| Methods |
See Karlowski 1975a. This is regular supplementation plus therapeutic arm |
| Participants |
57 vitamin C |
| Interventions |
3 g/d vitamin C and 3 g/d therapeutic from the onset of cold for 5 days |
| Outcomes |
Incidence (Analysis 1.1) and duration (Analysis 2.1) |
| Notes |
— |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
|
| Allocation concealment (selection bias) |
Low risk |
|
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
|
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
|
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
|
| Vitamin C and placebo indistinguishable? |
Unclear risk |
? |
