Kmet, Lee, & Cook (2004) checklist for assessing the quality of quantitative studies	Audrain et al. [67]	Barendse et al. [68]	Braden et al. [64]	Chan et al. [86]	Chantiluke et al. [59]	Churches et al. [81]	Cook et al. [92]	Cooper et al. [90]	Desaunay et al., [79]	Gaigg, et al. [89]	Greimel et al., [82]	Gunji et al. [80]
1. Question/objective sufficiently described?	2	2	2	2	2	2	2	2	2	2	2	2
2. Study design evident and appropriate?	2	2	2	2	2	2	2	2	2	2	2	2
3. Method of subject/comparison group selection or source of information/input variables described and appropriate?	1	2	2	2	2	2	2	2	2	2	2	2
4. Subject (and comparison group, if applicable) characteristics sufficiently described?	2	2	2	2	2	1	2	2	2	2	2	1
5. If interventional and random allocation was possible, was it described?	N/A	N/A	N/A	N/A	2	N/A	N/A	N/A	N/A	N/A	N/A	N/A
6. If interventional and blinding of investigators was possible, was it reported?	N/A	N/A	N/A	N/A	1	N/A	N/A	N/A	N/A	N/A	N/A	N/A
7. If interventional and blinding of subjects was possible, was it reported?	N/A	N/A	N/A	N/A	1	N/A	N/A	N/A	N/A	N/A	N/A	N/A
8. Outcome and (if applicable) exposure measure(s) well defined and robust to measurement/misclassification bias? Means of assessment reported?	2	2	2	2	2	2	2	2	2	2	2	2
9. Sample size appropriate?	2	1	1	2	1	1	1	2	2	1	1	0
10. Analytic methods described/justified and appropriate?	2	2	2	2	2	2	2	2	2	2	2	2
11. Some estimate of variance is reported for the main results?	2	2	2	2	2	2	2	2	2	2	2	2
12. Controlled for confounding?	2	2	2	2	2	2	2	2	2	2	2	2
13. Results reported in sufficient detail?	2	2	2	2	2	2	2	2	2	2	2	2
14. Conclusions supported by the results?	2	2	2	2	2	2	2	2	2	2	2	2
Total score	21	21	21	22	25	20	21	22	22	21	21	19
Percentage	95%	95%	95%	100%	89%	91%	95%	100%	100%	95%	95%	86%