Version May 29, 2012
Trial | Vitamin C | Placebo | Difference | P(one-tail) |
---|---|---|---|---|
RITZEL (1961) | ||||
Schoolchildren in a skiing camp in Swiss Alps, 1 g/day vit C, 1 week | ||||
Participants | 139 | 140 | ||
Common cold episodes | 17 | 31 | -45% | 0.015 |
Duration of colds, mean | 1.8 | 2.6 | -31% | <0.05 |
Days per group | 31 | 80 | -61% | |
Constitutional symptoms during the common cold (headache, muscle ache, etc.) | ||||
Cases | 8 | 21 | -62% | 0.006 |
Days per group | 9 | 48 | -81% | |
COWAN et al. (1942) | ||||
Schoolchildren in USA, 0.2 g/day vit C, 4 months | ||||
Participants | 208 | 155 | ||
Cold episodes, mean per person | 1.9 (SD 1.0) | 2.2 (SD 1.0) | -14% | 0.003 |
Days lost from school per person | 1.1 (SD 1.1) | 1.6 (SD 1.6) | -31% | 0.0003 |
FRANZ et al. (1956) | ||||
Schoolchildren in USA, 0.2 g/day vit C, 4 months | ||||
Participants | 44 | 45 | ||
Common cold episodes | 14 | 15 | ||
Colds cured or improved in 5 days | 13 | 8 | +74% | 0.012 |