Table 2.
Risk of bias assessment using BMJ quality assessment for prevalence studies
| Item 1 | Item 2 | Item 3 | Item 4 | Item 5 | Item 6 | Item 7 | Item 8 | Item 9 | Item 10 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tadros et al. 2016 [15] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Oates et al. 2009 [16] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Holtyn et al. 2017 [17] | USA | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 3 |
| Brown et al. 2010 [18] | UK | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Cheung et al. 2015 [19] | Canada | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 |
| Brown et al. 2013 [20] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Raven et al. 2017 [21] | USA | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 1 | 4 |
| Ku et al. 2010 [22] | USA | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 2 |
| Feldman et al. 2017 [23] | USA | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| Jackson et al. 2019 [24] | USA | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 4 |
| Lee et al. 2019 [25] | Australia | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 5 |
| Tsai et al. 2013 (a) [26] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 |
| Rodriguez et al. 2009 [27] | USA | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 3 |
| Lin et al. 2015 [28] | USA | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 |
| Mackelprang et al. 2014 [29] | USA | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 1 | 4 |
| Doran et al. 2016 [30] | USA | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 |
| Moore et al. 2011 [31] | Australia | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Hammig et al. 2014 [32] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Mackelprang et al. 2015 [33] | USA | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 |
| Feldman et al. 2018 [34] | USA | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 |
| Tsai et al. 2013 (b) [35] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 |
| Moulin et al. 2018 [36] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Cheallaigh et al. 2017 [37] | Ireland | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 1 |
| Yeniocak et al. 2017 [38] | Turkey | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 |
| Lloyd et al. 2017 [39] | Australia | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 0 | 1 | 4 |
| Lombardi et al. 2019 [40] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
| Hastings et al. 2013 [41] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Lam et al. 2016 [42] | USA | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Stenius-Ayoade. 2017 [43] | Finland | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 2 | |
| Post et al. 2013 [44] | USA | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 3 |
| Moore et al. 2012 [45] | Australia | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 |
| Doran et al. 2018 [46] | USA | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 |
| Doran et al. 2013 [47] | USA | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Ku et al. 2014 [48] | USA | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 3 |
| Coe et al. 2015 [49] | USA | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 2 |
| Amato et al. 2018 [50] | USA | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 2 |
Item 1: Was the study’s target population a close representation of the national population in relation to relevant variables, e.g. age, sex, occupation? Item 2: Was the sampling frame a true or close representation of the target population? Item 3: Was some form of random selection used to select the sample, or was a census undertaken? Item 4: Was the likelihood of non-response bias minimal? Item 5: Were data collected directly from the subjects (as opposed to a proxy)? Item 6: Was an acceptable case definition used in the study? Item 7: Was the study instrument that measured the parameter of interest (e.g. prevalence of low back pain) shown to have reliability and validity (if necessary)? Item 8: Was the same mode of data collection used for all subjects? Item 9: Were the numerator(s) and denominator(s) for the parameter of interest appropriate Item 10: Summary on the overall risk of study bias