Table 1 Demographic information of included studies
First author (Ref.) | Year | SS | Gender (M/F) | Population (ethnicity) | Age | Flow time (months) | NOSa | |
|---|---|---|---|---|---|---|---|---|
≤ 30 | >  30 | |||||||
Maniotis AJ, [34] | 1999 | 234 | NA | USA (C) | NA | NA | 480 | 7 |
Massi D, [35] | 2004 | 45 | 22/23 | Italy (C) | – | 45 | 120 | 8 |
Hillen F, [37] | 2008 | 58 | 18/40 | Netherland (C) | 16 | 42 | 120 | 8 |
Zhang SH, [38] | 2009 | 124 | 67/57 | China (A) | NA | NA | 250 | 6 |
Shi L, [39] | 2010 | 45 | 31/14 | China (A) | – | 45 | 100 | 7 |
Beurden BV, [40] | 2012 | 123 | 58/65 | Netherland (C) | 41 | 82 | 200 | 9 |
Itzhaki O, [41] | 2013 | 15 | 10/5 | Israel (C) | 1 | 14 | NA | 7 |
Song H, [42] | 2015 | 62 | 34/28 | China (A) | NA | NA | 90 | 7 |
Baocun S, [43] | 2015 | 60 | NA | China (A) | NA | NA | 39 | 8 |
Zhao X, [44] | 2015 | 79 | 47/32 | China (A) | NA | NA | 200 | 7 |
Liang X, [45] | 2017 | 81 | 54/27 | China (A) | 59 | 22 | 100 | 7 |
Zhang W, [46] | 2017 | 52 | 36/16 | China (A) | 37 | 15 | 80 | 7 |