The makers of highly caffeinated energy drinks such as Red Bull or Monster claim that the energy drinks have nutritional value and improve performance, concentration, and endurance. The main active ingredients of such drinks include caffeine, guarana extract, taurine, and ginseng, and there are increasing reports in the medical literature that consuming such drinks can have adverse effects on adolescent and young adult health. Investigators launched a study to determine whether consuming energy drinks was associated with anxiety among young adults. They enrolled 900 young adults in a 3-year study. In this cohort, 497 reported that they regularly consumed energy drinks at events such as dance parties and other gatherings. At the end of 3 years, 376 of the energy drink consumers had been seen by their primary care physicians and referred to a psychiatrist for anxiety symptoms. Among the non-energy drinkers, 31 had been seen by their primary care physicians and referred to a psychiatrist for anxiety symptoms.

1. What type of cohort study is this?

Cross-sectional

Case-control

Retrospective Cohort

Prospective cohort study

2. Clearly state the exposure and outcome for this study, including the sample sizes for each group. Match:

Exposure-

N exposed

Outcome

N with outcome

-279

-407

-497

- 145

Cardiac sysmtoms

-consuming energy drink

-anxiety

3. Construct a 2x2 table for this study. Clearly identify the exposure and outcome.

4. What is the appropriate measure of association for this study?

5. Calculate the incidence rates per 1,000 for the exposed group and the unexposed group. State the formula and show all your work. Be sure your answer is clear and complete, including all steps of your calculations.

6. Calculate the measure of association. State the formula and show all your work.(use two decimal points)

7. Which statement is correct?

• The odds of developing cardiac symptoms were 7.68 times greater among young adults who consumed energy drinks than among young adults who did not consume energy drinks.
• Those who had cardiac symptoms had 668% greater odds of consuming energy drinks than those who did not have cardiac symptoms.
• The risk of developing cardiac symptoms was 9.84 times greater among young adults who regularly consumed energy drinks than among those who did not consume energy drinks.
• Drinkers of energy beverages had 884% greater risk of developing cardiac symptoms than did non-drinkers.

8. The following table provides data on the development of coronary heart disease in Framingham, Massachusetts after 16 years for men ages 35 - 44 years, by level of serum cholesterol.

PAY CLOSE ATTENTION TO THE WAY THE TABLE IS SET UP!

	Coronary Heart Disease
Serum Cholesterol	No	Yes	Total
>260 mg/dL	343	94	437
< 260 mg/dL	962	109	1,071
Total	1,305	203	1,508

Use these data to calculate the relative risk of CHD, comparing serum cholesterol >260 to those with levels < 260 (the comparison group).

2.11

0.67

2.41

0.41

9. Use the data from Q17 to calculate the risk difference per 1,000.

113

113 per 1,000

0.113 per 1,000

0.113% per 1,000

10. Interpret the risk difference.

• There were 113 excess cases of CHD among people with high cholesterol (>260 mg/dL) compared to those with low cholesterol (<260 mg/dL)
• There were 113 per 1,000 excess cases of CHD among people with high cholesterol (>260 mg/dL) compared to those with low cholesterol (<260 mg/dL)
• There were 0.113 per 1,000 excess cases of CHD among people with high cholesterol (>260 mg/dL) compared to those with low cholesterol (<260 mg/dL)
• There were 0.113% cases of CHD per 1,000 among people with high cholesterol (>260 mg/dL) compared to those with low cholesterol (<260 mg/dL)

11. What are some characteristics of cohort studies? (check all that apply)

a. Useful to explore several risk factors

b. Categorize participants on the base of their exposure

c. Enroll a group of participants with the disease and another group without the disease

d. Generally used to study rare diseases

e. Best design when you have rare exposures

f. a and b

g. b and c

h. c and e

i. All the above

12. Based on the information provided, indicate whether the study is cross-sectional, ecological, case-control, prospective cohort, or retrospective cohort:

In 2015, a group of 10,000 women in their 40s were identified as having had tuberculosis during their adolescence. They were classified as having chest X-rays (4,000) and not having chest X-rays (6,000) to monitor their disease. The women were followed-up for approximately 20 years to see if those receiving chest X-rays were more likely to develop breast cancer. What type of study is this?

Cross-sectional

Case-control

Retrospective Cohort

Prospective cohort study

13. Based on the information provided, indicate whether the study is cross-sectional, ecological, case-control, prospective cohort, or retrospective cohort:

Researchers were interested in investigating the relationship between living in food swamps and cancer. Food swamps are areas in which fast food, junk food outlets, convenience stores, and liquor stores outnumber healthy food stores) They collected data on food swamps in all Philadelphia zip codes. Cancer rates were estimated from the Pennsylvania cancer registry.

What type of study is this?

• Ecological
• Cross-sectional
• Case-control
• Cohort

14. Based on the information provided, indicate whether the study is cross-sectional, ecological, case-control, prospective cohort, or retrospective cohort:

An assessment of sleep, visual, olfactory, psychiatric and motor symptoms was conducted among 124 patients with Parkinson's disease who were dementia-free at the beginning of the study. After 5 years of follow-up all the patients were evaluated for dementia. What type of study is this?

• Cross-sectional
• Case-control
• Retrospective Cohort
• Prospective cohort study

15. Based on the information provided, indicate whether the study is cross-sectional, ecological, case-control, prospective cohort, or retrospective cohort:

A representative sample of college students in the U.S. completed the 2011 National Youth Tobacco Survey. In 2020, researchers published a study of the prevalence of ever and current e-cigarette use among these college students. What type of study is this?

• Cross-sectional
• Case-control
• Retrospective Cohort
• Prospective cohort study