Table 1.
Characteristics of all included studies.
| Author | Year | Country | Type of study | Nº of participants | Vitamin D level (Mean ± SD) (ng/mL) | Cutoff value | Baseline characteristics between the groups | NOS score |
|---|---|---|---|---|---|---|---|---|
| Mulligan14 | 2011 | USA | Retrospective | CRS: 29 Control: 14 |
CRS: 36.62 ± 12.99 Control: 51 ± 4 |
<20 ng/mL | No significant differences in gender, race, BMI. | 7 |
| Mulligan15 | 2012 | USA | Retrospective | CRS: 22 Control: 14 |
CRS: 30.07 ± 6.96 Control: 38.4 ± 14 |
<20 ng/mL | NG | 6 |
| Mulligan16 | 2014 | USA | Retrospective | CRS: 85 Control: 21 |
CRS: 29.31 ± 15.91 Control: 37.48 ± 20.89 |
<32 ng/mL | NG | 6 |
| Carroll17 | 2016 | USA | Retrospective | CRS: 13 Control: 6 |
CRS: 34.5 ± 21.1 Control: 20.8 ± 9.7 |
<20 ng/mL | The average age was 52 years for control patients and 50 years for CRSwNP patients. 25% of control patients were male and 47% of CRSwNP patients were male. | 6 |
| Erdag18 | 2016 | Turkey | Prospective | CRS: 46 Control: 40 |
CRS: 13.38 ± 14.08 Control: 10.57 ± 6.44 |
<20 ng/mL | No significant differences in age, gender. | 7 |
| Mostafa7 | 2016 | Egypt | Prospective | CRS: 30 Control: 19 |
CRS: 38.6 ± 28.2 Control: 63.3 ± 17.3 |
NG | No significant differences in age, gender. | 7 |
| Shanaki19 | 2017 | Iran | Prospective | CRS: 45 Control: 44 |
CRS: 16.62 ± 5.16 Control: 26.08 ± 14.16 |
<20 ng/mL | NG | 6 |
| Wang20 | 2018 | China | Retrospective | CRS: 67 Control: 21 |
CRS: 42.2 ± 11.49 Control: 54.1 ± 17.1 |
<20 ng/mL | No significant differences in age, gender, BMI, smoke history, atopic status and asthma | 7 |
95% CI, 95% confidence intervals; WMD, weighted mean difference; CRS, chronic rhinosinusitis; CRSwNP, chronic rhinosinusitis with nasal polyps; CRSsNP, chronic rhinosinusitis without nasal polyps; NOS, Newcastle-Ottawa quality assessment scale; NG, not given.