Table 2 Detailed risk of bias according to the Newcastle Ottawa Scale (NOS)

Folaranmi et al. (2014)

***

**

***

8

Sedky et al. (2017)

****

*

***

8

Akhter et al. (2017)

***

**

***

8

Alhammad et al. (2010)

****

**

*

7

Nqcobo et al. (2012)

***

**

**

7

Sinha et al. (2015)

***

**

*

6

Quritum et al. (2022)

***

**

*

6

Wyne et al. (2017)

***

**

**

7

Oredugba et al. (2008)

***

**

***

8

Pansrimangkorn et al. (2023)

***

**

**

7

Rose et al. (2022)

***

**

*

6

Ruchi et al. (2021)

****

*

*

6

Dalvand et al. (2021)

***

**

*

6

Nouri et al. (2015)

***

**

**

7

Du et al. (2010)

***

**

***

8

Al Hashmi et al. (20,017)

***

**

***

8

Kachwinya et al. (2022)

****

*

***

8

Denloye et al. (2012)

****

*

*

6

Daraniyagala et al. (2019)

****

*

**

7

Altun et al. (2010)

****

**

**

8

Nzomiwu et al. (2022)

***

**

**

7

Hadeya et al. (2017)

***

*

***

7

Vandal et al. (2018)

**

**

***

7

Jawed et al. (2020)

****

*

***

8

Aburahma et al. (2021)

***

**

**

7