Table 1 Characteristics of included trials
From: Vitamin C reduces the severity of common colds: a meta-analysis
Trial [ref] Country | Participants | Age mean (y) | Number of colds | Vitamin C dose (g/day) | Duration of the trial (months) |
|---|---|---|---|---|---|
Ludvigsson (1977 L) [30] Sweden | Schoolchildren | 9 | 1279 | 1 | 3 |
Pitt (1979) [41] USA | Marine recruits | 19 | 1219 | 2 | 2 |
Canada | Adults | 29 | 1170 | 1 + 3 | 3 |
Anderson 1974#3 [26] Canada | Adults | 34 | 611 | 2 | 3 |
Anderson 1974#1 [26] Canada | Adults | 34 | 581 | 1 + 3 | 3 |
Anderson 1974#2 [26] Canada | Adults | 34 | 560 | 1 | 3 |
Ludvigsson (1977P) [30] Sweden | Schoolchildren | 10 | 236 | 1 | 3 |
Carr (1981T) [42] Australia | Twin adults and adolescents together | 25 | 164 | 1 | 3 |
Carr (1981 A) [42] Australia | Twin adults and adolescents apart | 25 | 128 | 1 | 3 |
Miller (1977) [43] USA | Schoolchildren | 12 1) | 118 | 1 | 5 |
Constantini (2011 F) [36] Israel | Adolescent female competitive swimmers | 14 | 51 | 1 | 3 |
Switzerland | Schoolchildren in a skiing camp | 12 1) | 48 | 1 | 0.2 |
Constantini (2011 M) [36] Israel | Adolescent male competitive swimmers | 14 | 47 | 1 | 3 |
Himmelstein (1998) [35] USA | Adults | 44 | 26 | 1 | 3 |
Sabiston 1974 [44] | Marine recruits | 25 | 20 | 1 | 0.2 |