Methodological quality assessment.

*1. title and abstract, 2. background, 3. objectives, 4. study design, 5. setting, 6. participants, 7. variables, 8. data sources/measurement, 9. bias, 10. study size, 11. quantitative variables, 12 statistical methods, 14a. descriptive data, 16a. main results, 17. other analyses, 18. key results, 19. limitations, 20. interpretation, 21. generalizability, 22. funding. Items 12d, 12e, 13, 14 b, 14c, 15, 16b en 16c were not applicable for assessing the included studies.+ = present, +/− = partially present, - = not present, NA. = not applicable.