Table 4.
Quality assessment of included studies according NOS criteria.
| References | Selection | Comparability | Outcome | Total |
|---|---|---|---|---|
| Abdoh (13) | ★★★ | ★★ | ★★★ | 8 |
| Bak et al. (14) | ★★★★ | ★★ | ★★★★ | 10 |
| Dadaczynski et al. (15) | ★★★★ | ★★ | ★★★ | 9 |
| Hsu (16) | ★★★ | ★★ | ★★★ | 8 |
| Htay et al. (17) | ★★★★ | ★★ | ★★★ | 9 |
| Mangono et al. (18) | ★★★★ | ★★ | ★★★ | 9 |
| Neely et al. (19) | ★★★★ | ★★ | ★★★ | 9 |
| Rew et al. (20) | ★★★ | ★★ | ★★★ | 8 |
| Rosário et al. (21) | ★★★★ | ★★ | ★★★ | 9 |
| Rovetta and Bhagavathula (22) | ★★★★ | ★★ | ★★★ | 9 |
| Vrdelja et al. (23) | ★★★★ | ★★ | ★★★ | 9 |
| Zakar et al. (24) | ★★★★ | ★★ | ★★★ | 9 |
| Zhang et al. (25) | ★★★ | ★★ | ★★★★ | 9 |
| Zhao and Basnyat (26) | ★★★★ | ★★ | ★★★★ | 10 |
| Zhao et al. (27) | ★★★★ | ★★ | ★★★ | 9 |
| Component | Description | |||
| Selection | ||||
| 1. Representativeness of the exposed cohort | The study sample is drawn from a clearly defined population and is representative of the population that it is intended to represent. | |||
| 2. Selection of the non-exposed cohort | The selection of the non-exposed cohort should be drawn from the same community as the exposed cohort. It should be established that the selection of the non-exposed cohort is independent of exposure status. | |||
| 3. Ascertainment of exposure | The exposure of interest should be clearly defined and the methods for ascertainment should be valid and reliable. | |||
| Outcome | ||||
| 4. Demonstration that outcome of interest was not present at start of study | The outcome of interest was not present at the start of the study. | |||
| 5. Assessment of outcome | The outcome of interest is determined by objective and reliable means, and the follow-up is long enough for outcomes to occur. | |||
| 6. Was follow-up long enough for outcomes to occur? | The follow-up period was sufficient for the outcomes of interest to occur. | |||
| Comparability | ||||
| 7. Comparability of cohorts on the basis of the design or analysis | The cohorts were comparable on the basis of the design or analysis. | |||
| 8. Control for any additional factors | There was control for any additional factors. | |||
| 9. Assessment of outcome | The outcome of interest is determined by objective and reliable means, and the follow-up is long enough for outcomes to occur. | |||
*Note that the maximum score for selection is 5, comparability is 2, and outcome is 3. The total score ranges from 0 to 10.