Table 1.

Quality assessment.

Study items		Siedner et al [24] (n=8)	Ownby et al [26] (n=6)	Robinson et al [27] (n=6)	Woods et al [25] (n=6)	Blackstock et al [28] (n=8)	Kim et al [29] (n=4)	Krishnan et al [30] (n=6)
Randomized controlled trial
	1. Was true randomization used for assignment of participants to treatment groups?	✔
	2. Was allocation to treatment groups concealed?
	3. Were treatment groups similar at the baseline?
	4. Were participants blind to treatment assignment?
	5. Were those delivering treatment blind to treatment assignment?
	6. Were outcomes assessors blind to treatment assignment?
	7. Were treatment groups treated identically other than the intervention of interest?	✔
	8. Was follow-up complete and, if not, were differences between groups in terms of their follow-up adequately described and analyzed?	✔
	9. Were participants analyzed in the groups to which they were randomized?	✔
	10. Were outcomes measured in the same way for treatment groups?	✔
	11. Were outcomes measured in a reliable way?	✔
	12. Was appropriate statistical analysis used?	✔
	13. Was the trial design appropriate, and any deviations from the standard randomized controlled trial design (individual randomization, parallel groups) accounted for in the conduct and analysis of the trial?	✔
Quasi-experimental studies
	1. Is it clear in the study what is the “cause” and what is the “effect” (ie, there is no confusion about which variable comes first)?		✔	✔	✔
	2. Were the participants included in any comparisons similar?				✔
	3. Were the participants included in any comparisons receiving similar treatment or care, other than the exposure or intervention of interest?
	4. Was there a control group?				✔
	5. Were there multiple measurements of the outcome both pre and post the intervention or exposure?		✔	✔
	6. Was follow-up complete and, if not, were differences between groups in terms of their follow-up adequately described and analyzed?		✔	✔
	7. Were the outcomes of participants included in any comparisons measured in the same way?		✔	✔	✔
	8. Were outcomes measured in a reliable way?		✔	✔	✔
	9. Was appropriate statistical analysis used?		✔	✔	✔
Cross-sectional studies
	1. Were the criteria for inclusion in the sample clearly defined?					✔	✔	✔
	2. Were the study subjects and the setting described in detail?					✔	✔	✔
	3. Was the exposure measured in a valid and reliable way?					✔		✔
	4. Were objective, standard criteria used for measurement of the condition?					✔		✔
	5. Were confounding factors identified?					✔	✔
	6. Were strategies to deal with confounding factors stated?					✔
	7. Were the outcomes measured in a valid and reliable way?					✔		✔
	8. Was appropriate statistical analysis used?					✔	✔	✔