TABLE 2.
Characteristics of the selected studies for the meta‐analysis
| Study | Country | Total | Smoke cessation or non‐smoker | Smoker | Duration |
|---|---|---|---|---|---|
| Møller 14 | Denmark | 108 | 56 | 52 | Not stated |
| Sørensen 15 | Denmark | 57 | 27 | 30 | 1998 to March 2001 |
| Sørensen 16 | Denmark | 149 | 101 | 48 | October 1998 and October 2000 |
| Lindström 17 | Sweden | 102 | 48 | 54 | February 2004 and December 2006 |
| Kehlet 18 | Denmark | 28 | 11 | 17 | March 2011 to September 2012 |
| Borad 19 | USA | 169 458 | 136 485 | 32 973 | 2005 to 2014 |
| Petro 20 | USA | 836 | 418 | 418 | The database of the Americas Hernia Society Quality Collaborative |
| Bohlin 21 | Sweden | 651 | 141 | 510 | November 2015 to December 6, 2017 |
| Ayazi 22 | Iran | 163 | 86 | 77 | November 2015 and November 2016 |
| Lauridsen 23 | Denmark | 94 | 47 | 47 | 2014 and 2018 |
| Brajcich 24 | USA | 46 921 | 39 250 | 7671 | 2017 ACS NSQIP dataset |
| Total | 218 567 | 176 670 | 41 897 |