Table 1.

AMSTAR results for included systematic reviews.

Author	1. Was an “a priori” design provided?	2. Was there duplicate study selection and data extraction?	3. Was a comprehensive literature search performed?	4. Was the status of publication (i.e., grey literature) used as inclusion criteria?	5. Was a list of studies (included and excluded) provided?	6. Were the characteristics of the included studies provided?	7. Was the scientific quality of the included studies assessed and documented?	8. Was the scientific quality of the included studies used appropriately in formulating conclusions?	9. Were the methods used to combine the findings of studies appropriate?	10. Was the likelihood of publication bias assessed?	11. Was the conflict of interest included?
Aubin et al, 201217	No	No	Yes	Can't Answer	No	Yes	Yes	No	N/A	N/A	No
Howell et al, 201218	No	Yes	Yes	No	No	Yes	Yes	Yes	Can't Answer	Yes	No
Lamb et al, 201119	No	No	Yes	Can't Answer	No	No	No	No	Yes	No	No
Lewis et al, 200920	Yes	Yes	Yes	Yes	No	Yes	Yes	Yes	No	No	No
Ouwens et al, 200921	No	Yes	Yes	Yes	No	Yes	No	No	Yes	No	No

Note: The “can't answer” option is chosen when the item is relevant but not described by the authors. The “not applicable” option is selected when the item is not relevant (e.g. when a meta-analysis was not attempted by the authors).