Table 2.
Effectiveness of vitamin D supplementation on reducing RT‐PCR–confirmed influenza and non‐influenza respiratory infections
| Outcome | RT‐PCR–confirmed infection | HRa (95% CI) | |
|---|---|---|---|
| Vitamin D | Placebo | ||
| Non‐influenza virus infection | |||
| All Years | 146/650 (22.5%) | 185/650 (28.5%) | 0.76 (0.61‐0.94) |
| Year 1 | 54/200 (27.0%) | 75/200 (37.50%) | 0.65 (0.46‐0.93) |
| Year 2 | 92/450 (20.4%) | 110/450 (24.4%) | 0.82 (0.62‐1.08) |
| Influenza virus infection | |||
| All Years | 50/650 (7.7%) | 43/650 (6.6%) | 1.18 (0.79‐1.77) |
| Year 1 | 25/200 (12.5%) | 29/200 (14.5%) | 0.85 (0.50‐1.46) |
| Year 2 | 25/450 (5.6%) | 14/450 (3.1%) | 1.82 (0.95‐3.52) |
| All viral infections | |||
| All Years | 177/650 (27.2%) | 209/650 (32.2%) | 0.81 (0.67‐0.99) |
| Year 1 | 72/200 (36.0%) | 90/200 (45.0%) | 0.73 (0.53‐0.99) |
| Year 2 | 105/450 (23.3%) | 119/450 (26.4%) | 0.87 (0.67‐1.13) |
a
All hazard ratios were calculated using the participants’ first infection with the virus.