It’s all relative! JANUARY 20, 2015

Overview of Today 1) Feedback about posts/Readings for this week

2) Some discussion of your thoughts and comments

3) Activity: What is more risky?

4) Activity: How do we relate two quantities?

5) Begin Discussion of study design in health statistics

Feedback –What were your experiences with reading/writing the journal posts?

Be sure to include a descriptive title, and then tag the entry with the journal entry number

Make sure you are not just restating facts/concepts discussed in class, but using them to further engage with the readings, outside sources and your own reflections.

Make sure your post actually publishes!

Sorry for the glitches with some of you being unable to post appropriately, but please try to post by Sunday 4PM in future weeks.

Readings for this week Go through modules and start thinking about ways that you would incorporate study design into your journal postings

Read the Numeracy review and start to brainstorm: 1) why numeracy is important; 2) how numeracy affects our perceptions of health risk; 3) some ways researchers might measure health risks;

Have the paper accessible to you in class on Thursday!

Some of your questions/thoughts

Why are we more afraid of some things than others?

Who is responsible for making sure that numbers and statistics are reported accurately?

Why are Americans so prone to quoting statistics? Does it really make a difference in our behavior?

How does the epidemiological definition of risk interact with other definitions of risk we have encountered?

How do we determine which sources are credible and which are not so credible?

Prompt for Journal Entry 2 ***Be sure to have an engaging title Prompt: Talk with a roommate/friend who is not in the class for about 15-20 minutes. Try to explain the differences between the study designs to your colleague. Try to use examples beyond what we discussed in class. How did you use the class readings/texts to help with your discussion? In your post, describe how the interaction went—what types of examples did you use? What questions did the friend ask? What questions came to your mind as you tried to explain the concepts?

In the tag, include the entry Journal entry #2

Comment on 1-2 of your peers articles

(Follow word count and Honor Code guidelines as described for Journal Entry 1)

What is MORE risky? What's more common in the United States, (a) suicide or (b) homicide?

What's the more frequent cause of death in the United States, (a) pool drowning or (b) falling out of bed?

What are the top five causes of accidental death in America, following motor-vehicle accidents, and which is the biggest one?

What is MORE risky? Of the top two causes of nonaccidental death in America, (a) cancer and (b) heart disease, which kills more women?

What are the next three causes of nonaccidental death in the United States?

What is MORE Risky? How many Americans die from AIDS every year, (a) 12,995, (b) 129,950, or (c) 1,299,500?

How many Americans die from diabetes every year? (a) 72,820, (b) 728,200, or (c) 7,282,000?

Which kills more Americans, (a) appendicitis or (b) salmonella?

Which kills more Americans, (a) pregnancy and childbirth or (b) malnutrition?

Which has killed more Americans, bird flu or mad cow disease?

Activity: How do we relate two quantities?

Some facts:

1) In the year 2000, there were 275,306,000 people in America

2) 151,268 DIED of external (non-disease) related activities

3) The life expectancy of an individual is 79.6 years

How many deaths do you think occur each year from these causes?Which are most likely/least likely to occur?

1. Accidental drowning

2. Assault

3. Car occupant

4. Air and space accidents

5. Falling, jumping or being pushed from a high place

6. Lightning

7. Operations of war

8. Catacyclsmic storms

9. Bicycling

10. Pedestrian

Handout—Talk through how you would calculate these

1. First—rank the Lifetime odds of the items discussed below from least to greatest lifetime odds of death. Then answer the following questions:

2. What proportion of Americans died from accidental drowning?

3. What proportion of deaths are from bicycling?

4. What are your lifetime odds of dying in a cataclysmic storm? How does this compare to your lifetime odds of dying of a lightning storm?

5. What are your

6. How might these statistics look different if you were only considering young Americans? Old Americans? Women?

7. What other outcomes besides death might be more interesting to look at?

Study Design

Components of an epidemiological study

Population---need to define your population in terms of age, race, SES, etc. ; How many people will you try to recruit?

Disease—need a case definition

Time frame-How long will you follow people?

Study design- How will you collect information? How will you verify information? What resources do you have?

We will focus on observational study designs: cohort, case-control, cross-sectional

Take EPID 600 if you are interested in this stuff!

Cohort Study

Cohort Study

Directionality: Always forwardData collection: Prospective or Retrospective

Cohort study

Yes (E+) No (E-)

Yes (D+) a b m1

No (D-) c d m0

n1 n0 N

Disease

Exposure

22

A cohort study: heart attack survivors after 5 years of follow up

Smoke Quit

Dead 27 14 41

Alive 48 67 115

Total 75 81 156

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What is the 5-year risk of dying among the exposed? 0.36

What is the 5-year risk of dying among the non-exposed? 0.17

What is the ratio of the two risks? 2.1

What is the difference between two risks? 0.19

The ratio of two risksRisk Ratio (RR) a.k.a. Relative Risk

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??smokingquit who thoseamongRisk

smokers continous amongRisk RR

Interpretation? Risk of disease in Exposed is 2.1 times the risk of disease in non-exposed, over 5 years.

exposednot amongRisk

exposed amongRisk

CI

CI

0

1 RR

P

POdds

1ocurringnot event ofy Probabilit

ocurringevent ofy Probabilit

Depends on a definition of the eventFor example, in sports betting…

winningofy Probabilit

winningNOT ofy ProbabilitOdds

Case control study

An easy way to calculate OR

Yes (E+) No (E-)

Yes (D+) a b m1

No (D-) c d m0

n1 n0 N

Disease

Exposure

26

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