Table 1 Risk of bias assessment form for the recruited studies

Study Design (11√)

 1. Objective – clearly defined (√)

 2. Population – adequately described (√)

 3. Sample size – considered adequate (√)

 4. Selection criteria – clearly described (√), adequate (√)

 5. Randomization or consecutive selection – stated (√)

 6. Follow-up length – clearly described (√)

 7. Timing – prospective design (√)

 8. Type of Study – RCT (3√), CCT (2√), Cohort study (√)

Study measurements (3√)

 9. Measurement method – appropriate (√)

 10. Blinding – stated (√)

 11. Reliability – Described (√)

Statistical Analysis (4√)

 12. Dropouts – accounted (√)

 13. Statistical analysis – appropriate (√)

 14. Presentation of data – exact P value (√), variability measures (SD or CI) stated (√)

Baseline (1√)

 15. Datum line situation: − two groups were calibrated and most consistent (√)