Question

3. You performed a cross-sectional study at BMCC looking at students who drink energy drinks and their levels of anxiety. You got a sample of 100 students. Thirty of them drank energy drinks regularly, and of those, 15 reported feelings of anxiety. Of those who did not drink energy drinks, 12 reported feelings of anxiety. a. What is the "disease" in this example? What is the "exposure"? b. Construct a 2 x 2 table using these data. c. Calculate the prevalence of anxiety in the entire sample, and then in the sub-groups (those who drink energy drinks and those who don't). From these results, do you think there is a link between drinking energy drinks and anxiety? d. Calculate the risk ratio (relative risk) of drinking energy drinks and anxiety symptoms. Interpret the result.

Answer 1

A cross-sectional study at BMCC looking at students who drink energy drinks and their levels of anxiety.

Of the total 100 students, 30 of them drank energy drinks regularly and from those 15 reported feelings of anxiety, of those who did not drink energy drinks, 12 reported feelings of anxiety.

a. Here anxiety is the disease and drinking an energy drink is the exposure.

b.

	Having anxiety	No anxiety	Total
Drinking energy drink	15 (a)	15 (b)	30
Not drinking	12 (c)	58 (d)	70
	27	73	100

c. Prevalence of anxiety from the total sample

27 having anxiety from 100 people.

%

(27 = 100) x 100 = 27

Answer - 27% of people having anxiety.

Prevalence of anxiety from the Exposed group

Total of 30 students are drinking an energy drink and 15 of them having anxiety.

%

(15-30) 100 = 50

Answer - 50% of people having anxiety in the exposed group.

Prevalence of anxiety from the unexposed group

Total of 70 students are not drinking an energy drink and 12 of them having anxiety.

%

(12 = 70) x 100 = 17.14

Answer - 17.14% of people having anxiety in the unexposed group.

It clearly shows there is an association between Drinking energy drink and Anxiety.

d. Relative risk = incidence rate in the exposed group/incidence rate of non exposed group

RR = {a/(a+b)}/{c/(c+d)}

= 0.5/0.17

= 2.94

So, exposed students have 2.94 times more risk of developing depression than non exposed students.