1. In the News In the News Is the association causal?
RR = 7
In Investigation 3-1: In the News, students will begin to distinguish between an association and a cause. They will realize that an association between an exposure and disease does not necessarily occur because the exposure causes the disease; other explanations can be found for why the exposure and disease turn up together.
Next Slide
In the News
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

2. Where are we and where are we going?
1. How is this disease distributed and what hypotheses might explain that distribution?
2. Is there an association between the hypothesized cause and the disease?
3. Is the association causal?
4. What should individuals and society do when preventable causes of disease are found?
Remind students that they have learned how epidemiologists answer the first and second Essential Questions:
■ “How is this disease distributed and what hypotheses might explain that distribution?”
■ “Is there an association between the hypothesized cause and the disease?”
In the Module 3 investigations, they will now learn how to answer the third Essential Question: “Is the association causal?”
In the Module 4 and 5 investigations, they will learn how epidemiologists answer the following questions, respectively: “What should individuals and society do when preventable causes of disease are found?”, “Did the prevention strategy work?”
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5. Did the prevention strategy work?
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

3. Where are we and where are we going?1
How is this disease
distributed?
Hypotheses 2
Is there
an association? 3
Is the association
causal?
Why did the exposure and the disease turn up together?
What’s my hypothesis?
Did the exposure and the disease turn up together? 4
What should be done
to prevent the disease?
Tell students that this Concept Map is another way to look at the Essential Questions.
In Module 1 investigations, students learned how epidemiologists answer the question “How is this disease distributed?” or “What’s my hypothesis?”
In Module 2 investigations, students learned how epidemiologists answer the question “Is there an association?” or “Did the exposure and the disease turn up together?”
And now, in Module 3 investigations, students will learn how epidemiologists answer the question “Is the association causal?” or “Why did the exposure and the disease turn up together?”
Next Slide 5
Did the prevention
strategy work?
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

4. Association Found Between Coffee and Diabetes1
What does it mean?
Give each student an Investigation 3-1: Epi Log Worksheet.
Students should complete their Investigation 3-1: Epi Log Worksheet by describing what the following headline means to them: “Association Found Between Coffee and Diabetes.”
Ask students:
■ What are you thinking after you read that headline?
■ What do you think the article will tell you?
After students have completed their descriptions, tell them they will revisit this headline later in the Module.
☼ Teacher Alert: Students will be asked to interpret this headline again at the end of Investigation 3-7: Weighing the Evidence. At that point, their interpretation should be more thorough and reflect their understanding that associations are not necessarily causal.
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Association Found Between Coffee and Diabetes
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

5. Intro to Epidemiology – Investigation 3-1: In the News
What does it mean?
Tied
Related
Associated
Linked
What do we mean when we say that there is an association between two things?
Things that are associated are linked in some way that makes them turn up together.
Ask students:
■ What do we mean when we say that two things are tied, linked, related, or associated with each other?
■ What does it mean to say that there is an association between two things?
Probe.
Tell students that one definition of association is that “things that are associated are linked in some way that makes them turn up together.”
☼ Teacher Alert: This curriculum makes a distinction between correlation and association, and purposefully uses the term association to describe relationships of interest to epidemiologists.
To explain, let’s start with correlations. Statisticians and scientists use the term correlation to describe a relationship where two factors vary together, such as the relationship between a person’s height and weight. The measure of how closely the two things vary is the correlation. Correlation has a specific quantifiable meaning on a defined scale (for example, a coefficient of correlation). In the calculation of a correlation, nothing is said or implied about a causal link.
When the possibility of causality is being explored, a different kind of calculation can be made to quantify a relationship where one variable may affect the other. An example is the relationship between the amount of a medication administered and the perceived level of pain. Calculations to quantify such a relationship (for example, regressions) are different from calculations of correlation and yield different results.
To clarify this distinction, epidemiologists and epidemiology curricula use the term association to describe the relationships between factors of interest.
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

6. Association
Things that are associated are linked in some way that makes them turn up together.
Happy Birthday
Why did Jaime and Peter turn up together at the party?
Present the following scenario:
Two middle school students, Jennifer and Michael, were both invited to the same party and turned up at the same time at the front door of the house where the party was being given.
Ask students:
■ Can you think of any reasons why these two people turned up together at the party?
Possibilities include the following:
■ They arranged with each other to go to the party together.
■ By coincidence, they showed up at the door at the same time.
■ Someone called both of them and told them to arrive at exactly 7:15 PM.
■ Jennifer hid in the bushes and waited for Michael, so it would look as though they were coming together.
Explore these ideas with the class. We see two things turn up together and try to explain why.
■ How is this scenario similar to an epidemiologic investigation? (Epidemiologists try to find things, exposures and diseases, that turn up together. And just as the students considered different explanations for why Jennifer and Michael turned up together at the front door, they need to do the same when an exposure and a disease turn up together in an epidemiologic study.)
Associations are not necessarily causal; other explanations must be considered.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

7. Things that Turn Up Together
Things that are associated are linked in some way that makes them turn up together.
Have students identify some things that turn up together.
Write their responses on the board.
(Students’ responses may include the following: peanut butter and jelly, firemen and policemen, salt and pepper, cream and sugar, hot dogs and baseball, ants and a picnic, bacon and eggs, smoking and drinking, milk and cookies, popcorn and soda, hammer and nails, chips and dip, paper and pen, shampoo and conditioner, coffee and sugar, coffee and donuts, dishes and sink, cream cheese and jelly, sneakers and shoelaces, boyfriend and girlfriend, and spaghetti and meatballs.)
Ask students:
■ What does it mean when we say things turn up together?
Probe with further questions:
■ Does it mean that these two things always turn up together?
■ Does it mean that these two things go together most of the time?
■ Why do these things turn up together?
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

8. Intro to Epidemiology – Investigation 3-1: In the News
Review
Epi Speak
Association
Things that are linked in some way that makes them turn up together.
Ask students to find “Association” in the Epi Speak list.
Review its definition.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

9. In the News Suicide Higher in Areas with Guns
Smoking Linked to Youth Eating Disorders
Family Meals Are Good for Mental Health
Study Links Iron Deficiency to Math Scores
Study Concludes: Movies Influence Youth Smoking
Lack of High School Diploma Tied to US Death Rate
Study Links Spanking to Aggression
Depressed Teens More Likely to Smoke
Snacks Key to Kids’ TV- Linked Obesity: China Study
Tell the class that the headlines shown on the slide were found on the Internet.
Ask students:
■ Are these examples of associations about exposures and outcomes that turned up together? (Yes)
■ Can you think of why these exposures and outcomes turned up together?
☼ Teacher Alert: Depending on time, decide how many of these associations to focus on. Be sure to emphasize to students that these associations are based on single studies and are not necessarily causal or even true.
Have students create their own list of exposures and disease that they think turn up together and then explain why they believe the two are linked. (Examples include stress and heart attack, smoking and lung cancer, junk food and obesity, cell phones and car accidents, diet soda and cancer, violent video games and violent behavior, air pollution and lung cancer, drunk driving and accidents).
Next Slide
Breakfast Each Day May Keep Colds Away
Pollution Linked with Birth Defects in US Study
Kids Who Watch R-Rated Movies More Likely to Drink, Smoke
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

10. Intro to Epidemiology – Investigation 3-1: In the News
Review
Epi Speak
Epidemiology
The study of how and why diseases or other health-related conditions are distributed in a population the way they are, in other words, why some people get sick and others do not.
Emphasize that the part of epidemiology that students will be focusing on during Module 3 is “… why diseases are distributed in a population the way they are ….”
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

11. Review
Time
Random Assignment - E DZ
Study Design: Trial
Healthy People
Time - E DZ
Study Design: Cohort Study
Healthy People
Is there an association between the hypothesized cause and the disease?
Time - DZ E
Study Design: Case-Control Study
Time - DZ E
Study Design: Cross-Sectional Study
Remind students that in answering Essential Question 2—“Is there an association between the hypothesized cause and the disease?”—they learned about analytical epidemiology and the study designs epidemiologists use to test hypotheses by determining whether or not an exposure and a disease turn up together.
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

12. In the News Suicide Higher in Areas with Guns
Smoking Linked to Youth Eating Disorders
Family Meals Are Good for Mental Health
Study Links Iron Deficiency to Math Scores
Study Concludes: Movies Influence Youth Smoking
Lack of High School Diploma Tied to US Death Rate
Study Links Spanking to Aggression
Depressed Teens More Likely to Smoke
Snacks Key to Kids’ TV- Linked Obesity: China Study
Point out that analytical epidemiologic studies go on all the time. Literally hundreds, if not thousands, of things are found that turn up together.
The challenge is to make sense of all of the findings. Some are just associations, like spaghetti and meatballs, and do not mean that the exposure caused the disease or outcome. However, there are often other reasons for an association.
The next slide will give students some practice in sorting out what it all means.
Next Slide
Breakfast Each Day May Keep Colds Away
Pollution Linked with Birth Defects in US Study
Kids Who Watch R-Rated Movies More Likely to Drink, Smoke
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

13. In the News: The New York Times, 1 / 22 / 02
Relate a true story about an acne drug called Accutane that has been in the news, as in this The New York Times article, frequently during the past several years. It is a very effective drug for treating severe acne, but questions have been raised about serious side effects.
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

14. Intro to Epidemiology – Investigation 3-1: In the News
Mother of Teenage Suicide Pilot Sues Maker of Acne Drug She Says He Used
Students should now take out the newspaper article they were asked to read for homework, “Mother of Teenage Suicide Pilot Sues Maker of Acne Drug She Says He Used.”
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

15. Intro to Epidemiology – Investigation 3-1: In the News
Charles Bishop, age 15, killed himself in January 2002 by crashing a small plane into a Tampa high rise office building.
His mother believes his suicide was caused by the prescription drug, Accutane, manufactured by Hoffman-LaRoche (HLR).
The charge is that HLR has been aware of the medication causing depression, psychosis, and suicidal tendencies.
HLR claims that 13 million people have safely used Accutane since 1982.
The company has investigated “minor and rare” reports of adverse psychological effects but found “no scientific basis to link to either depression or suicide.”
Review the major points of the article with the class.
Engage students in a discussion of whether or not they think Accutane caused Charles Bishop’s death.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

16. Intro to Epidemiology – Investigation 3-1: In the News
The Accutane packaging warns against possible psychological effects.
Toxicologists found no traces of Accutane in the boy’s system.
The suicide note stated that he was acting alone but supported efforts of Al Qaeda.
Suicide is one of the leading causes of death in teenagers and young adults.
Since 1992, more than 500 adverse reactions to Accutane have been recorded by national and international agencies.
Continue to review the major points of the article.
Keep students discussing whether or not they think Accutane caused Charles Bishop’s death.
Ask students:
■ What other explanations may account for this event?
☼ Teacher Alert: Give students the article but delete the headline. During discussion of the article, ask them to create an appropriate headline.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

17. Always Remember Intro to Epidemiology – Investigation 3-1: In the News
Association is not necessarily causation.
Ask students:
■ Can you explain what is meant by the statement “Association is not necessarily causation”?
Probe with further questions:
■ Are all associations causal? (No)
■ Are all causal relationships associations? (Yes)
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

18. Do Not Ever Forget
Association is not necessarily causation.
Reinforce the idea that association is not necessarily causation. This is one of the central points in understanding epidemiology. Testing a hypothesis and finding that an exposure and a disease turn up together is an important step. However, interpreting study results is challenging because several explanations for why an association is found may be possible.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

19. Investigation 3-1

20. Intro to Epidemiology – Investigation 3-1: In the News
Epi Speak
Epi Speak
Cause
Anything that produces an effect.
Ask students to find “Cause” in the Epi Speak list.
Review its definition.
☼ Teacher Alert: Students’ concepts of cause and effect may be limited to those that are obvious, immediate, and one to one—for example, being hit by a baseball causes pain. However, this is not the case with all cause-effect relationships. A virus that causes a head cold several days after exposure is not obvious, immediate, or one to one.
Address misconceptions.
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Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

21. Intro to Epidemiology – Investigation 3-1: In the News
Epi Speak
Epi Speak
Risk Factor
An exposure that increases the likelihood of a specific outcome.
Ask students to find “Risk factor” in the Epi Speak list.
Review its definition.
Epidemiologists commonly use ”risk factor” instead of “cause.”
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

22. Intro to Epidemiology – Investigation 3-1: In the News
Epi Speak
Epi Speak
Interpret
To give the meaning of, explain, or make clear.
Ask students to find “Interpret” in the Epi Speak list.
Review its definition.
Next Slide
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

23. Possible Explanations for Finding an Association
Investigations
Explanations
3-2
Cause
3-3
Chance
3-4
Confounding
3-5
Reverse Time Order
The Module 3 investigations will look at several possible explanations for an association:
■ Cause: Because the exposure is responsible for the occurrence of the outcome.
■ Chance: Because of a coincidence.
■ Confounding: Because there is a third factor, linked to the exposure, that is responsible for the occurrence of the outcome.
■ Reversed time order: Because, although we hypothesized that the exposure caused the outcome, it was actually the outcome that caused the exposure.
■ Bias: Because the study was carried out in such a way that, even though no association really existed between the exposure and the outcome, the study found an association.
Next Slide
3-6
Bias
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1

24. Investigation 3-1 has ended.
In the News
Investigation has ended.
CDC
This concludes Investigation 3-1: In the News and students can now put away their Epi Logs.
Intro to Epidemiology – Investigation 3-1: In the News
Investigation 3-1