Table 2.
Quality assessment of the included cross-sectional studies using the adopted Newcastle-Ottawa Scale (NOS)
| Selection | Comparability | Outcome | Total | |||||
|---|---|---|---|---|---|---|---|---|
| Author | Representativeness of the sample (⋆) | Sample size (⋆) | Non-respondents (⋆) | Ascertainment of the exposure (risk factor) (⋆⋆) | (⋆⋆) | Assessment of outcome (⋆⋆) | Statistical test (⋆) | (*10) |
| Alkhalaf et al., 2019 [46] | * | – | – | – | – | * | * | 3 |
| Ibrahim et al., 2018 [7] | * | – | – | ** | – | – | – | 3 |
| Almarhabi et al., 2018 [41] | * | * | – | – | * | ** | * | 6 |
| Alshomrani, 2015 [36] | * | – | – | * | – | ** | * | 5 |
| Khalil, 2011 [45] | – | – | – | ** | – | ** | * | 5 |
| Alzahrani AJ et al., 2009 [37] | – | – | – | – | – | ** | – | 2 |
| Bassiony, 2008 [28] | – | – | – | ** | – | * | * | 4 |
| Alzahrani AJ, 2005 [39] | * | – | – | – | – | ** | – | 3 |
| AbuMadini et al., 2008 [29] | * | – | – | ** | – | ** | * | 6 |
| Abalkhail, 2001 [30] | * | – | – | – | – | ** | * | 4 |
| Iqbal, 2000 [31] | * | – | – | ** | – | ** | – | 5 |
| al-Nahedh, 1999 [32] | * | – | – | – | – | * | * | 3 |
| Njoh and Zimmo, 1997 [40] | * | – | – | ** | – | ** | – | 5 |
| Hafeiz, 1995 [33] | * | – | – | ** | – | * | – | 4 |
| Osman, 1992 [17] | * | – | – | * | – | ** | – | 4 |
| Qureshi, 1992 [34] | – | – | – | ** | * | ** | * | 6 |
| Iqbal, 2001 [35] | – | – | – | ** | – | * | – | 3 |
| Alzahrani H et al., 2015 [44] | * | * | – | – | * | ** | * | 6 |
| Omer and Ezzat, 1999 [47] | – | – | – | * | – | * | * | 3 |