Table 1.
Quality assessment of studies included in the systematic review using a modified Newcastle–Ottawa Quality Assessment Scale for case–control studies [16] and cross-sectional studies [17].
| Case–Control Studies | |||||
|---|---|---|---|---|---|
| Authors | Selection (Max. 4 Stars) |
Comparability (Max. 2 Stars) |
Exposure (Max. 3 Stars) |
Total Points (Max. 9) |
Quality |
| Balat et al. [18] | 3 | 2 | 2 | 7 | High |
| Duvan et al. [19] | 3 | 2 | 2 | 7 | High |
| Fathizadeh et al. [20] | 3 | 2 | 2 | 7 | High |
| Foster et al. [21] | 3 | 2 | 2 | 7 | High |
| Incebiyik et al. [22] | 1 | 2 | 1 | 4 | Medium |
| Tuladhar and Rao [23] | 2 | 2 | 2 | 6 | Medium |
| Cross-Sectional Studies | |||||
| Authors |
Selection
(Max. 5 Stars) |
Comparability
(Max. 2 Stars) |
Outcome
(Max. 3 Stars) |
Sum
(Max. 10) |
Quality |
| Azizieh et al. [24] | 1 | 2 | 2 | 5 | Medium |
| Bahrami et al. [25] | 3 | 2 | 3 | 8 | High |
| Bahrami et al. [26] | 2 | 2 | 3 | 7 | High |
| Bertone-Johnson et al. [27] | 2 | 2 | 3 | 7 | High |
| Fatemi et al. [28] | 2 | 0 | 3 | 5 | Medium |
Case–control studies (range of total points 0–9): 0 to 3 points—low-quality study, 4 to 6 points—medium-quality study, and 7 to 9 points—high-quality study. Cross-sectional studies (range of total points 0–10): 0 to 3 points—low-quality study, 4 to 6 points—medium-quality study, and 7 to 10 points—high-quality study.