Table 1.
Characteristics of studies entered into the meta-analysis
| Row | Author [References] | Publication year | Area | Age of case group | Age of control group | Case Group Size | Control group Size |
|---|---|---|---|---|---|---|---|
| 1 | Alam, S [21]. | 2017 | Bangladesh | 39.1 ± 8.6 | 29.64 ± 7.03 | 99 | 75 |
| 2 | Baclig, M. O [22]. | 2014 | Philippines | 20–70 | 20–70 | 32 | 36 |
| 3 | Bhatt, S. P [23]. | 2013 | India | 38.2 ± 7 | 37.1 ± 6.9 | 162 | 173 |
| 4 | Chen, L. Z [24]. | 2019 | China | 26.71 ± 2.81 | 22.48 ± 3.12 | 512 | 451 |
| 5 | Choobini, Neda [19] | 2016 | Iran | 47.9 ± 12.3 | 40 ± 13.9 | 95 | 183 |
| 6 | Di Costanzo, A [25]. | 2018 | Italy | 54 | 49.7 | 218 | 227 |
| 7 | Gorden, A [26]. | 2013 | America | 47 ± 10.6 | 46 ± 11.8 | 748 | 344 |
| 8 | Hotta, K [27]. | 2010 | Japan | 51.7 ± 15 | 47.2 ± 14.8 | 253 | 578 |
| 9 | Hudert, C. A [28]. | 2019 | Germany | 14.11 ± 2.15 | 46.73 ± 16.3 | 70 | 200 |
| 10 | Karoli, R [29]. | 2019 | India | 45 ± 8.2 | 46 ± 7 | 100 | 100 |
| 11 | Kawaguchi, Takahisa [30] | 2012 | Japan | 52.05 ± 14.85 | 48.8 ± 16.3 | 529 | 932 |
| 21 | Krishnasamy, N [31]. | 2020 | India | 43.15 ± 9.245 | 41.99 ± 12.7 | 105 | 102 |
| 13 | Lee, S. S [32]. | 2014 | Korea | 45.3 ± 15.5 | 45.3 ± 10.6 | 155 | 184 |
| 14 | Li, Y. L. [33] | 2012 | China | 46.7 ± 13.6 | 43.1 ± 13.4 | 203 | 202 |
| 15 | Liu, W. Y [34]. | 2019 | China | 40.2 ± 12.5 | 46.6 ± 9.2 | 349 | 58 |
| 16 | Niriella, M. A [35]. | 2017 | Sri Lanka | 42–71 | (42–71) | 1360 | 391 |
| 17 | Niu, T. H [36]. | 2014 | China | 49.7 ± 16.7 | 47.69 ± 15.68 | 390 | 409 |
| 18 | Oniki, Kentaro [37] | 2015 | Argentina | 61.2 ± 10.5 | 67.5 ± 6 | 393 | 740 |
| 19 | Park, J. H [38]. | 2015 | South Korea | 48.9 ± 7 | 49.1 ± 7.2 | 602 | 761 |
| 20 | Peng, X. E [39]. | 2012 | China | 45.33 ± 12.48 | 43.87 ± 13 | 553 | 553 |
| 21 | Rametta, R [40]. | 2014 | Italy | 49.7 ± 12.1 | 47.7 ± 12.1 | 137 | 260 |
| 22 | Shang, X. R [41]. | 2015 | China | 11.81 ± 2.20 | 11.44 ± 2.99 | 162 | 865 |
| 23 | Uygun, A [42]. | 2017 | Turkey | 42.1 ± 11.4 | 34.1 ± 12.8 | 216 | 150 |
| 24 | Valenti, L. [43] | 2012 | Italy | 49.5 ± 12 | 48(1 ± 2 | 144 | 257 |
| 25 | Valenti, L. [44] | 2010 | Italy | 46.4 ± 11 | 48.4 ± 13 | 253 | 179 |
| 26 | Vespasiani-Gentilucci, U [45]. | 2016 | Italy | 51.5 ± 12.3 | 40.1 ± 13.1 | 60 | 125 |
| 27 | Wang, C. W [18]. | 2011 | Taiwan | 48.11 ± 12.05 | 45.4 ± 15.93 | 156 | 723 |
| 28 | Wang, X. L. [46] | 2016 | China | 45 ± 13 | 45 ± 13 | 376 | 382 |
| 29 | Xia, M. F [16]. | 2016 | China | 60 | 61 | 1385 | 2915 |
| 30 | Yang, H. H [47]. | 2018 | China | 70.95 ± 4.73 | 72.53 ± 4.73 | 97 | 362 |
| 31 | Zhang, R. N [48]. | 2016 | China | 38.2 ± 13.78 | 42.64 ± 10.58 | 59 | 72 |