Table 1 Main characteristics of included studies
First author | Year | Country | Study design | Method | Season of sampling | Latitude | Number of CHB patients (male) | Age of CHB patients (years)a | Number of healthy controls (male) | Age of healthy controls (years)a | HBV genotype: B/C (n, %) | HBV viral loadsa | HBeAg status: P/N (n, %) | Vitamin D in patients (mean ± SD)(ng/mL) | Prevalence of vitamin D deficiency in CHB patients (%) | VitaminD in controls (mean ± SD)(ng/mL) | Correlation coefficient(r) | NOS score |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Iacob [24] | 2012 | Romania | Observational | ELISA | Autumn to spring | NA | 12(NA) | NA | 22 (7) | 36.22 ± 13.86 | NA | NA | NA | 11.5 ± 6.36 | NA | 12.04 ± 3.99 | NA | 7 |
Mohamadkhani [25] | 2015 | Iran | Observational | ELISA | NA | NA | 173 (118) | 37 ± 9.7 | NA | NA | NA | 3.94 ± 1.08c | NA | 22.19 ± 8.28 | 42 | NA | −0.32 | 6 |
Chen [26] | 2015 | China | Observational | ECL | All year round | NA | 128 (92) | 33.57 ± 8.47 | 128 (95) | 35.17 ± 8.02 | 83 (64.8)/45 (35.2) | 6.38 ± 2.32d | 91 (71.1)/37 (28.9) | 16.88 ± 6.4 | 75 | 20.16 ± 5.5 | −0.392 | 8 |
Hoan [27] | 2016 | Vietnam | Observational | ELISA | NA | NA | 165 (135) | 39 (18–79)b | 122 (82) | 40 (19–58)b | NA | 5.6 (2.4–10.1)b,c | NA | 21.2 ± 8.9 | 32.5 | 23.6 ± 9.5 | −0.57f | 7 |
Gao [28] | 2016 | China | Observational | ELISA | Winter and summer | NA | 142 (0) | 25.8 ± 3.5 | 251 (0) | 26.5 ± 3.8 | NA | NA | 110 (77.5)/32 (22.5) | 12.05 ± 3.3 | 98.6 | 13.63 ± 5.5 | NG | 7 |
Zhao [29] | 2016 | China | Observational | HPLC-TMS | Winter | 38°3′N-39°54′N | 115 (89) | 51.29 ± 9.26 | 115 (89) | 51.41 ± 9.17 | NA | 4.10 ± 1.80e | 38 (33.0)/77 (67.0) | 7.83 ± 3.47 | NA | 9.76 ± 4.36 | NG | 8 |
Sajith [30] | 2017 | India | Observational | CL | NA | NA | 79 (79) | 40.5 ± 10 | 58 (58) | 38 ± 6.2 | NA | NA | NA | 23.2 ± 12.6 | 31 | 26.8 ± 8.7 | NG | 9 |