Table 5.
Sensitivity analysis for bolus or monthly administration of vitamin D
| Group | Study number; Patient number | Dose–response meta-analysis, RR (95% CI) | Pairwise Meta-analysis, RR (95% CI) | ||
|---|---|---|---|---|---|
| 400 IU/d | 800 IU/d | 1200 IU/d | |||
| Sensitivity analysis | |||||
| Bolus or monthly administration [30, 36–38, 43, 46–48, 51, 53, 55, 63, 66–68] | 15; 27,668 | 0.99 (0.96–1.03) | 0.99 (0.94–1.05) | 0.99 (0.93–1.06) | 1.00 (0.98–1.03) |
| Subgroups | |||||
| Age group (years) | |||||
| < 7 [30, 37, 51, 67] | 4; 4133 | NA | NA | NA | 0.99 (0.85–1.16) |
| 7–17 [55] | 1; 62 | NA | NA | NA | 1.01 (0.99–1.03) |
| 18–65 [38, 46, 47] | 3; 812 | NA | NA | NA | 0.99 (0.95–1.03) |
| > 65 [36, 43, 48, 53, 63, 66, 68] | 7; 22,661 | 0.99 (0.97–1.00) | 0.99 (0.95–1.01) | 0.98 (0.94–1.01) | 0.99 (0.97–1.02) |
| Gender proportion (%) | |||||
| Male > 60 [36, 47, 51, 67] | 4; 1056 | NA | NA | NA | 1.08 (1.03–1.13) |
| Male ≤ 60 [30, 37, 38, 43, 46, 48, 53, 55, 63, 66, 68] | 11; 26,612 | 0.99 (0.98–1.00) | 0.99 (0.97–1.00) | 0.98 (0.96–1.00) | 0.99 (0.97–1.02) |
| Comorbidity | |||||
| General [37, 38, 43, 48, 53, 63, 66, 68] | 8; 25,847 | 0.99 (0.98–1.01) | 0.99 (0.96–1.01) | 0.98 (0.95–1.01) | 0.99 (0.98–1.01) |
| Disease-specific [30, 36, 46, 47, 51, 55, 67] | 7; 1821 | 0.96 (0.87–1.07) | 0.95 (0.83–1.09) | 0.9 (0.84–1.08) | 0.99 (0.93–1.06) |
| Baseline 25-hydroxyvitamin D levels (nmol/L) | |||||
| < 50 [36, 43, 46–48, 55] | 6; 1209 | 0.96 (0.91–1.01) | 0.93 (0.85–1.03) | 0.92 (0.82–1.03) | 1.01 (0.99–1.03) |
| > 50 [38, 53, 63, 66] | 4; 6326 | NA | NA | NA | 1.00 (0.97–1.04) |
| Trial duration (months) | |||||
| < 4 [30] | 1; 453 | NA | NA | NA | 0.77 (0.63–0.94) |
| 4–12 [51, 67] | 2; 634 | NA | NA | NA | 1.08 (1.04–1.13) |
| > 12 [36–38, 43, 46–48, 53, 55, 63, 66, 68] | 12; 26,581 | 0.99 (0.98–1.00) | 0.99 (0.97–1.00) | 0.98 (0.96–1.00) | 1.00 (0.99–1.01) |
| Climatic zone | |||||
| Tropical or Subtropical [67] | 1; 310 | NA | NA | NA | 1.08 (1.04–1.13) |
| Temperate [30, 36–38, 43, 46–48, 51, 53, 55, 63, 66, 68] | 14; 27,358 | 0.99 (0.98–1.00) | 0.98 (0.97–1.00) | 0.98 (0.96–1.00) | 1.00 (0.98–1.02) |
| Summer | |||||
| Summer-inclusive [36–38, 43, 46–48, 51, 53, 55, 63, 66–68] | 14; 27,215 | 1.00 (0.98–1.03) | 1.00 (0.96–1.06) | 1.01 (0.96–1.07) | 1.01 (0.99–1.03) |
| Summer-sparing [30] | 1; 453 | NA | NA | NA | 0.77 (0.63–0.94) |
| Winter | |||||
| Winter-dominant [30] | 1; 453 | NA | NA | NA | 0.77 (0.63–0.94) |
| Winter-non-dominant [36–38, 43, 46–48, 51, 53, 55, 63, 66–68] | 14; 27,215 | 1.00 (0.98–1.03) | 1.01 (0.96–1.06) | 1.01 (0.96–1.07) | 1.01 (0.99–1.03 |
| Sensitivity analysis | |||||
| Type of ARIs | |||||
| Mixed upper and lower respiratory tract infections [48, 53, 55, 63, 66, 67] | 6; 6422 | 1.14 (0.00-NA) | 1.25 (0.00-NA) | 1.29 (0.00-NA) | 1.03 (0.99–1.07) |
| Upper respiratory tract infections [38, 43, 46, 47, 68] | 5; 17,241 | 0.99 (0.97–1.01) | 0.98 (0.95–1.02) | 0.98 (0.94–1.02) | 0.98 (0.97–1.00) |
| Lower respiratory tract infections [30, 36, 37, 51] | 4; 4005 | NA | NA | NA | 0.96 (0.79–1.16) |
| Influenza [53, 55] | 2; 169 | NA | NA | NA | 0.89 (0.61–1.29) |
ARI Acute respiratory infection, NA Not available