3. Characteristics of included studies (III).
| Study ID | Vitamin | Calcium (mg) | Regimen* | Treatment (weeks) | Follow‐up (weeks) | Cointervention | |||
| D3 (IU) | D2 (IU) | 25(OH)D (IU) | 1,25(OH)2D (µg) | ||||||
| Abu‐Mouch 2011 | 2000 | ‐ | ‐ | ‐ | ‐ | Daily | 48 | 72 | PEG‐INF, RBV |
| Atsukawa 2016 | 2000 | ‐ | ‐ | ‐ | ‐ | Daily | 16 | 16 | PEG‐INF, RBV, SP |
| Barchetta 2016 | 2000 | ‐ | ‐ | ‐ | ‐ | Daily | 24 | 24 | ‐ |
| Esmat 2015 | 2143 | ‐ | ‐ | ‐ | ‐ | Weekly | 48 | 72 | PEG‐INF, RBV |
| Foroughi 2016 | 7143 | ‐ | ‐ | ‐ | ‐ | Weekly | 10 | 10 | ‐ |
| Lorvand Amiri 2016 | 1000 | ‐ | ‐ | ‐ | 500 | Daily | 10 | 12 | ‐ |
| Mobarhan 1984 | ‐ | 17,857 | 2400 | ‐ | ‐ | Daily | 52 | 52 | ‐ |
| Nimer 2012 | 2000 | ‐ | ‐ | ‐ | ‐ | Daily | 24 | 48 | PEG‐INF, RBV |
| Pilz 2016 | 2800 | ‐ | ‐ | ‐ | ‐ | Daily | 8 | 8 | ‐ |
| Sharifi 2014 | 3571 | ‐ | ‐ | ‐ | ‐ | Twice a week | 16 | 16 | ‐ |
| Shiomi 1999a | ‐ | ‐ | ‐ | 1 | ‐ | Daily | 52 | 52 | ‐ |
| Shiomi 1999b | ‐ | ‐ | ‐ | 1 | ‐ | Daily | 52 | 52 | ‐ |
| Vosoghinia 2016 | 1600 | ‐ | ‐ | ‐ | ‐ | Daily | 12 | 12 | PEG‐INF, RBV |
| Xing 2013 | ‐ | ‐ | ‐ | 0.25 | 1000 | Daily | 4 | 4 | ‐ |
| Yokoyama 2014 | 1000 | ‐ | ‐ | ‐ | ‐ | Daily | 16 | 24 | PEG‐INF, RBV |
* Vitamin D was administered orally in all trials. 1,25(OH)2D: calcitriol; 25(OH)D: calcidiol; PEG‐INF: pegylated‐interferon; RBV: ribavirin; SP: simeprevir.