Table 3.
Cold outcomes in participants ingesting 1000 mg vitamin C versus placebo daily for eight weeks *.
| n | Participants with colds | Total number of colds | Cold duration, days (mean ± SD) | Cold severity score (mean ± SD) | Impact of cold on daily living score (mean ± SD) | |
|---|---|---|---|---|---|---|
| Vitamin C | 15 | 7 | 12 | 2.2 ± 1.4 | 10.7 ± 6.0 | 2.6 ± 1.6 |
| Placebo | 13 | 11 | 17 | 5.4 ± 4.5 | 18.6 ± 17.5 | 2.4 ± 2.1 |
| RR or change 95% CI | 0.55 a [0.33, 0.94] | 0.66 a [0.28, 1.55] | −3.2 b [−7.0, 0.6] | −7.9 b [−22.5, 6.7] | 0.2 b [−1.8, 2.2] | |
| Effect size c | 0.170 | 0.075 | 0.003 | |||
| p value d | 0.04 | 0.11 | 0.06 | 0.54 | 0.72 |
* Severity score: daily average total symptom score (ten items scored individually from 1 “very mild” to 7 “severe”: runny nose, plugged nose, sneezing, sore throat, scratchy throat, cough, hoarseness, head congestion chest congestion, feeling tired) for cold episodes. Impact of cold on daily living score: daily average total score (nine items scored individually from 1 “very mildly” to 7 “severely”: think clearly, sleep well, breathe easily, walk/climb stairs/exercise, accomplish daily activities, work outside the home, work inside the home, interact with others, live your personal life) for cold episodes. a Rate ratio; b treatment effect: average change; c partial eta squared; d Mann-Whitney U test or Chi Square test for “Participants with colds”.