Study design | Setting | Number of studies | |
Hospital-based | Community/population-based | ||
Case-control | - | 2 | 2 |
Cross-sectional | 4 | 7 | 11 |
Cohort | - | 1 | 1 |
Cross-sectional time-series | 1 | 5 | 6 |
Case-findings approach | 2 | - | 2 |
Literature review | - | - | 1 |
Total | 7 | 15 | 23 |