Table 3.
List of the risk of bias in the studies.
| Domain | Elements | Benn et al. [19] | Bhat et al. [17] | Brantley et al. [33] | Crespo et al. [30] | Diakowska et al. [14] | Hu et al. [15] | Jamnagerwalla et al. [12] | Kumar et al. [21] | Laisupasin et al. [22] | Lofterød et al. [31] | Llanos et al. [18] | Ma et al. [29] | Mosapasour et al. [34] | Nowak et al. [20] | Raza et al. [24] | Rodrigues dos Santos et al. [25, 26] | Saito et al. [28] | Wan et al. [23] | Xie et al. [27] | Yang et al. [13] | Yuan et al. [32] |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Study question | Clearly focused and appropriate question | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Study population | Description of study population | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Sample size justification | A | A | A | A | A | A | A | A | A | A | A | NR | NR | A | A | A | A | A | A | A | A | |
| Comparability of subjects | Specific inclusion/exclusion criteria | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Criteria applied equally to all groups | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |
| Comparability of groups at baseline with regard to disease status and prognostic factors | A | a | A | A | a | A | A | A | a | a | a | a | A | a | a | A | A | A | a | A | a | |
| Study groups comparable to nonparticipants with regard to confounding factors | a | A | a | a | A | a | a | a | A | a | a | a | I | a | I | a | a | NR | a | NR | a | |
| Use of concurrent controls | A | A | a | a | A | a | a | a | A | a | a | a | A | a | A | a | a | A | a | I | a | |
| Comparability of follow-up among groups | A | a | a | A | a | A | A | a | a | a | a | a | a | a | a | A | A | a | a | a | a | |
| Exposure or intervention | Clear definition of exposure | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Measurement method standard, valid, and reliable | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |
| Exposure measured equally in all study groups | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |
| Outcome measurement | Primary/secondary outcomes clearly defined | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Outcomes assessed blind to exposure or intervention status | a | a | a | a | a | a | A | a | a | a | a | a | a | a | a | a | a | a | a | a | A | |
| Method of outcome assessment standard, valid, and reliable | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | |
| Length of follow-up adequate for question | A | a | A | A | a | A | A | a | a | a | a | a | a | a | a | A | A | a | a | a | a | |
| Statistical analysis | Statistical tests appropriate | A | A | A | A | A | A | A | A | A | A | A | A | I | A | A | A | A | A | A | A | A |
| Multiple comparisons taken into consideration | A | NR | A | A | I | A | A | A | NR | A | NR | NR | NR | A | NR | A | A | A | A | NR | A | |
| Modelling and multivariate techniques appropriate | A | NR | A | A | A | A | A | A | NR | A | NR | NR | NR | A | NR | A | A | A | A | NR | A | |
| Power calculation provided | A | NR | NR | NR | A | A | A | A | NR | A | A | NR | NR | A | NR | NR | NR | NR | NR | NR | NR | |
| Assessment of confounding variables | A | NR | A | A | A | A | A | A | NR | A | a | NR | NR | A | NR | A | A | NR | NR | NR | A | |
| Dose–response assessment, if appropriate | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | a | |
| Results | Measure of effect for outcomes and appropriate measure of precision | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A | A |
| Adequacy of follow-up for each study group | A | a | A | A | a | A | A | a | a | a | a | a | a | a | a | A | A | a | a | a | a | |
| Discussion | Conclusions supported by results with biases and limitations taken into consideration | A | a | A | NR | A | A | A | A | A | A | A | NR | I | A | I | A | A | A | A | I | I |
| Funding or sponsorship | Type and sources of support for study | A | NR | A | A | NR | A | A | NR | A | A | A | A | A | A | NR | A | A | NR | A | A | A |
A: adequate; I: inadequate; NR: not reported; a: not applicable to the study design.