Background
Vitamin D metabolism and status classification
Literature review strategy and methods
Epidemiology of vitamin D deficiency in Europe
History of treatment of airway infection
Clinical associations of vitamin D with tuberculosis
Author (ref.) | Publication year | N (total) | Age (years) | Initial 25OHD (nmol/l) | In-study 25OHD (nmol/l) | Mean vitamin D dose (IU) | Duration | Endpoint | ||
---|---|---|---|---|---|---|---|---|---|---|
Vit D | Placebo | Vit D | Placebo | |||||||
Nursyam [39] | 2006 | 67 | 31 | ND | ND | ND | ND | 10,000 daily | 6 weeks | Sputum conversion |
Wejse [40] | 2009 | 365 | 37 | 77 | 79 | 98 | 95 | 100,000 quarterly | 12 months | Sputum conversion |
Martineau [41] | 2011 | 146 | 31 | 21 | 21 | 101 | 23 | 4 × 100,000 | 6 days | Sputum conversion |
Salahuddin [42] | 2013 | 259 | 28 | 52 | 58 | 220 | 50 | 2 × 600,000 | 12 weeks | Sputum conversion |
Ralph [43] | 2013 | 200 | 28 | ND | ND | ND | ND | 50,000 monthly | 8 weeks | Sputum conversion |
Daley [44] | 2015 | 247 | 43 | 58 | 54 | 72 | 60 | 100,000 quarterly | 12 months | Sputum conversion |
Clinical associations of vitamin D with acute airway infections
Author (ref.) | Publication year | N (total) | Age (years) | 25OHD (nmol/l) | 25OHD (nmol/l) | Mean vitamin D dose (IU) | Duration | Endpoint | ||
---|---|---|---|---|---|---|---|---|---|---|
Initial | In-study | |||||||||
Vit D | Placebo | Vit D | Placebo | |||||||
Aloia [54] | 2007 | 208 | 60.6 | 46.9 | 43 | 86.9 | 43 | 800/2000 daily | 3 years | Influenza |
Li-Ng [55] | 2009 | 148 | 58.7 | 58.7 | 63 | 88.5 | 60.9 | 2000 daily | 3 months | URTI |
Laaksi [52] | 2010 | 164 | Young men | 78.7 | 74.4 | 72 | 51 | 400 daily | 6 months | Acute RTI |
Manaseki-Holland [56] | 2010 | 453 | 1.2 | ND | ND | ND | ND | 100,000 (single dose) | 3 weeks | Pneumonia |
Urashima [57] | 2010 | 334 | 10.2 | ND | ND | ND | ND | 1200 daily | 4 months | Influenza A |
Majak [58] | 2011 | 48 | 11.5 | 64.3 | 88 | 94 | 80 | 500 daily | 6 months | Acute RTI |
Bergman [59] | 2012 | 124 | 53.1 | 51.5 | 46.9 | 117.4 | 44 | 4000 daily | 12 months | RTI |
Camargo [60] | 2012 | 244 | 19.9 | 17.5 | 17 | 47.3 | 18 | 300 daily | 7 weeks | Acute RTI |
Jorde [61] | 2012 | 569 | 63 | ND | ND | ND | ND | 3344c
| 12 months | Influenza-like |
Manaseki-Holland [62] | 2012 | 3046 | 0.8 | ND | ND |
a
|
b
| 100,000 quarterly | 18 months | Pneumonia |
Murdoch [63] | 2012 | 322 | 47.5 | 75.5 | 70 | 122.5 | 55 | 100,000 monthlyd
| 18 months | URTI |
Rees [64] | 2013 | 759 | 58.1 | 62 | 63.1 | ND | ND | 1000 daily | 3–5 years | URTI |
Urashima [65] | 2014 | 247 | Students | ND | ND | ND | ND | 2000 daily | 2 months | Influenza A |
Goodall [66] | 2014 | 471 | 19 | ND | ND | ND | ND | 10,000 weekly | 2 months | URTI |
Simpson [67] | 2015 | 34 | Healthy adults | 60.5 | 76.4 | 107 | 46 | 20,000 weekly | 17 weeks | RTI |
Martineau [68] | 2015 | 250 | 47.9 | 49.8 | 49.4 | 69.4 | 46.5 | 120,000 bimonthly | 1 year | Acute RTI |
Molecular effects of vitamin D on the immune system
Innate immunity | • Cell types: Monocytes/macrophages, keratinocytes, gastrointestinal/bronchial epithelial cells, decidual cells, trophoblastic cells, natural killer cells • Vitamin D effects: Antimicrobial peptides (cathelicidin, defensins)↑ Autophagy↑ Reactive oxygen species↑, Nitric oxide↑ Cytokines (e.g. interleukins 6, 8, 12, tumour necrosis factor-α)↑ Chemokines (e.g. CCL3, CCL4, CCL8, CCL20)↑ |
Adaptive immunity | • Cell types: T cells, dendritic cells • Vitamin D effects: T-regulatory cells↑, T helper cells type 17↓ T helper cells type 1↓, T helper cells type 2↑ Pro-inflammatory cytokines (e.g. interleukin 6, tumour necrosis factor-α)↓ Anti-inflammatory cytokines (e.g. interleukins 4 and 10)↑ Immunoglobulin E↑ |