Table 1 Risk of bias assessment using the Newcastle–Ottawa Scale

Preau et al. [1]

***●

●

**

Newcastle–Ottawa Scale adapted for cohort studies

Very good

7

Mitchell et al. [2]

***

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Very good

5

Rubenis et al. [3]

***

*

*●●

Newcastle–Ottawa Scale adapted for cohort studies

Very good

7

Brown et al. [4]

**

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

3

Tracy et al. [5]

***

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Very good

5

Yen et al. [6]

**

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Satisfactory

3

Strada et al. [7]

**

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

3

Wang et al. [8]

***

*

*●●

Newcastle–Ottawa Scale adapted for cohort studies

Very good

7

Ubuguyu et al. [9]

***●

*

*●

Newcastle–Ottawa Scale adapted for cohort studies

Very good

7

Lahmek et al. [10]

***

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

4

Pokhrel et al. [11]

***

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

4

Kertesz et al. [12]

*●

*

*

Newcastle–Ottawa Scale adapted for cohort studies

Satisfactory

4

Dawson et al. [13]

***

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Very good

5

Korthuis et al. [14]

***

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

4

Lev-Ran et al. [15]

***

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Very good

5

Daeppen et al. [16]

***

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Good

4

Byrne et al. [17]

***

*

*

Newcastle–Ottawa Scale adapted for cross-sectional studies

Very good

5