Odds ratio is a measure of association used in epidemiological studies to assess the relationship between disease and exposure. In this exercise, you will calculate and interpret odds ratio using real-world examples.

Odds Ratio

In case control studies the odds ratio (OR) is the measure of the association between the frequency of an exposure and the frequency of an outcome. The OR is an indirect measure of risk in case control studies because incidence rates cannot be calculated.

The formula for odds ratio is: (A/C) ÷ (B/D) or (AD)/(BC).

Remember, data from an output source may not be ordered according to the table. Ensure that the output data corresponds to the table, or you will calculate incorrectly when you apply the formula.

	Disease Status
Exposure Status	Yes	No	Total
Yes	A	B	A + B
No	C	D	C + D
Total	A+C	B+D	A+B+C+D

For this assignment:

1. Retrieve the "BRFSS Web-Enabled Analysis Tool" resource provided in the study materials.
   1. Select "Cross Tabulation."
   2. Select "2015" for the year.
   3. Select "Arizona" for the state.
   4. Select "Alcohol Consumption: Binge drinkers (males having five or more drinks on one occasion, females having four or more drinks on one occasion)" for Step 2 Select Row.
   5. Select "Chronic Health Conditions: Ever diagnosed with a depressive disorder, including depression, major depression, dysthymia, or minor depression" for Step 3 Select Column.
   6. Skip Steps 4 and 5.
   7. Select "Sample Size" for Step 6 Select Statistics and run the report for the cross tabulation.

Part 1

Using the data from the cross-tabulation results, calculate the odds ratio for depression among those exposed to binge drinking. Refer to the formula provided above.

1. Present or describe the formula you used to arrive at your answer. Show all calculations.

2. Interpret the odds ratio. In your interpretation, describe the association between the variables and indicate whether there is a positive, negative, or no association.

Part 2

Use the study material, "BRFSS Web-Enabled Analysis Tool," located on the CDC website, and run a report for two variables of interest to you.

Exposure Status	Yes	No	Total
Yes
No
Total

1. Present or describe the formula you used to arrive at your answer.

2. Interpret the odds ratio. In your interpretation describe the association between the variables and indicate whether there is a positive, negative, or no association.

3. Discuss the public health importance of the association.

Calculating Odds Ratio

Odds ratio is a measure of association used in epidemiological studies to assess the relationship between disease and exposure. In this exercise, you will calculate and interpret odds ratio using real-world examples.

Odds Ratio

In case control studies the odds ratio (OR) is the measure of the association between the frequency of an exposure and the frequency of an outcome. The OR is an indirect measure of risk in case control studies because incidence rates cannot be calculated.

The formula for odds ratio is: (A/C) ÷ (B/D) or (AD)/(BC).

Remember, data from an output source may not be ordered according to the table. Ensure that the output data corresponds to the table, or you will calculate incorrectly when you apply the formula.

Exposure Status	Yes	No	Total
Yes
No
Total

	Disease Status
Exposure Status	Yes	No	Total
Yes	A	B	A + B
No	C	D	C + D
Total	A+C	B+D	A+B+C+D

For this assignment:

1. Retrieve the "BRFSS Web-Enabled Analysis Tool" resource provided in the study materials.
   1. Select "Cross Tabulation."
   2. Select "2015" for the year.
   3. Select "Arizona" for the state.
   4. Select "Alcohol Consumption: Binge drinkers (males having five or more drinks on one occasion, females having four or more drinks on one occasion)" for Step 2 Select Row.
   5. Select "Chronic Health Conditions: Ever diagnosed with a depressive disorder, including depression, major depression, dysthymia, or minor depression" for Step 3 Select Column.
   6. Skip Steps 4 and 5.
   7. Select "Sample Size" for Step 6 Select Statistics and run the report for the cross tabulation.

Part 1

Using the data from the cross-tabulation results, calculate the odds ratio for depression among those exposed to binge drinking. Refer to the formula provided above.

1. Present or describe the formula you used to arrive at your answer. Show all calculations.

2. Interpret the odds ratio. In your interpretation, describe the association between the variables and indicate whether there is a positive, negative, or no association.

Part 2

Use the study material, "BRFSS Web-Enabled Analysis Tool," located on the CDC website, and run a report for two variables of interest to you.

Exposure Status	Yes	No	Total
Yes
No
Total

1. Present or describe the formula you used to arrive at your answer.

2. Interpret the odds ratio. In your interpretation describe the association between the variables and indicate whether there is a positive, negative, or no association.

3. Discuss the public health importance of the association.

Exposure Status	Yes	No	Total
Yes
No
Total