| Moghimi 2019 [20] | Iran | NA (n = 8) | NA (n = 62) | 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59 | Case-control |
| Yang 2016 [24] | China | NA (n = 64) | NA (n = 289) | 18 HPV genotypes including 16,45,52,59,18,33,68,81 | Cross-sectional |
| Garolla 2016 [21] | Italy | NA (n = 54) | NA (n = 172) | NA | Cross-sectional |
| Foresta 2015 [22] | Italy | 37.1 ± 7.4 (n = 179) | 38.2 ± 8.1 (n = 440) | 6, 11, 16, 18, 26, 31, 33, 35, 39, 40,42, 43, 44, 45, 51, 52, 53, 54, 56, 58, 59, 66, 68, 69, 71, 70, 73, 74, | Cohort |
| Yang 2015 [25] | China | NA (n = 86) | NA (n = 41) | 6,11,16,18,31,33,45,52,56,58 | Cross-sectional |
| Zheng 2014 [26] | China | NA (n = 30) | NA (n = 300) | 6,16,18,31,33,52,58 | Cross-sectional |
| Foresta 2013 [23] | Italy | 38.8 ± 9.8 (n = 16) | 37.5 ± 5.9 (n = 16) | HPV-16 | Cross-sectional |
| Yang 2013 [19] | China | NA (n = 107) | NA (n = 508) | At least 20 HPV genotypes, including 6, 11,16, 18, 31, 33,39, 40, 42, 43,45, 51, 52, 53,54, 59, 66, 68,70, 81 | Cross-sectional |
| Garolla 2013 [17] | Italy | 35.3 ± 4.7 (n = 61) | 34.2 ± 3.8 (n = 104) | 6, 11, 16, 18, 26, 31, 33, 35, 39, 40, 42, 43, 44, 45, 51, 52, 53, 54, 56, 58, 59, 66, 68, 69/71, 70, 73, 74, 82. | Cross-sectional |
| Foresta 2010 [18] | Italy | NA (n = 11) | NA (n = 97) | 6,16,18,52,53,56,61,66,70,84,90 | Cross-sectional |
