
Total	140	360	500

2. Researchers are concerned that alcohol consumption may be a confounder. So they separated the data based on the present of the third variable, alcohol to get the data below. Comparing the RR obtained from the CMH method to the crude RR (calculated using the first table). Is the following statement true or false based on your comparison? “Alcohol is not a confounder.”

Alcohol	Cancer	No Cancer	Total		No Alcohol	Cancer	No Cancer	Total
Smoker	100	50	150		Smoker	45	55	100
Not a smoker	15	185	200		Not a smoker	15	35	50
Total	115	235	350		Total	60	90	150

4. True
5. False

Answer 1