Table 1 Distribution of cohort characteristics, overall and between treatment allocations
|  | Placebo n = 16 (47.1%) | Treatment n = 18 (52.9%) |
|---|---|---|
Total infections during the study | 54 | 44 |
Infection type | Â | Â |
  Respiratory tract infection | 32 (59.3) | 36 (81.8) |
  Gastrointestinal infection | 11 (20.4) | 5 (11.4) |
  Urinary tract infection | 0 | 0 |
  Skin infection | 2 (3.7) | 0 |
  Ear infection | 1 (1.9) | 0 |
  Eye infection | 0 | 1 (2.3) |
  Cold sore | 5 (9.3) | 2 (4.6) |
  Systemic/nonspecific | 3 (5.6) | 0 |
Sex | Â | Â |
  Male | 5 (31.3) | 9 (50.0) |
  Female | 11 (68.8) | 9 (50.0) |
Birthplace | Â | Â |
  Australia | 15 (88.2) | 14 (82.4) |
  New Zealand | 1 (5.9) | 1 (5.9) |
  United Kingdom | 0 | 2 (11.8) |
  Singapore | 1 (5.9) | 0 |
BMI at baseline | Â | Â |
  < 18.5 | 1 (6.3) | 0 |
  18.5–24.9 | 8 (50.0) | 10 (55.6) |
  25.0–29.9 | 6 (37.5) | 7 (38.9) |
  30 or greater | 1 (6.3) | 1 (5.6) |
Taking any medications at baseline? | Â | Â |
  No | 9 (56.3) | 9 (50.0) |
  Yes | 7 (43.8) | 9 (50.0) |
Taking any supplements at baseline? | Â | Â |
  No | 12 (75.0) | 15 (83.3) |
  Yes | 4 (25.0) | 3 (16.7) |
Ever smoked? | Â | Â |
  No | 12 (75.0) | 15 (83.3) |
  Yes | 4 (25.0) | 3 (16.7) |
How much time do you usually spend in the sun on weekends and holidays in summer? | Â | Â |
  < 30 min/day | 1 (6.3) | 1 (5.6) |
  30–60 min/day | 2 (12.5) | 3 (16.7) |
  1–2 h/day | 6 (37.5) | 4 (22.2) |
  2–3 h/day | 5 (31.3) | 4 (22.2) |
  3–4 h/day | 2 (12.5) | 4 (22.2) |
  4 or more hours/day | 0 | 2 (11.1) |
Age | 35.0 (12.5; 19–51) | 30.3 (11.8; 18–52) |
Baseline 25(OH)D (nmol/L) | 76.4 (27.3; 36–132) | 60.5 (13.9; 32–78) |