“Our” Study:

Vitamin C for Colds among College Students in Colorado (CCCC)

Below is a skeleton of the study you are to visualize that we have done. Your task is to write only the required parts of a Discussion Section of the research report that we would submit to a scientific journal if we had actually done the research. I encourage you to go through a visualization exercise to picture conducting the study, from deciding its research question to recruiting subjects to gathering and analyzing the data. Use the review and research reports I gave you, along with the research report you found, as the previous research. You may augment this skeleton with any other specific procedures that you would include, and even add data for them. Whatever you add must be compatible with what is here.

Subjects:

3,000 undergraduates at the University of Colorado, recruited as entering freshmen. We initially recruited 3,500 students, expecting a substantial dropout rate because of the long duration of the study, and analyzed data for 3,000.

Procedures:

The study lasted 2 academic years, September 1, 2015 – May 30, 2017. In the first, the students' freshman year, we gathered data on incidence, duration, and severity of upper respiratory tract infections; severity was indicated by the number of times the volunteers went to the doctor. There was no intervention, and all subjects agreed to take no vitamin C supplements. At the end of the academic year, we characterized the students according to their incidence of URTIs: low (0-2.9 colds) or high (3-9 colds).

In the second year, we divided all subjects into two cohorts, one consisting of students who had had low incidence of URTIs in the first year and the other consisting of students who had had high incidence. Within each cohort we randomly assigned a third of the students to take 500 mg of vitamin C a day, a third to take 2,000 mg a day, and a third to take a placebo. The number of subjects in each group varied slightly, but the difference was not statistically significant.


Results:

From year 1:

LOW INCIDENCE / HIGH INCIDENCE
No. of subjects / 1,620 / 1,730
Average no. of colds * / 1.4 / 4.5
Range / 0 – 2.9 / 3 - 9
Average no. of days of symptoms in the observational period* / 3.4 / 20
Range / 0 – 6 / 6.1 - 30
Average no. of doctor visits* / 0.8 / 4
Range of dr. visits / 0 – 2.9 / 3 - 8

* Averages in the two groups were significantly different from each other (p < 0.05).

From year 2:

LO
PL / HI
PL / LO
500 / HI
500 / LO
2000 / HI
2000
No. of subjects / 496 / 504 / 497 / 503 / 497 / 503
Average no. of colds / 1.5# / 3.7*# / 1.7 # / 3.2*# + / 1.4 / 2.1*+%
Range / 0-2 / 2-8 / 0-2 / 0-7 / 0-2 / 0-4.5
Average no. of days of symptoms in the intervention period / 2.9# / 16.0*# / 2.5#+ / 14.0*#+ / 2.0#+% / 8.0*#+%
Range / 0-5 / 4-35 / 0-5 / 0-30 / 0-6 / 0-20
Average no. of doctor visits / 0.8# / 3.8# / 0.9# / 2.9#% / 0.1# / 1.6*#%
Range of dr. visits / 0-2 / 2-8 / 0-2 / 0-6 / 0-2 / 0-4

* Value was significantly different from value for respective cohort in first year.

# Value was significantly different from value for group with same dose in other cohort (e.g., LO 500 vs HI 500).

+ Value was significantly different from value for group with other dose in same cohort (e.g., LO 500 vs LO 2000).

% Value was significantly different from value in corresponding placebo group.

All p < 0.05.

VitCStudy.docx revised summer 2017