Table 2.
Risk of bias/methodological quality (Hoy et al., 2012) of included studies.
| References | 1. N representative-ness | 2. N frame | 3. Randomization | 4. Non-response bias | 5. Primary data | 6. Operationali-zation | 7. Instrument | 8. Consistency | 9. Period | 10. Estimation | Total risk score | Risk category§ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Anbazhagan et al. (2016) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Asaoka et al. (2013) | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Barger et al. (2015) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Booker et al. (2020) | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | Low |
| Chen et al. (2020) | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 4 | Moderate |
| Di Milia et al. (2013) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Drake et al. (2004) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Fadeyi et al. (2018) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | Low |
| Flo et al. (2012) | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Francy et al. (2019) | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | Low |
| Haile et al. (2019) | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Inoue et al. (2000) | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 5 | Moderate |
| Joseph et al. (2018) | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 5 | Moderate |
| Kalmbach et al. (2015) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Kerkhof (2018) | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 4 | Moderate |
| Kim et al. (2006) | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 5 | Moderate |
| Lahtinen et al. (2019) | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Li and Fan (2018) | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 5 | Moderate |
| Mizuno et al. (2016) | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Rajaratnam et al. (2011) | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 5 | Moderate |
| Shi and Fan (2018) | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 7 | High |
| Stamatiou et al. (2016) | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 6 | Moderate |
| Tangkumnerd (2018) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Taniyama et al. (2015) | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 4 | Low |
| Vanttola et al. (2020) | 1 | 0 | 0 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 3 | Low |
| Voinescu (2018) | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 5 | Moderate |
| Vora et al. (2019) | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 5 | Moderate |
| Waage et al. (2009) | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 2 | Low |
| Zaki et al. (2016) | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | Low |
Item score: (0: low risk, 1: high risk).
§
Total quality/risk score: [range (0–10): high quality/low risk (0–3), moderate quality/risk (4–6), poor quality/high risk (7–10)].