Table 3.
Assessment of bias risk using NOS scale for case-control studies.
| Selection | Comparability | Exposure | ||||||
|---|---|---|---|---|---|---|---|---|
| References | Is the case definition adequate? | Representatives of the case | Controls selection | Controls definition | Comparability of cases and controls based on the design or analysis | Ascertainment of exposure | Same method of ascertainment for cases and controls | Non-response rate |
| Abji, 2017 (34) | A* | A* | B | A* | A* | D | A* | C |
| Ahmed, 2014 (109) | A* | B | A* | A* | AB** | D | A* | C |
| Alenius, 2002 (93) | A* | B | B | A* | D | A* | C | |
| Alenius, 2004 (20) | A* | B | A* | B | B* | D | A* | C |
| Alenius, 2009 (102) | A* | B | B | A* | D | A* | C | |
| Alonso, 2016 (64) | C | B | B | B | B* | D | A* | C |
| Amin, 2016 (59) | A* | A* | C | A* | A* | D | A* | C |
| Arias de la rosa, 2020 (125) | A* | B | B | A* | A* | D | A* | C |
| Armas-Gonzales, 2015 (58) | A* | B | B | A* | D | A* | C | |
| Ausavarungnirun, 2017 (66) | A* | A* | B | A* | AB** | D | A* | C |
| Bandinelli, 2015 (86) | A* | B | B | D | A* | C | ||
| Batliwalla, 2006 (22) | A* | B | A* | B | A* | D | A* | C |
| Bosè, 2014 (55) | A* | B | B | B | D | A* | C | |
| Bowes, 2011 (25) | A* | A* | B | B* | D | A* | C | |
| Boyd, 2020 (129) | A* | A* | A* | B | D | A* | C | |
| Butt, 2007 (24) | A* | A* | A* | A* | B* | D | A* | C |
| Calzavara, 1999 (43) | A* | B | C | B | D | A* | C | |
| Caputo, 2020 (37) | A* | A* | B | A* | A* | D | A* | C |
| Cascella, 2017 (33) | A* | A* | B | A* | D | A* | C | |
| Celis, 2011 (104) | A* | B | D | C | ||||
| Chandran, 2010 (10) | A* | A* | B | A* | AB** | D | A* | C |
| Chandran, 2014 (30) | A* | B | B | A* | A | D | A* | C |
| Chandran, 2019 (15) | A* | B | B | A* | A* | D | A* | C |
| CheleschI, 2021 (42) | A* | A* | B | A* | A* | C | A* | C |
| Chen, 2019 (35) | A* | B | C | A* | B* | D | A* | C |
| Chou, 2010 (44) | A* | A* | B | A* | A | D | A* | C |
| Chung, 2021 (92) | A* | A* | C | A* | A* | D | A* | C |
| Ciancio, 2017 (32) | A* | B | C | A* | D | A* | C | |
| Colak, 2018 (121) | A* | A* | D | |||||
| Coras, 2019 (120) | A* | B | D | |||||
| Coras, 2019 (123) | A* | B | D | |||||
| Coras, 2021 (130) | A* | A* | A* | B | A* | D | A* | C |
| Cretu, 2014 (11) | A* | B | B | A* | AB** | D | A* | C |
| Cretu, 2018 (24) | A* | B | A* | A* | B* | D | A* | C |
| Cuervo, 2021 (73) | A* | A* | B | A* | B* | D | A* | C |
| Dalbeth, 2010 (89) | A* | B | B | A* | D | A* | C | |
| Dalmády 2013 (45) | A* | A* | A* | A* | D | A* | C | |
| Diani, 2019 (16) | A* | A* | C | B | A* | D | A* | C |
| Dikbas, 2014 (113) | A* | B | C | B | D | A* | C | |
| Dolcino, 2014 (46) | A* | B | C | A* | B* | D | A* | C |
| Dolcino, 2015 (12) | A* | A* | C | A* | AB** | D | A* | C |
| Eder, 2011 (26) | A* | A* | A* | A* | D | A* | C | |
| Eder, 2012 (27) | A* | B | B | B | D | A* | C | |
| Eissa, 2013 (107) | B | B | B | B | AB** | D | A* | C |
| Ek, 2021 (80) | B | A* | B | A* | A* | D | A* | C |
| Elkayam, 2000 (98) | A* | B | B | D | A* | C | ||
| Elkayam, 2000 (97) | A* | B | C | B | D | A* | C | |
| Elkayam, 2004 (19) | A* | A* | C | B | D | A* | C | |
| Esawy, 2020 (71) | A* | A* | B | A* | D | A* | C | |
| Farouk, 2010 (9) | A* | A* | A* | B | AB** | D | A* | C |
| Farrag, 2017 (68) | A* | A* | C | A* | AB** | D | A* | C |
| Fink, 2007 (100) | A* | B | C | A* | D | A* | C | |
| Firuzi, 2008 (53) | A* | B | C | A* | D | A* | C | |
| Foell, 2003 (87) | B | B | C | B | D | A* | C | |
| Frasca, 2018 (48) | A* | B | B | A* | A* | D | A* | C |
| Grossi, 2017 (65) | A* | A* | C | A* | D | A* | C | |
| Gudmann, 2016 (60) | A* | A* | A* | B | B* | D | A* | C |
| Hansson, 2014 (54) | A* | B | C | B | AB** | D | A* | C |
| Helliwell, 1991 (84) | A* | B | D | |||||
| Hu, 2018 (47) | A* | B | C | A* | A* | D | A* | C |
| Husakova, 2015 (101) | A* | B | C | B | A* | D | A* | C |
| Ibrahim, 2017 (96) | A* | B | C | B | A* | D | A* | C |
| Inciarte-Mundo, 2016 (115) | A* | B | B | A | B* | D | A* | C |
| Jadon, 2017 (13) | A* | A* | A* | A* | AB** | D | A* | C |
| Jarlborg, 2020 (126) | B | A* | B | A* | A* | D | A* | C |
| Jensen, 2012v (106) | A* | B | B | A* | A* | D | A* | C |
| Kane, 2003 (87) | A* | B | B | A* | D | A* | C | |
| Kayikci, 2013 (97) | A* | A* | C | B | D | A* | C | |
| Kim, 2015 (57) | A* | A* | B | A* | AB** | D | A* | C |
| Kishikawa, 2021 (75) | A* | A* | B | B | A* | C | A* | C |
| Korendowych, 2005 (94) | A* | B | D | |||||
| Leijten E, 2021 (74) | A* | A* | B | B | A* | C | A* | C |
| Leijten EF, 2021 (79) | A* | A* | B | A* | A* | C | A* | C |
| Lin, 2020 (38) | A* | B | C | A* | D | A* | C | |
| Looby, 2021 (78) | A* | A* | B | A* | A* | D | A* | C |
| Madland, 2007 (101) | A* | B | D | |||||
| Maejima, 2014 (56) | A* | B | C | A* | A* | A* | C | |
| Maejima, 2017 (67) | B | A* | C | B | D | A* | C | |
| Maejima, 2017 (118) | A* | B | B | B | D | A* | C | |
| Mansson, 2001 (8) | A* | A* | A* | A* | D | A* | C | |
| Marzaioli, 2022 (82) | A* | A* | B | A* | A* | D | A* | C |
| Matt, 2015 (111) | A* | B | C | B | A* | D | A* | C |
| Mc Ardle, 2021 (83) | A* | A* | B | A* | A* | D | A* | C |
| McHugh, 2003 (85) | A* | B | A* | |||||
| Medvedeva, 2020 (127) | A* | B | B | A | A* | A* | C | |
| Munk, 2015 (114) | A* | B | C | B | A* | D | A* | C |
| Muntyanu, 2016 (61) | A* | A* | B | A* | D | A* | C | |
| Ozisler, 2019 (124) | A* | B | C | B | A* | D | A* | C |
| Pasquali, 2020 (39) | A* | A* | B | A* | A* | D | A* | C |
| Peled, 2015 (112) | A* | B | B | A* | B* | D | A* | C |
| Perez-Alamino, 2014 (95) | A* | B | D | |||||
| Pongratz, 2010 (103) | A* | A* | D | |||||
| Przepiera-Będzak, 2013 (105) | A* | B | C | B | A* | D | A* | C |
| Przepiera-Będzak, 2016 (116) | A* | B | C | B | A* | D | A* | C |
| Ramonda, 2013 (91) | A* | A* | C | B | A* | D | A* | C |
| Ravindran, 2004 (21) | A* | A* | A* | B | D | A* | C | |
| Reindl, 2016 (63) | A* | B | C | B | D | A* | C | |
| Rooney, 2004 (99) | A* | B | C | B | D | A* | C | |
| Sakellariou, 2019 (122) | A* | B | B | B | A* | D | A* | C |
| Sinkeviciute, 2020 (69) | A* | B | C | B | D | A* | C | |
| Skoumal, 2008 (88) | A* | B | B | A* | D | A* | C | |
| Smith, 2020 (36) | A* | B | A* | A* | D | A* | C | |
| Souto-Carneiro, 2020 (72) | B | B | B | B | B* | D | A* | C |
| Stoeckmann, 2006 | A* | B | C | A* | A* | D | A* | C |
| Szodoray, 2007 (52) | A* | B | C | A* | AB** | D | A* | C |
| van Kuijk, 2010 (90) | A* | A* | D | C | ||||
| Veale, 1993 (51) | A* | B | C | A* | AB** | D | A* | C |
| Vinci, 2020 (50) | A* | B | B | B | D | A* | C | |
| Wade, 2018 (119) | A* | B | B | B | D | A* | C | |
| Wang N., 2022 (81) | A* | A* | B | A* | A* | D | A* | C |
| Waszczykowski, 2020 (17) | A* | A* | C | A* | A* | D | A* | C |
| Waszczykowski, 2021 (18) | A* | B | C | A* | A* | D | A* | C |
| Wcisło-Dziadecka, 2020 (128) | B | B | C | A* | D | A* | C | |
| Winchester, 2012 (28) | A* | A* | B | A* | B* | D | A* | C |
| Yuan, 2019 (49) | A* | B | B | B | AB** | D | A* | C |
| Zhang, 2016 (31) | A* | B | A* | A* | B* | D | A* | C |
| Zhu, 2021 (77) | A* | A* | B | B | A* | D | A* | C |
Selection. 1) Is the case definition adequate? A: yes, with independent validation*; B: yes, eg record linkage or based on self-reports; C: no description.
2) Representativeness of the cases A) consecutive or obviously representative series of cases*; B) potential for selection biases or not stated.
3) Selection of Controls A: community controls*; B: hospital controls; C: no description.
4) Definition of Controls A: no history of disease (endpoint)*; B: no description of source.
Comparability. Comparability of cases and controls on the basis of the design or analysis A: study controls for …*; B: study controls for any additional factor*.
Exposure. 1) Ascertainment of exposure A: secure record (eg surgical records)*; B: structured interview where blind to case/control status; C: interview not blinded to case/control status; D: written self-report or medical record only; E: no description.
2) Same method of ascertainment for cases and controls A: yes*; B: no.
3) Non-Response rate A: Same rate for both groups*; B: non respondents described; C: rate different and no designation.